diff options
Diffstat (limited to 'plugins/AdvaImg/src/LibPNG/pngwutil.c')
| -rw-r--r-- | plugins/AdvaImg/src/LibPNG/pngwutil.c | 3180 |
1 files changed, 3180 insertions, 0 deletions
diff --git a/plugins/AdvaImg/src/LibPNG/pngwutil.c b/plugins/AdvaImg/src/LibPNG/pngwutil.c new file mode 100644 index 0000000000..64888f7c6c --- /dev/null +++ b/plugins/AdvaImg/src/LibPNG/pngwutil.c @@ -0,0 +1,3180 @@ +
+/* pngwutil.c - utilities to write a PNG file
+ *
+ * Last changed in libpng 1.5.6 [November 3, 2011]
+ * Copyright (c) 1998-2011 Glenn Randers-Pehrson
+ * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
+ * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
+ *
+ * This code is released under the libpng license.
+ * For conditions of distribution and use, see the disclaimer
+ * and license in png.h
+ */
+
+#include "pngpriv.h"
+
+#ifdef PNG_WRITE_SUPPORTED
+
+#ifdef PNG_WRITE_INT_FUNCTIONS_SUPPORTED
+/* Place a 32-bit number into a buffer in PNG byte order. We work
+ * with unsigned numbers for convenience, although one supported
+ * ancillary chunk uses signed (two's complement) numbers.
+ */
+void PNGAPI
+png_save_uint_32(png_bytep buf, png_uint_32 i)
+{
+ buf[0] = (png_byte)((i >> 24) & 0xff);
+ buf[1] = (png_byte)((i >> 16) & 0xff);
+ buf[2] = (png_byte)((i >> 8) & 0xff);
+ buf[3] = (png_byte)(i & 0xff);
+}
+
+#ifdef PNG_SAVE_INT_32_SUPPORTED
+/* The png_save_int_32 function assumes integers are stored in two's
+ * complement format. If this isn't the case, then this routine needs to
+ * be modified to write data in two's complement format. Note that,
+ * the following works correctly even if png_int_32 has more than 32 bits
+ * (compare the more complex code required on read for sign extention.)
+ */
+void PNGAPI
+png_save_int_32(png_bytep buf, png_int_32 i)
+{
+ buf[0] = (png_byte)((i >> 24) & 0xff);
+ buf[1] = (png_byte)((i >> 16) & 0xff);
+ buf[2] = (png_byte)((i >> 8) & 0xff);
+ buf[3] = (png_byte)(i & 0xff);
+}
+#endif
+
+/* Place a 16-bit number into a buffer in PNG byte order.
+ * The parameter is declared unsigned int, not png_uint_16,
+ * just to avoid potential problems on pre-ANSI C compilers.
+ */
+void PNGAPI
+png_save_uint_16(png_bytep buf, unsigned int i)
+{
+ buf[0] = (png_byte)((i >> 8) & 0xff);
+ buf[1] = (png_byte)(i & 0xff);
+}
+#endif
+
+/* Simple function to write the signature. If we have already written
+ * the magic bytes of the signature, or more likely, the PNG stream is
+ * being embedded into another stream and doesn't need its own signature,
+ * we should call png_set_sig_bytes() to tell libpng how many of the
+ * bytes have already been written.
+ */
+void PNGAPI
+png_write_sig(png_structp png_ptr)
+{
+ png_byte png_signature[8] = {137, 80, 78, 71, 13, 10, 26, 10};
+
+#ifdef PNG_IO_STATE_SUPPORTED
+ /* Inform the I/O callback that the signature is being written */
+ png_ptr->io_state = PNG_IO_WRITING | PNG_IO_SIGNATURE;
+#endif
+
+ /* Write the rest of the 8 byte signature */
+ png_write_data(png_ptr, &png_signature[png_ptr->sig_bytes],
+ (png_size_t)(8 - png_ptr->sig_bytes));
+
+ if (png_ptr->sig_bytes < 3)
+ png_ptr->mode |= PNG_HAVE_PNG_SIGNATURE;
+}
+
+/* Write the start of a PNG chunk. The type is the chunk type.
+ * The total_length is the sum of the lengths of all the data you will be
+ * passing in png_write_chunk_data().
+ */
+static void
+png_write_chunk_header(png_structp png_ptr, png_uint_32 chunk_name,
+ png_uint_32 length)
+{
+ png_byte buf[8];
+
+#if defined(PNG_DEBUG) && (PNG_DEBUG > 0)
+ PNG_CSTRING_FROM_CHUNK(buf, chunk_name);
+ png_debug2(0, "Writing %s chunk, length = %lu", buf, (unsigned long)length);
+#endif
+
+ if (png_ptr == NULL)
+ return;
+
+#ifdef PNG_IO_STATE_SUPPORTED
+ /* Inform the I/O callback that the chunk header is being written.
+ * PNG_IO_CHUNK_HDR requires a single I/O call.
+ */
+ png_ptr->io_state = PNG_IO_WRITING | PNG_IO_CHUNK_HDR;
+#endif
+
+ /* Write the length and the chunk name */
+ png_save_uint_32(buf, length);
+ png_save_uint_32(buf + 4, chunk_name);
+ png_write_data(png_ptr, buf, 8);
+
+ /* Put the chunk name into png_ptr->chunk_name */
+ png_ptr->chunk_name = chunk_name;
+
+ /* Reset the crc and run it over the chunk name */
+ png_reset_crc(png_ptr);
+
+ png_calculate_crc(png_ptr, buf + 4, 4);
+
+#ifdef PNG_IO_STATE_SUPPORTED
+ /* Inform the I/O callback that chunk data will (possibly) be written.
+ * PNG_IO_CHUNK_DATA does NOT require a specific number of I/O calls.
+ */
+ png_ptr->io_state = PNG_IO_WRITING | PNG_IO_CHUNK_DATA;
+#endif
+}
+
+void PNGAPI
+png_write_chunk_start(png_structp png_ptr, png_const_bytep chunk_string,
+ png_uint_32 length)
+{
+ png_write_chunk_header(png_ptr, PNG_CHUNK_FROM_STRING(chunk_string), length);
+}
+
+/* Write the data of a PNG chunk started with png_write_chunk_header().
+ * Note that multiple calls to this function are allowed, and that the
+ * sum of the lengths from these calls *must* add up to the total_length
+ * given to png_write_chunk_header().
+ */
+void PNGAPI
+png_write_chunk_data(png_structp png_ptr, png_const_bytep data,
+ png_size_t length)
+{
+ /* Write the data, and run the CRC over it */
+ if (png_ptr == NULL)
+ return;
+
+ if (data != NULL && length > 0)
+ {
+ png_write_data(png_ptr, data, length);
+
+ /* Update the CRC after writing the data,
+ * in case that the user I/O routine alters it.
+ */
+ png_calculate_crc(png_ptr, data, length);
+ }
+}
+
+/* Finish a chunk started with png_write_chunk_header(). */
+void PNGAPI
+png_write_chunk_end(png_structp png_ptr)
+{
+ png_byte buf[4];
+
+ if (png_ptr == NULL) return;
+
+#ifdef PNG_IO_STATE_SUPPORTED
+ /* Inform the I/O callback that the chunk CRC is being written.
+ * PNG_IO_CHUNK_CRC requires a single I/O function call.
+ */
+ png_ptr->io_state = PNG_IO_WRITING | PNG_IO_CHUNK_CRC;
+#endif
+
+ /* Write the crc in a single operation */
+ png_save_uint_32(buf, png_ptr->crc);
+
+ png_write_data(png_ptr, buf, (png_size_t)4);
+}
+
+/* Write a PNG chunk all at once. The type is an array of ASCII characters
+ * representing the chunk name. The array must be at least 4 bytes in
+ * length, and does not need to be null terminated. To be safe, pass the
+ * pre-defined chunk names here, and if you need a new one, define it
+ * where the others are defined. The length is the length of the data.
+ * All the data must be present. If that is not possible, use the
+ * png_write_chunk_start(), png_write_chunk_data(), and png_write_chunk_end()
+ * functions instead.
+ */
+static void
+png_write_complete_chunk(png_structp png_ptr, png_uint_32 chunk_name,
+ png_const_bytep data, png_size_t length)
+{
+ if (png_ptr == NULL)
+ return;
+
+ /* On 64 bit architectures 'length' may not fit in a png_uint_32. */
+ if (length > PNG_UINT_32_MAX)
+ png_error(png_ptr, "length exceeds PNG maxima");
+
+ png_write_chunk_header(png_ptr, chunk_name, (png_uint_32)length);
+ png_write_chunk_data(png_ptr, data, length);
+ png_write_chunk_end(png_ptr);
+}
+
+/* This is the API that calls the internal function above. */
+void PNGAPI
+png_write_chunk(png_structp png_ptr, png_const_bytep chunk_string,
+ png_const_bytep data, png_size_t length)
+{
+ png_write_complete_chunk(png_ptr, PNG_CHUNK_FROM_STRING(chunk_string), data,
+ length);
+}
+
+/* Initialize the compressor for the appropriate type of compression. */
+static void
+png_zlib_claim(png_structp png_ptr, png_uint_32 state)
+{
+ if (!(png_ptr->zlib_state & PNG_ZLIB_IN_USE))
+ {
+ /* If already initialized for 'state' do not re-init. */
+ if (png_ptr->zlib_state != state)
+ {
+ int ret = Z_OK;
+ png_const_charp who = "-";
+
+ /* If actually initialized for another state do a deflateEnd. */
+ if (png_ptr->zlib_state != PNG_ZLIB_UNINITIALIZED)
+ {
+ ret = deflateEnd(&png_ptr->zstream);
+ who = "end";
+ png_ptr->zlib_state = PNG_ZLIB_UNINITIALIZED;
+ }
+
+ /* zlib itself detects an incomplete state on deflateEnd */
+ if (ret == Z_OK) switch (state)
+ {
+# ifdef PNG_WRITE_COMPRESSED_TEXT_SUPPORTED
+ case PNG_ZLIB_FOR_TEXT:
+ ret = deflateInit2(&png_ptr->zstream,
+ png_ptr->zlib_text_level, png_ptr->zlib_text_method,
+ png_ptr->zlib_text_window_bits,
+ png_ptr->zlib_text_mem_level, png_ptr->zlib_text_strategy);
+ who = "text";
+ break;
+# endif
+
+ case PNG_ZLIB_FOR_IDAT:
+ ret = deflateInit2(&png_ptr->zstream, png_ptr->zlib_level,
+ png_ptr->zlib_method, png_ptr->zlib_window_bits,
+ png_ptr->zlib_mem_level, png_ptr->zlib_strategy);
+ who = "IDAT";
+ break;
+
+ default:
+ png_error(png_ptr, "invalid zlib state");
+ }
+
+ if (ret == Z_OK)
+ png_ptr->zlib_state = state;
+
+ else /* an error in deflateEnd or deflateInit2 */
+ {
+ size_t pos = 0;
+ char msg[64];
+
+ pos = png_safecat(msg, sizeof msg, pos,
+ "zlib failed to initialize compressor (");
+ pos = png_safecat(msg, sizeof msg, pos, who);
+
+ switch (ret)
+ {
+ case Z_VERSION_ERROR:
+ pos = png_safecat(msg, sizeof msg, pos, ") version error");
+ break;
+
+ case Z_STREAM_ERROR:
+ pos = png_safecat(msg, sizeof msg, pos, ") stream error");
+ break;
+
+ case Z_MEM_ERROR:
+ pos = png_safecat(msg, sizeof msg, pos, ") memory error");
+ break;
+
+ default:
+ pos = png_safecat(msg, sizeof msg, pos, ") unknown error");
+ break;
+ }
+
+ png_error(png_ptr, msg);
+ }
+ }
+
+ /* Here on success, claim the zstream: */
+ png_ptr->zlib_state |= PNG_ZLIB_IN_USE;
+ }
+
+ else
+ png_error(png_ptr, "zstream already in use (internal error)");
+}
+
+/* The opposite: release the stream. It is also reset, this API will warn on
+ * error but will not fail.
+ */
+static void
+png_zlib_release(png_structp png_ptr)
+{
+ if (png_ptr->zlib_state & PNG_ZLIB_IN_USE)
+ {
+ int ret = deflateReset(&png_ptr->zstream);
+
+ png_ptr->zlib_state &= ~PNG_ZLIB_IN_USE;
+
+ if (ret != Z_OK)
+ {
+ png_const_charp err;
+ PNG_WARNING_PARAMETERS(p)
+
+ switch (ret)
+ {
+ case Z_VERSION_ERROR:
+ err = "version";
+ break;
+
+ case Z_STREAM_ERROR:
+ err = "stream";
+ break;
+
+ case Z_MEM_ERROR:
+ err = "memory";
+ break;
+
+ default:
+ err = "unknown";
+ break;
+ }
+
+ png_warning_parameter_signed(p, 1, PNG_NUMBER_FORMAT_d, ret);
+ png_warning_parameter(p, 2, err);
+
+ if (png_ptr->zstream.msg)
+ err = png_ptr->zstream.msg;
+ else
+ err = "[no zlib message]";
+
+ png_warning_parameter(p, 3, err);
+
+ png_formatted_warning(png_ptr, p,
+ "zlib failed to reset compressor: @1(@2): @3");
+ }
+ }
+
+ else
+ png_warning(png_ptr, "zstream not in use (internal error)");
+}
+
+#ifdef PNG_WRITE_COMPRESSED_TEXT_SUPPORTED
+/* This pair of functions encapsulates the operation of (a) compressing a
+ * text string, and (b) issuing it later as a series of chunk data writes.
+ * The compression_state structure is shared context for these functions
+ * set up by the caller in order to make the whole mess thread-safe.
