1 2 /* 3 * Copyright 2012 The Android Open Source Project 4 * 5 * Use of this source code is governed by a BSD-style license that can be 6 * found in the LICENSE file. 7 */ 8 9 /** 10 * Functions to transform scanlines between packed-pixel formats. 11 */ 12 13 #include "SkBitmap.h" 14 #include "SkColor.h" 15 #include "SkColorPriv.h" 16 #include "SkPreConfig.h" 17 #include "SkUnPreMultiply.h" 18 19 /** 20 * Function template for transforming scanlines. 21 * Transform 'width' pixels from 'src' buffer into 'dst' buffer, 22 * repacking color channel data as appropriate for the given transformation. 23 */ 24 typedef void (*transform_scanline_proc)(const char* SK_RESTRICT src, 25 int width, char* SK_RESTRICT dst); 26 27 /** 28 * Identity transformation: just copy bytes from src to dst. 29 */ 30 static void transform_scanline_memcpy(const char* SK_RESTRICT src, int width, 31 char* SK_RESTRICT dst) { 32 memcpy(dst, src, width); 33 } 34 35 /** 36 * Transform from kRGB_565_Config to 3-bytes-per-pixel RGB. 37 * Alpha channel data is not present in kRGB_565_Config format, so there is no 38 * alpha channel data to preserve. 39 */ 40 static void transform_scanline_565(const char* SK_RESTRICT src, int width, 41 char* SK_RESTRICT dst) { 42 const uint16_t* SK_RESTRICT srcP = (const uint16_t*)src; 43 for (int i = 0; i < width; i++) { 44 unsigned c = *srcP++; 45 *dst++ = SkPacked16ToR32(c); 46 *dst++ = SkPacked16ToG32(c); 47 *dst++ = SkPacked16ToB32(c); 48 } 49 } 50 51 /** 52 * Transform from kARGB_8888_Config to 3-bytes-per-pixel RGB. 53 * Alpha channel data, if any, is abandoned. 54 */ 55 static void transform_scanline_888(const char* SK_RESTRICT src, int width, 56 char* SK_RESTRICT dst) { 57 const SkPMColor* SK_RESTRICT srcP = (const SkPMColor*)src; 58 for (int i = 0; i < width; i++) { 59 SkPMColor c = *srcP++; 60 *dst++ = SkGetPackedR32(c); 61 *dst++ = SkGetPackedG32(c); 62 *dst++ = SkGetPackedB32(c); 63 } 64 } 65 66 /** 67 * Transform from kARGB_4444_Config to 3-bytes-per-pixel RGB. 68 * Alpha channel data, if any, is abandoned. 69 */ 70 static void transform_scanline_444(const char* SK_RESTRICT src, int width, 71 char* SK_RESTRICT dst) { 72 const SkPMColor16* SK_RESTRICT srcP = (const SkPMColor16*)src; 73 for (int i = 0; i < width; i++) { 74 SkPMColor16 c = *srcP++; 75 *dst++ = SkPacked4444ToR32(c); 76 *dst++ = SkPacked4444ToG32(c); 77 *dst++ = SkPacked4444ToB32(c); 78 } 79 } 80 81 /** 82 * Transform from kARGB_8888_Config to 4-bytes-per-pixel RGBA. 83 * (This would be the identity transformation, except for byte-order and 84 * scaling of RGB based on alpha channel). 85 */ 86 static void transform_scanline_8888(const char* SK_RESTRICT src, int width, 87 char* SK_RESTRICT dst) { 88 const SkPMColor* SK_RESTRICT srcP = (const SkPMColor*)src; 89 const SkUnPreMultiply::Scale* SK_RESTRICT table = 90 SkUnPreMultiply::GetScaleTable(); 91 92 for (int i = 0; i < width; i++) { 93 SkPMColor c = *srcP++; 94 unsigned a = SkGetPackedA32(c); 95 unsigned r = SkGetPackedR32(c); 96 unsigned g = SkGetPackedG32(c); 97 unsigned b = SkGetPackedB32(c); 98 99 if (0 != a && 255 != a) { 100 SkUnPreMultiply::Scale scale = table[a]; 101 r = SkUnPreMultiply::ApplyScale(scale, r); 102 g = SkUnPreMultiply::ApplyScale(scale, g); 103 b = SkUnPreMultiply::ApplyScale(scale, b); 104 } 105 *dst++ = r; 106 *dst++ = g; 107 *dst++ = b; 108 *dst++ = a; 109 } 110 } 111 112 /** 113 * Transform from kARGB_8888_Config to 4-bytes-per-pixel RGBA, 114 * with scaling of RGB based on alpha channel. 115 */ 116 static void transform_scanline_4444(const char* SK_RESTRICT src, int width, 117 char* SK_RESTRICT dst) { 118 const SkPMColor16* SK_RESTRICT srcP = (const SkPMColor16*)src; 119 const SkUnPreMultiply::Scale* SK_RESTRICT table = 120 SkUnPreMultiply::GetScaleTable(); 121 122 for (int i = 0; i < width; i++) { 123 SkPMColor16 c = *srcP++; 124 unsigned a = SkPacked4444ToA32(c); 125 unsigned r = SkPacked4444ToR32(c); 126 unsigned g = SkPacked4444ToG32(c); 127 unsigned b = SkPacked4444ToB32(c); 128 129 if (0 != a && 255 != a) { 130 SkUnPreMultiply::Scale scale = table[a]; 131 r = SkUnPreMultiply::ApplyScale(scale, r); 132 g = SkUnPreMultiply::ApplyScale(scale, g); 133 b = SkUnPreMultiply::ApplyScale(scale, b); 134 } 135 *dst++ = r; 136 *dst++ = g; 137 *dst++ = b; 138 *dst++ = a; 139 } 140 } 141
