src/effects/SkAvoidXfermode.cpp - platform/external/skia - Git at Google

 /* libs/graphics/effects/SkAvoidXfermode.cpp
 **
 ** Copyright 2006, The Android Open Source Project
 **
 ** Licensed under the Apache License, Version 2.0 (the "License");
 ** you may not use this file except in compliance with the License.
 ** You may obtain a copy of the License at
 **
 **     http://www.apache.org/licenses/LICENSE-2.0
 **
 ** Unless required by applicable law or agreed to in writing, software
 ** distributed under the License is distributed on an "AS IS" BASIS,
 ** WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 ** See the License for the specific language governing permissions and
 ** limitations under the License.
 */

 #include "SkAvoidXfermode.h"
 #include "SkColorPriv.h"

 SkAvoidXfermode::SkAvoidXfermode(SkColor opColor, U8CPU tolerance, Mode mode)
 {
     if (tolerance > 255) {
         tolerance = 255;
     }

     fOpColor = opColor;
     fDistMul = (256 << 14) / (tolerance + 1);
     fMode = mode;
 }

 SkAvoidXfermode::SkAvoidXfermode(SkFlattenableReadBuffer& buffer)
     : INHERITED(buffer)
 {
     fOpColor = buffer.readU32();
     fDistMul = buffer.readU32();
     fMode = (Mode)buffer.readU8();
 }

 void SkAvoidXfermode::flatten(SkFlattenableWriteBuffer& buffer)
 {
     this->INHERITED::flatten(buffer);

     buffer.write32(fOpColor);
     buffer.write32(fDistMul);
     buffer.write8(fMode);
 }

 SkFlattenable* SkAvoidXfermode::Create(SkFlattenableReadBuffer& rb)
 {
     return SkNEW_ARGS(SkAvoidXfermode, (rb));
 }

 SkFlattenable::Factory SkAvoidXfermode::getFactory()
 {
     return Create;
 }

 // returns 0..31
 static unsigned color_dist16(uint16_t c, unsigned r, unsigned g, unsigned b)
 {
     SkASSERT(r <= SK_R16_MASK);
     SkASSERT(g <= SK_G16_MASK);
     SkASSERT(b <= SK_B16_MASK);

     unsigned dr = SkAbs32(SkGetPackedR16(c) - r);
     unsigned dg = SkAbs32(SkGetPackedG16(c) - g) >> (SK_G16_BITS - SK_R16_BITS);
     unsigned db = SkAbs32(SkGetPackedB16(c) - b);

     return SkMax32(dr, SkMax32(dg, db));
 }

 // returns 0..15
 static unsigned color_dist4444(uint16_t c, unsigned r, unsigned g, unsigned b)
 {
     SkASSERT(r <= 0xF);
     SkASSERT(g <= 0xF);
     SkASSERT(b <= 0xF);

     unsigned dr = SkAbs32(SkGetPackedR4444(c) - r);
     unsigned dg = SkAbs32(SkGetPackedG4444(c) - g);
     unsigned db = SkAbs32(SkGetPackedB4444(c) - b);

     return SkMax32(dr, SkMax32(dg, db));
 }

 // returns 0..255
 static unsigned color_dist32(SkPMColor c, U8CPU r, U8CPU g, U8CPU b)
 {
     SkASSERT(r <= 0xFF);
     SkASSERT(g <= 0xFF);
     SkASSERT(b <= 0xFF);

     unsigned dr = SkAbs32(SkGetPackedR32(c) - r);
     unsigned dg = SkAbs32(SkGetPackedG32(c) - g);
     unsigned db = SkAbs32(SkGetPackedB32(c) - b);

     return SkMax32(dr, SkMax32(dg, db));
 }

 static int scale_dist_14(int dist, uint32_t mul, uint32_t sub)
 {
     int tmp = dist * mul - sub;
     int result = (tmp + (1 << 13)) >> 14;

     return result;
 }

 static SkPMColor SkFourByteInterp(SkPMColor src, SkPMColor dst, unsigned scale)
 {
     unsigned a = SkAlphaBlend(SkGetPackedA32(src), SkGetPackedA32(dst), scale);
     unsigned r = SkAlphaBlend(SkGetPackedR32(src), SkGetPackedR32(dst), scale);
     unsigned g = SkAlphaBlend(SkGetPackedG32(src), SkGetPackedG32(dst), scale);
     unsigned b = SkAlphaBlend(SkGetPackedB32(src), SkGetPackedB32(dst), scale);

     return SkPackARGB32(a, r, g, b);
 }

 static inline unsigned Accurate255To256(unsigned x) {
     return x + (x >> 7);
 }

