[24942] | 1 | /** @file
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| 2 | *
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| 3 | * Image resampling code, used for snapshot thumbnails.
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| 4 | */
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| 5 |
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[24373] | 6 | /*
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[24942] | 7 | * Copyright (C) 2009 Sun Microsystems, Inc.
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| 8 | *
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| 9 | * This file is part of VirtualBox Open Source Edition (OSE), as
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| 10 | * available from http://www.virtualbox.org. This file is free software;
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| 11 | * you can redistribute it and/or modify it under the terms of the GNU
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| 12 | * General Public License (GPL) as published by the Free Software
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| 13 | * Foundation, in version 2 as it comes in the "COPYING" file of the
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| 14 | * VirtualBox OSE distribution. VirtualBox OSE is distributed in the
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| 15 | * hope that it will be useful, but WITHOUT ANY WARRANTY of any kind.
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| 16 | *
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| 17 | * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa
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| 18 | * Clara, CA 95054 USA or visit http://www.sun.com if you need
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| 19 | * additional information or have any questions.
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| 20 | */
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| 21 |
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| 22 | /*
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[24373] | 23 | * Based on gdImageCopyResampled from libgd.
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[24942] | 24 | * Original copyright notice follows:
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[24373] | 25 |
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| 26 | Portions copyright 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007
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[24942] | 27 | Pierre-Alain Joye (pierre@libgd.org).
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[24373] | 28 |
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| 29 | Permission has been granted to copy, distribute and modify gd in
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| 30 | any context without fee, including a commercial application,
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| 31 | provided that this notice is present in user-accessible supporting
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| 32 | documentation.
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| 33 |
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[24942] | 34 | This does not affect your ownership of the derived work itself, and
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[24373] | 35 | the intent is to assure proper credit for the authors of gd, not to
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| 36 | interfere with your productive use of gd. If you have questions,
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[24942] | 37 | ask. "Derived works" includes all programs that utilize the
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[24373] | 38 | library. Credit must be given in user-accessible documentation.
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| 39 |
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[24942] | 40 | This software is provided "AS IS." The copyright holders disclaim
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[24373] | 41 | all warranties, either express or implied, including but not
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| 42 | limited to implied warranties of merchantability and fitness for a
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[24942] | 43 | particular purpose, with respect to this code and accompanying
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[24373] | 44 | documentation.
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| 45 | */
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| 46 |
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| 47 | /*
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| 48 | *
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| 49 | * @todo Simplify: Offsets of images are 0,0 => no dstX, dstY, srcX, srcY;
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| 50 | * Screenshot has no alpha channel => no processing of alpha byte.
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| 51 | */
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| 52 |
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| 53 | #include <iprt/types.h>
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| 54 |
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[24942] | 55 | /* 2.0.10: cast instead of floor() yields 35% performance improvement.
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[24373] | 56 | Thanks to John Buckman. */
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| 57 |
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| 58 | #define floor2(exp) ((long) exp)
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| 59 | /*#define floor2(exp) floor(exp)*/
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| 60 |
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| 61 | typedef uint8_t *gdImagePtr;
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| 62 |
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| 63 | DECLINLINE(int) gdImageGetTrueColorPixel (gdImagePtr im, int x, int y, int w)
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| 64 | {
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| 65 | return *(int32_t *)(im + y * w * 4 + x * 4);
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| 66 | }
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| 67 |
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| 68 | DECLINLINE(void) gdImageSetPixel (gdImagePtr im, int x, int y, int color, int w)
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| 69 | {
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| 70 | *(int32_t *)(im + y * w * 4 + x * 4) = color;
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| 71 | }
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| 72 |
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| 73 | #define gdAlphaMax 127
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| 74 | #define gdAlphaOpaque 0
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| 75 | #define gdAlphaTransparent 127
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| 76 | #define gdRedMax 255
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| 77 | #define gdGreenMax 255
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| 78 | #define gdBlueMax 255
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| 79 | #define gdTrueColorGetAlpha(c) (((c) & 0x7F000000) >> 24)
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| 80 | #define gdTrueColorGetRed(c) (((c) & 0xFF0000) >> 16)
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| 81 | #define gdTrueColorGetGreen(c) (((c) & 0x00FF00) >> 8)
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| 82 | #define gdTrueColorGetBlue(c) ((c) & 0x0000FF)
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| 83 | #define gdTrueColorAlpha(r, g, b, a) (((a) << 24) + \
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| 84 | ((r) << 16) + \
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| 85 | ((g) << 8) + \
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| 86 | (b))
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| 87 |
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| 88 | void gdImageCopyResampled (uint8_t *dst,
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| 89 | uint8_t *src,
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| 90 | int dstX, int dstY,
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| 91 | int srcX, int srcY,
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| 92 | int dstW, int dstH, int srcW, int srcH)
