VirtualBox

source: vbox/trunk/src/VBox/GuestHost/OpenGL/util/bmpscale.cpp@ 76553

Last change on this file since 76553 was 76553, checked in by vboxsync, 6 years ago

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File size: 9.9 KB
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1/** @file
2 * Image resampling code, used for snapshot thumbnails.
3 */
4
5/*
6 * Copyright (C) 2009-2019 Oracle Corporation
7 *
8 * This file is part of VirtualBox Open Source Edition (OSE), as
9 * available from http://www.virtualbox.org. This file is free software;
10 * you can redistribute it and/or modify it under the terms of the GNU
11 * General Public License (GPL) as published by the Free Software
12 * Foundation, in version 2 as it comes in the "COPYING" file of the
13 * VirtualBox OSE distribution. VirtualBox OSE is distributed in the
14 * hope that it will be useful, but WITHOUT ANY WARRANTY of any kind.
15 */
16
17/*
18 * Based on gdImageCopyResampled from libgd.
19 * Original copyright notice follows:
20
21 Portions copyright 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007
22 Pierre-Alain Joye (pierre@libgd.org).
23
24 Permission has been granted to copy, distribute and modify gd in
25 any context without fee, including a commercial application,
26 provided that this notice is present in user-accessible supporting
27 documentation.
28
29 This does not affect your ownership of the derived work itself, and
30 the intent is to assure proper credit for the authors of gd, not to
31 interfere with your productive use of gd. If you have questions,
32 ask. "Derived works" includes all programs that utilize the
33 library. Credit must be given in user-accessible documentation.
34
35 This software is provided "AS IS." The copyright holders disclaim
36 all warranties, either express or implied, including but not
37 limited to implied warranties of merchantability and fitness for a
38 particular purpose, with respect to this code and accompanying
39 documentation.
40 */
41
42/*
43 *
44 * @todo Simplify: Offsets of images are 0,0 => no dstX, dstY, srcX, srcY;
45 * Screenshot has no alpha channel => no processing of alpha byte.
46 */
47
48#include <cr_bmpscale.h>
49
50/* 2.0.10: cast instead of floor() yields 35% performance improvement.
51 Thanks to John Buckman. */
52
53#define floor2(exp) ((long) exp)
54/*#define floor2(exp) floor(exp)*/
55
56typedef uint8_t *gdImagePtr;
57
58DECLINLINE(int) gdImageGetTrueColorPixel (gdImagePtr im, int x, int y, int w)
59{
60 return *(int32_t *)(im + y * w * 4 + x * 4);
61}
62
63DECLINLINE(void) gdImageSetPixel (gdImagePtr im, int x, int y, int color, int cbLine)
64{
65 *(int32_t *)(im + y * cbLine + x * 4) = color;
66}
67
68#define gdAlphaMax 127
69#define gdAlphaOpaque 0
70#define gdAlphaTransparent 127
71#define gdRedMax 255
72#define gdGreenMax 255
73#define gdBlueMax 255
