src/core/SkBitmapProcBicubic.cpp - platform/external/skia - Gitiles

 /*
  * Copyright 2013 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */

 #include "SkBitmapProcState.h"
 #include "SkBitmap.h"
 #include "SkColor.h"
 #include "SkColorPriv.h"
 #include "SkUnPreMultiply.h"
 #include "SkRTConf.h"
 #include "SkShader.h"

 #define DS(x) SkDoubleToScalar(x)

 #define MUL(a, b)   ((a) * (b))

 static inline SkPMColor cubicBlend(const SkFixed cc[4], SkPMColor c0, SkPMColor c1, SkPMColor c2, SkPMColor c3) {
     SkFixed fa = MUL(cc[0], SkGetPackedA32(c0)) + MUL(cc[1], SkGetPackedA32(c1)) + MUL(cc[2], SkGetPackedA32(c2)) + MUL(cc[3], SkGetPackedA32(c3));
     SkFixed fr = MUL(cc[0], SkGetPackedR32(c0)) + MUL(cc[1], SkGetPackedR32(c1)) + MUL(cc[2], SkGetPackedR32(c2)) + MUL(cc[3], SkGetPackedR32(c3));
     SkFixed fg = MUL(cc[0], SkGetPackedG32(c0)) + MUL(cc[1], SkGetPackedG32(c1)) + MUL(cc[2], SkGetPackedG32(c2)) + MUL(cc[3], SkGetPackedG32(c3));
     SkFixed fb = MUL(cc[0], SkGetPackedB32(c0)) + MUL(cc[1], SkGetPackedB32(c1)) + MUL(cc[2], SkGetPackedB32(c2)) + MUL(cc[3], SkGetPackedB32(c3));

     int a = SkClampMax(SkFixedRoundToInt(fa), 255);
     int r = SkClampMax(SkFixedRoundToInt(fr), a);
     int g = SkClampMax(SkFixedRoundToInt(fg), a);
     int b = SkClampMax(SkFixedRoundToInt(fb), a);

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

 static float poly_eval(const float cc[4], float t) {
     return cc[0] + t * (cc[1] + t * (cc[2] + t * cc[3]));
 }

 static void build_coeff4(SkFixed dst[4], float t) {
     static const SkScalar coefficients[16] = {
         DS( 1.0 / 18.0), DS(-9.0 / 18.0), DS( 15.0 / 18.0), DS( -7.0 / 18.0),
         DS(16.0 / 18.0), DS( 0.0 / 18.0), DS(-36.0 / 18.0), DS( 21.0 / 18.0),
         DS( 1.0 / 18.0), DS( 9.0 / 18.0), DS( 27.0 / 18.0), DS(-21.0 / 18.0),
         DS( 0.0 / 18.0), DS( 0.0 / 18.0), DS( -6.0 / 18.0), DS(  7.0 / 18.0),
     };

     dst[0] = SkFloatToFixed(poly_eval(&coefficients[ 0], t));
     dst[1] = SkFloatToFixed(poly_eval(&coefficients[ 4], t));
     dst[2] = SkFloatToFixed(poly_eval(&coefficients[ 8], t));
     dst[3] = SkFloatToFixed(poly_eval(&coefficients[12], t));
 }