+ */
+
+typedef struct
+{
+ png_const_bytep input; /* The uncompressed input data */
+ png_size_t input_len; /* Its length */
+ int num_output_ptr; /* Number of output pointers used */
+ int max_output_ptr; /* Size of output_ptr */
+ png_bytep *output_ptr; /* Array of pointers to output */
+} compression_state;
+
+/* Compress given text into storage in the png_ptr structure */
+static int /* PRIVATE */
+png_text_compress(png_structp png_ptr,
+ png_const_charp text, png_size_t text_len, int compression,
+ compression_state *comp)
+{
+ int ret;
+
+ comp->num_output_ptr = 0;
+ comp->max_output_ptr = 0;
+ comp->output_ptr = NULL;
+ comp->input = NULL;
+ comp->input_len = text_len;
+
+ /* We may just want to pass the text right through */
+ if (compression == PNG_TEXT_COMPRESSION_NONE)
+ {
+ comp->input = (png_const_bytep)text;
+ return((int)text_len);
+ }
+
+ if (compression >= PNG_TEXT_COMPRESSION_LAST)
+ {
+ PNG_WARNING_PARAMETERS(p)
+
+ png_warning_parameter_signed(p, 1, PNG_NUMBER_FORMAT_d,
+ compression);
+ png_formatted_warning(png_ptr, p, "Unknown compression type @1");
+ }
+
+ /* We can't write the chunk until we find out how much data we have,
+ * which means we need to run the compressor first and save the
+ * output. This shouldn't be a problem, as the vast majority of
+ * comments should be reasonable, but we will set up an array of
+ * malloc'd pointers to be sure.
+ *
+ * If we knew the application was well behaved, we could simplify this
+ * greatly by assuming we can always malloc an output buffer large
+ * enough to hold the compressed text ((1001 * text_len / 1000) + 12)
+ * and malloc this directly. The only time this would be a bad idea is
+ * if we can't malloc more than 64K and we have 64K of random input
+ * data, or if the input string is incredibly large (although this
+ * wouldn't cause a failure, just a slowdown due to swapping).
+ */
+ png_zlib_claim(png_ptr, PNG_ZLIB_FOR_TEXT);
+
+ /* Set up the compression buffers */
+ /* TODO: the following cast hides a potential overflow problem. */
+ png_ptr->zstream.avail_in = (uInt)text_len;
+
+ /* NOTE: assume zlib doesn't overwrite the input */
+ png_ptr->zstream.next_in = (Bytef *)text;
+ png_ptr->zstream.avail_out = png_ptr->zbuf_size;
+ png_ptr->zstream.next_out = png_ptr->zbuf;
+
+ /* This is the same compression loop as in png_write_row() */
+ do
+ {
+ /* Compress the data */
+ ret = deflate(&png_ptr->zstream, Z_NO_FLUSH);
+
+ if (ret != Z_OK)
+ {
+ /* Error */
+ if (png_ptr->zstream.msg != NULL)
+ png_error(png_ptr, png_ptr->zstream.msg);
+
+ else
+ png_error(png_ptr, "zlib error");
+ }
+
+ /* Check to see if we need more room */
+ if (!(png_ptr->zstream.avail_out))
+ {
+ /* Make sure the output array has room */
+ if (comp->num_output_ptr >= comp->max_output_ptr)
+ {
+ int old_max;
+
+ old_max = comp->max_output_ptr;
+ comp->max_output_ptr = comp->num_output_ptr + 4;
+ if (comp->output_ptr != NULL)
+ {
+ png_bytepp old_ptr;
+
+ old_ptr = comp->output_ptr;
+
+ comp->output_ptr = (png_bytepp)png_malloc(png_ptr,
+ (png_alloc_size_t)
+ (comp->max_output_ptr * png_sizeof(png_charpp)));
+
+ png_memcpy(comp->output_ptr, old_ptr, old_max
+ * png_sizeof(png_charp));
+
+ png_free(png_ptr, old_ptr);
+ }
+ else
+ comp->output_ptr = (png_bytepp)png_malloc(png_ptr,
+ (png_alloc_size_t)
+ (comp->max_output_ptr * png_sizeof(png_charp)));
+ }
+
+ /* Save the data */
+ comp->output_ptr[comp->num_output_ptr] =
+ (png_bytep)png_malloc(png_ptr,
+ (png_alloc_size_t)png_ptr->zbuf_size);
+
+ png_memcpy(comp->output_ptr[comp->num_output_ptr], png_ptr->zbuf,
+ png_ptr->zbuf_size);
+
+ comp->num_output_ptr++;
+
+ /* and reset the buffer */
+ png_ptr->zstream.avail_out = (uInt)png_ptr->zbuf_size;
+ png_ptr->zstream.next_out = png_ptr->zbuf;
+ }
+ /* Continue until we don't have any more to compress */
+ } while (png_ptr->zstream.avail_in);
+
+ /* Finish the compression */
+ do
+ {
+ /* Tell zlib we are finished */
+ ret = deflate(&png_ptr->zstream, Z_FINISH);
+
+ if (ret == Z_OK)
+ {
+ /* Check to see if we need more room */
+ if (!(png_ptr->zstream.avail_out))
+ {
+ /* Check to make sure our output array has room */
+ if (comp->num_output_ptr >= comp->max_output_ptr)
+ {
+ int old_max;
+
+ old_max = comp->max_output_ptr;
+ comp->max_output_ptr = comp->num_output_ptr + 4;
+ if (comp->output_ptr != NULL)
+ {
+ png_bytepp old_ptr;
+
+ old_ptr = comp->output_ptr;
+
+ /* This could be optimized to realloc() */
+ comp->output_ptr = (png_bytepp)png_malloc(png_ptr,
+ (png_alloc_size_t)(comp->max_output_ptr *
+ png_sizeof(png_charp)));
+
+ png_memcpy(comp->output_ptr, old_ptr,
+ old_max * png_sizeof(png_charp));
+
+ png_free(png_ptr, old_ptr);
+ }
+
+ else
+ comp->output_ptr = (png_bytepp)png_malloc(png_ptr,
+ (png_alloc_size_t)(comp->max_output_ptr *
+ png_sizeof(png_charp)));
+ }
+
+ /* Save the data */
+ comp->output_ptr[comp->num_output_ptr] =
+ (png_bytep)png_malloc(png_ptr,
+ (png_alloc_size_t)png_ptr->zbuf_size);
+
+ png_memcpy(comp->output_ptr[comp->num_output_ptr], png_ptr->zbuf,
+ png_ptr->zbuf_size);
+
+ comp->num_output_ptr++;
+
+ /* and reset the buffer pointers */
+ png_ptr->zstream.avail_out = (uInt)png_ptr->zbuf_size;
+ png_ptr->zstream.next_out = png_ptr->zbuf;
+ }
+ }
+ else if (ret != Z_STREAM_END)
+ {
+ /* We got an error */
+ if (png_ptr->zstream.msg != NULL)
+ png_error(png_ptr, png_ptr->zstream.msg);
+
+ else
+ png_error(png_ptr, "zlib error");
+ }
+ } while (ret != Z_STREAM_END);
+
+ /* Text length is number of buffers plus last buffer */
+ text_len = png_ptr->zbuf_size * comp->num_output_ptr;
+
+ if (png_ptr->zstream.avail_out < png_ptr->zbuf_size)
+ text_len += png_ptr->zbuf_size - (png_size_t)png_ptr->zstream.avail_out;
+
+ return((int)text_len);
+}
+
+/* Ship the compressed text out via chunk writes */
+static void /* PRIVATE */
+png_write_compressed_data_out(png_structp png_ptr, compression_state *comp)
+{
+ int i;
+
+ /* Handle the no-compression case */
+ if (comp->input)
+ {
+ png_write_chunk_data(png_ptr, comp->input, comp->input_len);
+
+ return;
+ }
+
+#ifdef PNG_WRITE_OPTIMIZE_CMF_SUPPORTED
+ /* The zbuf_size test is because the code below doesn't work if zbuf_size is
+ * '1'; simply skip it to avoid memory overwrite.
+ */
+ if (comp->input_len >= 2 && comp->input_len < 16384 && png_ptr->zbuf_size > 1)
+ {
+ unsigned int z_cmf; /* zlib compression method and flags */
+
+ /* Optimize the CMF field in the zlib stream. This hack of the zlib
+ * stream is compliant to the stream specification.
+ */
+
+ if (comp->num_output_ptr)
+ z_cmf = comp->output_ptr[0][0];
+ else
+ z_cmf = png_ptr->zbuf[0];
+
+ if ((z_cmf & 0x0f) == 8 && (z_cmf & 0xf0) <= 0x70)
+ {
+ unsigned int z_cinfo;
+ unsigned int half_z_window_size;
+ png_size_t uncompressed_text_size = comp->input_len;
+
+ z_cinfo = z_cmf >> 4;
+ half_z_window_size = 1 << (z_cinfo + 7);
+
+ while (uncompressed_text_size <= half_z_window_size &&
+ half_z_window_size >= 256)
+ {
+ z_cinfo--;
+ half_z_window_size >>= 1;
+ }
+
+ z_cmf = (z_cmf & 0x0f) | (z_cinfo << 4);
+
+ if (comp->num_output_ptr)
+ {
+
+ if (comp->output_ptr[0][0] != z_cmf)
+ {
+ int tmp;
+
+ comp->output_ptr[0][0] = (png_byte)z_cmf;
+ tmp = comp->output_ptr[0][1] & 0xe0;
+ tmp += 0x1f - ((z_cmf << 8) + tmp) % 0x1f;
+ comp->output_ptr[0][1] = (png_byte)tmp;
+ }
+ }
+ else
+ {
+ int tmp;
+
+ png_ptr->zbuf[0] = (png_byte)z_cmf;
+ tmp = png_ptr->zbuf[1] & 0xe0;
+ tmp += 0x1f - ((z_cmf << 8) + tmp) % 0x1f;
+ png_ptr->zbuf[1] = (png_byte)tmp;
+ }
+ }
+
+ else
+ png_error(png_ptr,
+ "Invalid zlib compression method or flags in non-IDAT chunk");
+ }
+#endif /* PNG_WRITE_OPTIMIZE_CMF_SUPPORTED */
+
+ /* Write saved output buffers, if any */
+ for (i = 0; i < comp->num_output_ptr; i++)
+ {
+ png_write_chunk_data(png_ptr, comp->output_ptr[i],
+ (png_size_t)png_ptr->zbuf_size);
+
+ png_free(png_ptr, comp->output_ptr[i]);
+ }
+
+ if (comp->max_output_ptr != 0)
+ png_free(png_ptr, comp->output_ptr);
+
+ /* Write anything left in zbuf */
+ if (png_ptr->zstream.avail_out < (png_uint_32)png_ptr->zbuf_size)
+ png_write_chunk_data(png_ptr, png_ptr->zbuf,
+ (png_size_t)(png_ptr->zbuf_size - png_ptr->zstream.avail_out));
+
+ /* Reset zlib for another zTXt/iTXt or image data */
+ png_zlib_release(png_ptr);
+}
+#endif /* PNG_WRITE_COMPRESSED_TEXT_SUPPORTED */
+
+/* Write the IHDR chunk, and update the png_struct with the necessary
+ * information. Note that the rest of this code depends upon this
+ * information being correct.
