michael@0: /*
michael@0:  * Copyright 2006 The Android Open Source Project
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 "SkAvoidXfermode.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: SkAvoidXfermode::SkAvoidXfermode(SkColor opColor, U8CPU tolerance, Mode mode) {
michael@0:     if (tolerance > 255) {
michael@0:         tolerance = 255;
michael@0:     }
michael@0: 
michael@0:     fOpColor = opColor;
michael@0:     fDistMul = (256 << 14) / (tolerance + 1);
michael@0:     fMode = mode;
michael@0: }
michael@0: 
michael@0: SkAvoidXfermode::SkAvoidXfermode(SkReadBuffer& buffer)
michael@0:     : INHERITED(buffer) {
michael@0:     fOpColor = buffer.readColor();
michael@0:     fDistMul = buffer.readUInt();
michael@0:     fMode = (Mode)buffer.readUInt();
michael@0: }
michael@0: 
michael@0: void SkAvoidXfermode::flatten(SkWriteBuffer& buffer) const {
michael@0:     this->INHERITED::flatten(buffer);
michael@0: 
michael@0:     buffer.writeColor(fOpColor);
michael@0:     buffer.writeUInt(fDistMul);
michael@0:     buffer.writeUInt(fMode);
michael@0: }
michael@0: 
michael@0: // returns 0..31
michael@0: static unsigned color_dist16(uint16_t c, unsigned r, unsigned g, unsigned b) {
michael@0:     SkASSERT(r <= SK_R16_MASK);
michael@0:     SkASSERT(g <= SK_G16_MASK);
michael@0:     SkASSERT(b <= SK_B16_MASK);
michael@0: 
michael@0:     unsigned dr = SkAbs32(SkGetPackedR16(c) - r);
michael@0:     unsigned dg = SkAbs32(SkGetPackedG16(c) - g) >> (SK_G16_BITS - SK_R16_BITS);
michael@0:     unsigned db = SkAbs32(SkGetPackedB16(c) - b);
michael@0: 
michael@0:     return SkMax32(dr, SkMax32(dg, db));
michael@0: }
michael@0: 
michael@0: // returns 0..255
michael@0: static unsigned color_dist32(SkPMColor c, U8CPU r, U8CPU g, U8CPU b) {
michael@0:     SkASSERT(r <= 0xFF);
michael@0:     SkASSERT(g <= 0xFF);
michael@0:     SkASSERT(b <= 0xFF);
michael@0: 
michael@0:     unsigned dr = SkAbs32(SkGetPackedR32(c) - r);
michael@0:     unsigned dg = SkAbs32(SkGetPackedG32(c) - g);
michael@0:     unsigned db = SkAbs32(SkGetPackedB32(c) - b);
michael@0: 
michael@0:     return SkMax32(dr, SkMax32(dg, db));
michael@0: }
michael@0: 
michael@0: static int scale_dist_14(int dist, uint32_t mul, uint32_t sub) {
michael@0:     int tmp = dist * mul - sub;
michael@0:     int result = (tmp + (1 << 13)) >> 14;
michael@0: 
michael@0:     return result;
michael@0: }
michael@0: 
michael@0: static inline unsigned Accurate255To256(unsigned x) {
michael@0:     return x + (x >> 7);
michael@0: }
michael@0: 
michael@0: void SkAvoidXfermode::xfer32(SkPMColor dst[], const SkPMColor src[], int count,
michael@0:                              const SkAlpha aa[]) const {
michael@0:     unsigned    opR = SkColorGetR(fOpColor);
michael@0:     unsigned    opG = SkColorGetG(fOpColor);
michael@0:     unsigned    opB = SkColorGetB(fOpColor);
michael@0:     uint32_t    mul = fDistMul;
michael@0:     uint32_t    sub = (fDistMul - (1 << 14)) << 8;
michael@0: 
michael@0:     int MAX, mask;
michael@0: 
michael@0:     if (kTargetColor_Mode == fMode) {
michael@0:         mask = -1;
michael@0:         MAX = 255;
michael@0:     } else {
michael@0:         mask = 0;
michael@0:         MAX = 0;
michael@0:     }
michael@0: 
michael@0:     for (int i = 0; i < count; i++) {
michael@0:         int d = color_dist32(dst[i], opR, opG, opB);
michael@0:         // now reverse d if we need to
michael@0:         d = MAX + (d ^ mask) - mask;
