1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/gfx/skia/trunk/src/core/SkComposeShader.cpp Wed Dec 31 06:09:35 2014 +0100
1.3 @@ -0,0 +1,194 @@
1.4 +
1.5 +/*
1.6 + * Copyright 2006 The Android Open Source Project
1.7 + *
1.8 + * Use of this source code is governed by a BSD-style license that can be
1.9 + * found in the LICENSE file.
1.10 + */
1.11 +
1.12 +
1.13 +#include "SkComposeShader.h"
1.14 +#include "SkColorFilter.h"
1.15 +#include "SkColorPriv.h"
1.16 +#include "SkColorShader.h"
1.17 +#include "SkReadBuffer.h"
1.18 +#include "SkWriteBuffer.h"
1.19 +#include "SkXfermode.h"
1.20 +#include "SkString.h"
1.21 +
1.22 +///////////////////////////////////////////////////////////////////////////////
1.23 +
1.24 +SkComposeShader::SkComposeShader(SkShader* sA, SkShader* sB, SkXfermode* mode) {
1.25 + fShaderA = sA; sA->ref();
1.26 + fShaderB = sB; sB->ref();
1.27 + // mode may be null
1.28 + fMode = mode;
1.29 + SkSafeRef(mode);
1.30 +}
1.31 +
1.32 +SkComposeShader::SkComposeShader(SkReadBuffer& buffer) :
1.33 + INHERITED(buffer) {
1.34 + fShaderA = buffer.readShader();
1.35 + if (NULL == fShaderA) {
1.36 + fShaderA = SkNEW_ARGS(SkColorShader, (0));
1.37 + }
1.38 + fShaderB = buffer.readShader();
1.39 + if (NULL == fShaderB) {
1.40 + fShaderB = SkNEW_ARGS(SkColorShader, (0));
1.41 + }
1.42 + fMode = buffer.readXfermode();
1.43 +}
1.44 +
1.45 +SkComposeShader::~SkComposeShader() {
1.46 + SkSafeUnref(fMode);
1.47 + fShaderB->unref();
1.48 + fShaderA->unref();
1.49 +}
1.50 +
1.51 +class SkAutoAlphaRestore {
1.52 +public:
1.53 + SkAutoAlphaRestore(SkPaint* paint, uint8_t newAlpha) {
1.54 + fAlpha = paint->getAlpha();
1.55 + fPaint = paint;
1.56 + paint->setAlpha(newAlpha);
1.57 + }
1.58 +
1.59 + ~SkAutoAlphaRestore() {
1.60 + fPaint->setAlpha(fAlpha);
1.61 + }
1.62 +private:
1.63 + SkPaint* fPaint;
1.64 + uint8_t fAlpha;
1.65 +};
1.66 +#define SkAutoAlphaRestore(...) SK_REQUIRE_LOCAL_VAR(SkAutoAlphaRestore)
1.67 +
1.68 +void SkComposeShader::flatten(SkWriteBuffer& buffer) const {
1.69 + this->INHERITED::flatten(buffer);
1.70 + buffer.writeFlattenable(fShaderA);
1.71 + buffer.writeFlattenable(fShaderB);
1.72 + buffer.writeFlattenable(fMode);
1.73 +}
1.74 +
1.75 +/* We call setContext on our two worker shaders. However, we
1.76 + always let them see opaque alpha, and if the paint really
1.77 + is translucent, then we apply that after the fact.
1.78 +
1.79 + We need to keep the calls to setContext/endContext balanced, since if we
1.80 + return false, our endContext() will not be called.