+ */
+void /* PRIVATE */
+png_write_IHDR(png_structp png_ptr, png_uint_32 width, png_uint_32 height,
+ int bit_depth, int color_type, int compression_type, int filter_type,
+ int interlace_type)
+{
+ png_byte buf[13]; /* Buffer to store the IHDR info */
+
+ png_debug(1, "in png_write_IHDR");
+
+ /* Check that we have valid input data from the application info */
+ switch (color_type)
+ {
+ case PNG_COLOR_TYPE_GRAY:
+ switch (bit_depth)
+ {
+ case 1:
+ case 2:
+ case 4:
+ case 8:
+#ifdef PNG_WRITE_16BIT_SUPPORTED
+ case 16:
+#endif
+ png_ptr->channels = 1; break;
+
+ default:
+ png_error(png_ptr,
+ "Invalid bit depth for grayscale image");
+ }
+ break;
+
+ case PNG_COLOR_TYPE_RGB:
+#ifdef PNG_WRITE_16BIT_SUPPORTED
+ if (bit_depth != 8 && bit_depth != 16)
+#else
+ if (bit_depth != 8)
+#endif
+ png_error(png_ptr, "Invalid bit depth for RGB image");
+
+ png_ptr->channels = 3;
+ break;
+
+ case PNG_COLOR_TYPE_PALETTE:
+ switch (bit_depth)
+ {
+ case 1:
+ case 2:
+ case 4:
+ case 8:
+ png_ptr->channels = 1;
+ break;
+
+ default:
+ png_error(png_ptr, "Invalid bit depth for paletted image");
+ }
+ break;
+
+ case PNG_COLOR_TYPE_GRAY_ALPHA:
+ if (bit_depth != 8 && bit_depth != 16)
+ png_error(png_ptr, "Invalid bit depth for grayscale+alpha image");
+
+ png_ptr->channels = 2;
+ break;
+
+ case PNG_COLOR_TYPE_RGB_ALPHA:
+#ifdef PNG_WRITE_16BIT_SUPPORTED
+ if (bit_depth != 8 && bit_depth != 16)
+#else
+ if (bit_depth != 8)
+#endif
+ png_error(png_ptr, "Invalid bit depth for RGBA image");
+
+ png_ptr->channels = 4;
+ break;
+
+ default:
+ png_error(png_ptr, "Invalid image color type specified");
+ }
+
+ if (compression_type != PNG_COMPRESSION_TYPE_BASE)
+ {
+ png_warning(png_ptr, "Invalid compression type specified");
+ compression_type = PNG_COMPRESSION_TYPE_BASE;
+ }
+
+ /* Write filter_method 64 (intrapixel differencing) only if
+ * 1. Libpng was compiled with PNG_MNG_FEATURES_SUPPORTED and
+ * 2. Libpng did not write a PNG signature (this filter_method is only
+ * used in PNG datastreams that are embedded in MNG datastreams) and
+ * 3. The application called png_permit_mng_features with a mask that
+ * included PNG_FLAG_MNG_FILTER_64 and
+ * 4. The filter_method is 64 and
+ * 5. The color_type is RGB or RGBA
+ */
+ if (
+#ifdef PNG_MNG_FEATURES_SUPPORTED
+ !((png_ptr->mng_features_permitted & PNG_FLAG_MNG_FILTER_64) &&
+ ((png_ptr->mode&PNG_HAVE_PNG_SIGNATURE) == 0) &&
+ (color_type == PNG_COLOR_TYPE_RGB ||
+ color_type == PNG_COLOR_TYPE_RGB_ALPHA) &&
+ (filter_type == PNG_INTRAPIXEL_DIFFERENCING)) &&
+#endif
+ filter_type != PNG_FILTER_TYPE_BASE)
+ {
+ png_warning(png_ptr, "Invalid filter type specified");
+ filter_type = PNG_FILTER_TYPE_BASE;
+ }
+
+#ifdef PNG_WRITE_INTERLACING_SUPPORTED
+ if (interlace_type != PNG_INTERLACE_NONE &&
+ interlace_type != PNG_INTERLACE_ADAM7)
+ {
+ png_warning(png_ptr, "Invalid interlace type specified");
+ interlace_type = PNG_INTERLACE_ADAM7;
+ }
+#else
+ interlace_type=PNG_INTERLACE_NONE;
+#endif
+
+ /* Save the relevent information */
+ png_ptr->bit_depth = (png_byte)bit_depth;
+ png_ptr->color_type = (png_byte)color_type;
+ png_ptr->interlaced = (png_byte)interlace_type;
+#ifdef PNG_MNG_FEATURES_SUPPORTED
+ png_ptr->filter_type = (png_byte)filter_type;
+#endif
+ png_ptr->compression_type = (png_byte)compression_type;
+ png_ptr->width = width;
+ png_ptr->height = height;
+
+ png_ptr->pixel_depth = (png_byte)(bit_depth * png_ptr->channels);
+ png_ptr->rowbytes = PNG_ROWBYTES(png_ptr->pixel_depth, width);
+ /* Set the usr info, so any transformations can modify it */
+ png_ptr->usr_width = png_ptr->width;
+ png_ptr->usr_bit_depth = png_ptr->bit_depth;
+ png_ptr->usr_channels = png_ptr->channels;
+
+ /* Pack the header information into the buffer */
+ png_save_uint_32(buf, width);
+ png_save_uint_32(buf + 4, height);
+ buf[8] = (png_byte)bit_depth;
+ buf[9] = (png_byte)color_type;
+ buf[10] = (png_byte)compression_type;
+ buf[11] = (png_byte)filter_type;
+ buf[12] = (png_byte)interlace_type;
+
+ /* Write the chunk */
+ png_write_complete_chunk(png_ptr, png_IHDR, buf, (png_size_t)13);
+
+ /* Initialize zlib with PNG info */
+ png_ptr->zstream.zalloc = png_zalloc;
+ png_ptr->zstream.zfree = png_zfree;
+ png_ptr->zstream.opaque = (voidpf)png_ptr;
+
+ if (!(png_ptr->do_filter))
+ {
+ if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE ||
+ png_ptr->bit_depth < 8)
+ png_ptr->do_filter = PNG_FILTER_NONE;
+
+ else
+ png_ptr->do_filter = PNG_ALL_FILTERS;
+ }
+
+ if (!(png_ptr->flags & PNG_FLAG_ZLIB_CUSTOM_STRATEGY))
+ {
+ if (png_ptr->do_filter != PNG_FILTER_NONE)
+ png_ptr->zlib_strategy = Z_FILTERED;
+
+ else
+ png_ptr->zlib_strategy = Z_DEFAULT_STRATEGY;
+ }
+
+ if (!(png_ptr->flags & PNG_FLAG_ZLIB_CUSTOM_LEVEL))
+ png_ptr->zlib_level = Z_DEFAULT_COMPRESSION;
+
+ if (!(png_ptr->flags & PNG_FLAG_ZLIB_CUSTOM_MEM_LEVEL))
+ png_ptr->zlib_mem_level = 8;
+
+ if (!(png_ptr->flags & PNG_FLAG_ZLIB_CUSTOM_WINDOW_BITS))
+ png_ptr->zlib_window_bits = 15;
+
+ if (!(png_ptr->flags & PNG_FLAG_ZLIB_CUSTOM_METHOD))
+ png_ptr->zlib_method = 8;
+
+#ifdef PNG_WRITE_COMPRESSED_TEXT_SUPPORTED
+#ifdef PNG_WRITE_CUSTOMIZE_ZTXT_COMPRESSION_SUPPORTED
+ if (!(png_ptr->flags & PNG_FLAG_ZTXT_CUSTOM_STRATEGY))
+ png_ptr->zlib_text_strategy = Z_DEFAULT_STRATEGY;
+
+ if (!(png_ptr->flags & PNG_FLAG_ZTXT_CUSTOM_LEVEL))
+ png_ptr->zlib_text_level = png_ptr->zlib_level;
+
+ if (!(png_ptr->flags & PNG_FLAG_ZTXT_CUSTOM_MEM_LEVEL))
+ png_ptr->zlib_text_mem_level = png_ptr->zlib_mem_level;
+
+ if (!(png_ptr->flags & PNG_FLAG_ZTXT_CUSTOM_WINDOW_BITS))
+ png_ptr->zlib_text_window_bits = png_ptr->zlib_window_bits;
+
+ if (!(png_ptr->flags & PNG_FLAG_ZTXT_CUSTOM_METHOD))
+ png_ptr->zlib_text_method = png_ptr->zlib_method;
+#else
+ png_ptr->zlib_text_strategy = Z_DEFAULT_STRATEGY;
+ png_ptr->zlib_text_level = png_ptr->zlib_level;
+ png_ptr->zlib_text_mem_level = png_ptr->zlib_mem_level;
+ png_ptr->zlib_text_window_bits = png_ptr->zlib_window_bits;
+ png_ptr->zlib_text_method = png_ptr->zlib_method;
+#endif /* PNG_WRITE_CUSTOMIZE_ZTXT_COMPRESSION_SUPPORTED */
+#endif /* PNG_WRITE_COMPRESSED_TEXT_SUPPORTED */
+
+ /* Record that the compressor has not yet been initialized. */
+ png_ptr->zlib_state = PNG_ZLIB_UNINITIALIZED;
+
+ png_ptr->mode = PNG_HAVE_IHDR; /* not READY_FOR_ZTXT */
+}
+
+/* Write the palette. We are careful not to trust png_color to be in the
+ * correct order for PNG, so people can redefine it to any convenient
+ * structure.
+ */
+void /* PRIVATE */
+png_write_PLTE(png_structp png_ptr, png_const_colorp palette,
+ png_uint_32 num_pal)
+{
+ png_uint_32 i;
+ png_const_colorp pal_ptr;
+ png_byte buf[3];
+
+ png_debug(1, "in png_write_PLTE");
+
+ if ((
+#ifdef PNG_MNG_FEATURES_SUPPORTED
+ !(png_ptr->mng_features_permitted & PNG_FLAG_MNG_EMPTY_PLTE) &&
+#endif
+ num_pal == 0) || num_pal > 256)
+ {
+ if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
+ {
+ png_error(png_ptr, "Invalid number of colors in palette");
+ }
+
+ else
+ {
+ png_warning(png_ptr, "Invalid number of colors in palette");
+ return;
+ }
+ }
+
+ if (!(png_ptr->color_type&PNG_COLOR_MASK_COLOR))
+ {
+ png_warning(png_ptr,
+ "Ignoring request to write a PLTE chunk in grayscale PNG");
+
+ return;
+ }
+
+ png_ptr->num_palette = (png_uint_16)num_pal;
+ png_debug1(3, "num_palette = %d", png_ptr->num_palette);
+
+ png_write_chunk_header(png_ptr, png_PLTE, (png_uint_32)(num_pal * 3));
+#ifdef PNG_POINTER_INDEXING_SUPPORTED
+
+ for (i = 0, pal_ptr = palette; i < num_pal; i++, pal_ptr++)
+ {
+ buf[0] = pal_ptr->red;
+ buf[1] = pal_ptr->green;
+ buf[2] = pal_ptr->blue;
+ png_write_chunk_data(png_ptr, buf, (png_size_t)3);
+ }
+
+#else
+ /* This is a little slower but some buggy compilers need to do this
+ * instead
+ */
+ pal_ptr=palette;
+
+ for (i = 0; i < num_pal; i++)
+ {
+ buf[0] = pal_ptr[i].red;
+ buf[1] = pal_ptr[i].green;
+ buf[2] = pal_ptr[i].blue;
+ png_write_chunk_data(png_ptr, buf, (png_size_t)3);
+ }
+
+#endif
+ png_write_chunk_end(png_ptr);
+ png_ptr->mode |= PNG_HAVE_PLTE;
+}
+
+/* Write an IDAT chunk */
+void /* PRIVATE */
+png_write_IDAT(png_structp png_ptr, png_bytep data, png_size_t length)
+{
+ png_debug(1, "in png_write_IDAT");
+
+#ifdef PNG_WRITE_OPTIMIZE_CMF_SUPPORTED
+ if (!(png_ptr->mode & PNG_HAVE_IDAT) &&
+ png_ptr->compression_type == PNG_COMPRESSION_TYPE_BASE)
+ {
+ /* Optimize the CMF field in the zlib stream. This hack of the zlib
+ * stream is compliant to the stream specification.
+ */
+ unsigned int z_cmf = data[0]; /* zlib compression method and flags */
+
+ if ((z_cmf & 0x0f) == 8 && (z_cmf & 0xf0) <= 0x70)
+ {
+ /* Avoid memory underflows and multiplication overflows.
+ *
+ * The conditions below are practically always satisfied;
+ * however, they still must be checked.
+ */
+ if (length >= 2 &&
+ png_ptr->height < 16384 && png_ptr->width < 16384)
+ {
+ /* Compute the maximum possible length of the datastream */
+
+ /* Number of pixels, plus for each row a filter byte
+ * and possibly a padding byte, so increase the maximum
+ * size to account for these.
+ */
+ unsigned int z_cinfo;
+ unsigned int half_z_window_size;
+ png_uint_32 uncompressed_idat_size = png_ptr->height *
+ ((png_ptr->width *
+ png_ptr->channels * png_ptr->bit_depth + 15) >> 3);
+
+ /* If it's interlaced, each block of 8 rows is sent as up to
+ * 14 rows, i.e., 6 additional rows, each with a filter byte
+ * and possibly a padding byte
+ */
+ if (png_ptr->interlaced)
+ uncompressed_idat_size += ((png_ptr->height + 7)/8) *
+ (png_ptr->bit_depth < 8 ? 12 : 6);
+
+ z_cinfo = z_cmf >> 4;
+ half_z_window_size = 1 << (z_cinfo + 7);
+
+ while (uncompressed_idat_size <= half_z_window_size &&
+ half_z_window_size >= 256)
+ {
+ z_cinfo--;
+ half_z_window_size >>= 1;
+ }
+
+ z_cmf = (z_cmf & 0x0f) | (z_cinfo << 4);
+
+ if (data[0] != z_cmf)
+ {
+ int tmp;
+ data[0] = (png_byte)z_cmf;
+ tmp = data[1] & 0xe0;
+ tmp += 0x1f - ((z_cmf << 8) + tmp) % 0x1f;
+ data[1] = (png_byte)tmp;
+ }
+ }
+ }
+
+ else
+ png_error(png_ptr,
+ "Invalid zlib compression method or flags in IDAT");
+ }
+#endif /* PNG_WRITE_OPTIMIZE_CMF_SUPPORTED */
+
+ png_write_complete_chunk(png_ptr, png_IDAT, data, length);
+ png_ptr->mode |= PNG_HAVE_IDAT;
+
+ /* Prior to 1.5.4 this code was replicated in every caller (except at the
+ * end, where it isn't technically necessary). Since this function has
+ * flushed the data we can safely reset the zlib output buffer here.
