1 /*
2 * Copyright 2013 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 "SkLerpXfermode.h"
9 #include "SkColorPriv.h"
10 #include "SkReadBuffer.h"
11 #include "SkWriteBuffer.h"
12 #include "SkString.h"
13
Create(SkScalar scale)14 SkXfermode* SkLerpXfermode::Create(SkScalar scale) {
15 int scale256 = SkScalarRoundToInt(scale * 256);
16 if (scale256 >= 256) {
17 return SkXfermode::Create(SkXfermode::kSrc_Mode);
18 } else if (scale256 <= 0) {
19 return SkXfermode::Create(SkXfermode::kDst_Mode);
20 }
21 return SkNEW_ARGS(SkLerpXfermode, (scale256));
22 }
23
SkLerpXfermode(unsigned scale256)24 SkLerpXfermode::SkLerpXfermode(unsigned scale256) : fScale256(scale256) {}
25
flatten(SkWriteBuffer & buffer) const26 void SkLerpXfermode::flatten(SkWriteBuffer& buffer) const {
27 buffer.writeUInt(fScale256);
28 }
29
CreateProc(SkReadBuffer & buffer)30 SkFlattenable* SkLerpXfermode::CreateProc(SkReadBuffer& buffer) {
31 return SkNEW_ARGS(SkLerpXfermode, (buffer.readUInt()));
32 }
33
xfer32(SkPMColor dst[],const SkPMColor src[],int count,const SkAlpha aa[]) const34 void SkLerpXfermode::xfer32(SkPMColor dst[], const SkPMColor src[], int count,
35 const SkAlpha aa[]) const {
36 const int scale = fScale256;
37
38 if (aa) {
39 for (int i = 0; i < count; ++i) {
40 unsigned a = aa[i];
41 if (a) {
42 SkPMColor dstC = dst[i];
43 SkPMColor resC = SkFastFourByteInterp256(src[i], dstC, scale);
44 if (a < 255) {
45 resC = SkFastFourByteInterp256(resC, dstC, a + (a >> 7));
46 }
47 dst[i] = resC;
48 }
49 }
50 } else {
51 for (int i = 0; i < count; ++i) {
52 dst[i] = SkFastFourByteInterp256(src[i], dst[i], scale);
53 }
54 }
55 }
56
xfer16(uint16_t dst[],const SkPMColor src[],int count,const SkAlpha aa[]) const57 void SkLerpXfermode::xfer16(uint16_t dst[], const SkPMColor src[], int count,
58 const SkAlpha aa[]) const {
59 const int scale = fScale256;
60
61 if (aa) {
62 for (int i = 0; i < count; ++i) {
63 unsigned a = aa[i];
64 if (a) {
65 SkPMColor dstC = SkPixel16ToPixel32(dst[i]);
66 SkPMColor resC = SkFastFourByteInterp256(src[i], dstC, scale);
67 if (a < 255) {
68 resC = SkFastFourByteInterp256(resC, dstC, a + (a >> 7));
69 }
70 dst[i] = SkPixel32ToPixel16(resC);
71 }
72 }
73 } else {
74 for (int i = 0; i < count; ++i) {
75 SkPMColor dstC = SkPixel16ToPixel32(dst[i]);
76 SkPMColor resC = SkFastFourByteInterp256(src[i], dstC, scale);
77 dst[i] = SkPixel32ToPixel16(resC);
78 }
79 }
80 }
81
xferA8(SkAlpha dst[],const SkPMColor src[],int count,const SkAlpha aa[]) const82 void SkLerpXfermode::xferA8(SkAlpha dst[], const SkPMColor src[], int count,
83 const SkAlpha aa[]) const {
84 const int scale = fScale256;
85
86 if (aa) {
87 for (int i = 0; i < count; ++i) {
88 unsigned a = aa[i];
89 if (a) {
90 unsigned dstA = dst[i];
91 unsigned resA = SkAlphaBlend(SkGetPackedA32(src[i]), dstA, scale);
92 if (a < 255) {
93 resA = SkAlphaBlend(resA, dstA, a + (a >> 7));
94 }
95 dst[i] = resA;
96 }
97 }
98 } else {
99 for (int i = 0; i < count; ++i) {
100 dst[i] = SkAlphaBlend(SkGetPackedA32(src[i]), dst[i], scale);
101 }
102 }
103 }
104
105 #ifndef SK_IGNORE_TO_STRING
toString(SkString * str) const106 void SkLerpXfermode::toString(SkString* str) const {
107 str->printf("SkLerpXfermode: scale: %g", fScale256 / 256.0);
108 }
109 #endif
110