1.81 + */
1.82 +bool SkComposeShader::setContext(const SkBitmap& device,
1.83 + const SkPaint& paint,
1.84 + const SkMatrix& matrix) {
1.85 + if (!this->INHERITED::setContext(device, paint, matrix)) {
1.86 + return false;
1.87 + }
1.88 +
1.89 + // we preconcat our localMatrix (if any) with the device matrix
1.90 + // before calling our sub-shaders
1.91 +
1.92 + SkMatrix tmpM;
1.93 +
1.94 + tmpM.setConcat(matrix, this->getLocalMatrix());
1.95 +
1.96 + SkAutoAlphaRestore restore(const_cast<SkPaint*>(&paint), 0xFF);
1.97 +
1.98 + bool setContextA = fShaderA->setContext(device, paint, tmpM);
1.99 + bool setContextB = fShaderB->setContext(device, paint, tmpM);
1.100 + if (!setContextA || !setContextB) {
1.101 + if (setContextB) {
1.102 + fShaderB->endContext();
1.103 + }
1.104 + else if (setContextA) {
1.105 + fShaderA->endContext();
1.106 + }
1.107 + this->INHERITED::endContext();
1.108 + return false;
1.109 + }
1.110 + return true;
1.111 +}
1.112 +
1.113 +void SkComposeShader::endContext() {
1.114 + fShaderB->endContext();
1.115 + fShaderA->endContext();
1.116 + this->INHERITED::endContext();
1.117 +}
1.118 +
1.119 +// larger is better (fewer times we have to loop), but we shouldn't
1.120 +// take up too much stack-space (each element is 4 bytes)
1.121 +#define TMP_COLOR_COUNT 64
1.122 +
1.123 +void SkComposeShader::shadeSpan(int x, int y, SkPMColor result[], int count) {
1.124 + SkShader* shaderA = fShaderA;
1.125 + SkShader* shaderB = fShaderB;
1.126 + SkXfermode* mode = fMode;
1.127 + unsigned scale = SkAlpha255To256(this->getPaintAlpha());
1.128 +
1.129 + SkPMColor tmp[TMP_COLOR_COUNT];
1.130 +
1.131 + if (NULL == mode) { // implied SRC_OVER
1.132 + // TODO: when we have a good test-case, should use SkBlitRow::Proc32
1.133 + // for these loops
1.134 + do {
1.135 + int n = count;
1.136 + if (n > TMP_COLOR_COUNT) {
1.137 + n = TMP_COLOR_COUNT;
1.138 + }
1.139 +
1.140 + shaderA->shadeSpan(x, y, result, n);
1.141 + shaderB->shadeSpan(x, y, tmp, n);
1.142 +
1.143 + if (256 == scale) {
1.144 + for (int i = 0; i < n; i++) {
1.145 + result[i] = SkPMSrcOver(tmp[i], result[i]);
1.146 + }
1.147 + } else {
1.148 + for (int i = 0; i < n; i++) {
1.149 + result[i] = SkAlphaMulQ(SkPMSrcOver(tmp[i], result[i]),
1.150 + scale);
1.151 + }
1.152 + }
1.153 +
1.154 + result += n;
1.155 + x += n;
1.156 + count -= n;
1.157 + } while (count > 0);
1.158 + } else { // use mode for the composition
1.159 + do {
1.160 + int n = count;
1.161 + if (n > TMP_COLOR_COUNT) {
1.162 + n = TMP_COLOR_COUNT;
1.163 + }
1.164 +
1.165 + shaderA->shadeSpan(x, y, result, n);
1.166 + shaderB->shadeSpan(x, y, tmp, n);
1.167 + mode->xfer32(result, tmp, n, NULL);
1.168 +
1.169 + if (256 == scale) {
1.170 + for (int i = 0; i < n; i++) {
1.171 + result[i] = SkAlphaMulQ(result[i], scale);
1.172 + }
1.173 + }
1.174 +
1.175 + result += n;
1.176 + x += n;
1.177 + count -= n;
1.178 + } while (count > 0);
1.179 + }
1.180 +}
1.181 +
1.182 +#ifndef SK_IGNORE_TO_STRING
1.183 +void SkComposeShader::toString(SkString* str) const {
1.184 + str->append("SkComposeShader: (");
1.185 +
1.186 + str->append("ShaderA: ");
1.187 + fShaderA->toString(str);
1.188 + str->append(" ShaderB: ");
1.189 + fShaderB->toString(str);
1.190 + str->append(" Xfermode: ");
1.191 + fMode->toString(str);
1.192 +
1.193 + this->INHERITED::toString(str);
1.194 +
1.195 + str->append(")");
1.196 +}
1.197 +#endif