 void SkAvoidXfermode::xfer32(SkPMColor dst[], const SkPMColor src[], int count,
                              const SkAlpha aa[])
 {
     unsigned    opR = SkColorGetR(fOpColor);
     unsigned    opG = SkColorGetG(fOpColor);
     unsigned    opB = SkColorGetB(fOpColor);
     uint32_t    mul = fDistMul;
     uint32_t    sub = (fDistMul - (1 << 14)) << 8;

     int MAX, mask;

     if (kTargetColor_Mode == fMode) {
         mask = -1;
         MAX = 255;
     } else {
         mask = 0;
         MAX = 0;
     }

     for (int i = 0; i < count; i++) {
         int d = color_dist32(dst[i], opR, opG, opB);
         // now reverse d if we need to
         d = MAX + (d ^ mask) - mask;
         SkASSERT((unsigned)d <= 255);
         d = Accurate255To256(d);

         d = scale_dist_14(d, mul, sub);
         SkASSERT(d <= 256);

         if (d > 0) {
             if (NULL != aa) {
                 d = SkAlphaMul(d, Accurate255To256(*aa++));
                 if (0 == d) {
                     continue;
                 }
             }
             dst[i] = SkFourByteInterp(src[i], dst[i], d);
         }
     }
 }

 static inline U16CPU SkBlend3216(SkPMColor src, U16CPU dst, unsigned scale)
 {
     SkASSERT(scale <= 32);
     scale <<= 3;

     return SkPackRGB16( SkAlphaBlend(SkPacked32ToR16(src), SkGetPackedR16(dst), scale),
                         SkAlphaBlend(SkPacked32ToG16(src), SkGetPackedG16(dst), scale),
                         SkAlphaBlend(SkPacked32ToB16(src), SkGetPackedB16(dst), scale));
 }

 void SkAvoidXfermode::xfer16(uint16_t dst[], const SkPMColor src[], int count,
                              const SkAlpha aa[])
 {
     unsigned    opR = SkColorGetR(fOpColor) >> (8 - SK_R16_BITS);
     unsigned    opG = SkColorGetG(fOpColor) >> (8 - SK_G16_BITS);
     unsigned    opB = SkColorGetB(fOpColor) >> (8 - SK_R16_BITS);
     uint32_t    mul = fDistMul;
     uint32_t    sub = (fDistMul - (1 << 14)) << SK_R16_BITS;

     int MAX, mask;

     if (kTargetColor_Mode == fMode) {
         mask = -1;
         MAX = 31;
     } else {
         mask = 0;
         MAX = 0;
     }

     for (int i = 0; i < count; i++) {
         int d = color_dist16(dst[i], opR, opG, opB);
         // now reverse d if we need to
         d = MAX + (d ^ mask) - mask;
         SkASSERT((unsigned)d <= 31);
         // convert from 0..31 to 0..32
         d += d >> 4;
         d = scale_dist_14(d, mul, sub);
         SkASSERT(d <= 32);

         if (d > 0) {
             if (NULL != aa) {
                 d = SkAlphaMul(d, Accurate255To256(*aa++));
                 if (0 == d) {
                     continue;
                 }
             }
             dst[i] = SkBlend3216(src[i], dst[i], d);
         }
     }
 }

 void SkAvoidXfermode::xfer4444(uint16_t dst[], const SkPMColor src[], int count,
                                const SkAlpha aa[])
 {
     unsigned    opR = SkColorGetR(fOpColor) >> 4;
     unsigned    opG = SkColorGetG(fOpColor) >> 4;
     unsigned    opB = SkColorGetB(fOpColor) >> 4;
     uint32_t    mul = fDistMul;
     uint32_t    sub = (fDistMul - (1 << 14)) << 4;

     int MAX, mask;

     if (kTargetColor_Mode == fMode) {
         mask = -1;
         MAX = 15;
     } else {
         mask = 0;
         MAX = 0;
     }

     for (int i = 0; i < count; i++) {
         int d = color_dist4444(dst[i], opR, opG, opB);
         // now reverse d if we need to
         d = MAX + (d ^ mask) - mask;
         SkASSERT((unsigned)d <= 15);
         // convert from 0..15 to 0..16
         d += d >> 3;
         d = scale_dist_14(d, mul, sub);
         SkASSERT(d <= 16);

         if (d > 0) {
             if (NULL != aa) {
                 d = SkAlphaMul(d, Accurate255To256(*aa++));
                 if (0 == d) {
                     continue;
                 }
             }
             dst[i] = SkBlend4444(SkPixel32ToPixel4444(src[i]), dst[i], d);
         }
     }
 }

 void SkAvoidXfermode::xferA8(SkAlpha dst[], const SkPMColor src[], int count, const SkAlpha aa[])
 {
     // override in subclass
 }

 static SkFlattenable::Registrar
     gSkAvoidXfermodeReg("SkAvoidXfermode", SkAvoidXfermode::CreateProc);
	/* libs/graphics/effects/SkAvoidXfermode.cpp
	**
	** Copyright 2006, The Android Open Source Project
	**
	** Licensed under the Apache License, Version 2.0 (the "License");
	** you may not use this file except in compliance with the License.
	** You may obtain a copy of the License at
	**
	** http://www.apache.org/licenses/LICENSE-2.0
	**
	** Unless required by applicable law or agreed to in writing, software
	** distributed under the License is distributed on an "AS IS" BASIS,
	** WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
	** See the License for the specific language governing permissions and
	** limitations under the License.
	*/