+ */
+ png_ptr->zstream.next_out = png_ptr->zbuf;
+ png_ptr->zstream.avail_out = (uInt)png_ptr->zbuf_size;
+}
+
+/* Write an IEND chunk */
+void /* PRIVATE */
+png_write_IEND(png_structp png_ptr)
+{
+ png_debug(1, "in png_write_IEND");
+
+ png_write_complete_chunk(png_ptr, png_IEND, NULL, (png_size_t)0);
+ png_ptr->mode |= PNG_HAVE_IEND;
+}
+
+#ifdef PNG_WRITE_gAMA_SUPPORTED
+/* Write a gAMA chunk */
+void /* PRIVATE */
+png_write_gAMA_fixed(png_structp png_ptr, png_fixed_point file_gamma)
+{
+ png_byte buf[4];
+
+ png_debug(1, "in png_write_gAMA");
+
+ /* file_gamma is saved in 1/100,000ths */
+ png_save_uint_32(buf, (png_uint_32)file_gamma);
+ png_write_complete_chunk(png_ptr, png_gAMA, buf, (png_size_t)4);
+}
+#endif
+
+#ifdef PNG_WRITE_sRGB_SUPPORTED
+/* Write a sRGB chunk */
+void /* PRIVATE */
+png_write_sRGB(png_structp png_ptr, int srgb_intent)
+{
+ png_byte buf[1];
+
+ png_debug(1, "in png_write_sRGB");
+
+ if (srgb_intent >= PNG_sRGB_INTENT_LAST)
+ png_warning(png_ptr,
+ "Invalid sRGB rendering intent specified");
+
+ buf[0]=(png_byte)srgb_intent;
+ png_write_complete_chunk(png_ptr, png_sRGB, buf, (png_size_t)1);
+}
+#endif
+
+#ifdef PNG_WRITE_iCCP_SUPPORTED
+/* Write an iCCP chunk */
+void /* PRIVATE */
+png_write_iCCP(png_structp png_ptr, png_const_charp name, int compression_type,
+ png_const_charp profile, int profile_len)
+{
+ png_size_t name_len;
+ png_charp new_name;
+ compression_state comp;
+ int embedded_profile_len = 0;
+
+ png_debug(1, "in png_write_iCCP");
+
+ comp.num_output_ptr = 0;
+ comp.max_output_ptr = 0;
+ comp.output_ptr = NULL;
+ comp.input = NULL;
+ comp.input_len = 0;
+
+ if ((name_len = png_check_keyword(png_ptr, name, &new_name)) == 0)
+ return;
+
+ if (compression_type != PNG_COMPRESSION_TYPE_BASE)
+ png_warning(png_ptr, "Unknown compression type in iCCP chunk");
+
+ if (profile == NULL)
+ profile_len = 0;
+
+ if (profile_len > 3)
+ embedded_profile_len =
+ ((*( (png_const_bytep)profile ))<<24) |
+ ((*( (png_const_bytep)profile + 1))<<16) |
+ ((*( (png_const_bytep)profile + 2))<< 8) |
+ ((*( (png_const_bytep)profile + 3)) );
+
+ if (embedded_profile_len < 0)
+ {
+ png_warning(png_ptr,
+ "Embedded profile length in iCCP chunk is negative");
+
+ png_free(png_ptr, new_name);
+ return;
+ }
+
+ if (profile_len < embedded_profile_len)
+ {
+ png_warning(png_ptr,
+ "Embedded profile length too large in iCCP chunk");
+
+ png_free(png_ptr, new_name);
+ return;
+ }
+
+ if (profile_len > embedded_profile_len)
+ {
+ png_warning(png_ptr,
+ "Truncating profile to actual length in iCCP chunk");
+
+ profile_len = embedded_profile_len;
+ }
+
+ if (profile_len)
+ profile_len = png_text_compress(png_ptr, profile,
+ (png_size_t)profile_len, PNG_COMPRESSION_TYPE_BASE, &comp);
+
+ /* Make sure we include the NULL after the name and the compression type */
+ png_write_chunk_header(png_ptr, png_iCCP,
+ (png_uint_32)(name_len + profile_len + 2));
+
+ new_name[name_len + 1] = 0x00;
+
+ png_write_chunk_data(png_ptr, (png_bytep)new_name,
+ (png_size_t)(name_len + 2));
+
+ if (profile_len)
+ {
+ comp.input_len = profile_len;
+ png_write_compressed_data_out(png_ptr, &comp);
+ }
+
+ png_write_chunk_end(png_ptr);
+ png_free(png_ptr, new_name);
+}
+#endif
+
+#ifdef PNG_WRITE_sPLT_SUPPORTED
+/* Write a sPLT chunk */
+void /* PRIVATE */
+png_write_sPLT(png_structp png_ptr, png_const_sPLT_tp spalette)
+{
+ png_size_t name_len;
+ png_charp new_name;
+ png_byte entrybuf[10];
+ png_size_t entry_size = (spalette->depth == 8 ? 6 : 10);
+ png_size_t palette_size = entry_size * spalette->nentries;
+ png_sPLT_entryp ep;
+#ifndef PNG_POINTER_INDEXING_SUPPORTED
+ int i;
+#endif
+
+ png_debug(1, "in png_write_sPLT");
+
+ if ((name_len = png_check_keyword(png_ptr,spalette->name, &new_name))==0)
+ return;
+
+ /* Make sure we include the NULL after the name */
+ png_write_chunk_header(png_ptr, png_sPLT,
+ (png_uint_32)(name_len + 2 + palette_size));
+
+ png_write_chunk_data(png_ptr, (png_bytep)new_name,
+ (png_size_t)(name_len + 1));
+
+ png_write_chunk_data(png_ptr, &spalette->depth, (png_size_t)1);
+
+ /* Loop through each palette entry, writing appropriately */
+#ifdef PNG_POINTER_INDEXING_SUPPORTED
+ for (ep = spalette->entries; ep<spalette->entries + spalette->nentries; ep++)
+ {
+ if (spalette->depth == 8)
+ {
+ entrybuf[0] = (png_byte)ep->red;
+ entrybuf[1] = (png_byte)ep->green;
+ entrybuf[2] = (png_byte)ep->blue;
+ entrybuf[3] = (png_byte)ep->alpha;
+ png_save_uint_16(entrybuf + 4, ep->frequency);
+ }
+
+ else
+ {
+ png_save_uint_16(entrybuf + 0, ep->red);
+ png_save_uint_16(entrybuf + 2, ep->green);
+ png_save_uint_16(entrybuf + 4, ep->blue);
+ png_save_uint_16(entrybuf + 6, ep->alpha);
+ png_save_uint_16(entrybuf + 8, ep->frequency);
+ }
+
+ png_write_chunk_data(png_ptr, entrybuf, (png_size_t)entry_size);
+ }
+#else
+ ep=spalette->entries;
+ for (i = 0; i>spalette->nentries; i++)
+ {
+ if (spalette->depth == 8)
+ {
+ entrybuf[0] = (png_byte)ep[i].red;
+ entrybuf[1] = (png_byte)ep[i].green;
+ entrybuf[2] = (png_byte)ep[i].blue;
+ entrybuf[3] = (png_byte)ep[i].alpha;
+ png_save_uint_16(entrybuf + 4, ep[i].frequency);
+ }
+
+ else
+ {
+ png_save_uint_16(entrybuf + 0, ep[i].red);
+ png_save_uint_16(entrybuf + 2, ep[i].green);
+ png_save_uint_16(entrybuf + 4, ep[i].blue);
+ png_save_uint_16(entrybuf + 6, ep[i].alpha);
+ png_save_uint_16(entrybuf + 8, ep[i].frequency);
+ }
+
+ png_write_chunk_data(png_ptr, entrybuf, (png_size_t)entry_size);
+ }
+#endif
+
+ png_write_chunk_end(png_ptr);
+ png_free(png_ptr, new_name);
+}
+#endif
+
+#ifdef PNG_WRITE_sBIT_SUPPORTED
+/* Write the sBIT chunk */
+void /* PRIVATE */
+png_write_sBIT(png_structp png_ptr, png_const_color_8p sbit, int color_type)
+{
+ png_byte buf[4];
+ png_size_t size;
+
+ png_debug(1, "in png_write_sBIT");
+
+ /* Make sure we don't depend upon the order of PNG_COLOR_8 */
+ if (color_type & PNG_COLOR_MASK_COLOR)
+ {
+ png_byte maxbits;
+
+ maxbits = (png_byte)(color_type==PNG_COLOR_TYPE_PALETTE ? 8 :
+ png_ptr->usr_bit_depth);
+
+ if (sbit->red == 0 || sbit->red > maxbits ||
+ sbit->green == 0 || sbit->green > maxbits ||
+ sbit->blue == 0 || sbit->blue > maxbits)
+ {
+ png_warning(png_ptr, "Invalid sBIT depth specified");
+ return;
+ }
+
+ buf[0] = sbit->red;
+ buf[1] = sbit->green;
+ buf[2] = sbit->blue;
+ size = 3;
+ }
+
+ else
+ {
+ if (sbit->gray == 0 || sbit->gray > png_ptr->usr_bit_depth)
+ {
+ png_warning(png_ptr, "Invalid sBIT depth specified");
+ return;
+ }
+
+ buf[0] = sbit->gray;
+ size = 1;
+ }
+
+ if (color_type & PNG_COLOR_MASK_ALPHA)
+ {
+ if (sbit->alpha == 0 || sbit->alpha > png_ptr->usr_bit_depth)
+ {
+ png_warning(png_ptr, "Invalid sBIT depth specified");
+ return;
+ }
+
+ buf[size++] = sbit->alpha;
+ }
+
+ png_write_complete_chunk(png_ptr, png_sBIT, buf, size);
+}
+#endif
+
+#ifdef PNG_WRITE_cHRM_SUPPORTED
+/* Write the cHRM chunk */
+void /* PRIVATE */
+png_write_cHRM_fixed(png_structp png_ptr, png_fixed_point white_x,
+ png_fixed_point white_y, png_fixed_point red_x, png_fixed_point red_y,
+ png_fixed_point green_x, png_fixed_point green_y, png_fixed_point blue_x,
+ png_fixed_point blue_y)
+{
+ png_byte buf[32];
+
+ png_debug(1, "in png_write_cHRM");
+
+ /* Each value is saved in 1/100,000ths */
+#ifdef PNG_CHECK_cHRM_SUPPORTED
+ if (png_check_cHRM_fixed(png_ptr, white_x, white_y, red_x, red_y,
+ green_x, green_y, blue_x, blue_y))
+#endif
+ {
+ png_save_uint_32(buf, (png_uint_32)white_x);
+ png_save_uint_32(buf + 4, (png_uint_32)white_y);
+
+ png_save_uint_32(buf + 8, (png_uint_32)red_x);
+ png_save_uint_32(buf + 12, (png_uint_32)red_y);
+
+ png_save_uint_32(buf + 16, (png_uint_32)green_x);
+ png_save_uint_32(buf + 20, (png_uint_32)green_y);
+
+ png_save_uint_32(buf + 24, (png_uint_32)blue_x);
+ png_save_uint_32(buf + 28, (png_uint_32)blue_y);
+
+ png_write_complete_chunk(png_ptr, png_cHRM, buf, (png_size_t)32);
+ }
+}
+#endif
+
+#ifdef PNG_WRITE_tRNS_SUPPORTED
+/* Write the tRNS chunk */
+void /* PRIVATE */
+png_write_tRNS(png_structp png_ptr, png_const_bytep trans_alpha,
+ png_const_color_16p tran, int num_trans, int color_type)
+{
+ png_byte buf[6];
+
+ png_debug(1, "in png_write_tRNS");
+
+ if (color_type == PNG_COLOR_TYPE_PALETTE)
+ {
+ if (num_trans <= 0 || num_trans > (int)png_ptr->num_palette)
+ {
+ png_warning(png_ptr, "Invalid number of transparent colors specified");
+ return;
+ }
+
+ /* Write the chunk out as it is */
+ png_write_complete_chunk(png_ptr, png_tRNS, trans_alpha, (png_size_t)num_trans);
+ }
+
+ else if (color_type == PNG_COLOR_TYPE_GRAY)
+ {
+ /* One 16 bit value */
+ if (tran->gray >= (1 << png_ptr->bit_depth))
+ {
+ png_warning(png_ptr,
+ "Ignoring attempt to write tRNS chunk out-of-range for bit_depth");
+
+ return;
+ }
+
+ png_save_uint_16(buf, tran->gray);
+ png_write_complete_chunk(png_ptr, png_tRNS, buf, (png_size_t)2);
+ }
+
+ else if (color_type == PNG_COLOR_TYPE_RGB)
+ {
+ /* Three 16 bit values */
+ png_save_uint_16(buf, tran->red);
+ png_save_uint_16(buf + 2, tran->green);
+ png_save_uint_16(buf + 4, tran->blue);
+#ifdef PNG_WRITE_16BIT_SUPPORTED
+ if (png_ptr->bit_depth == 8 && (buf[0] | buf[2] | buf[4]))
+#else
+ if (buf[0] | buf[2] | buf[4])
+#endif
+ {
+ png_warning(png_ptr,
+ "Ignoring attempt to write 16-bit tRNS chunk when bit_depth is 8");
+ return;
+ }
+
+ png_write_complete_chunk(png_ptr, png_tRNS, buf, (png_size_t)6);
+ }
+
+ else
+ {
+ png_warning(png_ptr, "Can't write tRNS with an alpha channel");
+ }
+}
+#endif
+
+#ifdef PNG_WRITE_bKGD_SUPPORTED
+/* Write the background chunk */
+void /* PRIVATE */
+png_write_bKGD(png_structp png_ptr, png_const_color_16p back, int color_type)
+{
+ png_byte buf[6];
+
+ png_debug(1, "in png_write_bKGD");
+
+ if (color_type == PNG_COLOR_TYPE_PALETTE)
+ {
+ if (
+#ifdef PNG_MNG_FEATURES_SUPPORTED
+ (png_ptr->num_palette ||
+ (!(png_ptr->mng_features_permitted & PNG_FLAG_MNG_EMPTY_PLTE))) &&
+#endif
+ back->index >= png_ptr->num_palette)
+ {
+ png_warning(png_ptr, "Invalid background palette index");
+ return;
+ }
+
+ buf[0] = back->index;
+ png_write_complete_chunk(png_ptr, png_bKGD, buf, (png_size_t)1);
+ }
+
+ else if (color_type & PNG_COLOR_MASK_COLOR)
+ {
+ png_save_uint_16(buf, back->red);
+ png_save_uint_16(buf + 2, back->green);
+ png_save_uint_16(buf + 4, back->blue);
+#ifdef PNG_WRITE_16BIT_SUPPORTED
+ if (png_ptr->bit_depth == 8 && (buf[0] | buf[2] | buf[4]))
+#else
+ if (buf[0] | buf[2] | buf[4])
+#endif
+ {
+ png_warning(png_ptr,
+ "Ignoring attempt to write 16-bit bKGD chunk when bit_depth is 8");
+
+ return;
+ }
+
+ png_write_complete_chunk(png_ptr, png_bKGD, buf, (png_size_t)6);
+ }
+
+ else
+ {
+ if (back->gray >= (1 << png_ptr->bit_depth))
+ {
+ png_warning(png_ptr,
+ "Ignoring attempt to write bKGD chunk out-of-range for bit_depth");
+
+ return;
+ }
+
+ png_save_uint_16(buf, back->gray);
+ png_write_complete_chunk(png_ptr, png_bKGD, buf, (png_size_t)2);
+ }
+}
+#endif
+
+#ifdef PNG_WRITE_hIST_SUPPORTED
+/* Write the histogram */
+void /* PRIVATE */
+png_write_hIST(png_structp png_ptr, png_const_uint_16p hist, int num_hist)
+{
+ int i;
+ png_byte buf[3];
+
+ png_debug(1, "in png_write_hIST");
+
+ if (num_hist > (int)png_ptr->num_palette)
+ {
+ png_debug2(3, "num_hist = %d, num_palette = %d", num_hist,
+ png_ptr->num_palette);
+
+ png_warning(png_ptr, "Invalid number of histogram entries specified");
+ return;
+ }
+
+ png_write_chunk_header(png_ptr, png_hIST, (png_uint_32)(num_hist * 2));
+
+ for (i = 0; i < num_hist; i++)
+ {
+ png_save_uint_16(buf, hist[i]);
+ png_write_chunk_data(png_ptr, buf, (png_size_t)2);
+ }
+
+ png_write_chunk_end(png_ptr);
+}
+#endif
+
+#if defined(PNG_WRITE_TEXT_SUPPORTED) || defined(PNG_WRITE_pCAL_SUPPORTED) || \
+ defined(PNG_WRITE_iCCP_SUPPORTED) || defined(PNG_WRITE_sPLT_SUPPORTED)
+/* Check that the tEXt or zTXt keyword is valid per PNG 1.0 specification,
+ * and if invalid, correct the keyword rather than discarding the entire
+ * chunk. The PNG 1.0 specification requires keywords 1-79 characters in
+ * length, forbids leading or trailing whitespace, multiple internal spaces,
+ * and the non-break space (0x80) from ISO 8859-1. Returns keyword length.
+ *
+ * The new_key is allocated to hold the corrected keyword and must be freed
+ * by the calling routine. This avoids problems with trying to write to
+ * static keywords without having to have duplicate copies of the strings.