michael@0:         SkASSERT((unsigned)d <= 255);
michael@0:         d = Accurate255To256(d);
michael@0: 
michael@0:         d = scale_dist_14(d, mul, sub);
michael@0:         SkASSERT(d <= 256);
michael@0: 
michael@0:         if (d > 0) {
michael@0:             if (NULL != aa) {
michael@0:                 d = SkAlphaMul(d, Accurate255To256(*aa++));
michael@0:                 if (0 == d) {
michael@0:                     continue;
michael@0:                 }
michael@0:             }
michael@0:             dst[i] = SkFourByteInterp256(src[i], dst[i], d);
michael@0:         }
michael@0:     }
michael@0: }
michael@0: 
michael@0: static inline U16CPU SkBlend3216(SkPMColor src, U16CPU dst, unsigned scale) {
michael@0:     SkASSERT(scale <= 32);
michael@0:     scale <<= 3;
michael@0: 
michael@0:     return SkPackRGB16( SkAlphaBlend(SkPacked32ToR16(src), SkGetPackedR16(dst), scale),
michael@0:                         SkAlphaBlend(SkPacked32ToG16(src), SkGetPackedG16(dst), scale),
michael@0:                         SkAlphaBlend(SkPacked32ToB16(src), SkGetPackedB16(dst), scale));
michael@0: }
michael@0: 
michael@0: void SkAvoidXfermode::xfer16(uint16_t dst[], const SkPMColor src[], int count,
michael@0:                              const SkAlpha aa[]) const {
michael@0:     unsigned    opR = SkColorGetR(fOpColor) >> (8 - SK_R16_BITS);
michael@0:     unsigned    opG = SkColorGetG(fOpColor) >> (8 - SK_G16_BITS);
michael@0:     unsigned    opB = SkColorGetB(fOpColor) >> (8 - SK_R16_BITS);
michael@0:     uint32_t    mul = fDistMul;
michael@0:     uint32_t    sub = (fDistMul - (1 << 14)) << SK_R16_BITS;
michael@0: 
michael@0:     int MAX, mask;
michael@0: 
michael@0:     if (kTargetColor_Mode == fMode) {
michael@0:         mask = -1;
michael@0:         MAX = 31;
michael@0:     } else {
michael@0:         mask = 0;
michael@0:         MAX = 0;
michael@0:     }
michael@0: 
michael@0:     for (int i = 0; i < count; i++) {
michael@0:         int d = color_dist16(dst[i], opR, opG, opB);
michael@0:         // now reverse d if we need to
michael@0:         d = MAX + (d ^ mask) - mask;
michael@0:         SkASSERT((unsigned)d <= 31);
michael@0:         // convert from 0..31 to 0..32
michael@0:         d += d >> 4;
michael@0:         d = scale_dist_14(d, mul, sub);
michael@0:         SkASSERT(d <= 32);
michael@0: 
michael@0:         if (d > 0) {
michael@0:             if (NULL != aa) {
michael@0:                 d = SkAlphaMul(d, Accurate255To256(*aa++));
michael@0:                 if (0 == d) {
michael@0:                     continue;
michael@0:                 }
michael@0:             }
michael@0:             dst[i] = SkBlend3216(src[i], dst[i], d);
michael@0:         }
michael@0:     }
michael@0: }
michael@0: 
michael@0: void SkAvoidXfermode::xferA8(SkAlpha dst[], const SkPMColor src[], int count,
michael@0:                              const SkAlpha aa[]) const {
michael@0:     // override in subclass
michael@0: }
michael@0: 
michael@0: #ifndef SK_IGNORE_TO_STRING
michael@0: void SkAvoidXfermode::toString(SkString* str) const {
michael@0:     str->append("SkAvoidXfermode: opColor: ");
michael@0:     str->appendHex(fOpColor);
michael@0:     str->appendf("distMul: %d ", fDistMul);
michael@0: 
michael@0:     static const char* gModeStrings[] = { "Avoid", "Target" };
michael@0: 
michael@0:     str->appendf("mode: %s", gModeStrings[fMode]);
michael@0: }
michael@0: #endif