1/*
2 * Copyright 2010 Google Inc.
3 *
4 * Use of this source code is governed by a BSD-style license that can be
5 * found in the LICENSE file.
6 */
7
8#include "include/private/SkImageInfoPriv.h"
9#include "src/core/SkReadBuffer.h"
10#include "src/core/SkSafeMath.h"
11#include "src/core/SkWriteBuffer.h"
12
13int SkColorTypeBytesPerPixel(SkColorType ct) {
14 switch (ct) {
15 case kUnknown_SkColorType: return 0;
16 case kAlpha_8_SkColorType: return 1;
17 case kRGB_565_SkColorType: return 2;
18 case kARGB_4444_SkColorType: return 2;
19 case kRGBA_8888_SkColorType: return 4;
20 case kBGRA_8888_SkColorType: return 4;
21 case kRGB_888x_SkColorType: return 4;
22 case kRGBA_1010102_SkColorType: return 4;
23 case kRGB_101010x_SkColorType: return 4;
24 case kBGRA_1010102_SkColorType: return 4;
25 case kBGR_101010x_SkColorType: return 4;
26 case kGray_8_SkColorType: return 1;
27 case kRGBA_F16Norm_SkColorType: return 8;
28 case kRGBA_F16_SkColorType: return 8;
29 case kRGBA_F32_SkColorType: return 16;
30 case kR8G8_unorm_SkColorType: return 2;
31 case kA16_unorm_SkColorType: return 2;
32 case kR16G16_unorm_SkColorType: return 4;
33 case kA16_float_SkColorType: return 2;
34 case kR16G16_float_SkColorType: return 4;
35 case kR16G16B16A16_unorm_SkColorType: return 8;
36 }
37 SkUNREACHABLE;
38}
39
40bool SkColorTypeIsAlwaysOpaque(SkColorType ct) {
41 return !(SkColorTypeChannelFlags(ct) & kAlpha_SkColorChannelFlag);
42}
43
44///////////////////////////////////////////////////////////////////////////////////////////////////
45
46int SkColorInfo::bytesPerPixel() const { return SkColorTypeBytesPerPixel(fColorType); }
47
48int SkColorInfo::shiftPerPixel() const { return SkColorTypeShiftPerPixel(fColorType); }
49
50///////////////////////////////////////////////////////////////////////////////////////////////////
51
52size_t SkImageInfo::computeOffset(int x, int y, size_t rowBytes) const {
53 SkASSERT((unsigned)x < (unsigned)this->width());
54 SkASSERT((unsigned)y < (unsigned)this->height());
55 return SkColorTypeComputeOffset(this->colorType(), x, y, rowBytes);
56}
57
58size_t SkImageInfo::computeByteSize(size_t rowBytes) const {
59 if (0 == this->height()) {
60 return 0;
61 }
62 SkSafeMath safe;
63 size_t bytes = safe.add(safe.mul(safe.addInt(this->height(), -1), rowBytes),
64 safe.mul(this->width(), this->bytesPerPixel()));
65 return safe.ok() ? bytes : SIZE_MAX;
66}
67
68SkImageInfo SkImageInfo::MakeS32(int width, int height, SkAlphaType at) {
69 return SkImageInfo({width, height}, {kN32_SkColorType, at, SkColorSpace::MakeSRGB()});
70}
71
72#ifdef SK_DEBUG
73void SkImageInfo::validate() const {
74 SkASSERT(fDimensions.width() >= 0);
75 SkASSERT(fDimensions.height() >= 0);
76 SkASSERT(SkColorTypeIsValid(this->colorType()));
77 SkASSERT(SkAlphaTypeIsValid(this->alphaType()));
78}
79#endif
80
81bool SkColorTypeValidateAlphaType(SkColorType colorType, SkAlphaType alphaType,
82 SkAlphaType* canonical) {
83 switch (colorType) {
84 case kUnknown_SkColorType:
85 alphaType = kUnknown_SkAlphaType;
86 break;
87 case kAlpha_8_SkColorType: // fall-through
