FreeImage: folders restructurization

git-svn-id: http://svn.miranda-ng.org/main/trunk@1884 1316c22d-e87f-b044-9b9b-93d7a3e3ba9c

1 files changed, 917 insertions, 0 deletions

diff --git a/plugins/FreeImage/src/FreeImageToolkit/ClassicRotate.cpp b/plugins/FreeImage/src/FreeImageToolkit/ClassicRotate.cpp
new file mode 100644
index 0000000000..d38d8c1bcd
--- /dev/null
+++ b/plugins/FreeImage/src/FreeImageToolkit/ClassicRotate.cpp
@@ -0,0 +1,917 @@
+// ==========================================================
+// Bitmap rotation by means of 3 shears.
+//
+// Design and implementation by
+// - Hervé Drolon (drolon@infonie.fr)
+// - Thorsten Radde (support@IdealSoftware.com)
+// - Mihail Naydenov (mnaydenov@users.sourceforge.net)
+//
+// This file is part of FreeImage 3
+//
+// COVERED CODE IS PROVIDED UNDER THIS LICENSE ON AN "AS IS" BASIS, WITHOUT WARRANTY
+// OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING, WITHOUT LIMITATION, WARRANTIES
+// THAT THE COVERED CODE IS FREE OF DEFECTS, MERCHANTABLE, FIT FOR A PARTICULAR PURPOSE
+// OR NON-INFRINGING. THE ENTIRE RISK AS TO THE QUALITY AND PERFORMANCE OF THE COVERED
+// CODE IS WITH YOU. SHOULD ANY COVERED CODE PROVE DEFECTIVE IN ANY RESPECT, YOU (NOT
+// THE INITIAL DEVELOPER OR ANY OTHER CONTRIBUTOR) ASSUME THE COST OF ANY NECESSARY
+// SERVICING, REPAIR OR CORRECTION. THIS DISCLAIMER OF WARRANTY CONSTITUTES AN ESSENTIAL
+// PART OF THIS LICENSE. NO USE OF ANY COVERED CODE IS AUTHORIZED HEREUNDER EXCEPT UNDER
+// THIS DISCLAIMER.
+//
+// Use at your own risk!
+// ==========================================================
+
+/* 
+ ============================================================
+ References : 
+ [1] Paeth A., A Fast Algorithm for General Raster Rotation. 
+ Graphics Gems, p. 179, Andrew Glassner editor, Academic Press, 1990. 
+ [2] Yariv E., High quality image rotation (rotate by shear). 
+ [Online] http://www.codeproject.com/bitmap/rotatebyshear.asp
+ [3] Treskunov A., Fast and high quality true-color bitmap rotation function.
+ [Online] http://anton.treskunov.net/Software/doc/fast_and_high_quality_true_color_bitmap_rotation_function.html
+ ============================================================
+*/
+
+#include "FreeImage.h"
+#include "Utilities.h"
+
+#define RBLOCK		64	// image blocks of RBLOCK*RBLOCK pixels
+
+// --------------------------------------------------------------------------
+
+/**
+Skews a row horizontally (with filtered weights). 
+Limited to 45 degree skewing only. Filters two adjacent pixels.
+Parameter T can be BYTE, WORD of float. 
+@param src Pointer to source image to rotate
+@param dst Pointer to destination image
+@param row Row index
+@param iOffset Skew offset
+@param dWeight Relative weight of right pixel
+@param bkcolor Background color
+*/
+template <class T> void 
+HorizontalSkewT(FIBITMAP *src, FIBITMAP *dst, int row, int iOffset, double weight, const void *bkcolor = NULL) {
+	int iXPos;
+
+	const unsigned src_width  = FreeImage_GetWidth(src);
+	const unsigned dst_width  = FreeImage_GetWidth(dst);
+
+	T pxlSrc[4], pxlLeft[4], pxlOldLeft[4];	// 4 = 4*sizeof(T) max
+	
+	// background
+	const T pxlBlack[4] = {0, 0, 0, 0 };
+	const T *pxlBkg = static_cast<const T*>(bkcolor); // assume at least bytespp and 4*sizeof(T) max
+	if (!pxlBkg) {
