1 /*
2 * Copyright 2007 The Android Open Source Project
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 "SkMask.h"
9
10 #include "SkMalloc.h"
11 #include "SkSafeMath.h"
12 #include "SkTo.h"
13
14 /** returns the product if it is positive and fits in 31 bits. Otherwise this
15 returns 0.
16 */
safeMul32(int32_t a,int32_t b)17 static int32_t safeMul32(int32_t a, int32_t b) {
18 int64_t size = sk_64_mul(a, b);
19 if (size > 0 && SkTFitsIn<int32_t>(size)) {
20 return size;
21 }
22 return 0;
23 }
24
computeImageSize() const25 size_t SkMask::computeImageSize() const {
26 return safeMul32(fBounds.height(), fRowBytes);
27 }
28
computeTotalImageSize() const29 size_t SkMask::computeTotalImageSize() const {
30 size_t size = this->computeImageSize();
31 if (fFormat == SkMask::k3D_Format) {
32 size = safeMul32(SkToS32(size), 3);
33 }
34 return size;
35 }
36
37 /** We explicitly use this allocator for SkBimap pixels, so that we can
38 freely assign memory allocated by one class to the other.
39 */
AllocImage(size_t size,AllocType at)40 uint8_t* SkMask::AllocImage(size_t size, AllocType at) {
41 size_t aligned_size = SkSafeMath::Align4(size);
42 unsigned flags = SK_MALLOC_THROW;
43 if (at == kZeroInit_Alloc) {
44 flags |= SK_MALLOC_ZERO_INITIALIZE;
45 }
46 return static_cast<uint8_t*>(sk_malloc_flags(aligned_size, flags));
47 }
48
49 /** We explicitly use this allocator for SkBimap pixels, so that we can
50 freely assign memory allocated by one class to the other.
51 */
FreeImage(void * image)52 void SkMask::FreeImage(void* image) {
53 sk_free(image);
54 }
55
PrepareDestination(int radiusX,int radiusY,const SkMask & src)56 SkMask SkMask::PrepareDestination(int radiusX, int radiusY, const SkMask& src) {
57 SkSafeMath safe;
58
59 SkMask dst;
60 // dstW = srcW + 2 * radiusX;
61 size_t dstW = safe.add(src.fBounds.width(), safe.add(radiusX, radiusX));
62 // dstH = srcH + 2 * radiusY;
63 size_t dstH = safe.add(src.fBounds.height(), safe.add(radiusY, radiusY));
64
65 if (!SkTFitsIn<int>(dstW) || !SkTFitsIn<int>(dstH)) {
66 dst.fBounds.setEmpty();
67 dst.fRowBytes = 0;
68 } else {
69 dst.fBounds.set(0, 0, SkTo<int>(dstW), SkTo<int>(dstH));
70 dst.fBounds.offset(src.fBounds.x(), src.fBounds.y());
71 dst.fBounds.offset(-radiusX, -radiusY);
72 dst.fRowBytes = SkTo<uint32_t>(dstW);
73 }
74
75 dst.fImage = nullptr;
76 dst.fFormat = SkMask::kA8_Format;
77
78 size_t toAlloc = safe.mul(dstW, dstH);
79
80 if (safe && src.fImage != nullptr) {
81 dst.fImage = SkMask::AllocImage(toAlloc);
82 }
83
84 return dst;
85 }
86
87
88 ///////////////////////////////////////////////////////////////////////////////
89
90 static const int gMaskFormatToShift[] = {
91 ~0, // BW -- not supported
92 0, // A8
93 0, // 3D
94 2, // ARGB32
95 1, // LCD16
96 0, // SDF
97 };
98
maskFormatToShift(SkMask::Format format)99 static int maskFormatToShift(SkMask::Format format) {
100 SkASSERT((unsigned)format < SK_ARRAY_COUNT(gMaskFormatToShift));
101 SkASSERT(SkMask::kBW_Format != format);
102 return gMaskFormatToShift[format];
103 }
104
getAddr(int x,int y) const105 void* SkMask::getAddr(int x, int y) const {
106 SkASSERT(kBW_Format != fFormat);
107 SkASSERT(fBounds.contains(x, y));
108 SkASSERT(fImage);
109
110 char* addr = (char*)fImage;
111 addr += (y - fBounds.fTop) * fRowBytes;
112 addr += (x - fBounds.fLeft) << maskFormatToShift(fFormat);
113 return addr;
114 }
115