88 case kA16_unorm_SkColorType: // fall-through
89 case kA16_float_SkColorType:
90 if (kUnpremul_SkAlphaType == alphaType) {
91 alphaType = kPremul_SkAlphaType;
92 }
93 [[fallthrough]];
94 case kARGB_4444_SkColorType:
95 case kRGBA_8888_SkColorType:
96 case kBGRA_8888_SkColorType:
97 case kRGBA_1010102_SkColorType:
98 case kBGRA_1010102_SkColorType:
99 case kRGBA_F16Norm_SkColorType:
100 case kRGBA_F16_SkColorType:
101 case kRGBA_F32_SkColorType:
102 case kR16G16B16A16_unorm_SkColorType:
103 if (kUnknown_SkAlphaType == alphaType) {
104 return false;
105 }
106 break;
107 case kGray_8_SkColorType:
108 case kR8G8_unorm_SkColorType:
109 case kR16G16_unorm_SkColorType:
110 case kR16G16_float_SkColorType:
111 case kRGB_565_SkColorType:
112 case kRGB_888x_SkColorType:
113 case kRGB_101010x_SkColorType:
114 case kBGR_101010x_SkColorType:
115 alphaType = kOpaque_SkAlphaType;
116 break;
117 }
118 if (canonical) {
119 *canonical = alphaType;
120 }
121 return true;
122}
123
124///////////////////////////////////////////////////////////////////////////////////////////////////
125
126#include "src/image/SkReadPixelsRec.h"
127
128bool SkReadPixelsRec::trim(int srcWidth, int srcHeight) {
129 if (nullptr == fPixels || fRowBytes < fInfo.minRowBytes()) {
130 return false;
131 }
132 if (0 >= fInfo.width() || 0 >= fInfo.height()) {
133 return false;
134 }
135
136 int x = fX;
137 int y = fY;
138 SkIRect srcR = SkIRect::MakeXYWH(x, y, fInfo.width(), fInfo.height());
139 if (!srcR.intersect({0, 0, srcWidth, srcHeight})) {
140 return false;
141 }
142
143 // if x or y are negative, then we have to adjust pixels
144 if (x > 0) {
145 x = 0;
146 }
147 if (y > 0) {
148 y = 0;
149 }
150 // here x,y are either 0 or negative
151 // we negate and add them so UBSAN (pointer-overflow) doesn't get confused.
152 fPixels = ((char*)fPixels + -y*fRowBytes + -x*fInfo.bytesPerPixel());
153 // the intersect may have shrunk info's logical size
154 fInfo = fInfo.makeDimensions(srcR.size());
155 fX = srcR.x();
156 fY = srcR.y();
157
158 return true;
159}
160
161///////////////////////////////////////////////////////////////////////////////////////////////////
162
163#include "src/core/SkWritePixelsRec.h"
164
165bool SkWritePixelsRec::trim(int dstWidth, int dstHeight) {
166 if (nullptr == fPixels || fRowBytes < fInfo.minRowBytes()) {
167 return false;
168 }
169 if (0 >= fInfo.width() || 0 >= fInfo.height()) {
170 return false;
171 }
172
173 int x = fX;
174 int y = fY;
175 SkIRect dstR = SkIRect::MakeXYWH(x, y, fInfo.width(), fInfo.height());
176 if (!dstR.intersect({0, 0, dstWidth, dstHeight})) {
177 return false;
178 }
179
180 // if x or y are negative, then we have to adjust pixels
181 if (x > 0) {
182 x = 0;
183 }
184 if (y > 0) {
185 y = 0;
186 }
187 // here x,y are either 0 or negative
188 // we negate and add them so UBSAN (pointer-overflow) doesn't get confused.
189 fPixels = ((const char*)fPixels + -y*fRowBytes + -x*fInfo.bytesPerPixel());
190 // the intersect may have shrunk info's logical size
191 fInfo = fInfo.makeDimensions(dstR.size());
192 fX = dstR.x();
193 fY = dstR.y();
194
195 return true;
196}
197