74#define gdTrueColorGetAlpha(c) (((c) & 0x7F000000) >> 24)
75#define gdTrueColorGetRed(c) (((c) & 0xFF0000) >> 16)
76#define gdTrueColorGetGreen(c) (((c) & 0x00FF00) >> 8)
77#define gdTrueColorGetBlue(c) ((c) & 0x0000FF)
78#define gdTrueColorAlpha(r, g, b, a) (((a) << 24) + \
79 ((r) << 16) + \
80 ((g) << 8) + \
81 (b))
82
83void gdImageCopyResampled (uint8_t *dst,
84 uint8_t *src,
85 int dstX, int dstY,
86 int srcX, int srcY,
87 int dstW, int dstH, int srcW, int srcH)
88{
89 int x, y;
90 double sy1, sy2, sx1, sx2;
91 for (y = dstY; (y < dstY + dstH); y++)
92 {
93 sy1 = ((double) y - (double) dstY) * (double) srcH / (double) dstH;
94 sy2 = ((double) (y + 1) - (double) dstY) * (double) srcH /
95 (double) dstH;
96 for (x = dstX; (x < dstX + dstW); x++)
97 {
98 double sx, sy;
99 double spixels = 0;
100 double red = 0.0, green = 0.0, blue = 0.0, alpha = 0.0;
101 sx1 = ((double) x - (double) dstX) * (double) srcW / dstW;
102 sx2 = ((double) (x + 1) - (double) dstX) * (double) srcW / dstW;
103 sy = sy1;
104 do
105 {
106 double yportion;
107 if (floor2 (sy) == floor2 (sy1))
108 {
109 yportion = 1.0 - (sy - floor2 (sy));
110 if (yportion > sy2 - sy1)
111 {
112 yportion = sy2 - sy1;
113 }
114 sy = floor2 (sy);
115 }
116 else if (sy == floor2 (sy2))
117 {
118 yportion = sy2 - floor2 (sy2);
119 }
120 else
121 {
122 yportion = 1.0;
123 }
124 sx = sx1;
125 do
126 {
127 double xportion;
128 double pcontribution;
129 int p;
130 if (floor2 (sx) == floor2 (sx1))
131 {
132 xportion = 1.0 - (sx - floor2 (sx));
133 if (xportion > sx2 - sx1)
134 {
135 xportion = sx2 - sx1;
136 }
137 sx = floor2 (sx);
138 }
139 else if (sx == floor2 (sx2))
140 {
141 xportion = sx2 - floor2 (sx2);
142 }
143 else
144 {
145 xportion = 1.0;
146 }
147 pcontribution = xportion * yportion;
148 /* 2.08: previously srcX and srcY were ignored.
149 Andrew Pattison */
150 p = gdImageGetTrueColorPixel (src,
151 (int) sx + srcX,
152 (int) sy + srcY, srcW);
153 red += gdTrueColorGetRed (p) * pcontribution;
154 green += gdTrueColorGetGreen (p) * pcontribution;
155 blue += gdTrueColorGetBlue (p) * pcontribution;
156 alpha += gdTrueColorGetAlpha (p) * pcontribution;
157 spixels += xportion * yportion;
158 sx += 1.0;
159 }
160 while (sx < sx2);
161 sy += 1.0;
162 }
163 while (sy < sy2);
164 if (spixels != 0.0)
165 {
166 red /= spixels;
167 green /= spixels;
168 blue /= spixels;
169 alpha /= spixels;
170 }
171 /* Clamping to allow for rounding errors above */
172 if (red > 255.0)
173 {
174 red = 255.0;
175 }
176 if (green > 255.0)
177 {
178 green = 255.0;
179 }
180 if (blue > 255.0)
181 {
182 blue = 255.0;
183 }
184 if (alpha > gdAlphaMax)
185 {
186 alpha = gdAlphaMax;
187 }
188 gdImageSetPixel (dst,
189 x, y,
190 gdTrueColorAlpha ((int) red,
191 (int) green,
192 (int) blue, (int) alpha), dstW * 4);
193 }
194 }
195}
196
197/* Fast integer implementation for 32 bpp bitmap scaling.
198 * Use fixed point values * 16.