	#include "SkAvoidXfermode.h"
	#include "SkColorPriv.h"

	SkAvoidXfermode::SkAvoidXfermode(SkColor opColor, U8CPU tolerance, Mode mode)
	{
	if (tolerance > 255) {
	tolerance = 255;
	}

	fOpColor = opColor;
	fDistMul = (256 << 14) / (tolerance + 1);
	fMode = mode;
	}

	SkAvoidXfermode::SkAvoidXfermode(SkFlattenableReadBuffer& buffer)
	: INHERITED(buffer)
	{
	fOpColor = buffer.readU32();
	fDistMul = buffer.readU32();
	fMode = (Mode)buffer.readU8();
	}

	void SkAvoidXfermode::flatten(SkFlattenableWriteBuffer& buffer)
	{
	this->INHERITED::flatten(buffer);

	buffer.write32(fOpColor);
	buffer.write32(fDistMul);
	buffer.write8(fMode);
	}

	SkFlattenable* SkAvoidXfermode::Create(SkFlattenableReadBuffer& rb)
	{
	return SkNEW_ARGS(SkAvoidXfermode, (rb));
	}

	SkFlattenable::Factory SkAvoidXfermode::getFactory()
	{
	return Create;
	}

	// returns 0..31
	static unsigned color_dist16(uint16_t c, unsigned r, unsigned g, unsigned b)
	{
	SkASSERT(r <= SK_R16_MASK);
	SkASSERT(g <= SK_G16_MASK);
	SkASSERT(b <= SK_B16_MASK);

	unsigned dr = SkAbs32(SkGetPackedR16(c) - r);
	unsigned dg = SkAbs32(SkGetPackedG16(c) - g) >> (SK_G16_BITS - SK_R16_BITS);
	unsigned db = SkAbs32(SkGetPackedB16(c) - b);

	return SkMax32(dr, SkMax32(dg, db));
	}

	// returns 0..15
	static unsigned color_dist4444(uint16_t c, unsigned r, unsigned g, unsigned b)
	{
	SkASSERT(r <= 0xF);
	SkASSERT(g <= 0xF);
	SkASSERT(b <= 0xF);

	unsigned dr = SkAbs32(SkGetPackedR4444(c) - r);
	unsigned dg = SkAbs32(SkGetPackedG4444(c) - g);
	unsigned db = SkAbs32(SkGetPackedB4444(c) - b);

	return SkMax32(dr, SkMax32(dg, db));
	}

	// returns 0..255
	static unsigned color_dist32(SkPMColor c, U8CPU r, U8CPU g, U8CPU b)
	{
	SkASSERT(r <= 0xFF);
	SkASSERT(g <= 0xFF);
	SkASSERT(b <= 0xFF);

	unsigned dr = SkAbs32(SkGetPackedR32(c) - r);
	unsigned dg = SkAbs32(SkGetPackedG32(c) - g);
	unsigned db = SkAbs32(SkGetPackedB32(c) - b);

	return SkMax32(dr, SkMax32(dg, db));
	}

	static int scale_dist_14(int dist, uint32_t mul, uint32_t sub)
	{
	int tmp = dist * mul - sub;
	int result = (tmp + (1 << 13)) >> 14;

	return result;
	}

	static SkPMColor SkFourByteInterp(SkPMColor src, SkPMColor dst, unsigned scale)
	{
	unsigned a = SkAlphaBlend(SkGetPackedA32(src), SkGetPackedA32(dst), scale);
	unsigned r = SkAlphaBlend(SkGetPackedR32(src), SkGetPackedR32(dst), scale);
	unsigned g = SkAlphaBlend(SkGetPackedG32(src), SkGetPackedG32(dst), scale);
	unsigned b = SkAlphaBlend(SkGetPackedB32(src), SkGetPackedB32(dst), scale);