+		// default background color is black
+		pxlBkg = pxlBlack;
+	}
+
+	// calculate the number of bytes per pixel
+	const unsigned bytespp = FreeImage_GetLine(src) / FreeImage_GetWidth(src);
+	// calculate the number of samples per pixel
+	const unsigned samples = bytespp / sizeof(T);
+
+	BYTE *src_bits = FreeImage_GetScanLine(src, row);
+	BYTE *dst_bits = FreeImage_GetScanLine(dst, row);
+
+	// fill gap left of skew with background
+	if(bkcolor) {
+		for(int k = 0; k < iOffset; k++) {
+			memcpy(&dst_bits[k * bytespp], bkcolor, bytespp);
+		}
+		AssignPixel((BYTE*)&pxlOldLeft[0], (BYTE*)bkcolor, bytespp);
+	} else {
+		if(iOffset > 0) {
+			memset(dst_bits, 0, iOffset * bytespp);
+		}		
+		memset(&pxlOldLeft[0], 0, bytespp);
+	}
+
+	for(unsigned i = 0; i < src_width; i++) {
+		// loop through row pixels
+		AssignPixel((BYTE*)&pxlSrc[0], (BYTE*)src_bits, bytespp);
+		// calculate weights
+		for(unsigned j = 0; j < samples; j++) {
+			pxlLeft[j] = static_cast<T>(pxlBkg[j] + (pxlSrc[j] - pxlBkg[j]) * weight + 0.5);
+		}
+		// check boundaries 
+		iXPos = i + iOffset;
+		if ((iXPos >= 0) && (iXPos < (int)dst_width)) {
+			// update left over on source
+			for(unsigned j = 0; j < samples; j++) {
+				pxlSrc[j] = pxlSrc[j] - (pxlLeft[j] - pxlOldLeft[j]);
+			}
+			AssignPixel((BYTE*)&dst_bits[iXPos*bytespp], (BYTE*)&pxlSrc[0], bytespp);
+		}
+		// save leftover for next pixel in scan
+		AssignPixel((BYTE*)&pxlOldLeft[0], (BYTE*)&pxlLeft[0], bytespp);
+
+		// next pixel in scan
+		src_bits += bytespp;
+	}			
+
+	// go to rightmost point of skew
+	iXPos = src_width + iOffset; 
+
+	if ((iXPos >= 0) && (iXPos < (int)dst_width)) {
+		dst_bits = FreeImage_GetScanLine(dst, row) + iXPos * bytespp;
+
+		// If still in image bounds, put leftovers there
+		AssignPixel((BYTE*)dst_bits, (BYTE*)&pxlOldLeft[0], bytespp);
+
+		// clear to the right of the skewed line with background
+		dst_bits += bytespp;
+		if(bkcolor) {
+			for(unsigned i = 0; i < dst_width - iXPos - 1; i++) {
+				memcpy(&dst_bits[i * bytespp], bkcolor, bytespp);
+			}
+		} else {
+			memset(dst_bits, 0, bytespp * (dst_width - iXPos - 1));
+		}
+
+	}
+}
+
+/**
+Skews a row horizontally (with filtered weights). 
+Limited to 45 degree skewing only. Filters two adjacent pixels.
+@param src Pointer to source image to rotate
+@param dst Pointer to destination image
+@param row Row index
+@param iOffset Skew offset
+@param dWeight Relative weight of right pixel
+@param bkcolor Background color
+*/
+static void 
+HorizontalSkew(FIBITMAP *src, FIBITMAP *dst, int row, int iOffset, double dWeight, const void *bkcolor) {
+	FREE_IMAGE_TYPE image_type = FreeImage_GetImageType(src);
+
+	switch(image_type) {
+		case FIT_BITMAP:
+			switch(FreeImage_GetBPP(src)) {
+				case 8:
+				case 24:
+				case 32:
+					HorizontalSkewT<BYTE>(src, dst, row, iOffset, dWeight, bkcolor);
+				break;
+			}
+			break;
+		case FIT_UINT16:
+		case FIT_RGB16:
+		case FIT_RGBA16:
+			HorizontalSkewT<WORD>(src, dst, row, iOffset, dWeight, bkcolor);
+			break;
+		case FIT_FLOAT:
+		case FIT_RGBF:
+		case FIT_RGBAF:
+			HorizontalSkewT<float>(src, dst, row, iOffset, dWeight, bkcolor);
+			break;
+	}
+}
+
+/**
+Skews a column vertically (with filtered weights). 
+Limited to 45 degree skewing only. Filters two adjacent pixels.
+Parameter T can be BYTE, WORD of float. 