 static SkPMColor doBicubicFilter(const SkBitmap *bm, SkFixed coeffX[4], SkFixed coeffY[4],
                             int x0, int x1, int x2, int x3,
                             int y0, int y1, int y2, int y3 )
 {
     SkPMColor s00 = *bm->getAddr32(x0, y0);
     SkPMColor s10 = *bm->getAddr32(x1, y0);
     SkPMColor s20 = *bm->getAddr32(x2, y0);
     SkPMColor s30 = *bm->getAddr32(x3, y0);
     SkPMColor s0 = cubicBlend(coeffX, s00, s10, s20, s30);
     SkPMColor s01 = *bm->getAddr32(x0, y1);
     SkPMColor s11 = *bm->getAddr32(x1, y1);
     SkPMColor s21 = *bm->getAddr32(x2, y1);
     SkPMColor s31 = *bm->getAddr32(x3, y1);
     SkPMColor s1 = cubicBlend(coeffX, s01, s11, s21, s31);
     SkPMColor s02 = *bm->getAddr32(x0, y2);
     SkPMColor s12 = *bm->getAddr32(x1, y2);
     SkPMColor s22 = *bm->getAddr32(x2, y2);
     SkPMColor s32 = *bm->getAddr32(x3, y2);
     SkPMColor s2 = cubicBlend(coeffX, s02, s12, s22, s32);
     SkPMColor s03 = *bm->getAddr32(x0, y3);
     SkPMColor s13 = *bm->getAddr32(x1, y3);
     SkPMColor s23 = *bm->getAddr32(x2, y3);
     SkPMColor s33 = *bm->getAddr32(x3, y3);
     SkPMColor s3 = cubicBlend(coeffX, s03, s13, s23, s33);
     return cubicBlend(coeffY, s0, s1, s2, s3);
 }

 static void bicubicFilter(const SkBitmapProcState& s, int x, int y,
                           SkPMColor* SK_RESTRICT colors, int count) {

     const int maxX = s.fBitmap->width() - 1;
     const int maxY = s.fBitmap->height() - 1;

     while (count-- > 0) {
         SkPoint srcPt;
         s.fInvProc(*s.fInvMatrix, SkIntToScalar(x),
                     SkIntToScalar(y), &srcPt);
         srcPt.fX -= SK_ScalarHalf;
         srcPt.fY -= SK_ScalarHalf;
         SkScalar fractx = srcPt.fX - SkScalarFloorToScalar(srcPt.fX);
         SkScalar fracty = srcPt.fY - SkScalarFloorToScalar(srcPt.fY);

         SkFixed coeffX[4], coeffY[4];
         build_coeff4(coeffX, fractx);
         build_coeff4(coeffY, fracty);

         int sx = SkScalarFloorToInt(srcPt.fX);
         int sy = SkScalarFloorToInt(srcPt.fY);

         // Here is where we can support other tile modes (e.g. repeat or mirror)
         int x0 = SkClampMax(sx - 1, maxX);
         int x1 = SkClampMax(sx    , maxX);
         int x2 = SkClampMax(sx + 1, maxX);
         int x3 = SkClampMax(sx + 2, maxX);
         int y0 = SkClampMax(sy - 1, maxY);
         int y1 = SkClampMax(sy    , maxY);
         int y2 = SkClampMax(sy + 1, maxY);
         int y3 = SkClampMax(sy + 2, maxY);

         *colors++ = doBicubicFilter( s.fBitmap, coeffX, coeffY, x0, x1, x2, x3, y0, y1, y2, y3 );

         x++;
     }
 }

 static void bicubicFilter_ScaleOnly(const SkBitmapProcState &s, int x, int y,
                                     SkPMColor *SK_RESTRICT colors, int count) {
     const int maxX = s.fBitmap->width() - 1;
     const int maxY = s.fBitmap->height() - 1;

     SkPoint srcPt;
     s.fInvProc(*s.fInvMatrix, SkIntToScalar(x), SkIntToScalar(y), &srcPt);
     srcPt.fY -= SK_ScalarHalf;
     SkScalar fracty = srcPt.fY - SkScalarFloorToScalar(srcPt.fY);
     SkFixed coeffX[4], coeffY[4];
     build_coeff4(coeffY, fracty);
     int sy = SkScalarFloorToInt(srcPt.fY);
     int y0 = SkClampMax(sy - 1, maxY);
     int y1 = SkClampMax(sy    , maxY);
     int y2 = SkClampMax(sy + 1, maxY);
     int y3 = SkClampMax(sy + 2, maxY);

     while (count-- > 0) {
         s.fInvProc(*s.fInvMatrix, SkIntToScalar(x), SkIntToScalar(y), &srcPt);
         srcPt.fX -= SK_ScalarHalf;
         SkScalar fractx = srcPt.fX - SkScalarFloorToScalar(srcPt.fX);

         build_coeff4(coeffX, fractx);

         int sx = SkScalarFloorToInt(srcPt.fX);