199 */
200typedef int32_t FIXEDPOINT;
201#define INT_TO_FIXEDPOINT(i) (FIXEDPOINT)((i) << 4)
202#define FIXEDPOINT_TO_INT(v) (int)((v) >> 4)
203#define FIXEDPOINT_FLOOR(v) ((v) & ~0xF)
204#define FIXEDPOINT_FRACTION(v) ((v) & 0xF)
205
206/* For 32 bit source only. */
207VBOXBMPSCALEDECL(void) CrBmpScale32 (uint8_t *dst,
208 int iDstDeltaLine,
209 int dstW, int dstH,
210 const uint8_t *src,
211 int iSrcDeltaLine,
212 int srcW, int srcH)
213{
214 int x, y;
215
216 for (y = 0; y < dstH; y++)
217 {
218 FIXEDPOINT sy1 = INT_TO_FIXEDPOINT(y * srcH) / dstH;
219 FIXEDPOINT sy2 = INT_TO_FIXEDPOINT((y + 1) * srcH) / dstH;
220
221 for (x = 0; x < dstW; x++)
222 {
223 FIXEDPOINT red = 0, green = 0, blue = 0;
224
225 FIXEDPOINT sx1 = INT_TO_FIXEDPOINT(x * srcW) / dstW;
226 FIXEDPOINT sx2 = INT_TO_FIXEDPOINT((x + 1) * srcW) / dstW;
227
228 FIXEDPOINT spixels = (sx2 - sx1) * (sy2 - sy1);
229
230 FIXEDPOINT sy = sy1;
231
232 do
233 {
234 FIXEDPOINT yportion;
235 if (FIXEDPOINT_FLOOR (sy) == FIXEDPOINT_FLOOR (sy1))
236 {
237 yportion = INT_TO_FIXEDPOINT(1) - FIXEDPOINT_FRACTION(sy);
238 if (yportion > sy2 - sy1)
239 {
240 yportion = sy2 - sy1;
241 }
242 sy = FIXEDPOINT_FLOOR (sy);
243 }
244 else if (sy == FIXEDPOINT_FLOOR (sy2))
245 {
246 yportion = FIXEDPOINT_FRACTION(sy2);
247 }
248 else
249 {
250 yportion = INT_TO_FIXEDPOINT(1);
251 }
252
253 const uint8_t *pu8SrcLine = src + iSrcDeltaLine * FIXEDPOINT_TO_INT(sy);
254 FIXEDPOINT sx = sx1;
255 do
256 {
257 FIXEDPOINT xportion;
258 FIXEDPOINT pcontribution;
259 int p;
260 if (FIXEDPOINT_FLOOR (sx) == FIXEDPOINT_FLOOR (sx1))
261 {
262 xportion = INT_TO_FIXEDPOINT(1) - FIXEDPOINT_FRACTION(sx);
263 if (xportion > sx2 - sx1)
264 {
265 xportion = sx2 - sx1;
266 }
267 pcontribution = xportion * yportion;
268 sx = FIXEDPOINT_FLOOR (sx);
269 }
270 else if (sx == FIXEDPOINT_FLOOR (sx2))
271 {
272 xportion = FIXEDPOINT_FRACTION(sx2);
273 pcontribution = xportion * yportion;
274 }
275 else
276 {
277 xportion = INT_TO_FIXEDPOINT(1);
278 pcontribution = xportion * yportion;
279 }
280 /* Color depth specific code begin */
281 p = *(uint32_t *)(pu8SrcLine + FIXEDPOINT_TO_INT(sx) * 4);
282 /* Color depth specific code end */
283 red += gdTrueColorGetRed (p) * pcontribution;
284 green += gdTrueColorGetGreen (p) * pcontribution;
285 blue += gdTrueColorGetBlue (p) * pcontribution;
286
287 sx += INT_TO_FIXEDPOINT(1);
288 } while (sx < sx2);
289
290 sy += INT_TO_FIXEDPOINT(1);
291 } while (sy < sy2);
292
293 if (spixels != 0)
294 {
295 red /= spixels;
296 green /= spixels;
297 blue /= spixels;
298 }
299 /* Clamping to allow for rounding errors above */
300 if (red > 255)
301 {
302 red = 255;
303 }
304 if (green > 255)
305 {
306 green = 255;
307 }
308 if (blue > 255)
309 {
310 blue = 255;
311 }
312 gdImageSetPixel (dst,
313 x, y,
314 ( ((int) red) << 16) + (((int) green) << 8) + ((int) blue),
315 iDstDeltaLine);
316 }
317 }
318}
319
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