+@param src Pointer to source image to rotate
+@param dst Pointer to destination image
+@param col Column index
+@param iOffset Skew offset
+@param dWeight Relative weight of upper pixel
+@param bkcolor Background color
+*/
+template <class T> void 
+VerticalSkewT(FIBITMAP *src, FIBITMAP *dst, int col, int iOffset, double weight, const void *bkcolor = NULL) {
+	int iYPos;
+
+	unsigned src_height = FreeImage_GetHeight(src);
+	unsigned dst_height = FreeImage_GetHeight(dst);
+
+	T pxlSrc[4], pxlLeft[4], pxlOldLeft[4];	// 4 = 4*sizeof(T) max
+
+	// background
+	const T pxlBlack[4] = {0, 0, 0, 0 };
+	const T *pxlBkg = static_cast<const T*>(bkcolor); // assume at least bytespp and 4*sizeof(T) max
+	if (!pxlBkg) {
+		// default background color is black
+		pxlBkg = pxlBlack;
+	}
+
+	// calculate the number of bytes per pixel
+	const unsigned bytespp = FreeImage_GetLine(src) / FreeImage_GetWidth(src);
+	// calculate the number of samples per pixel
+	const unsigned samples = bytespp / sizeof(T);
+
+	const unsigned src_pitch = FreeImage_GetPitch(src);
+	const unsigned dst_pitch = FreeImage_GetPitch(dst);
+	const unsigned index = col * bytespp;
+
+	BYTE *src_bits = FreeImage_GetBits(src) + index;
+	BYTE *dst_bits = FreeImage_GetBits(dst) + index;
+
+	// fill gap above skew with background
+	if(bkcolor) {
+		for(int k = 0; k < iOffset; k++) {
+			memcpy(dst_bits, bkcolor, bytespp);
+			dst_bits += dst_pitch;
+		}
+		memcpy(&pxlOldLeft[0], bkcolor, bytespp);
+	} else {
+		for(int k = 0; k < iOffset; k++) {
+			memset(dst_bits, 0, bytespp);
+			dst_bits += dst_pitch;
+		}
+		memset(&pxlOldLeft[0], 0, bytespp);
+	}
+
+	for(unsigned i = 0; i < src_height; i++) {
+		// loop through column pixels
+		AssignPixel((BYTE*)(&pxlSrc[0]), src_bits, bytespp);
+		// calculate weights
+		for(unsigned j = 0; j < samples; j++) {
+			pxlLeft[j] = static_cast<T>(pxlBkg[j] + (pxlSrc[j] - pxlBkg[j]) * weight + 0.5);
+		}
+		// check boundaries
+		iYPos = i + iOffset;
+		if ((iYPos >= 0) && (iYPos < (int)dst_height)) {
+			// update left over on source
+			for(unsigned j = 0; j < samples; j++) {
+				pxlSrc[j] = pxlSrc[j] - (pxlLeft[j] - pxlOldLeft[j]);
+			}
+			dst_bits = FreeImage_GetScanLine(dst, iYPos) + index;
+			AssignPixel(dst_bits, (BYTE*)(&pxlSrc[0]), bytespp);
+		}
+		// save leftover for next pixel in scan
+		AssignPixel((BYTE*)(&pxlOldLeft[0]), (BYTE*)(&pxlLeft[0]), bytespp);
+
+		// next pixel in scan
+		src_bits += src_pitch;
+	}
+	// go to bottom point of skew
+	iYPos = src_height + iOffset;
+
+	if ((iYPos >= 0) && (iYPos < (int)dst_height)) {
+		dst_bits = FreeImage_GetScanLine(dst, iYPos) + index;
+
+		// if still in image bounds, put leftovers there				
+		AssignPixel((BYTE*)(dst_bits), (BYTE*)(&pxlOldLeft[0]), bytespp);
+
+		// clear below skewed line with background
+		if(bkcolor) {
+			while(++iYPos < (int)dst_height) {					
+				dst_bits += dst_pitch;
+				AssignPixel((BYTE*)(dst_bits), (BYTE*)(bkcolor), bytespp);
+			}
+		} else {
+			while(++iYPos < (int)dst_height) {					
+				dst_bits += dst_pitch;
+				memset(dst_bits, 0, bytespp);
+			}
+		}
+	}
+}
+
+/**
+Skews a column vertically (with filtered weights). 
+Limited to 45 degree skewing only. Filters two adjacent pixels.
+@param src Pointer to source image to rotate
+@param dst Pointer to destination image
+@param col Column index
+@param iOffset Skew offset
+@param dWeight Relative weight of upper pixel
+@param bkcolor Background color
+*/
+static void 
+VerticalSkew(FIBITMAP *src, FIBITMAP *dst, int col, int iOffset, double dWeight, const void *bkcolor) {
+	FREE_IMAGE_TYPE image_type = FreeImage_GetImageType(src);
+
+	switch(image_type) {
+		case FIT_BITMAP:
+			switch(FreeImage_GetBPP(src)) {
+				case 8:
+				case 24:
+				case 32:
+					VerticalSkewT<BYTE>(src, dst, col, iOffset, dWeight, bkcolor);
+					break;
+			}
+			break;
+			case FIT_UINT16:
+			case FIT_RGB16:
+			case FIT_RGBA16:
+				VerticalSkewT<WORD>(src, dst, col, iOffset, dWeight, bkcolor);
+				break;
+			case FIT_FLOAT:
+			case FIT_RGBF:
+			case FIT_RGBAF:
+				VerticalSkewT<float>(src, dst, col, iOffset, dWeight, bkcolor);
+				break;
+	}
+} 
+
+/**
+Rotates an image by 90 degrees (counter clockwise). 