+ */
+png_size_t /* PRIVATE */
+png_check_keyword(png_structp png_ptr, png_const_charp key, png_charpp new_key)
+{
+ png_size_t key_len;
+ png_const_charp ikp;
+ png_charp kp, dp;
+ int kflag;
+ int kwarn=0;
+
+ png_debug(1, "in png_check_keyword");
+
+ *new_key = NULL;
+
+ if (key == NULL || (key_len = png_strlen(key)) == 0)
+ {
+ png_warning(png_ptr, "zero length keyword");
+ return ((png_size_t)0);
+ }
+
+ png_debug1(2, "Keyword to be checked is '%s'", key);
+
+ *new_key = (png_charp)png_malloc_warn(png_ptr, (png_uint_32)(key_len + 2));
+
+ if (*new_key == NULL)
+ {
+ png_warning(png_ptr, "Out of memory while procesing keyword");
+ return ((png_size_t)0);
+ }
+
+ /* Replace non-printing characters with a blank and print a warning */
+ for (ikp = key, dp = *new_key; *ikp != '\0'; ikp++, dp++)
+ {
+ if ((png_byte)*ikp < 0x20 ||
+ ((png_byte)*ikp > 0x7E && (png_byte)*ikp < 0xA1))
+ {
+ PNG_WARNING_PARAMETERS(p)
+
+ png_warning_parameter_unsigned(p, 1, PNG_NUMBER_FORMAT_02x,
+ (png_byte)*ikp);
+ png_formatted_warning(png_ptr, p, "invalid keyword character 0x@1");
+ *dp = ' ';
+ }
+
+ else
+ {
+ *dp = *ikp;
+ }
+ }
+ *dp = '\0';
+
+ /* Remove any trailing white space. */
+ kp = *new_key + key_len - 1;
+ if (*kp == ' ')
+ {
+ png_warning(png_ptr, "trailing spaces removed from keyword");
+
+ while (*kp == ' ')
+ {
+ *(kp--) = '\0';
+ key_len--;
+ }
+ }
+
+ /* Remove any leading white space. */
+ kp = *new_key;
+ if (*kp == ' ')
+ {
+ png_warning(png_ptr, "leading spaces removed from keyword");
+
+ while (*kp == ' ')
+ {
+ kp++;
+ key_len--;
+ }
+ }
+
+ png_debug1(2, "Checking for multiple internal spaces in '%s'", kp);
+
+ /* Remove multiple internal spaces. */
+ for (kflag = 0, dp = *new_key; *kp != '\0'; kp++)
+ {
+ if (*kp == ' ' && kflag == 0)
+ {
+ *(dp++) = *kp;
+ kflag = 1;
+ }
+
+ else if (*kp == ' ')
+ {
+ key_len--;
+ kwarn = 1;
+ }
+
+ else
+ {
+ *(dp++) = *kp;
+ kflag = 0;
+ }
+ }
+ *dp = '\0';
+ if (kwarn)
+ png_warning(png_ptr, "extra interior spaces removed from keyword");
+
+ if (key_len == 0)
+ {
+ png_free(png_ptr, *new_key);
+ png_warning(png_ptr, "Zero length keyword");
+ }
+
+ if (key_len > 79)
+ {
+ png_warning(png_ptr, "keyword length must be 1 - 79 characters");
+ (*new_key)[79] = '\0';
+ key_len = 79;
+ }
+
+ return (key_len);
+}
+#endif
+
+#ifdef PNG_WRITE_tEXt_SUPPORTED
+/* Write a tEXt chunk */
+void /* PRIVATE */
+png_write_tEXt(png_structp png_ptr, png_const_charp key, png_const_charp text,
+ png_size_t text_len)
+{
+ png_size_t key_len;
+ png_charp new_key;
+
+ png_debug(1, "in png_write_tEXt");
+
+ if ((key_len = png_check_keyword(png_ptr, key, &new_key))==0)
+ return;
+
+ if (text == NULL || *text == '\0')
+ text_len = 0;
+
+ else
+ text_len = png_strlen(text);
+
+ /* Make sure we include the 0 after the key */
+ png_write_chunk_header(png_ptr, png_tEXt,
+ (png_uint_32)(key_len + text_len + 1));
+ /*
+ * We leave it to the application to meet PNG-1.0 requirements on the
+ * contents of the text. PNG-1.0 through PNG-1.2 discourage the use of
+ * any non-Latin-1 characters except for NEWLINE. ISO PNG will forbid them.
+ * The NUL character is forbidden by PNG-1.0 through PNG-1.2 and ISO PNG.
+ */
+ png_write_chunk_data(png_ptr, (png_bytep)new_key,
+ (png_size_t)(key_len + 1));
+
+ if (text_len)
+ png_write_chunk_data(png_ptr, (png_const_bytep)text,
+ (png_size_t)text_len);
+
+ png_write_chunk_end(png_ptr);
+ png_free(png_ptr, new_key);
+}
+#endif
+
+#ifdef PNG_WRITE_zTXt_SUPPORTED
+/* Write a compressed text chunk */
+void /* PRIVATE */
+png_write_zTXt(png_structp png_ptr, png_const_charp key, png_const_charp text,
+ png_size_t text_len, int compression)
+{
+ png_size_t key_len;
+ png_byte buf;
+ png_charp new_key;
+ compression_state comp;
+
+ png_debug(1, "in png_write_zTXt");
+
+ comp.num_output_ptr = 0;
+ comp.max_output_ptr = 0;
+ comp.output_ptr = NULL;
+ comp.input = NULL;
+ comp.input_len = 0;
+
+ if ((key_len = png_check_keyword(png_ptr, key, &new_key)) == 0)
+ {
+ png_free(png_ptr, new_key);
+ return;
+ }
+
+ if (text == NULL || *text == '\0' || compression==PNG_TEXT_COMPRESSION_NONE)
+ {
+ png_write_tEXt(png_ptr, new_key, text, (png_size_t)0);
+ png_free(png_ptr, new_key);
+ return;
+ }
+
+ text_len = png_strlen(text);
+
+ /* Compute the compressed data; do it now for the length */
+ text_len = png_text_compress(png_ptr, text, text_len, compression,
+ &comp);
+
+ /* Write start of chunk */
+ png_write_chunk_header(png_ptr, png_zTXt,
+ (png_uint_32)(key_len+text_len + 2));
+
+ /* Write key */
+ png_write_chunk_data(png_ptr, (png_bytep)new_key,
+ (png_size_t)(key_len + 1));
+
+ png_free(png_ptr, new_key);
+
+ buf = (png_byte)compression;
+
+ /* Write compression */
+ png_write_chunk_data(png_ptr, &buf, (png_size_t)1);
+
+ /* Write the compressed data */
+ comp.input_len = text_len;
+ png_write_compressed_data_out(png_ptr, &comp);
+
+ /* Close the chunk */
+ png_write_chunk_end(png_ptr);
+}
+#endif
+
+#ifdef PNG_WRITE_iTXt_SUPPORTED
+/* Write an iTXt chunk */
+void /* PRIVATE */
+png_write_iTXt(png_structp png_ptr, int compression, png_const_charp key,
+ png_const_charp lang, png_const_charp lang_key, png_const_charp text)
+{
+ png_size_t lang_len, key_len, lang_key_len, text_len;
+ png_charp new_lang;
+ png_charp new_key = NULL;
+ png_byte cbuf[2];
+ compression_state comp;
+
+ png_debug(1, "in png_write_iTXt");
+
+ comp.num_output_ptr = 0;
+ comp.max_output_ptr = 0;
+ comp.output_ptr = NULL;
+ comp.input = NULL;
+
+ if ((key_len = png_check_keyword(png_ptr, key, &new_key)) == 0)
+ return;
+
+ if ((lang_len = png_check_keyword(png_ptr, lang, &new_lang)) == 0)
+ {
+ png_warning(png_ptr, "Empty language field in iTXt chunk");
+ new_lang = NULL;
+ lang_len = 0;
+ }
+
+ if (lang_key == NULL)
+ lang_key_len = 0;
+
+ else
+ lang_key_len = png_strlen(lang_key);
+
+ if (text == NULL)
+ text_len = 0;
+
+ else
+ text_len = png_strlen(text);
+
+ /* Compute the compressed data; do it now for the length */
+ text_len = png_text_compress(png_ptr, text, text_len, compression - 2,
+ &comp);
+
+
+ /* Make sure we include the compression flag, the compression byte,
+ * and the NULs after the key, lang, and lang_key parts
+ */
+
+ png_write_chunk_header(png_ptr, png_iTXt, (png_uint_32)(
+ 5 /* comp byte, comp flag, terminators for key, lang and lang_key */
+ + key_len
+ + lang_len
+ + lang_key_len
+ + text_len));
+
+ /* We leave it to the application to meet PNG-1.0 requirements on the
+ * contents of the text. PNG-1.0 through PNG-1.2 discourage the use of
+ * any non-Latin-1 characters except for NEWLINE. ISO PNG will forbid them.
+ * The NUL character is forbidden by PNG-1.0 through PNG-1.2 and ISO PNG.
+ */
+ png_write_chunk_data(png_ptr, (png_bytep)new_key, (png_size_t)(key_len + 1));
+
+ /* Set the compression flag */
+ if (compression == PNG_ITXT_COMPRESSION_NONE ||
+ compression == PNG_TEXT_COMPRESSION_NONE)
+ cbuf[0] = 0;
+
+ else /* compression == PNG_ITXT_COMPRESSION_zTXt */
+ cbuf[0] = 1;
+
+ /* Set the compression method */
+ cbuf[1] = 0;
+
+ png_write_chunk_data(png_ptr, cbuf, (png_size_t)2);
+
+ cbuf[0] = 0;
+ png_write_chunk_data(png_ptr, (new_lang ? (png_const_bytep)new_lang : cbuf),
+ (png_size_t)(lang_len + 1));
+
+ png_write_chunk_data(png_ptr, (lang_key ? (png_const_bytep)lang_key : cbuf),
+ (png_size_t)(lang_key_len + 1));
+
+ png_write_compressed_data_out(png_ptr, &comp);
+
+ png_write_chunk_end(png_ptr);
+
+ png_free(png_ptr, new_key);
+ png_free(png_ptr, new_lang);
+}
+#endif
+
+#ifdef PNG_WRITE_oFFs_SUPPORTED
+/* Write the oFFs chunk */
+void /* PRIVATE */
+png_write_oFFs(png_structp png_ptr, png_int_32 x_offset, png_int_32 y_offset,
+ int unit_type)
+{
+ png_byte buf[9];
+
+ png_debug(1, "in png_write_oFFs");
+
+ if (unit_type >= PNG_OFFSET_LAST)
+ png_warning(png_ptr, "Unrecognized unit type for oFFs chunk");
+
+ png_save_int_32(buf, x_offset);
+ png_save_int_32(buf + 4, y_offset);
+ buf[8] = (png_byte)unit_type;
+
+ png_write_complete_chunk(png_ptr, png_oFFs, buf, (png_size_t)9);
+}
+#endif
+#ifdef PNG_WRITE_pCAL_SUPPORTED
+/* Write the pCAL chunk (described in the PNG extensions document) */
+void /* PRIVATE */
+png_write_pCAL(png_structp png_ptr, png_charp purpose, png_int_32 X0,
+ png_int_32 X1, int type, int nparams, png_const_charp units,
+ png_charpp params)
+{
+ png_size_t purpose_len, units_len, total_len;
+ png_size_tp params_len;
+ png_byte buf[10];
+ png_charp new_purpose;
+ int i;
+
+ png_debug1(1, "in png_write_pCAL (%d parameters)", nparams);
+
+ if (type >= PNG_EQUATION_LAST)
+ png_warning(png_ptr, "Unrecognized equation type for pCAL chunk");
+
+ purpose_len = png_check_keyword(png_ptr, purpose, &new_purpose) + 1;
+ png_debug1(3, "pCAL purpose length = %d", (int)purpose_len);
+ units_len = png_strlen(units) + (nparams == 0 ? 0 : 1);
+ png_debug1(3, "pCAL units length = %d", (int)units_len);
+ total_len = purpose_len + units_len + 10;
+
+ params_len = (png_size_tp)png_malloc(png_ptr,
+ (png_alloc_size_t)(nparams * png_sizeof(png_size_t)));
+
+ /* Find the length of each parameter, making sure we don't count the
+ * null terminator for the last parameter.
+ */
+ for (i = 0; i < nparams; i++)
+ {
+ params_len[i] = png_strlen(params[i]) + (i == nparams - 1 ? 0 : 1);
+ png_debug2(3, "pCAL parameter %d length = %lu", i,
+ (unsigned long)params_len[i]);
+ total_len += params_len[i];
+ }
+
+ png_debug1(3, "pCAL total length = %d", (int)total_len);
+ png_write_chunk_header(png_ptr, png_pCAL, (png_uint_32)total_len);
+ png_write_chunk_data(png_ptr, (png_const_bytep)new_purpose, purpose_len);
+ png_save_int_32(buf, X0);
+ png_save_int_32(buf + 4, X1);
+ buf[8] = (png_byte)type;
+ buf[9] = (png_byte)nparams;
+ png_write_chunk_data(png_ptr, buf, (png_size_t)10);
+ png_write_chunk_data(png_ptr, (png_const_bytep)units, (png_size_t)units_len);
+
+ png_free(png_ptr, new_purpose);
+
+ for (i = 0; i < nparams; i++)
+ {
+ png_write_chunk_data(png_ptr, (png_const_bytep)params[i], params_len[i]);
+ }
+
+ png_free(png_ptr, params_len);
+ png_write_chunk_end(png_ptr);
+}
+#endif
+
+#ifdef PNG_WRITE_sCAL_SUPPORTED
+/* Write the sCAL chunk */
+void /* PRIVATE */
+png_write_sCAL_s(png_structp png_ptr, int unit, png_const_charp width,
+ png_const_charp height)
+{
+ png_byte buf[64];
+ png_size_t wlen, hlen, total_len;
+
+ png_debug(1, "in png_write_sCAL_s");
+
+ wlen = png_strlen(width);
+ hlen = png_strlen(height);
+ total_len = wlen + hlen + 2;
+
+ if (total_len > 64)
+ {
+ png_warning(png_ptr, "Can't write sCAL (buffer too small)");
+ return;
+ }
+
+ buf[0] = (png_byte)unit;
+ png_memcpy(buf + 1, width, wlen + 1); /* Append the '\0' here */
+ png_memcpy(buf + wlen + 2, height, hlen); /* Do NOT append the '\0' here */
+
+ png_debug1(3, "sCAL total length = %u", (unsigned int)total_len);
+ png_write_complete_chunk(png_ptr, png_sCAL, buf, total_len);
+}
+#endif
+
+#ifdef PNG_WRITE_pHYs_SUPPORTED
+/* Write the pHYs chunk */
+void /* PRIVATE */
+png_write_pHYs(png_structp png_ptr, png_uint_32 x_pixels_per_unit,
+ png_uint_32 y_pixels_per_unit,
+ int unit_type)
+{
+ png_byte buf[9];
+
+ png_debug(1, "in png_write_pHYs");
+
+ if (unit_type >= PNG_RESOLUTION_LAST)
+ png_warning(png_ptr, "Unrecognized unit type for pHYs chunk");
+
+ png_save_uint_32(buf, x_pixels_per_unit);
+ png_save_uint_32(buf + 4, y_pixels_per_unit);
+ buf[8] = (png_byte)unit_type;
+
+ png_write_complete_chunk(png_ptr, png_pHYs, buf, (png_size_t)9);
+}
+#endif
+
+#ifdef PNG_WRITE_tIME_SUPPORTED
+/* Write the tIME chunk. Use either png_convert_from_struct_tm()
+ * or png_convert_from_time_t(), or fill in the structure yourself.