         // Here is where we can support other tile modes (e.g. repeat or mirror)
         int x0 = SkClampMax(sx - 1, maxX);
         int x1 = SkClampMax(sx    , maxX);
         int x2 = SkClampMax(sx + 1, maxX);
         int x3 = SkClampMax(sx + 2, maxX);

         *colors++ = doBicubicFilter( s.fBitmap, coeffX, coeffY, x0, x1, x2, x3, y0, y1, y2, y3 );

         x++;
     }
 }

 SkBitmapProcState::ShaderProc32
 SkBitmapProcState::chooseBicubicFilterProc(const SkPaint& paint) {
     // we need to be requested
     uint32_t mask = SkPaint::kFilterBitmap_Flag
                   | SkPaint::kBicubicFilterBitmap_Flag
                   ;
     if ((paint.getFlags() & mask) != mask) {
         return NULL;
     }

     // TODO: consider supporting other configs (e.g. 565, A8)
     if (fBitmap->config() != SkBitmap::kARGB_8888_Config) {
         return NULL;
     }

     // TODO: consider supporting repeat and mirror
     if (SkShader::kClamp_TileMode != fTileModeX || SkShader::kClamp_TileMode != fTileModeY) {
         return NULL;
     }

     // TODO: support blending inside our procs
     if (0xFF != paint.getAlpha()) {
         return NULL;
     }

     if (fInvType & SkMatrix::kAffine_Mask) {
         return bicubicFilter;
     } else if (fInvType & SkMatrix::kScale_Mask) {
         return bicubicFilter_ScaleOnly;
     } else {
         return NULL;
     }
 }
	/*
	* Copyright 2013 Google Inc.
	*
	* Use of this source code is governed by a BSD-style license that can be
	* found in the LICENSE file.
	*/

	#include "SkBitmapProcState.h"
	#include "SkBitmap.h"
	#include "SkColor.h"
	#include "SkColorPriv.h"
	#include "SkUnPreMultiply.h"
	#include "SkRTConf.h"
	#include "SkShader.h"

	#define DS(x) SkDoubleToScalar(x)

	#define MUL(a, b) ((a) * (b))

	static inline SkPMColor cubicBlend(const SkFixed cc[4], SkPMColor c0, SkPMColor c1, SkPMColor c2, SkPMColor c3) {
	SkFixed fa = MUL(cc[0], SkGetPackedA32(c0)) + MUL(cc[1], SkGetPackedA32(c1)) + MUL(cc[2], SkGetPackedA32(c2)) + MUL(cc[3], SkGetPackedA32(c3));
	SkFixed fr = MUL(cc[0], SkGetPackedR32(c0)) + MUL(cc[1], SkGetPackedR32(c1)) + MUL(cc[2], SkGetPackedR32(c2)) + MUL(cc[3], SkGetPackedR32(c3));
	SkFixed fg = MUL(cc[0], SkGetPackedG32(c0)) + MUL(cc[1], SkGetPackedG32(c1)) + MUL(cc[2], SkGetPackedG32(c2)) + MUL(cc[3], SkGetPackedG32(c3));
	SkFixed fb = MUL(cc[0], SkGetPackedB32(c0)) + MUL(cc[1], SkGetPackedB32(c1)) + MUL(cc[2], SkGetPackedB32(c2)) + MUL(cc[3], SkGetPackedB32(c3));

	int a = SkClampMax(SkFixedRoundToInt(fa), 255);
	int r = SkClampMax(SkFixedRoundToInt(fr), a);
	int g = SkClampMax(SkFixedRoundToInt(fg), a);
	int b = SkClampMax(SkFixedRoundToInt(fb), a);