+Precise rotation, no filters required.<br>
+Code adapted from CxImage (http://www.xdp.it/cximage.htm)
+@param src Pointer to source image to rotate
+@return Returns a pointer to a newly allocated rotated image if successful, returns NULL otherwise
+*/
+static FIBITMAP* 
+Rotate90(FIBITMAP *src) {
+
+	const unsigned bpp = FreeImage_GetBPP(src);
+
+	const unsigned src_width  = FreeImage_GetWidth(src);
+	const unsigned src_height = FreeImage_GetHeight(src);	
+	const unsigned dst_width  = src_height;
+	const unsigned dst_height = src_width;
+
+	FREE_IMAGE_TYPE image_type = FreeImage_GetImageType(src);
+
+	// allocate and clear dst image
+	FIBITMAP *dst = FreeImage_AllocateT(image_type, dst_width, dst_height, bpp);
+	if(NULL == dst) return NULL;
+
+	// get src and dst scan width
+	const unsigned src_pitch  = FreeImage_GetPitch(src);
+	const unsigned dst_pitch  = FreeImage_GetPitch(dst);
+
+	switch(image_type) {
+		case FIT_BITMAP:
+			if(bpp == 1) {
+				// speedy rotate for BW images
+
+				BYTE *bsrc  = FreeImage_GetBits(src); 
+				BYTE *bdest = FreeImage_GetBits(dst);
+
+				BYTE *dbitsmax = bdest + dst_height * dst_pitch - 1;
+
+				for(unsigned y = 0; y < src_height; y++) {
+					// figure out the column we are going to be copying to
+					const div_t div_r = div(y, 8);
+					// set bit pos of src column byte
+					const BYTE bitpos = (BYTE)(128 >> div_r.rem);
+					BYTE *srcdisp = bsrc + y * src_pitch;
+					for(unsigned x = 0; x < src_pitch; x++) {
+						// get source bits
+						BYTE *sbits = srcdisp + x;
+						// get destination column
+						BYTE *nrow = bdest + (dst_height - 1 - (x * 8)) * dst_pitch + div_r.quot;
+						for (int z = 0; z < 8; z++) {
+						   // get destination byte
+							BYTE *dbits = nrow - z * dst_pitch;
+							if ((dbits < bdest) || (dbits > dbitsmax)) break;
+							if (*sbits & (128 >> z)) *dbits |= bitpos;
+						}
+					}
+				}
+			}
+			else if ((bpp == 8) || (bpp == 24) || (bpp == 32)) {
+				// anything other than BW :
+				// This optimized version of rotation rotates image by smaller blocks. It is quite
+				// a bit faster than obvious algorithm, because it produces much less CPU cache misses.
+				// This optimization can be tuned by changing block size (RBLOCK). 96 is good value for current
+				// CPUs (tested on Athlon XP and Celeron D). Larger value (if CPU has enough cache) will increase
+				// speed somehow, but once you drop out of CPU's cache, things will slow down drastically.
+				// For older CPUs with less cache, lower value would yield better results.
+
+				BYTE *bsrc  = FreeImage_GetBits(src);  // source pixels
+				BYTE *bdest = FreeImage_GetBits(dst);  // destination pixels
+
+				// calculate the number of bytes per pixel (1 for 8-bit, 3 for 24-bit or 4 for 32-bit)
+				const unsigned bytespp = FreeImage_GetLine(src) / FreeImage_GetWidth(src);
+				
+				// for all image blocks of RBLOCK*RBLOCK pixels
+				
+				// x-segment
+				for(unsigned xs = 0; xs < dst_width; xs += RBLOCK) {
+					// y-segment
+					for(unsigned ys = 0; ys < dst_height; ys += RBLOCK) {
+						for(unsigned y = ys; y < MIN(dst_height, ys + RBLOCK); y++) {    // do rotation
+							const unsigned y2 = dst_height - y - 1;
+							// point to src pixel at (y2, xs)
+							BYTE *src_bits = bsrc + (xs * src_pitch) + (y2 * bytespp);
+							// point to dst pixel at (xs, y)
+							BYTE *dst_bits = bdest + (y * dst_pitch) + (xs * bytespp);
+							for(unsigned x = xs; x < MIN(dst_width, xs + RBLOCK); x++) {
+								// dst.SetPixel(x, y, src.GetPixel(y2, x));
+								AssignPixel(dst_bits, src_bits, bytespp);
+								dst_bits += bytespp;
+								src_bits += src_pitch;
+							}
+						}
+					}
+				}
+			}
+			break;
+		case FIT_UINT16:
+		case FIT_RGB16:
+		case FIT_RGBA16:
+		case FIT_FLOAT:
+		case FIT_RGBF:
+		case FIT_RGBAF:
+		{
+			BYTE *bsrc  = FreeImage_GetBits(src);  // source pixels
+			BYTE *bdest = FreeImage_GetBits(dst);  // destination pixels
+
+			// calculate the number of bytes per pixel
+			const unsigned bytespp = FreeImage_GetLine(src) / FreeImage_GetWidth(src);
+
+			for(unsigned y = 0; y < dst_height; y++) {
+				BYTE *src_bits = bsrc + (src_width - 1 - y) * bytespp;
+				BYTE *dst_bits = bdest + (y * dst_pitch);
+				for(unsigned x = 0; x < dst_width; x++) {
+					AssignPixel(dst_bits, src_bits, bytespp);
+					src_bits += src_pitch;
+					dst_bits += bytespp;
+				}
+			}
+		}
+		break;
+	}
+
+	return dst;
+}
+
+/**
+Rotates an image by 180 degrees (counter clockwise). 