+ */
+void /* PRIVATE */
+png_write_tIME(png_structp png_ptr, png_const_timep mod_time)
+{
+ png_byte buf[7];
+
+ png_debug(1, "in png_write_tIME");
+
+ if (mod_time->month > 12 || mod_time->month < 1 ||
+ mod_time->day > 31 || mod_time->day < 1 ||
+ mod_time->hour > 23 || mod_time->second > 60)
+ {
+ png_warning(png_ptr, "Invalid time specified for tIME chunk");
+ return;
+ }
+
+ png_save_uint_16(buf, mod_time->year);
+ buf[2] = mod_time->month;
+ buf[3] = mod_time->day;
+ buf[4] = mod_time->hour;
+ buf[5] = mod_time->minute;
+ buf[6] = mod_time->second;
+
+ png_write_complete_chunk(png_ptr, png_tIME, buf, (png_size_t)7);
+}
+#endif
+
+/* Initializes the row writing capability of libpng */
+void /* PRIVATE */
+png_write_start_row(png_structp png_ptr)
+{
+#ifdef PNG_WRITE_INTERLACING_SUPPORTED
+ /* Arrays to facilitate easy interlacing - use pass (0 - 6) as index */
+
+ /* Start of interlace block */
+ static PNG_CONST png_byte png_pass_start[7] = {0, 4, 0, 2, 0, 1, 0};
+
+ /* Offset to next interlace block */
+ static PNG_CONST png_byte png_pass_inc[7] = {8, 8, 4, 4, 2, 2, 1};
+
+ /* Start of interlace block in the y direction */
+ static PNG_CONST png_byte png_pass_ystart[7] = {0, 0, 4, 0, 2, 0, 1};
+
+ /* Offset to next interlace block in the y direction */
+ static PNG_CONST png_byte png_pass_yinc[7] = {8, 8, 8, 4, 4, 2, 2};
+#endif
+
+ png_alloc_size_t buf_size;
+ int usr_pixel_depth;
+
+ png_debug(1, "in png_write_start_row");
+
+ usr_pixel_depth = png_ptr->usr_channels * png_ptr->usr_bit_depth;
+ buf_size = PNG_ROWBYTES(usr_pixel_depth, png_ptr->width) + 1;
+
+ /* 1.5.6: added to allow checking in the row write code. */
+ png_ptr->transformed_pixel_depth = png_ptr->pixel_depth;
+ png_ptr->maximum_pixel_depth = (png_byte)usr_pixel_depth;
+
+ /* Set up row buffer */
+ png_ptr->row_buf = (png_bytep)png_malloc(png_ptr, buf_size);
+
+ png_ptr->row_buf[0] = PNG_FILTER_VALUE_NONE;
+
+#ifdef PNG_WRITE_FILTER_SUPPORTED
+ /* Set up filtering buffer, if using this filter */
+ if (png_ptr->do_filter & PNG_FILTER_SUB)
+ {
+ png_ptr->sub_row = (png_bytep)png_malloc(png_ptr, png_ptr->rowbytes + 1);
+
+ png_ptr->sub_row[0] = PNG_FILTER_VALUE_SUB;
+ }
+
+ /* We only need to keep the previous row if we are using one of these. */
+ if (png_ptr->do_filter & (PNG_FILTER_AVG | PNG_FILTER_UP | PNG_FILTER_PAETH))
+ {
+ /* Set up previous row buffer */
+ png_ptr->prev_row = (png_bytep)png_calloc(png_ptr, buf_size);
+
+ if (png_ptr->do_filter & PNG_FILTER_UP)
+ {
+ png_ptr->up_row = (png_bytep)png_malloc(png_ptr,
+ png_ptr->rowbytes + 1);
+
+ png_ptr->up_row[0] = PNG_FILTER_VALUE_UP;
+ }
+
+ if (png_ptr->do_filter & PNG_FILTER_AVG)
+ {
+ png_ptr->avg_row = (png_bytep)png_malloc(png_ptr,
+ png_ptr->rowbytes + 1);
+
+ png_ptr->avg_row[0] = PNG_FILTER_VALUE_AVG;
+ }
+
+ if (png_ptr->do_filter & PNG_FILTER_PAETH)
+ {
+ png_ptr->paeth_row = (png_bytep)png_malloc(png_ptr,
+ png_ptr->rowbytes + 1);
+
+ png_ptr->paeth_row[0] = PNG_FILTER_VALUE_PAETH;
+ }
+ }
+#endif /* PNG_WRITE_FILTER_SUPPORTED */
+
+#ifdef PNG_WRITE_INTERLACING_SUPPORTED
+ /* If interlaced, we need to set up width and height of pass */
+ if (png_ptr->interlaced)
+ {
+ if (!(png_ptr->transformations & PNG_INTERLACE))
+ {
+ png_ptr->num_rows = (png_ptr->height + png_pass_yinc[0] - 1 -
+ png_pass_ystart[0]) / png_pass_yinc[0];
+
+ png_ptr->usr_width = (png_ptr->width + png_pass_inc[0] - 1 -
+ png_pass_start[0]) / png_pass_inc[0];
+ }
+
+ else
+ {
+ png_ptr->num_rows = png_ptr->height;
+ png_ptr->usr_width = png_ptr->width;
+ }
+ }
+
+ else
+#endif
+ {
+ png_ptr->num_rows = png_ptr->height;
+ png_ptr->usr_width = png_ptr->width;
+ }
+
+ png_zlib_claim(png_ptr, PNG_ZLIB_FOR_IDAT);
+ png_ptr->zstream.avail_out = (uInt)png_ptr->zbuf_size;
+ png_ptr->zstream.next_out = png_ptr->zbuf;
+}
+
+/* Internal use only. Called when finished processing a row of data. */
+void /* PRIVATE */
+png_write_finish_row(png_structp png_ptr)
+{
+#ifdef PNG_WRITE_INTERLACING_SUPPORTED
+ /* Arrays to facilitate easy interlacing - use pass (0 - 6) as index */
+
+ /* Start of interlace block */
+ static PNG_CONST png_byte png_pass_start[7] = {0, 4, 0, 2, 0, 1, 0};
+
+ /* Offset to next interlace block */
+ static PNG_CONST png_byte png_pass_inc[7] = {8, 8, 4, 4, 2, 2, 1};
+
+ /* Start of interlace block in the y direction */
+ static PNG_CONST png_byte png_pass_ystart[7] = {0, 0, 4, 0, 2, 0, 1};
+
+ /* Offset to next interlace block in the y direction */
+ static PNG_CONST png_byte png_pass_yinc[7] = {8, 8, 8, 4, 4, 2, 2};
+#endif
+
+ int ret;
+
+ png_debug(1, "in png_write_finish_row");
+
+ /* Next row */
+ png_ptr->row_number++;
+
+ /* See if we are done */
+ if (png_ptr->row_number < png_ptr->num_rows)
+ return;
+
+#ifdef PNG_WRITE_INTERLACING_SUPPORTED
+ /* If interlaced, go to next pass */
+ if (png_ptr->interlaced)
+ {
+ png_ptr->row_number = 0;
+ if (png_ptr->transformations & PNG_INTERLACE)
+ {
+ png_ptr->pass++;
+ }
+
+ else
+ {
+ /* Loop until we find a non-zero width or height pass */
+ do
+ {
+ png_ptr->pass++;
+
+ if (png_ptr->pass >= 7)
+ break;
+
+ png_ptr->usr_width = (png_ptr->width +
+ png_pass_inc[png_ptr->pass] - 1 -
+ png_pass_start[png_ptr->pass]) /
+ png_pass_inc[png_ptr->pass];
+
+ png_ptr->num_rows = (png_ptr->height +
+ png_pass_yinc[png_ptr->pass] - 1 -
+ png_pass_ystart[png_ptr->pass]) /
+ png_pass_yinc[png_ptr->pass];
+
+ if (png_ptr->transformations & PNG_INTERLACE)
+ break;
+
+ } while (png_ptr->usr_width == 0 || png_ptr->num_rows == 0);
+
+ }
+
+ /* Reset the row above the image for the next pass */
+ if (png_ptr->pass < 7)
+ {
+ if (png_ptr->prev_row != NULL)
+ png_memset(png_ptr->prev_row, 0,
+ (png_size_t)(PNG_ROWBYTES(png_ptr->usr_channels*
+ png_ptr->usr_bit_depth, png_ptr->width)) + 1);
+
+ return;
+ }
+ }
+#endif
+
+ /* If we get here, we've just written the last row, so we need
+ to flush the compressor */
+ do
+ {
+ /* Tell the compressor we are done */
+ ret = deflate(&png_ptr->zstream, Z_FINISH);
+
+ /* Check for an error */
+ if (ret == Z_OK)
+ {
+ /* Check to see if we need more room */
+ if (!(png_ptr->zstream.avail_out))
+ {
+ png_write_IDAT(png_ptr, png_ptr->zbuf, png_ptr->zbuf_size);
+ png_ptr->zstream.next_out = png_ptr->zbuf;
+ png_ptr->zstream.avail_out = (uInt)png_ptr->zbuf_size;
+ }
+ }
+
+ else if (ret != Z_STREAM_END)
+ {
+ if (png_ptr->zstream.msg != NULL)
+ png_error(png_ptr, png_ptr->zstream.msg);
+
+ else
+ png_error(png_ptr, "zlib error");
+ }
+ } while (ret != Z_STREAM_END);
+
+ /* Write any extra space */
+ if (png_ptr->zstream.avail_out < png_ptr->zbuf_size)
+ {
+ png_write_IDAT(png_ptr, png_ptr->zbuf, png_ptr->zbuf_size -
+ png_ptr->zstream.avail_out);
+ }
+
+ png_zlib_release(png_ptr);
+ png_ptr->zstream.data_type = Z_BINARY;
+}
+
+#ifdef PNG_WRITE_INTERLACING_SUPPORTED
+/* Pick out the correct pixels for the interlace pass.
+ * The basic idea here is to go through the row with a source
+ * pointer and a destination pointer (sp and dp), and copy the
+ * correct pixels for the pass. As the row gets compacted,
+ * sp will always be >= dp, so we should never overwrite anything.
+ * See the default: case for the easiest code to understand.
+ */
+void /* PRIVATE */
+png_do_write_interlace(png_row_infop row_info, png_bytep row, int pass)
+{
+ /* Arrays to facilitate easy interlacing - use pass (0 - 6) as index */
+
+ /* Start of interlace block */
+ static PNG_CONST png_byte png_pass_start[7] = {0, 4, 0, 2, 0, 1, 0};
+
+ /* Offset to next interlace block */
+ static PNG_CONST png_byte png_pass_inc[7] = {8, 8, 4, 4, 2, 2, 1};
+
+ png_debug(1, "in png_do_write_interlace");
+
+ /* We don't have to do anything on the last pass (6) */
+ if (pass < 6)
+ {
+ /* Each pixel depth is handled separately */
+ switch (row_info->pixel_depth)
+ {
+ case 1:
+ {
+ png_bytep sp;
+ png_bytep dp;
+ int shift;
+ int d;
+ int value;
+ png_uint_32 i;
+ png_uint_32 row_width = row_info->width;
+
+ dp = row;
+ d = 0;
+ shift = 7;
+
+ for (i = png_pass_start[pass]; i < row_width;
+ i += png_pass_inc[pass])
+ {
+ sp = row + (png_size_t)(i >> 3);
+ value = (int)(*sp >> (7 - (int)(i & 0x07))) & 0x01;
+ d |= (value << shift);
+
+ if (shift == 0)
+ {
+ shift = 7;
+ *dp++ = (png_byte)d;
+ d = 0;
+ }
+
+ else
+ shift--;
+
+ }
+ if (shift != 7)
+ *dp = (png_byte)d;
+
+ break;
+ }
+
+ case 2:
+ {
+ png_bytep sp;
+ png_bytep dp;
+ int shift;
+ int d;
+ int value;
+ png_uint_32 i;
+ png_uint_32 row_width = row_info->width;
+
+ dp = row;
+ shift = 6;
+ d = 0;
+
+ for (i = png_pass_start[pass]; i < row_width;
+ i += png_pass_inc[pass])
+ {
+ sp = row + (png_size_t)(i >> 2);
+ value = (*sp >> ((3 - (int)(i & 0x03)) << 1)) & 0x03;
+ d |= (value << shift);
+
+ if (shift == 0)
+ {
+ shift = 6;
+ *dp++ = (png_byte)d;
+ d = 0;
+ }
+
+ else
+ shift -= 2;
+ }
+ if (shift != 6)
+ *dp = (png_byte)d;
+
+ break;
+ }
+
+ case 4:
+ {
+ png_bytep sp;
+ png_bytep dp;
+ int shift;
+ int d;
+ int value;
+ png_uint_32 i;
+ png_uint_32 row_width = row_info->width;
+
+ dp = row;
+ shift = 4;
+ d = 0;
+ for (i = png_pass_start[pass]; i < row_width;
+ i += png_pass_inc[pass])
+ {
+ sp = row + (png_size_t)(i >> 1);
+ value = (*sp >> ((1 - (int)(i & 0x01)) << 2)) & 0x0f;
+ d |= (value << shift);
+
+ if (shift == 0)
+ {
+ shift = 4;
+ *dp++ = (png_byte)d;
+ d = 0;
+ }
+
+ else
+ shift -= 4;
+ }
+ if (shift != 4)
+ *dp = (png_byte)d;
+
+ break;
+ }
+
+ default:
+ {
+ png_bytep sp;
+ png_bytep dp;
+ png_uint_32 i;
+ png_uint_32 row_width = row_info->width;
+ png_size_t pixel_bytes;
+
+ /* Start at the beginning */
+ dp = row;
+
+ /* Find out how many bytes each pixel takes up */
+ pixel_bytes = (row_info->pixel_depth >> 3);
+
+ /* Loop through the row, only looking at the pixels that matter */
+ for (i = png_pass_start[pass]; i < row_width;
+ i += png_pass_inc[pass])
+ {
+ /* Find out where the original pixel is */
+ sp = row + (png_size_t)i * pixel_bytes;
+
+ /* Move the pixel */
+ if (dp != sp)
+ png_memcpy(dp, sp, pixel_bytes);
+
+ /* Next pixel */
+ dp += pixel_bytes;
+ }
+ break;
+ }
+ }
+ /* Set new row width */
+ row_info->width = (row_info->width +
+ png_pass_inc[pass] - 1 -
+ png_pass_start[pass]) /
+ png_pass_inc[pass];
+
+ row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth,
+ row_info->width);
+ }
+}
+#endif
+
+/* This filters the row, chooses which filter to use, if it has not already
+ * been specified by the application, and then writes the row out with the
+ * chosen filter.
