michael@0: /*
michael@0:  * Copyright 2013 Google Inc.
michael@0:  *
michael@0:  * Use of this source code is governed by a BSD-style license that can be
michael@0:  * found in the LICENSE file.
michael@0:  */
michael@0: 
michael@0: #include "SkLerpXfermode.h"
michael@0: #include "SkColorPriv.h"
michael@0: #include "SkReadBuffer.h"
michael@0: #include "SkWriteBuffer.h"
michael@0: #include "SkString.h"
michael@0: 
michael@0: SkXfermode* SkLerpXfermode::Create(SkScalar scale) {
michael@0:     int scale256 = SkScalarRoundToInt(scale * 256);
michael@0:     if (scale256 >= 256) {
michael@0:         return SkXfermode::Create(SkXfermode::kSrc_Mode);
michael@0:     } else if (scale256 <= 0) {
michael@0:         return SkXfermode::Create(SkXfermode::kDst_Mode);
michael@0:     }
michael@0:     return SkNEW_ARGS(SkLerpXfermode, (scale256));
michael@0: }
michael@0: 
michael@0: SkLerpXfermode::SkLerpXfermode(unsigned scale256) : fScale256(scale256) {}
michael@0: 
michael@0: SkLerpXfermode::SkLerpXfermode(SkReadBuffer& buffer)
michael@0:     : INHERITED(buffer) {
michael@0:     fScale256 = buffer.readUInt();
michael@0: }
michael@0: 
michael@0: void SkLerpXfermode::flatten(SkWriteBuffer& buffer) const {
michael@0:     this->INHERITED::flatten(buffer);
michael@0:     buffer.writeUInt(fScale256);
michael@0: }
michael@0: 
michael@0: void SkLerpXfermode::xfer32(SkPMColor dst[], const SkPMColor src[], int count,
michael@0:                              const SkAlpha aa[]) const {
michael@0:     const int scale = fScale256;
michael@0: 
michael@0:     if (aa) {
michael@0:         for (int i = 0; i < count; ++i) {
michael@0:             unsigned a = aa[i];
michael@0:             if (a) {
michael@0:                 SkPMColor dstC = dst[i];
michael@0:                 SkPMColor resC = SkFastFourByteInterp256(src[i], dstC, scale);
michael@0:                 if (a < 255) {
michael@0:                     resC = SkFastFourByteInterp256(resC, dstC, a + (a >> 7));
michael@0:                 }
michael@0:                 dst[i] = resC;
michael@0:             }
michael@0:         }
michael@0:     } else {
michael@0:         for (int i = 0; i < count; ++i) {
michael@0:             dst[i] = SkFastFourByteInterp256(src[i], dst[i], scale);
michael@0:         }
michael@0:     }
michael@0: }
michael@0: 
michael@0: void SkLerpXfermode::xfer16(uint16_t dst[], const SkPMColor src[], int count,
michael@0:                              const SkAlpha aa[]) const {
michael@0:     const int scale = fScale256;
michael@0: 
michael@0:     if (aa) {
michael@0:         for (int i = 0; i < count; ++i) {
michael@0:             unsigned a = aa[i];
michael@0:             if (a) {
michael@0:                 SkPMColor dstC = SkPixel16ToPixel32(dst[i]);
michael@0:                 SkPMColor resC = SkFastFourByteInterp256(src[i], dstC, scale);
michael@0:                 if (a < 255) {
michael@0:                     resC = SkFastFourByteInterp256(resC, dstC, a + (a >> 7));
michael@0:                 }
michael@0:                 dst[i] = SkPixel32ToPixel16(resC);
michael@0:             }
michael@0:         }
michael@0:     } else {
michael@0:         for (int i = 0; i < count; ++i) {
michael@0:             SkPMColor dstC = SkPixel16ToPixel32(dst[i]);
michael@0:             SkPMColor resC = SkFastFourByteInterp256(src[i], dstC, scale);
michael@0:             dst[i] = SkPixel32ToPixel16(resC);
michael@0:         }
michael@0:     }
michael@0: }
michael@0: 
michael@0: void SkLerpXfermode::xferA8(SkAlpha dst[], const SkPMColor src[], int count,
michael@0:                              const SkAlpha aa[]) const {
michael@0:     const int scale = fScale256;
michael@0: 
michael@0:     if (aa) {
michael@0:         for (int i = 0; i < count; ++i) {
michael@0:             unsigned a = aa[i];
michael@0:             if (a) {
michael@0:                 unsigned dstA = dst[i];
michael@0:                 unsigned resA = SkAlphaBlend(SkGetPackedA32(src[i]), dstA, scale);
michael@0:                 if (a < 255) {
michael@0:                     resA = SkAlphaBlend(resA, dstA, a + (a >> 7));
michael@0:                 }
michael@0:                 dst[i] = resA;
michael@0:             }
michael@0:         }
michael@0:     } else {
michael@0:         for (int i = 0; i < count; ++i) {
michael@0:             dst[i] = SkAlphaBlend(SkGetPackedA32(src[i]), dst[i], scale);
michael@0:         }
michael@0:     }
michael@0: }
michael@0: 
michael@0: #ifndef SK_IGNORE_TO_STRING
michael@0: void SkLerpXfermode::toString(SkString* str) const {
michael@0:     str->printf("SkLerpXfermode: scale: %g", fScale256 / 256.0);
michael@0: }
michael@0: #endif