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

	static float poly_eval(const float cc[4], float t) {
	return cc[0] + t * (cc[1] + t * (cc[2] + t * cc[3]));
	}

	static void build_coeff4(SkFixed dst[4], float t) {
	static const SkScalar coefficients[16] = {
	DS( 1.0 / 18.0), DS(-9.0 / 18.0), DS( 15.0 / 18.0), DS( -7.0 / 18.0),
	DS(16.0 / 18.0), DS( 0.0 / 18.0), DS(-36.0 / 18.0), DS( 21.0 / 18.0),
	DS( 1.0 / 18.0), DS( 9.0 / 18.0), DS( 27.0 / 18.0), DS(-21.0 / 18.0),
	DS( 0.0 / 18.0), DS( 0.0 / 18.0), DS( -6.0 / 18.0), DS( 7.0 / 18.0),
	};

	dst[0] = SkFloatToFixed(poly_eval(&coefficients[ 0], t));
	dst[1] = SkFloatToFixed(poly_eval(&coefficients[ 4], t));
	dst[2] = SkFloatToFixed(poly_eval(&coefficients[ 8], t));
	dst[3] = SkFloatToFixed(poly_eval(&coefficients[12], t));
	}

	static SkPMColor doBicubicFilter(const SkBitmap *bm, SkFixed coeffX[4], SkFixed coeffY[4],
	int x0, int x1, int x2, int x3,
	int y0, int y1, int y2, int y3 )
	{
	SkPMColor s00 = *bm->getAddr32(x0, y0);
	SkPMColor s10 = *bm->getAddr32(x1, y0);
	SkPMColor s20 = *bm->getAddr32(x2, y0);
	SkPMColor s30 = *bm->getAddr32(x3, y0);
	SkPMColor s0 = cubicBlend(coeffX, s00, s10, s20, s30);
	SkPMColor s01 = *bm->getAddr32(x0, y1);
	SkPMColor s11 = *bm->getAddr32(x1, y1);
	SkPMColor s21 = *bm->getAddr32(x2, y1);
	SkPMColor s31 = *bm->getAddr32(x3, y1);
	SkPMColor s1 = cubicBlend(coeffX, s01, s11, s21, s31);
	SkPMColor s02 = *bm->getAddr32(x0, y2);
	SkPMColor s12 = *bm->getAddr32(x1, y2);
	SkPMColor s22 = *bm->getAddr32(x2, y2);
	SkPMColor s32 = *bm->getAddr32(x3, y2);
	SkPMColor s2 = cubicBlend(coeffX, s02, s12, s22, s32);
	SkPMColor s03 = *bm->getAddr32(x0, y3);
	SkPMColor s13 = *bm->getAddr32(x1, y3);
	SkPMColor s23 = *bm->getAddr32(x2, y3);
	SkPMColor s33 = *bm->getAddr32(x3, y3);
	SkPMColor s3 = cubicBlend(coeffX, s03, s13, s23, s33);
	return cubicBlend(coeffY, s0, s1, s2, s3);
	}

	static void bicubicFilter(const SkBitmapProcState& s, int x, int y,
	SkPMColor* SK_RESTRICT colors, int count) {

	const int maxX = s.fBitmap->width() - 1;
	const int maxY = s.fBitmap->height() - 1;

	while (count-- > 0) {
	SkPoint srcPt;
	s.fInvProc(*s.fInvMatrix, SkIntToScalar(x),
	SkIntToScalar(y), &srcPt);
	srcPt.fX -= SK_ScalarHalf;
	srcPt.fY -= SK_ScalarHalf;
	SkScalar fractx = srcPt.fX - SkScalarFloorToScalar(srcPt.fX);
	SkScalar fracty = srcPt.fY - SkScalarFloorToScalar(srcPt.fY);