+ */
+static void png_write_filtered_row(png_structp png_ptr, png_bytep filtered_row,
+ png_size_t row_bytes);
+
+#define PNG_MAXSUM (((png_uint_32)(-1)) >> 1)
+#define PNG_HISHIFT 10
+#define PNG_LOMASK ((png_uint_32)0xffffL)
+#define PNG_HIMASK ((png_uint_32)(~PNG_LOMASK >> PNG_HISHIFT))
+void /* PRIVATE */
+png_write_find_filter(png_structp png_ptr, png_row_infop row_info)
+{
+ png_bytep best_row;
+#ifdef PNG_WRITE_FILTER_SUPPORTED
+ png_bytep prev_row, row_buf;
+ png_uint_32 mins, bpp;
+ png_byte filter_to_do = png_ptr->do_filter;
+ png_size_t row_bytes = row_info->rowbytes;
+#ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED
+ int num_p_filters = png_ptr->num_prev_filters;
+#endif
+
+ png_debug(1, "in png_write_find_filter");
+
+#ifndef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED
+ if (png_ptr->row_number == 0 && filter_to_do == PNG_ALL_FILTERS)
+ {
+ /* These will never be selected so we need not test them. */
+ filter_to_do &= ~(PNG_FILTER_UP | PNG_FILTER_PAETH);
+ }
+#endif
+
+ /* Find out how many bytes offset each pixel is */
+ bpp = (row_info->pixel_depth + 7) >> 3;
+
+ prev_row = png_ptr->prev_row;
+#endif
+ best_row = png_ptr->row_buf;
+#ifdef PNG_WRITE_FILTER_SUPPORTED
+ row_buf = best_row;
+ mins = PNG_MAXSUM;
+
+ /* The prediction method we use is to find which method provides the
+ * smallest value when summing the absolute values of the distances
+ * from zero, using anything >= 128 as negative numbers. This is known
+ * as the "minimum sum of absolute differences" heuristic. Other
+ * heuristics are the "weighted minimum sum of absolute differences"
+ * (experimental and can in theory improve compression), and the "zlib
+ * predictive" method (not implemented yet), which does test compressions
+ * of lines using different filter methods, and then chooses the
+ * (series of) filter(s) that give minimum compressed data size (VERY
+ * computationally expensive).
+ *
+ * GRR 980525: consider also
+ *
+ * (1) minimum sum of absolute differences from running average (i.e.,
+ * keep running sum of non-absolute differences & count of bytes)
+ * [track dispersion, too? restart average if dispersion too large?]
+ *
+ * (1b) minimum sum of absolute differences from sliding average, probably
+ * with window size <= deflate window (usually 32K)
+ *
+ * (2) minimum sum of squared differences from zero or running average
+ * (i.e., ~ root-mean-square approach)
+ */
+
+
+ /* We don't need to test the 'no filter' case if this is the only filter
+ * that has been chosen, as it doesn't actually do anything to the data.
+ */
+ if ((filter_to_do & PNG_FILTER_NONE) && filter_to_do != PNG_FILTER_NONE)
+ {
+ png_bytep rp;
+ png_uint_32 sum = 0;
+ png_size_t i;
+ int v;
+
+ for (i = 0, rp = row_buf + 1; i < row_bytes; i++, rp++)
+ {
+ v = *rp;
+ sum += (v < 128) ? v : 256 - v;
+ }
+
+#ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED
+ if (png_ptr->heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED)
+ {
+ png_uint_32 sumhi, sumlo;
+ int j;
+ sumlo = sum & PNG_LOMASK;
+ sumhi = (sum >> PNG_HISHIFT) & PNG_HIMASK; /* Gives us some footroom */
+
+ /* Reduce the sum if we match any of the previous rows */
+ for (j = 0; j < num_p_filters; j++)
+ {
+ if (png_ptr->prev_filters[j] == PNG_FILTER_VALUE_NONE)
+ {
+ sumlo = (sumlo * png_ptr->filter_weights[j]) >>
+ PNG_WEIGHT_SHIFT;
+
+ sumhi = (sumhi * png_ptr->filter_weights[j]) >>
+ PNG_WEIGHT_SHIFT;
+ }
+ }
+
+ /* Factor in the cost of this filter (this is here for completeness,
+ * but it makes no sense to have a "cost" for the NONE filter, as
+ * it has the minimum possible computational cost - none).
+ */
+ sumlo = (sumlo * png_ptr->filter_costs[PNG_FILTER_VALUE_NONE]) >>
+ PNG_COST_SHIFT;
+
+ sumhi = (sumhi * png_ptr->filter_costs[PNG_FILTER_VALUE_NONE]) >>
+ PNG_COST_SHIFT;
+
+ if (sumhi > PNG_HIMASK)
+ sum = PNG_MAXSUM;
+
+ else
+ sum = (sumhi << PNG_HISHIFT) + sumlo;
+ }
+#endif
+ mins = sum;
+ }
+
+ /* Sub filter */
+ if (filter_to_do == PNG_FILTER_SUB)
+ /* It's the only filter so no testing is needed */
+ {
+ png_bytep rp, lp, dp;
+ png_size_t i;
+
+ for (i = 0, rp = row_buf + 1, dp = png_ptr->sub_row + 1; i < bpp;
+ i++, rp++, dp++)
+ {
+ *dp = *rp;
+ }
+
+ for (lp = row_buf + 1; i < row_bytes;
+ i++, rp++, lp++, dp++)
+ {
+ *dp = (png_byte)(((int)*rp - (int)*lp) & 0xff);
+ }
+
+ best_row = png_ptr->sub_row;
+ }
+
+ else if (filter_to_do & PNG_FILTER_SUB)
+ {
+ png_bytep rp, dp, lp;
+ png_uint_32 sum = 0, lmins = mins;
+ png_size_t i;
+ int v;
+
+#ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED
+ /* We temporarily increase the "minimum sum" by the factor we
+ * would reduce the sum of this filter, so that we can do the
+ * early exit comparison without scaling the sum each time.
+ */
+ if (png_ptr->heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED)
+ {
+ int j;
+ png_uint_32 lmhi, lmlo;
+ lmlo = lmins & PNG_LOMASK;
+ lmhi = (lmins >> PNG_HISHIFT) & PNG_HIMASK;
+
+ for (j = 0; j < num_p_filters; j++)
+ {
+ if (png_ptr->prev_filters[j] == PNG_FILTER_VALUE_SUB)
+ {
+ lmlo = (lmlo * png_ptr->inv_filter_weights[j]) >>
+ PNG_WEIGHT_SHIFT;
+
+ lmhi = (lmhi * png_ptr->inv_filter_weights[j]) >>
+ PNG_WEIGHT_SHIFT;
+ }
+ }
+
+ lmlo = (lmlo * png_ptr->inv_filter_costs[PNG_FILTER_VALUE_SUB]) >>
+ PNG_COST_SHIFT;
+
+ lmhi = (lmhi * png_ptr->inv_filter_costs[PNG_FILTER_VALUE_SUB]) >>
+ PNG_COST_SHIFT;
+
+ if (lmhi > PNG_HIMASK)
+ lmins = PNG_MAXSUM;
+
+ else
+ lmins = (lmhi << PNG_HISHIFT) + lmlo;
+ }
+#endif
+
+ for (i = 0, rp = row_buf + 1, dp = png_ptr->sub_row + 1; i < bpp;
+ i++, rp++, dp++)
+ {
+ v = *dp = *rp;
+
+ sum += (v < 128) ? v : 256 - v;
+ }
+
+ for (lp = row_buf + 1; i < row_bytes;
+ i++, rp++, lp++, dp++)
+ {
+ v = *dp = (png_byte)(((int)*rp - (int)*lp) & 0xff);
+
+ sum += (v < 128) ? v : 256 - v;
+
+ if (sum > lmins) /* We are already worse, don't continue. */
+ break;
+ }
+
+#ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED
+ if (png_ptr->heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED)
+ {
+ int j;
+ png_uint_32 sumhi, sumlo;
+ sumlo = sum & PNG_LOMASK;
+ sumhi = (sum >> PNG_HISHIFT) & PNG_HIMASK;
+
+ for (j = 0; j < num_p_filters; j++)
+ {
+ if (png_ptr->prev_filters[j] == PNG_FILTER_VALUE_SUB)
+ {
+ sumlo = (sumlo * png_ptr->inv_filter_weights[j]) >>
+ PNG_WEIGHT_SHIFT;
+
+ sumhi = (sumhi * png_ptr->inv_filter_weights[j]) >>
+ PNG_WEIGHT_SHIFT;
+ }
+ }
+
+ sumlo = (sumlo * png_ptr->inv_filter_costs[PNG_FILTER_VALUE_SUB]) >>
+ PNG_COST_SHIFT;
+
+ sumhi = (sumhi * png_ptr->inv_filter_costs[PNG_FILTER_VALUE_SUB]) >>
+ PNG_COST_SHIFT;
+
+ if (sumhi > PNG_HIMASK)
+ sum = PNG_MAXSUM;
+
+ else
+ sum = (sumhi << PNG_HISHIFT) + sumlo;
+ }
+#endif
+
+ if (sum < mins)
+ {
+ mins = sum;
+ best_row = png_ptr->sub_row;
+ }
+ }
+
+ /* Up filter */
+ if (filter_to_do == PNG_FILTER_UP)
+ {
+ png_bytep rp, dp, pp;
+ png_size_t i;
+
+ for (i = 0, rp = row_buf + 1, dp = png_ptr->up_row + 1,
+ pp = prev_row + 1; i < row_bytes;
+ i++, rp++, pp++, dp++)
+ {
+ *dp = (png_byte)(((int)*rp - (int)*pp) & 0xff);
+ }
+
+ best_row = png_ptr->up_row;
+ }
+
+ else if (filter_to_do & PNG_FILTER_UP)
+ {
+ png_bytep rp, dp, pp;
+ png_uint_32 sum = 0, lmins = mins;
+ png_size_t i;
+ int v;
+
+
+#ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED
+ if (png_ptr->heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED)
+ {
+ int j;
+ png_uint_32 lmhi, lmlo;
+ lmlo = lmins & PNG_LOMASK;
+ lmhi = (lmins >> PNG_HISHIFT) & PNG_HIMASK;
+
+ for (j = 0; j < num_p_filters; j++)
+ {
+ if (png_ptr->prev_filters[j] == PNG_FILTER_VALUE_UP)
+ {
+ lmlo = (lmlo * png_ptr->inv_filter_weights[j]) >>
+ PNG_WEIGHT_SHIFT;
+
+ lmhi = (lmhi * png_ptr->inv_filter_weights[j]) >>
+ PNG_WEIGHT_SHIFT;
+ }
+ }
+
+ lmlo = (lmlo * png_ptr->inv_filter_costs[PNG_FILTER_VALUE_UP]) >>
+ PNG_COST_SHIFT;
+
+ lmhi = (lmhi * png_ptr->inv_filter_costs[PNG_FILTER_VALUE_UP]) >>
+ PNG_COST_SHIFT;
+
+ if (lmhi > PNG_HIMASK)
+ lmins = PNG_MAXSUM;
+
+ else
+ lmins = (lmhi << PNG_HISHIFT) + lmlo;
+ }
+#endif
+
+ for (i = 0, rp = row_buf + 1, dp = png_ptr->up_row + 1,
+ pp = prev_row + 1; i < row_bytes; i++)
+ {
+ v = *dp++ = (png_byte)(((int)*rp++ - (int)*pp++) & 0xff);
+
+ sum += (v < 128) ? v : 256 - v;
+
+ if (sum > lmins) /* We are already worse, don't continue. */
+ break;
+ }
+
+#ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED
+ if (png_ptr->heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED)
+ {
+ int j;
+ png_uint_32 sumhi, sumlo;
+ sumlo = sum & PNG_LOMASK;
+ sumhi = (sum >> PNG_HISHIFT) & PNG_HIMASK;
+
+ for (j = 0; j < num_p_filters; j++)
+ {
+ if (png_ptr->prev_filters[j] == PNG_FILTER_VALUE_UP)
+ {
+ sumlo = (sumlo * png_ptr->filter_weights[j]) >>
+ PNG_WEIGHT_SHIFT;
+
+ sumhi = (sumhi * png_ptr->filter_weights[j]) >>
+ PNG_WEIGHT_SHIFT;
+ }
+ }
+
+ sumlo = (sumlo * png_ptr->filter_costs[PNG_FILTER_VALUE_UP]) >>
+ PNG_COST_SHIFT;
+
+ sumhi = (sumhi * png_ptr->filter_costs[PNG_FILTER_VALUE_UP]) >>
+ PNG_COST_SHIFT;
+
+ if (sumhi > PNG_HIMASK)
+ sum = PNG_MAXSUM;
+
+ else
+ sum = (sumhi << PNG_HISHIFT) + sumlo;
+ }
+#endif
+
+ if (sum < mins)
+ {
+ mins = sum;
+ best_row = png_ptr->up_row;
+ }
+ }
+
+ /* Avg filter */
+ if (filter_to_do == PNG_FILTER_AVG)
+ {
+ png_bytep rp, dp, pp, lp;
