1 | /* $Id: DisplayResampleImage.cpp 63486 2016-08-15 14:57:55Z vboxsync $ */
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2 | /** @file
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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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6 | /*
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7 | * Copyright (C) 2009-2016 Oracle Corporation
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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 |
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18 | #include <iprt/types.h>
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19 |
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20 | DECLINLINE(void) imageSetPixel (uint8_t *im, int x, int y, int color, int w)
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21 | {
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22 | *(int32_t *)(im + y * w * 4 + x * 4) = color;
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23 | }
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24 |
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25 | #define trueColorGetAlpha(c) (((c) & 0x7F000000) >> 24)
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26 | #define trueColorGetRed(c) (((c) & 0xFF0000) >> 16)
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27 | #define trueColorGetGreen(c) (((c) & 0x00FF00) >> 8)
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28 | #define trueColorGetBlue(c) ((c) & 0x0000FF)
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29 |
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30 | /* Fast integer implementation for 32 bpp bitmap scaling.
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31 | * Using fixed point values * 16.
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32 | */
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33 | typedef int32_t FIXEDPOINT;
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34 | #define INT_TO_FIXEDPOINT(i) (FIXEDPOINT)((i) << 4)
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35 | #define FIXEDPOINT_TO_INT(v) (int)((v) >> 4)
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36 | #define FIXEDPOINT_FLOOR(v) ((v) & ~0xF)
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37 | #define FIXEDPOINT_FRACTION(v) ((v) & 0xF)
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38 |
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39 | /* For 32 bit source only. */
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40 | void BitmapScale32 (uint8_t *dst,
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41 | int dstW, int dstH,
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42 | const uint8_t *src,
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43 | int iDeltaLine,
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44 | int srcW, int srcH)
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45 | {
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46 | int x, y;
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47 |
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48 | for (y = 0; y < dstH; y++)
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49 | {
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50 | FIXEDPOINT sy1 = INT_TO_FIXEDPOINT(y * srcH) / dstH;
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51 | FIXEDPOINT sy2 = INT_TO_FIXEDPOINT((y + 1) * srcH) / dstH;
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52 |
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53 | for (x = 0; x < dstW; x++)
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54 | {
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55 | FIXEDPOINT red = 0, green = 0, blue = 0;
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56 |
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57 | FIXEDPOINT sx1 = INT_TO_FIXEDPOINT(x * srcW) / dstW;
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58 | FIXEDPOINT sx2 = INT_TO_FIXEDPOINT((x + 1) * srcW) / dstW;
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59 |
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60 | FIXEDPOINT spixels = (sx2 - sx1) * (sy2 - sy1);
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61 |
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62 | FIXEDPOINT sy = sy1;
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63 |
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64 | do
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65 | {
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66 | FIXEDPOINT yportion;
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67 | if (FIXEDPOINT_FLOOR (sy) == FIXEDPOINT_FLOOR (sy1))
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68 | {
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69 | yportion = INT_TO_FIXEDPOINT(1) - FIXEDPOINT_FRACTION(sy);
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70 | if (yportion > sy2 - sy1)
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71 | {
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72 | yportion = sy2 - sy1;
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73 | }
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74 | sy = FIXEDPOINT_FLOOR (sy);
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75 | }
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76 | else if (sy == FIXEDPOINT_FLOOR (sy2))
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77 | {
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78 | yportion = FIXEDPOINT_FRACTION(sy2);
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79 | }
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80 | else
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81 | {
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82 | yportion = INT_TO_FIXEDPOINT(1);
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83 | }
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84 |
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85 | const uint8_t *pu8SrcLine = src + iDeltaLine * FIXEDPOINT_TO_INT(sy);
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86 | FIXEDPOINT sx = sx1;
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87 | do
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88 | {
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89 | FIXEDPOINT xportion;
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90 | FIXEDPOINT pcontribution;
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91 | int p;
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92 | if (FIXEDPOINT_FLOOR (sx) == FIXEDPOINT_FLOOR (sx1))
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93 | {
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94 | xportion = INT_TO_FIXEDPOINT(1) - FIXEDPOINT_FRACTION(sx);
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95 | if (xportion > sx2 - sx1)
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96 | {
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97 | xportion = sx2 - sx1;
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98 | }
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99 | pcontribution = xportion * yportion;
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100 | sx = FIXEDPOINT_FLOOR (sx);
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101 | }
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102 | else if (sx == FIXEDPOINT_FLOOR (sx2))
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103 | {
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104 | xportion = FIXEDPOINT_FRACTION(sx2);
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105 | pcontribution = xportion * yportion;
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106 | }
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107 | else
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108 | {
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109 | xportion = INT_TO_FIXEDPOINT(1);
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110 | pcontribution = xportion * yportion;
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111 | }
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112 | /* Color depth specific code begin */
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113 | p = *(uint32_t *)(pu8SrcLine + FIXEDPOINT_TO_INT(sx) * 4);
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114 | /* Color depth specific code end */
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115 | red += trueColorGetRed (p) * pcontribution;
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116 | green += trueColorGetGreen (p) * pcontribution;
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117 | blue += trueColorGetBlue (p) * pcontribution;
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118 |
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119 | sx += INT_TO_FIXEDPOINT(1);
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120 | } while (sx < sx2);
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121 |
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122 | sy += INT_TO_FIXEDPOINT(1);
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123 | } while (sy < sy2);
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124 |
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125 | if (spixels != 0)
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126 | {
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127 | red /= spixels;
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128 | green /= spixels;
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129 | blue /= spixels;
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130 | }
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131 | /* Clamping to allow for rounding errors above */
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132 | if (red > 255)
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133 | {
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134 | red = 255;
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135 | }
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136 | if (green > 255)
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137 | {
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138 | green = 255;
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139 | }
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140 | if (blue > 255)
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141 | {
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142 | blue = 255;
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143 | }
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144 | imageSetPixel (dst,
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145 | x, y,
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146 | ( ((int) red) << 16) + (((int) green) << 8) + ((int) blue),
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147 | dstW);
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148 | }
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149 | }
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150 | }
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