+Precise rotation, no filters required.
+@param src Pointer to source image to rotate
+@return Returns a pointer to a newly allocated rotated image if successful, returns NULL otherwise
+*/
+static FIBITMAP* 
+Rotate180(FIBITMAP *src) {
+	int x, y, k, pos;
+
+	const int bpp = FreeImage_GetBPP(src);
+
+	const int src_width  = FreeImage_GetWidth(src);
+	const int src_height = FreeImage_GetHeight(src);
+	const int dst_width  = src_width;
+	const int dst_height = src_height;
+
+	FREE_IMAGE_TYPE image_type = FreeImage_GetImageType(src);
+
+	FIBITMAP *dst = FreeImage_AllocateT(image_type, dst_width, dst_height, bpp);
+	if(NULL == dst) return NULL;
+
+	switch(image_type) {
+		case FIT_BITMAP:
+			if(bpp == 1) {
+				for(int y = 0; y < src_height; y++) {
+					BYTE *src_bits = FreeImage_GetScanLine(src, y);
+					BYTE *dst_bits = FreeImage_GetScanLine(dst, dst_height - y - 1);
+					for(int x = 0; x < src_width; x++) {
+						// get bit at (x, y)
+						k = (src_bits[x >> 3] & (0x80 >> (x & 0x07))) != 0;
+						// set bit at (dst_width - x - 1, dst_height - y - 1)
+						pos = dst_width - x - 1;
+						k ? dst_bits[pos >> 3] |= (0x80 >> (pos & 0x7)) : dst_bits[pos >> 3] &= (0xFF7F >> (pos & 0x7));
+					}			
+				}
+				break;
+			}
+			// else if ((bpp == 8) || (bpp == 24) || (bpp == 32)) FALL TROUGH
+		case FIT_UINT16:
+		case FIT_RGB16:
+		case FIT_RGBA16:
+		case FIT_FLOAT:
+		case FIT_RGBF:
+		case FIT_RGBAF:
+		{
+			 // Calculate the number of bytes per pixel
+			const int bytespp = FreeImage_GetLine(src) / FreeImage_GetWidth(src);
+
+			for(y = 0; y < src_height; y++) {
+				BYTE *src_bits = FreeImage_GetScanLine(src, y);
+				BYTE *dst_bits = FreeImage_GetScanLine(dst, dst_height - y - 1) + (dst_width - 1) * bytespp;
+				for(x = 0; x < src_width; x++) {
+					// get pixel at (x, y)
+					// set pixel at (dst_width - x - 1, dst_height - y - 1)
+					AssignPixel(dst_bits, src_bits, bytespp);
+					src_bits += bytespp;
+					dst_bits -= bytespp;					
+				}				
+			}
+		}
+		break;
+	}
+
+	return dst;
+}
+
+/**
+Rotates an image by 270 degrees (counter clockwise). 
+Precise rotation, no filters required.<br>
+Code adapted from CxImage (http://www.xdp.it/cximage.htm)
+@param src Pointer to source image to rotate
+@return Returns a pointer to a newly allocated rotated image if successful, returns NULL otherwise
+*/
+static FIBITMAP* 
+Rotate270(FIBITMAP *src) {
+	int x2, dlineup;
+
+	const unsigned bpp = FreeImage_GetBPP(src);
+
+	const unsigned src_width  = FreeImage_GetWidth(src);
+	const unsigned src_height = FreeImage_GetHeight(src);	
+	const unsigned dst_width  = src_height;
+	const unsigned dst_height = src_width;
+
+	FREE_IMAGE_TYPE image_type = FreeImage_GetImageType(src);
+
+	// allocate and clear dst image
+	FIBITMAP *dst = FreeImage_AllocateT(image_type, dst_width, dst_height, bpp);
+	if(NULL == dst) return NULL;
+
+	// get src and dst scan width
+	const unsigned src_pitch  = FreeImage_GetPitch(src);
+	const unsigned dst_pitch  = FreeImage_GetPitch(dst);
+	
+	switch(image_type) {
+		case FIT_BITMAP:
+			if(bpp == 1) {
+				// speedy rotate for BW images
+				
+				BYTE *bsrc  = FreeImage_GetBits(src); 
+				BYTE *bdest = FreeImage_GetBits(dst);
+				BYTE *dbitsmax = bdest + dst_height * dst_pitch - 1;
+				dlineup = 8 * dst_pitch - dst_width;
+
+				for(unsigned y = 0; y < src_height; y++) {
+					// figure out the column we are going to be copying to
+					const div_t div_r = div(y + dlineup, 8);
+					// set bit pos of src column byte
+					const BYTE bitpos = (BYTE)(1 << div_r.rem);
+					const BYTE *srcdisp = bsrc + y * src_pitch;
+					for(unsigned x = 0; x < src_pitch; x++) {
+						// get source bits
+						const BYTE *sbits = srcdisp + x;
+						// get destination column
+						BYTE *nrow = bdest + (x * 8) * dst_pitch + dst_pitch - 1 - div_r.quot;
+						for(unsigned z = 0; z < 8; z++) {
+						   // get destination byte
+							BYTE *dbits = nrow + z * dst_pitch;
+							if ((dbits < bdest) || (dbits > dbitsmax)) break;
+							if (*sbits & (128 >> z)) *dbits |= bitpos;
+						}
+					}
+				}
+			} 
+			else if ((bpp == 8) || (bpp == 24) || (bpp == 32)) {
+				// anything other than BW :
+				// This optimized version of rotation rotates image by smaller blocks. It is quite
+				// a bit faster than obvious algorithm, because it produces much less CPU cache misses.