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| 93 | {
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| 94 | int x, y;
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| 95 | double sy1, sy2, sx1, sx2;
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| 96 | for (y = dstY; (y < dstY + dstH); y++)
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| 97 | {
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| 98 | sy1 = ((double) y - (double) dstY) * (double) srcH / (double) dstH;
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| 99 | sy2 = ((double) (y + 1) - (double) dstY) * (double) srcH /
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| 100 | (double) dstH;
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| 101 | for (x = dstX; (x < dstX + dstW); x++)
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| 102 | {
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| 103 | double sx, sy;
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| 104 | double spixels = 0;
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| 105 | double red = 0.0, green = 0.0, blue = 0.0, alpha = 0.0;
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| 106 | sx1 = ((double) x - (double) dstX) * (double) srcW / dstW;
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| 107 | sx2 = ((double) (x + 1) - (double) dstX) * (double) srcW / dstW;
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| 108 | sy = sy1;
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| 109 | do
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| 110 | {
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| 111 | double yportion;
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| 112 | if (floor2 (sy) == floor2 (sy1))
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| 113 | {
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| 114 | yportion = 1.0 - (sy - floor2 (sy));
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| 115 | if (yportion > sy2 - sy1)
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| 116 | {
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| 117 | yportion = sy2 - sy1;
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| 118 | }
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| 119 | sy = floor2 (sy);
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| 120 | }
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| 121 | else if (sy == floor2 (sy2))
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| 122 | {
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| 123 | yportion = sy2 - floor2 (sy2);
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| 124 | }
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| 125 | else
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| 126 | {
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| 127 | yportion = 1.0;
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| 128 | }
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| 129 | sx = sx1;
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| 130 | do
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| 131 | {
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| 132 | double xportion;
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| 133 | double pcontribution;
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| 134 | int p;
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| 135 | if (floor2 (sx) == floor2 (sx1))
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| 136 | {
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| 137 | xportion = 1.0 - (sx - floor2 (sx));
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| 138 | if (xportion > sx2 - sx1)
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| 139 | {
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| 140 | xportion = sx2 - sx1;
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| 141 | }
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| 142 | sx = floor2 (sx);
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| 143 | }
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| 144 | else if (sx == floor2 (sx2))
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| 145 | {
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| 146 | xportion = sx2 - floor2 (sx2);
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| 147 | }
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| 148 | else
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| 149 | {
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| 150 | xportion = 1.0;
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| 151 | }
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| 152 | pcontribution = xportion * yportion;
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[24942] | 153 | /* 2.08: previously srcX and srcY were ignored.
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[24373] | 154 | Andrew Pattison */
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| 155 | p = gdImageGetTrueColorPixel (src,
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| 156 | (int) sx + srcX,
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| 157 | (int) sy + srcY, srcW);
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| 158 | red += gdTrueColorGetRed (p) * pcontribution;
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| 159 | green += gdTrueColorGetGreen (p) * pcontribution;
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| 160 | blue += gdTrueColorGetBlue (p) * pcontribution;
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| 161 | alpha += gdTrueColorGetAlpha (p) * pcontribution;
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| 162 | spixels += xportion * yportion;
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| 163 | sx += 1.0;
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| 164 | }
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| 165 | while (sx < sx2);
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| 166 | sy += 1.0;
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| 167 | }
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| 168 | while (sy < sy2);
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| 169 | if (spixels != 0.0)
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| 170 | {
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| 171 | red /= spixels;
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| 172 | green /= spixels;
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| 173 | blue /= spixels;
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| 174 | alpha /= spixels;
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| 175 | }
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| 176 | /* Clamping to allow for rounding errors above */
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| 177 | if (red > 255.0)
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| 178 | {
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| 179 | red = 255.0;
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| 180 | }
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| 181 | if (green > 255.0)
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| 182 | {
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| 183 | green = 255.0;
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| 184 | }
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| 185 | if (blue > 255.0)
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| 186 | {
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| 187 | blue = 255.0;
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| 188 | }
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| 189 | if (alpha > gdAlphaMax)
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| 190 | {
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| 191 | alpha = gdAlphaMax;
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| 192 | }
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| 193 | gdImageSetPixel (dst,
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| 194 | x, y,
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| 195 | gdTrueColorAlpha ((int) red,
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| 196 | (int) green,
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| 197 | (int) blue, (int) alpha), dstW);
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| 198 | }
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| 199 | }
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| 200 | }
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