	return SkPackARGB32(a, r, g, b);
	}

	static inline unsigned Accurate255To256(unsigned x) {
	return x + (x >> 7);
	}

	void SkAvoidXfermode::xfer32(SkPMColor dst[], const SkPMColor src[], int count,
	const SkAlpha aa[])
	{
	unsigned opR = SkColorGetR(fOpColor);
	unsigned opG = SkColorGetG(fOpColor);
	unsigned opB = SkColorGetB(fOpColor);
	uint32_t mul = fDistMul;
	uint32_t sub = (fDistMul - (1 << 14)) << 8;

	int MAX, mask;

	if (kTargetColor_Mode == fMode) {
	mask = -1;
	MAX = 255;
	} else {
	mask = 0;
	MAX = 0;
	}

	for (int i = 0; i < count; i++) {
	int d = color_dist32(dst[i], opR, opG, opB);
	// now reverse d if we need to
	d = MAX + (d ^ mask) - mask;
	SkASSERT((unsigned)d <= 255);
	d = Accurate255To256(d);

	d = scale_dist_14(d, mul, sub);
	SkASSERT(d <= 256);

	if (d > 0) {
	if (NULL != aa) {
	d = SkAlphaMul(d, Accurate255To256(*aa++));
	if (0 == d) {
	continue;
	}
	}
	dst[i] = SkFourByteInterp(src[i], dst[i], d);
	}
	}
	}

	static inline U16CPU SkBlend3216(SkPMColor src, U16CPU dst, unsigned scale)
	{
	SkASSERT(scale <= 32);
	scale <<= 3;

	return SkPackRGB16( SkAlphaBlend(SkPacked32ToR16(src), SkGetPackedR16(dst), scale),
	SkAlphaBlend(SkPacked32ToG16(src), SkGetPackedG16(dst), scale),
	SkAlphaBlend(SkPacked32ToB16(src), SkGetPackedB16(dst), scale));
	}

	void SkAvoidXfermode::xfer16(uint16_t dst[], const SkPMColor src[], int count,
	const SkAlpha aa[])
	{
	unsigned opR = SkColorGetR(fOpColor) >> (8 - SK_R16_BITS);
	unsigned opG = SkColorGetG(fOpColor) >> (8 - SK_G16_BITS);
	unsigned opB = SkColorGetB(fOpColor) >> (8 - SK_R16_BITS);
	uint32_t mul = fDistMul;
	uint32_t sub = (fDistMul - (1 << 14)) << SK_R16_BITS;

	int MAX, mask;

	if (kTargetColor_Mode == fMode) {
	mask = -1;
	MAX = 31;
	} else {
	mask = 0;
	MAX = 0;
	}

	for (int i = 0; i < count; i++) {
	int d = color_dist16(dst[i], opR, opG, opB);
	// now reverse d if we need to
	d = MAX + (d ^ mask) - mask;
	SkASSERT((unsigned)d <= 31);
	// convert from 0..31 to 0..32
	d += d >> 4;
	d = scale_dist_14(d, mul, sub);
	SkASSERT(d <= 32);

	if (d > 0) {
	if (NULL != aa) {
	d = SkAlphaMul(d, Accurate255To256(*aa++));
	if (0 == d) {
	continue;
	}
	}
	dst[i] = SkBlend3216(src[i], dst[i], d);
	}
	}
	}

	void SkAvoidXfermode::xfer4444(uint16_t dst[], const SkPMColor src[], int count,
	const SkAlpha aa[])
	{
	unsigned opR = SkColorGetR(fOpColor) >> 4;
	unsigned opG = SkColorGetG(fOpColor) >> 4;
	unsigned opB = SkColorGetB(fOpColor) >> 4;
	uint32_t mul = fDistMul;
	uint32_t sub = (fDistMul - (1 << 14)) << 4;

	int MAX, mask;

	if (kTargetColor_Mode == fMode) {
	mask = -1;
	MAX = 15;
	} else {
	mask = 0;
	MAX = 0;
	}

	for (int i = 0; i < count; i++) {
	int d = color_dist4444(dst[i], opR, opG, opB);
	// now reverse d if we need to
	d = MAX + (d ^ mask) - mask;
	SkASSERT((unsigned)d <= 15);
	// convert from 0..15 to 0..16
	d += d >> 3;
	d = scale_dist_14(d, mul, sub);
	SkASSERT(d <= 16);

	if (d > 0) {
	if (NULL != aa) {
	d = SkAlphaMul(d, Accurate255To256(*aa++));
	if (0 == d) {
	continue;
	}
	}
	dst[i] = SkBlend4444(SkPixel32ToPixel4444(src[i]), dst[i], d);
	}
	}
	}

	void SkAvoidXfermode::xferA8(SkAlpha dst[], const SkPMColor src[], int count, const SkAlpha aa[])
	{
	// override in subclass
	}

	static SkFlattenable::Registrar
	gSkAvoidXfermodeReg("SkAvoidXfermode", SkAvoidXfermode::CreateProc);