+				// This optimization can be tuned by changing block size (RBLOCK). 96 is good value for current
+				// CPUs (tested on Athlon XP and Celeron D). Larger value (if CPU has enough cache) will increase
+				// speed somehow, but once you drop out of CPU's cache, things will slow down drastically.
+				// For older CPUs with less cache, lower value would yield better results.
+
+				BYTE *bsrc  = FreeImage_GetBits(src);  // source pixels
+				BYTE *bdest = FreeImage_GetBits(dst);  // destination pixels
+
+				// Calculate the number of bytes per pixel (1 for 8-bit, 3 for 24-bit or 4 for 32-bit)
+				const unsigned bytespp = FreeImage_GetLine(src) / FreeImage_GetWidth(src);
+
+				// for all image blocks of RBLOCK*RBLOCK pixels
+
+				// x-segment
+				for(unsigned xs = 0; xs < dst_width; xs += RBLOCK) {
+					// y-segment
+					for(unsigned ys = 0; ys < dst_height; ys += RBLOCK) {
+						for(unsigned x = xs; x < MIN(dst_width, xs + RBLOCK); x++) {    // do rotation
+							x2 = dst_width - x - 1;
+							// point to src pixel at (ys, x2)
+							BYTE *src_bits = bsrc + (x2 * src_pitch) + (ys * bytespp);
+							// point to dst pixel at (x, ys)
+							BYTE *dst_bits = bdest + (ys * dst_pitch) + (x * bytespp);
+							for(unsigned y = ys; y < MIN(dst_height, ys + RBLOCK); y++) {
+								// dst.SetPixel(x, y, src.GetPixel(y, x2));
+								AssignPixel(dst_bits, src_bits, bytespp);
+								src_bits += bytespp;
+								dst_bits += dst_pitch;
+							}
+						}
+					}
+				}
+			}
+			break;
+		case FIT_UINT16:
+		case FIT_RGB16:
+		case FIT_RGBA16:
+		case FIT_FLOAT:
+		case FIT_RGBF:
+		case FIT_RGBAF:
+		{
+			BYTE *bsrc  = FreeImage_GetBits(src);  // source pixels
+			BYTE *bdest = FreeImage_GetBits(dst);  // destination pixels
+
+			// calculate the number of bytes per pixel
+			const unsigned bytespp = FreeImage_GetLine(src) / FreeImage_GetWidth(src);
+
+			for(unsigned y = 0; y < dst_height; y++) {
+				BYTE *src_bits = bsrc + (src_height - 1) * src_pitch + y * bytespp;
+				BYTE *dst_bits = bdest + (y * dst_pitch);
+				for(unsigned x = 0; x < dst_width; x++) {
+					AssignPixel(dst_bits, src_bits, bytespp);
+					src_bits -= src_pitch;
+					dst_bits += bytespp;
+				}
+			}
+		}
+		break;
+	}
+
+	return dst;
+}
+
+/**
+Rotates an image by a given degree in range [-45 .. +45] (counter clockwise) 
+using the 3-shear technique.