+ png_uint_32 i;
+
+ for (i = 0, rp = row_buf + 1, dp = png_ptr->avg_row + 1,
+ pp = prev_row + 1; i < bpp; i++)
+ {
+ *dp++ = (png_byte)(((int)*rp++ - ((int)*pp++ / 2)) & 0xff);
+ }
+
+ for (lp = row_buf + 1; i < row_bytes; i++)
+ {
+ *dp++ = (png_byte)(((int)*rp++ - (((int)*pp++ + (int)*lp++) / 2))
+ & 0xff);
+ }
+ best_row = png_ptr->avg_row;
+ }
+
+ else if (filter_to_do & PNG_FILTER_AVG)
+ {
+ png_bytep rp, dp, pp, lp;
+ png_uint_32 sum = 0, lmins = mins;
+ png_size_t i;
+ int v;
+
+#ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED
+ if (png_ptr->heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED)
+ {
+ int j;
+ png_uint_32 lmhi, lmlo;
+ lmlo = lmins & PNG_LOMASK;
+ lmhi = (lmins >> PNG_HISHIFT) & PNG_HIMASK;
+
+ for (j = 0; j < num_p_filters; j++)
+ {
+ if (png_ptr->prev_filters[j] == PNG_FILTER_VALUE_AVG)
+ {
+ lmlo = (lmlo * png_ptr->inv_filter_weights[j]) >>
+ PNG_WEIGHT_SHIFT;
+
+ lmhi = (lmhi * png_ptr->inv_filter_weights[j]) >>
+ PNG_WEIGHT_SHIFT;
+ }
+ }
+
+ lmlo = (lmlo * png_ptr->inv_filter_costs[PNG_FILTER_VALUE_AVG]) >>
+ PNG_COST_SHIFT;
+
+ lmhi = (lmhi * png_ptr->inv_filter_costs[PNG_FILTER_VALUE_AVG]) >>
+ PNG_COST_SHIFT;
+
+ if (lmhi > PNG_HIMASK)
+ lmins = PNG_MAXSUM;
+
+ else
+ lmins = (lmhi << PNG_HISHIFT) + lmlo;
+ }
+#endif
+
+ for (i = 0, rp = row_buf + 1, dp = png_ptr->avg_row + 1,
+ pp = prev_row + 1; i < bpp; i++)
+ {
+ v = *dp++ = (png_byte)(((int)*rp++ - ((int)*pp++ / 2)) & 0xff);
+
+ sum += (v < 128) ? v : 256 - v;
+ }
+
+ for (lp = row_buf + 1; i < row_bytes; i++)
+ {
+ v = *dp++ =
+ (png_byte)(((int)*rp++ - (((int)*pp++ + (int)*lp++) / 2)) & 0xff);
+
+ sum += (v < 128) ? v : 256 - v;
+
+ if (sum > lmins) /* We are already worse, don't continue. */
+ break;
+ }
+
+#ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED
+ if (png_ptr->heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED)
+ {
+ int j;
+ png_uint_32 sumhi, sumlo;
+ sumlo = sum & PNG_LOMASK;
+ sumhi = (sum >> PNG_HISHIFT) & PNG_HIMASK;
+
+ for (j = 0; j < num_p_filters; j++)
+ {
+ if (png_ptr->prev_filters[j] == PNG_FILTER_VALUE_NONE)
+ {
+ sumlo = (sumlo * png_ptr->filter_weights[j]) >>
+ PNG_WEIGHT_SHIFT;
+
+ sumhi = (sumhi * png_ptr->filter_weights[j]) >>
+ PNG_WEIGHT_SHIFT;
+ }
+ }
+
+ sumlo = (sumlo * png_ptr->filter_costs[PNG_FILTER_VALUE_AVG]) >>
+ PNG_COST_SHIFT;
+
+ sumhi = (sumhi * png_ptr->filter_costs[PNG_FILTER_VALUE_AVG]) >>
+ PNG_COST_SHIFT;
+
+ if (sumhi > PNG_HIMASK)
+ sum = PNG_MAXSUM;
+
+ else
+ sum = (sumhi << PNG_HISHIFT) + sumlo;
+ }
+#endif
+
+ if (sum < mins)
+ {
+ mins = sum;
+ best_row = png_ptr->avg_row;
+ }
+ }
+
+ /* Paeth filter */
+ if (filter_to_do == PNG_FILTER_PAETH)
+ {
+ png_bytep rp, dp, pp, cp, lp;
+ png_size_t i;
+
+ for (i = 0, rp = row_buf + 1, dp = png_ptr->paeth_row + 1,
+ pp = prev_row + 1; i < bpp; i++)
+ {
+ *dp++ = (png_byte)(((int)*rp++ - (int)*pp++) & 0xff);
+ }
+
+ for (lp = row_buf + 1, cp = prev_row + 1; i < row_bytes; i++)
+ {
+ int a, b, c, pa, pb, pc, p;
+
+ b = *pp++;
+ c = *cp++;
+ a = *lp++;
+
+ p = b - c;
+ pc = a - c;
+
+#ifdef PNG_USE_ABS
+ pa = abs(p);
+ pb = abs(pc);
+ pc = abs(p + pc);
+#else
+ pa = p < 0 ? -p : p;
+ pb = pc < 0 ? -pc : pc;
+ pc = (p + pc) < 0 ? -(p + pc) : p + pc;
+#endif
+
+ p = (pa <= pb && pa <=pc) ? a : (pb <= pc) ? b : c;
+
+ *dp++ = (png_byte)(((int)*rp++ - p) & 0xff);
+ }
+ best_row = png_ptr->paeth_row;
+ }
+
+ else if (filter_to_do & PNG_FILTER_PAETH)
+ {
+ png_bytep rp, dp, pp, cp, lp;
+ png_uint_32 sum = 0, lmins = mins;
+ png_size_t i;
+ int v;
+
+#ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED
+ if (png_ptr->heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED)
+ {
+ int j;
+ png_uint_32 lmhi, lmlo;
+ lmlo = lmins & PNG_LOMASK;
+ lmhi = (lmins >> PNG_HISHIFT) & PNG_HIMASK;
+
+ for (j = 0; j < num_p_filters; j++)
+ {
+ if (png_ptr->prev_filters[j] == PNG_FILTER_VALUE_PAETH)
+ {
+ lmlo = (lmlo * png_ptr->inv_filter_weights[j]) >>
+ PNG_WEIGHT_SHIFT;
+
+ lmhi = (lmhi * png_ptr->inv_filter_weights[j]) >>
+ PNG_WEIGHT_SHIFT;
+ }
+ }
+
+ lmlo = (lmlo * png_ptr->inv_filter_costs[PNG_FILTER_VALUE_PAETH]) >>
+ PNG_COST_SHIFT;
+
+ lmhi = (lmhi * png_ptr->inv_filter_costs[PNG_FILTER_VALUE_PAETH]) >>
+ PNG_COST_SHIFT;
+
+ if (lmhi > PNG_HIMASK)
+ lmins = PNG_MAXSUM;
+
+ else
+ lmins = (lmhi << PNG_HISHIFT) + lmlo;
+ }
+#endif
+
+ for (i = 0, rp = row_buf + 1, dp = png_ptr->paeth_row + 1,
+ pp = prev_row + 1; i < bpp; i++)
+ {
+ v = *dp++ = (png_byte)(((int)*rp++ - (int)*pp++) & 0xff);
+
+ sum += (v < 128) ? v : 256 - v;
+ }
+
+ for (lp = row_buf + 1, cp = prev_row + 1; i < row_bytes; i++)
+ {
+ int a, b, c, pa, pb, pc, p;
+
+ b = *pp++;
+ c = *cp++;
+ a = *lp++;
+
+#ifndef PNG_SLOW_PAETH
+ p = b - c;
+ pc = a - c;
+#ifdef PNG_USE_ABS
+ pa = abs(p);
+ pb = abs(pc);
+ pc = abs(p + pc);
+#else
+ pa = p < 0 ? -p : p;
+ pb = pc < 0 ? -pc : pc;
+ pc = (p + pc) < 0 ? -(p + pc) : p + pc;
+#endif
+ p = (pa <= pb && pa <=pc) ? a : (pb <= pc) ? b : c;
+#else /* PNG_SLOW_PAETH */
+ p = a + b - c;
+ pa = abs(p - a);
+ pb = abs(p - b);
+ pc = abs(p - c);
+
+ if (pa <= pb && pa <= pc)
+ p = a;
+
+ else if (pb <= pc)
+ p = b;
+
+ else
+ p = c;
+#endif /* PNG_SLOW_PAETH */
+
+ v = *dp++ = (png_byte)(((int)*rp++ - p) & 0xff);
+
+ sum += (v < 128) ? v : 256 - v;
+
+ if (sum > lmins) /* We are already worse, don't continue. */
+ break;
+ }
+
+#ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED
+ if (png_ptr->heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED)
+ {
+ int j;
+ png_uint_32 sumhi, sumlo;
+ sumlo = sum & PNG_LOMASK;
+ sumhi = (sum >> PNG_HISHIFT) & PNG_HIMASK;
+
+ for (j = 0; j < num_p_filters; j++)
+ {
+ if (png_ptr->prev_filters[j] == PNG_FILTER_VALUE_PAETH)
+ {
+ sumlo = (sumlo * png_ptr->filter_weights[j]) >>
+ PNG_WEIGHT_SHIFT;
+
+ sumhi = (sumhi * png_ptr->filter_weights[j]) >>
+ PNG_WEIGHT_SHIFT;
+ }
+ }
+
+ sumlo = (sumlo * png_ptr->filter_costs[PNG_FILTER_VALUE_PAETH]) >>
+ PNG_COST_SHIFT;
+
+ sumhi = (sumhi * png_ptr->filter_costs[PNG_FILTER_VALUE_PAETH]) >>
+ PNG_COST_SHIFT;
+
+ if (sumhi > PNG_HIMASK)
+ sum = PNG_MAXSUM;
+
+ else
+ sum = (sumhi << PNG_HISHIFT) + sumlo;
+ }
+#endif
+
+ if (sum < mins)
+ {
+ best_row = png_ptr->paeth_row;
+ }
+ }
+#endif /* PNG_WRITE_FILTER_SUPPORTED */
+
+ /* Do the actual writing of the filtered row data from the chosen filter. */
+ png_write_filtered_row(png_ptr, best_row, row_info->rowbytes+1);
+
+#ifdef PNG_WRITE_FILTER_SUPPORTED
+#ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED
+ /* Save the type of filter we picked this time for future calculations */
+ if (png_ptr->num_prev_filters > 0)
+ {
+ int j;
+
+ for (j = 1; j < num_p_filters; j++)
+ {
+ png_ptr->prev_filters[j] = png_ptr->prev_filters[j - 1];
+ }
+
+ png_ptr->prev_filters[j] = best_row[0];
+ }
+#endif
+#endif /* PNG_WRITE_FILTER_SUPPORTED */
+}
+
+
+/* Do the actual writing of a previously filtered row. */
+static void
+png_write_filtered_row(png_structp png_ptr, png_bytep filtered_row,
+ png_size_t avail/*includes filter byte*/)
+{
+ png_debug(1, "in png_write_filtered_row");
+
+ png_debug1(2, "filter = %d", filtered_row[0]);
+ /* Set up the zlib input buffer */
+
+ png_ptr->zstream.next_in = filtered_row;
+ png_ptr->zstream.avail_in = 0;
+ /* Repeat until we have compressed all the data */
+ do
+ {
+ int ret; /* Return of zlib */
+
+ /* Record the number of bytes available - zlib supports at least 65535
+ * bytes at one step, depending on the size of the zlib type 'uInt', the
+ * maximum size zlib can write at once is ZLIB_IO_MAX (from pngpriv.h).
+ * Use this because on 16 bit systems 'rowbytes' can be up to 65536 (i.e.
+ * one more than 16 bits) and, in this case 'rowbytes+1' can overflow a
+ * uInt. ZLIB_IO_MAX can be safely reduced to cause zlib to be called
+ * with smaller chunks of data.
+ */
+ if (png_ptr->zstream.avail_in == 0)
+ {
+ if (avail > ZLIB_IO_MAX)
+ {
+ png_ptr->zstream.avail_in = ZLIB_IO_MAX;
+ avail -= ZLIB_IO_MAX;
+ }
+
+ else
+ {
+ /* So this will fit in the available uInt space: */
+ png_ptr->zstream.avail_in = (uInt)avail;
+ avail = 0;
+ }
+ }
+
+ /* Compress the data */
+ ret = deflate(&png_ptr->zstream, Z_NO_FLUSH);
+
+ /* Check for compression errors */
+ if (ret != Z_OK)
+ {
+ if (png_ptr->zstream.msg != NULL)
+ png_error(png_ptr, png_ptr->zstream.msg);
+
+ else
+ png_error(png_ptr, "zlib error");
+ }
+
+ /* See if it is time to write another IDAT */
+ if (!(png_ptr->zstream.avail_out))
+ {
+ /* Write the IDAT and reset the zlib output buffer */
+ png_write_IDAT(png_ptr, png_ptr->zbuf, png_ptr->zbuf_size);
+ }
+ /* Repeat until all data has been compressed */
+ } while (avail > 0 || png_ptr->zstream.avail_in > 0);
+
+ /* Swap the current and previous rows */
+ if (png_ptr->prev_row != NULL)
+ {
+ png_bytep tptr;
+
+ tptr = png_ptr->prev_row;
+ png_ptr->prev_row = png_ptr->row_buf;
+ png_ptr->row_buf = tptr;
+ }
+
+ /* Finish row - updates counters and flushes zlib if last row */
+ png_write_finish_row(png_ptr);
+
+#ifdef PNG_WRITE_FLUSH_SUPPORTED
+ png_ptr->flush_rows++;
+
+ if (png_ptr->flush_dist > 0 &&
+ png_ptr->flush_rows >= png_ptr->flush_dist)
+ {
+ png_write_flush(png_ptr);
+ }
+#endif
+}
+#endif /* PNG_WRITE_SUPPORTED */
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