	SkFixed coeffX[4], coeffY[4];
	build_coeff4(coeffX, fractx);
	build_coeff4(coeffY, fracty);

	int sx = SkScalarFloorToInt(srcPt.fX);
	int sy = SkScalarFloorToInt(srcPt.fY);

	// Here is where we can support other tile modes (e.g. repeat or mirror)
	int x0 = SkClampMax(sx - 1, maxX);
	int x1 = SkClampMax(sx , maxX);
	int x2 = SkClampMax(sx + 1, maxX);
	int x3 = SkClampMax(sx + 2, maxX);
	int y0 = SkClampMax(sy - 1, maxY);
	int y1 = SkClampMax(sy , maxY);
	int y2 = SkClampMax(sy + 1, maxY);
	int y3 = SkClampMax(sy + 2, maxY);

	*colors++ = doBicubicFilter( s.fBitmap, coeffX, coeffY, x0, x1, x2, x3, y0, y1, y2, y3 );

	x++;
	}
	}

	static void bicubicFilter_ScaleOnly(const SkBitmapProcState &s, int x, int y,
	SkPMColor *SK_RESTRICT colors, int count) {
	const int maxX = s.fBitmap->width() - 1;
	const int maxY = s.fBitmap->height() - 1;

	SkPoint srcPt;
	s.fInvProc(*s.fInvMatrix, SkIntToScalar(x), SkIntToScalar(y), &srcPt);
	srcPt.fY -= SK_ScalarHalf;
	SkScalar fracty = srcPt.fY - SkScalarFloorToScalar(srcPt.fY);
	SkFixed coeffX[4], coeffY[4];
	build_coeff4(coeffY, fracty);
	int sy = SkScalarFloorToInt(srcPt.fY);
	int y0 = SkClampMax(sy - 1, maxY);
	int y1 = SkClampMax(sy , maxY);
	int y2 = SkClampMax(sy + 1, maxY);
	int y3 = SkClampMax(sy + 2, maxY);

	while (count-- > 0) {
	s.fInvProc(*s.fInvMatrix, SkIntToScalar(x), SkIntToScalar(y), &srcPt);
	srcPt.fX -= SK_ScalarHalf;
	SkScalar fractx = srcPt.fX - SkScalarFloorToScalar(srcPt.fX);

	build_coeff4(coeffX, fractx);

	int sx = SkScalarFloorToInt(srcPt.fX);

	// Here is where we can support other tile modes (e.g. repeat or mirror)
	int x0 = SkClampMax(sx - 1, maxX);
	int x1 = SkClampMax(sx , maxX);
	int x2 = SkClampMax(sx + 1, maxX);
	int x3 = SkClampMax(sx + 2, maxX);

	*colors++ = doBicubicFilter( s.fBitmap, coeffX, coeffY, x0, x1, x2, x3, y0, y1, y2, y3 );

	x++;
	}
	}

	SkBitmapProcState::ShaderProc32
	SkBitmapProcState::chooseBicubicFilterProc(const SkPaint& paint) {
	// we need to be requested
	uint32_t mask = SkPaint::kFilterBitmap_Flag
	\| SkPaint::kBicubicFilterBitmap_Flag
	;
	if ((paint.getFlags() & mask) != mask) {
	return NULL;
	}

	// TODO: consider supporting other configs (e.g. 565, A8)
	if (fBitmap->config() != SkBitmap::kARGB_8888_Config) {
	return NULL;
	}

	// TODO: consider supporting repeat and mirror
	if (SkShader::kClamp_TileMode != fTileModeX \|\| SkShader::kClamp_TileMode != fTileModeY) {
	return NULL;
	}

	// TODO: support blending inside our procs
	if (0xFF != paint.getAlpha()) {
	return NULL;
	}

	if (fInvType & SkMatrix::kAffine_Mask) {
	return bicubicFilter;
	} else if (fInvType & SkMatrix::kScale_Mask) {
	return bicubicFilter_ScaleOnly;
	} else {
	return NULL;
	}
	}