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 */
transform_scanline_memcpy(const char * SK_RESTRICT src,int width,char * SK_RESTRICT dst)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 */
transform_scanline_565(const char * SK_RESTRICT src,int width,char * SK_RESTRICT dst)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 */
transform_scanline_888(const char * SK_RESTRICT src,int width,char * SK_RESTRICT dst)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 */
transform_scanline_444(const char * SK_RESTRICT src,int width,char * SK_RESTRICT dst)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 */
transform_scanline_8888(const char * SK_RESTRICT src,int width,char * SK_RESTRICT dst)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 */
transform_scanline_4444(const char * SK_RESTRICT src,int width,char * SK_RESTRICT dst)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