+@param src Pointer to source image to rotate
+@param dAngle Rotation angle
+@return Returns a pointer to a newly allocated rotated image if successful, returns NULL otherwise
+*/
+static FIBITMAP* 
+Rotate45(FIBITMAP *src, double dAngle, const void *bkcolor) {
+	const double ROTATE_PI = double(3.1415926535897932384626433832795);
+
+	unsigned u;
+
+	const unsigned bpp = FreeImage_GetBPP(src);
+
+	const double dRadAngle = dAngle * ROTATE_PI / double(180); // Angle in radians
+	const double dSinE = sin(dRadAngle);
+	const double dTan = tan(dRadAngle / 2);
+
+	const unsigned src_width  = FreeImage_GetWidth(src);
+	const unsigned src_height = FreeImage_GetHeight(src);
+
+	FREE_IMAGE_TYPE image_type = FreeImage_GetImageType(src);
+
+	// Calc first shear (horizontal) destination image dimensions 
+	const unsigned width_1  = src_width + unsigned((double)src_height * fabs(dTan) + 0.5);
+	const unsigned height_1 = src_height; 
+
+	// Perform 1st shear (horizontal)
+	// ----------------------------------------------------------------------
+
+	// Allocate image for 1st shear
+	FIBITMAP *dst1 = FreeImage_AllocateT(image_type, width_1, height_1, bpp);
+	if(NULL == dst1) {
+		return NULL;
+	}
+	
+	for(u = 0; u < height_1; u++) {  
+		double dShear;
+
+		if(dTan >= 0)	{
+			// Positive angle
+			dShear = (u + 0.5) * dTan;
+		}
+		else {
+			// Negative angle
+			dShear = (double(u) - height_1 + 0.5) * dTan;
+		}
+		int iShear = int(floor(dShear));
+		HorizontalSkew(src, dst1, u, iShear, dShear - double(iShear), bkcolor);
+	}
+
+	// Perform 2nd shear  (vertical)
+	// ----------------------------------------------------------------------
+
+	// Calc 2nd shear (vertical) destination image dimensions
+	const unsigned width_2  = width_1;
+	unsigned height_2 = unsigned((double)src_width * fabs(dSinE) + (double)src_height * cos(dRadAngle) + 0.5) + 1;
+
+	// Allocate image for 2nd shear
+	FIBITMAP *dst2 = FreeImage_AllocateT(image_type, width_2, height_2, bpp);
+	if(NULL == dst2) {
+		FreeImage_Unload(dst1);
+		return NULL;
+	}
+
+	double dOffset;     // Variable skew offset
+	if(dSinE > 0)	{   
+		// Positive angle
+		dOffset = (src_width - 1.0) * dSinE;
+	}
+	else {
+		// Negative angle
+		dOffset = -dSinE * (double(src_width) - width_2);
+	}
+
+	for(u = 0; u < width_2; u++, dOffset -= dSinE) {
+		int iShear = int(floor(dOffset));
+		VerticalSkew(dst1, dst2, u, iShear, dOffset - double(iShear), bkcolor);
+	}
+
+	// Perform 3rd shear (horizontal)
+	// ----------------------------------------------------------------------
+
+	// Free result of 1st shear
+	FreeImage_Unload(dst1);
+
+	// Calc 3rd shear (horizontal) destination image dimensions
+	const unsigned width_3  = unsigned(double(src_height) * fabs(dSinE) + double(src_width) * cos(dRadAngle) + 0.5) + 1;
+	const unsigned height_3 = height_2;
+
+	// Allocate image for 3rd shear
+	FIBITMAP *dst3 = FreeImage_AllocateT(image_type, width_3, height_3, bpp);
+	if(NULL == dst3) {
+		FreeImage_Unload(dst2);
+		return NULL;
+	}
+
+	if(dSinE >= 0) {
+		// Positive angle
+		dOffset = (src_width - 1.0) * dSinE * -dTan;
+	}
+	else {
+		// Negative angle
+		dOffset = dTan * ( (src_width - 1.0) * -dSinE + (1.0 - height_3));
+	}
+	for(u = 0; u < height_3; u++, dOffset += dTan) {
+		int iShear = int(floor(dOffset));
+		HorizontalSkew(dst2, dst3, u, iShear, dOffset - double(iShear), bkcolor);
+	}
+	// Free result of 2nd shear    
+	FreeImage_Unload(dst2);
+
+	// Return result of 3rd shear
+	return dst3;      
+}
+
+/**
+Rotates a 1-, 8-, 24- or 32-bit image by a given angle (given in degree). 
+Angle is unlimited, except for 1-bit images (limited to integer multiples of 90 degree). 
+3-shears technique is used.
+@param src Pointer to source image to rotate
+@param dAngle Rotation angle
+@return Returns a pointer to a newly allocated rotated image if successful, returns NULL otherwise
+*/
+static FIBITMAP* 
+RotateAny(FIBITMAP *src, double dAngle, const void *bkcolor) {
+	if(NULL == src) {
+		return NULL;
+	}
+
+	FIBITMAP *image = src;
+
+	while(dAngle >= 360) {
+		// Bring angle to range of (-INF .. 360)
+		dAngle -= 360;
+	}
+	while(dAngle < 0) {
+		// Bring angle to range of [0 .. 360) 
+		dAngle += 360;
+	}
+	if ((dAngle > 45) && (dAngle <= 135)) {
+		// Angle in (45 .. 135] 
+		// Rotate image by 90 degrees into temporary image,
+		// so it requires only an extra rotation angle 
+		// of -45 .. +45 to complete rotation.
