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
SkColorTypeBytesPerPixel(SkColorType ct)13 int 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 case kSRGBA_8888_SkColorType: return 4;
37 }
38 SkUNREACHABLE;
39 }
40
SkColorTypeIsAlwaysOpaque(SkColorType ct)41 bool SkColorTypeIsAlwaysOpaque(SkColorType ct) {
42 return !(SkColorTypeChannelFlags(ct) & kAlpha_SkColorChannelFlag);
43 }
44
45 ///////////////////////////////////////////////////////////////////////////////////////////////////
46
bytesPerPixel() const47 int SkColorInfo::bytesPerPixel() const { return SkColorTypeBytesPerPixel(fColorType); }
48
shiftPerPixel() const49 int SkColorInfo::shiftPerPixel() const { return SkColorTypeShiftPerPixel(fColorType); }
50
51 ///////////////////////////////////////////////////////////////////////////////////////////////////
52
computeOffset(int x,int y,size_t rowBytes) const53 size_t SkImageInfo::computeOffset(int x, int y, size_t rowBytes) const {
54 SkASSERT((unsigned)x < (unsigned)this->width());
55 SkASSERT((unsigned)y < (unsigned)this->height());
56 return SkColorTypeComputeOffset(this->colorType(), x, y, rowBytes);
57 }
58
computeByteSize(size_t rowBytes) const59 size_t SkImageInfo::computeByteSize(size_t rowBytes) const {
60 if (0 == this->height()) {
61 return 0;
62 }
63 SkSafeMath safe;
64 size_t bytes = safe.add(safe.mul(safe.addInt(this->height(), -1), rowBytes),
65 safe.mul(this->width(), this->bytesPerPixel()));
66
67 // The CPU backend implements some memory operations on images using instructions that take a
68 // signed 32-bit offset from the base. If we ever make an image larger than that, overflow can
69 // cause us to read/write memory that starts 2GB *before* the buffer. (crbug.com/1264705)
70 constexpr size_t kMaxSigned32BitSize = SK_MaxS32;
71 return (safe.ok() && (bytes <= kMaxSigned32BitSize)) ? bytes : SIZE_MAX;
72 }
73
MakeS32(int width,int height,SkAlphaType at)74 SkImageInfo SkImageInfo::MakeS32(int width, int height, SkAlphaType at) {
75 return SkImageInfo({width, height}, {kN32_SkColorType, at, SkColorSpace::MakeSRGB()});
76 }
77
78 #ifdef SK_DEBUG
validate() const79 void SkImageInfo::validate() const {
80 SkASSERT(fDimensions.width() >= 0);
81 SkASSERT(fDimensions.height() >= 0);
82 SkASSERT(SkColorTypeIsValid(this->colorType()));
83 SkASSERT(SkAlphaTypeIsValid(this->alphaType()));
84 }
85 #endif
86
SkColorTypeValidateAlphaType(SkColorType colorType,SkAlphaType alphaType,SkAlphaType * canonical)87 bool SkColorTypeValidateAlphaType(SkColorType colorType, SkAlphaType alphaType,
88 SkAlphaType* canonical) {
89 switch (colorType) {
90 case kUnknown_SkColorType:
91 alphaType = kUnknown_SkAlphaType;
92 break;
93 case kAlpha_8_SkColorType: // fall-through
94 case kA16_unorm_SkColorType: // fall-through
95 case kA16_float_SkColorType:
96 if (kUnpremul_SkAlphaType == alphaType) {
97 alphaType = kPremul_SkAlphaType;
98 }
99 [[fallthrough]];
100 case kARGB_4444_SkColorType:
101 case kRGBA_8888_SkColorType:
102 case kSRGBA_8888_SkColorType:
103 case kBGRA_8888_SkColorType:
104 case kRGBA_1010102_SkColorType:
105 case kBGRA_1010102_SkColorType:
106 case kRGBA_F16Norm_SkColorType:
107 case kRGBA_F16_SkColorType:
108 case kRGBA_F32_SkColorType:
109 case kR16G16B16A16_unorm_SkColorType:
110 if (kUnknown_SkAlphaType == alphaType) {
111 return false;
112 }
113 break;
114 case kGray_8_SkColorType:
115 case kR8G8_unorm_SkColorType:
116 case kR16G16_unorm_SkColorType:
117 case kR16G16_float_SkColorType:
118 case kRGB_565_SkColorType:
119 case kRGB_888x_SkColorType:
120 case kRGB_101010x_SkColorType:
121 case kBGR_101010x_SkColorType:
122 alphaType = kOpaque_SkAlphaType;
123 break;
124 }
125 if (canonical) {
126 *canonical = alphaType;
127 }
128 return true;
129 }
130
131 ///////////////////////////////////////////////////////////////////////////////////////////////////
132
133 #include "src/image/SkReadPixelsRec.h"
134
trim(int srcWidth,int srcHeight)135 bool SkReadPixelsRec::trim(int srcWidth, int srcHeight) {
136 if (nullptr == fPixels || fRowBytes < fInfo.minRowBytes()) {
137 return false;
138 }
139 if (0 >= fInfo.width() || 0 >= fInfo.height()) {
140 return false;
141 }
142
143 int x = fX;
144 int y = fY;
145 SkIRect srcR = SkIRect::MakeXYWH(x, y, fInfo.width(), fInfo.height());
146 if (!srcR.intersect({0, 0, srcWidth, srcHeight})) {
147 return false;
148 }
149
150 // if x or y are negative, then we have to adjust pixels
151 if (x > 0) {
152 x = 0;
153 }
154 if (y > 0) {
155 y = 0;
156 }
157 // here x,y are either 0 or negative
158 // we negate and add them so UBSAN (pointer-overflow) doesn't get confused.
159 fPixels = ((char*)fPixels + -y*fRowBytes + -x*fInfo.bytesPerPixel());
160 // the intersect may have shrunk info's logical size
161 fInfo = fInfo.makeDimensions(srcR.size());
162 fX = srcR.x();
163 fY = srcR.y();
164
165 return true;
166 }
167
168 ///////////////////////////////////////////////////////////////////////////////////////////////////
169
170 #include "src/core/SkWritePixelsRec.h"
171
trim(int dstWidth,int dstHeight)172 bool SkWritePixelsRec::trim(int dstWidth, int dstHeight) {
173 if (nullptr == fPixels || fRowBytes < fInfo.minRowBytes()) {
174 return false;
175 }
176 if (0 >= fInfo.width() || 0 >= fInfo.height()) {
177 return false;
178 }
179
180 int x = fX;
181 int y = fY;
182 SkIRect dstR = SkIRect::MakeXYWH(x, y, fInfo.width(), fInfo.height());
183 if (!dstR.intersect({0, 0, dstWidth, dstHeight})) {
184 return false;
185 }
186
187 // if x or y are negative, then we have to adjust pixels
188 if (x > 0) {
189 x = 0;
190 }
191 if (y > 0) {
192 y = 0;
193 }
194 // here x,y are either 0 or negative
195 // we negate and add them so UBSAN (pointer-overflow) doesn't get confused.
196 fPixels = ((const char*)fPixels + -y*fRowBytes + -x*fInfo.bytesPerPixel());
197 // the intersect may have shrunk info's logical size
198 fInfo = fInfo.makeDimensions(dstR.size());
199 fX = dstR.x();
200 fY = dstR.y();
201
202 return true;
203 }
204