1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
|
// ==========================================================
// Upsampling / downsampling classes
//
// Design and implementation by
// - Hervé Drolon (drolon@infonie.fr)
// - Detlev Vendt (detlev.vendt@brillit.de)
// - Carsten Klein (cklein05@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!
// ==========================================================
#ifndef _RESIZE_H_
#define _RESIZE_H_
#include "FreeImage.h"
#include "Utilities.h"
#include "Filters.h"
/**
Filter weights table.<br>
This class stores contribution information for an entire line (row or column).
*/
class CWeightsTable
{
/**
Sampled filter weight table.<br>
Contribution information for a single pixel
*/
typedef struct {
/// Normalized weights of neighboring pixels
double *Weights;
/// Bounds of source pixels window
unsigned Left, Right;
} Contribution;
private:
/// Row (or column) of contribution weights
Contribution *m_WeightTable;
/// Filter window size (of affecting source pixels)
unsigned m_WindowSize;
/// Length of line (no. of rows / cols)
unsigned m_LineLength;
public:
/**
Constructor<br>
Allocate and compute the weights table
@param pFilter Filter used for upsampling or downsampling
@param uDstSize Length (in pixels) of the destination line buffer
@param uSrcSize Length (in pixels) of the source line buffer
*/
CWeightsTable(CGenericFilter *pFilter, unsigned uDstSize, unsigned uSrcSize);
/**
Destructor<br>
Destroy the weights table
*/
~CWeightsTable();
/** Retrieve a filter weight, given source and destination positions
@param dst_pos Pixel position in destination line buffer
@param src_pos Pixel position in source line buffer
@return Returns the filter weight
*/
double getWeight(unsigned dst_pos, unsigned src_pos) {
return m_WeightTable[dst_pos].Weights[src_pos];
}
/** Retrieve left boundary of source line buffer
@param dst_pos Pixel position in destination line buffer
@return Returns the left boundary of source line buffer
*/
unsigned getLeftBoundary(unsigned dst_pos) {
return m_WeightTable[dst_pos].Left;
}
/** Retrieve right boundary of source line buffer
@param dst_pos Pixel position in destination line buffer
@return Returns the right boundary of source line buffer
*/
unsigned getRightBoundary(unsigned dst_pos) {
return m_WeightTable[dst_pos].Right;
}
};
// ---------------------------------------------
/**
CResizeEngine<br>
This class performs filtered zoom. It scales an image to the desired dimensions with
any of the CGenericFilter derived filter class.<br>
It works with FIT_BITMAP buffers, WORD buffers (FIT_UINT16, FIT_RGB16, FIT_RGBA16)
and float buffers (FIT_FLOAT, FIT_RGBF, FIT_RGBAF).<br><br>
<b>References</b> : <br>
[1] Paul Heckbert, C code to zoom raster images up or down, with nice filtering.
UC Berkeley, August 1989. [online] http://www-2.cs.cmu.edu/afs/cs.cmu.edu/Web/People/ph/heckbert.html
[2] Eran Yariv, Two Pass Scaling using Filters. The Code Project, December 1999.
[online] http://www.codeproject.com/bitmap/2_pass_scaling.asp
*/
class CResizeEngine
{
private:
/// Pointer to the FIR / IIR filter
CGenericFilter* m_pFilter;
public:
/**
Constructor
@param filter FIR /IIR filter to be used
*/
CResizeEngine(CGenericFilter* filter):m_pFilter(filter) {}
/// Destructor
virtual ~CResizeEngine() {}
/** Scale an image to the desired dimensions.
Method CResizeEngine::scale, as well as the two filtering methods
CResizeEngine::horizontalFilter and CResizeEngine::verticalFilter take
four additional parameters, that define a rectangle in the source
image to be rescaled.
These are src_left, src_top, src_width and src_height and should work
like these of function FreeImage_Copy. However, src_left and src_top are
actually named src_offset_x and src_offset_y in the filtering methods.
Additionally, since src_height and dst_height are always the same for
method horizontalFilter as src_width and dst_width are always the same
for verticalFilter, these have been stripped down to a single parameter
height and width for horizontalFilter and verticalFilter respectively.
Currently, method scale is called with the actual size of the source
image. However, in a future version, we could provide a new function
called FreeImage_RescaleRect that rescales only part of an image.
@param src Pointer to the source image
@param dst_width Destination image width
@param dst_height Destination image height
@param src_left Left boundary of the source rectangle to be scaled
@param src_top Top boundary of the source rectangle to be scaled
@param src_width Width of the source rectangle to be scaled
@param src_height Height of the source rectangle to be scaled
@return Returns the scaled image if successful, returns NULL otherwise
*/
FIBITMAP* scale(FIBITMAP *src, unsigned dst_width, unsigned dst_height, unsigned src_left, unsigned src_top, unsigned src_width, unsigned src_height);
private:
/**
Performs horizontal image filtering
@param src Source image
@param height Source / Destination image height
@param src_width Source image width
@param src_offset_x
@param src_offset_y
@param src_pal
@param dst Destination image
@param dst_width Destination image width
*/
void horizontalFilter(FIBITMAP * const src, const unsigned height, const unsigned src_width,
const unsigned src_offset_x, const unsigned src_offset_y, const RGBQUAD * const src_pal,
FIBITMAP * const dst, const unsigned dst_width);
/**
Performs vertical image filtering
@param src Source image
@param width Source / Destination image width
@param src_height Source image height
@param src_offset_x
@param src_offset_y
@param src_pal
@param dst Destination image
@param dst_height Destination image height
*/
void verticalFilter(FIBITMAP * const src, const unsigned width, const unsigned src_height,
const unsigned src_offset_x, const unsigned src_offset_y, const RGBQUAD * const src_pal,
FIBITMAP * const dst, const unsigned dst_height);
};
#endif // _RESIZE_H_
|