+		image = Rotate90(src);
+		dAngle -= 90;
+	}
+	else if ((dAngle > 135) && (dAngle <= 225)) { 
+		// Angle in (135 .. 225] 
+		// Rotate image by 180 degrees into temporary image,
+		// so it requires only an extra rotation angle 
+		// of -45 .. +45 to complete rotation.
+		image = Rotate180(src);
+		dAngle -= 180;
+	}
+	else if ((dAngle > 225) && (dAngle <= 315)) { 
+		// Angle in (225 .. 315] 
+		// Rotate image by 270 degrees into temporary image,
+		// so it requires only an extra rotation angle 
+		// of -45 .. +45 to complete rotation.
+		image = Rotate270(src);
+		dAngle -= 270;
+	}
+
+	// If we got here, angle is in (-45 .. +45]
+
+	if(NULL == image)	{
+		// Failed to allocate middle image
+		return NULL;
+	}
+
+	if(0 == dAngle) {
+		if(image == src) {
+			// Nothing to do ...
+			return FreeImage_Clone(src);
+		} else {
+			// No more rotation needed
+			return image;
+		}
+	}
+	else {
+		// Perform last rotation
+		FIBITMAP *dst = Rotate45(image, dAngle, bkcolor);
+
+		if(src != image) {
+			// Middle image was required, free it now.
+			FreeImage_Unload(image);
+		}
+
+		return dst;
+	}
+}
+
+// ==========================================================
+
+FIBITMAP *DLL_CALLCONV 
+FreeImage_Rotate(FIBITMAP *dib, double angle, const void *bkcolor) {
+	if (!FreeImage_HasPixels(dib)) return NULL;
+
+	if(0 == angle) {
+		return FreeImage_Clone(dib);
+	}
+	// DIB are stored upside down ...
+	angle *= -1;
+
+	try {
+		unsigned bpp = FreeImage_GetBPP(dib);
+		FREE_IMAGE_TYPE image_type = FreeImage_GetImageType(dib);
+		
+		switch(image_type) {
+			case FIT_BITMAP:
+				if(bpp == 1) {
+					// only rotate for integer multiples of 90 degree
+					if(fmod(angle, 90) != 0)
+						return NULL;
+
+					// perform the rotation
+					FIBITMAP *dst = RotateAny(dib, angle, bkcolor);
+					if (!dst) throw(1);
+
+					// build a greyscale palette
+					RGBQUAD *dst_pal = FreeImage_GetPalette(dst);
+					if(FreeImage_GetColorType(dib) == FIC_MINISBLACK) {
+						dst_pal[0].rgbRed = dst_pal[0].rgbGreen = dst_pal[0].rgbBlue = 0;
+						dst_pal[1].rgbRed = dst_pal[1].rgbGreen = dst_pal[1].rgbBlue = 255;			
+					} else {
+						dst_pal[0].rgbRed = dst_pal[0].rgbGreen = dst_pal[0].rgbBlue = 255;
+						dst_pal[1].rgbRed = dst_pal[1].rgbGreen = dst_pal[1].rgbBlue = 0;			
+					}
+
+					// copy metadata from src to dst
+					FreeImage_CloneMetadata(dst, dib);
+
+					return dst;
+				}
+				else if ((bpp == 8) || (bpp == 24) || (bpp == 32)) {
+					FIBITMAP *dst = RotateAny(dib, angle, bkcolor);
+					if (!dst) throw(1);
+					
+					if(bpp == 8) {
+						// copy original palette to rotated bitmap
+						RGBQUAD *src_pal = FreeImage_GetPalette(dib);
+						RGBQUAD *dst_pal = FreeImage_GetPalette(dst);
+						memcpy(&dst_pal[0], &src_pal[0], 256 * sizeof(RGBQUAD));
+
+						// copy transparency table 
+						FreeImage_SetTransparencyTable(dst, FreeImage_GetTransparencyTable(dib), FreeImage_GetTransparencyCount(dib));
+
+						// copy background color 
+						RGBQUAD bkcolor; 
+						if ( FreeImage_GetBackgroundColor(dib, &bkcolor)) {
+							FreeImage_SetBackgroundColor(dst, &bkcolor); 
+						}
+
+					}
+
+					// copy metadata from src to dst
+					FreeImage_CloneMetadata(dst, dib);
+
+					return dst;
+				}
+				break;
+			case FIT_UINT16:
+			case FIT_RGB16:
+			case FIT_RGBA16:
+			case FIT_FLOAT:
+			case FIT_RGBF:
+			case FIT_RGBAF:
+			{
+				FIBITMAP *dst = RotateAny(dib, angle, bkcolor);
+				if (!dst) throw(1);
+
+				// copy metadata from src to dst
+				FreeImage_CloneMetadata(dst, dib);
+
+				return dst;
+			}
+			break;
+		}
+
+	} catch(int) {
+		return NULL;
+	}
+
+	return NULL;
+}
+