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/*
* 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], const float src[16], float t) {
dst[0] = SkFloatToFixed(poly_eval(&src[ 0], t));
dst[1] = SkFloatToFixed(poly_eval(&src[ 4], t));
dst[2] = SkFloatToFixed(poly_eval(&src[ 8], t));
dst[3] = SkFloatToFixed(poly_eval(&src[12], t));
}
static void bicubicFilter(const SkBitmapProcState& s, int x, int y,
SkPMColor* SK_RESTRICT colors, int count) {
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),
};
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, coefficients, fractx);
build_coeff4(coeffY, coefficients, 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);
SkPMColor s00 = *s.fBitmap->getAddr32(x0, y0);
SkPMColor s10 = *s.fBitmap->getAddr32(x1, y0);
SkPMColor s20 = *s.fBitmap->getAddr32(x2, y0);
SkPMColor s30 = *s.fBitmap->getAddr32(x3, y0);
SkPMColor s0 = cubicBlend(coeffX, s00, s10, s20, s30);
SkPMColor s01 = *s.fBitmap->getAddr32(x0, y1);
SkPMColor s11 = *s.fBitmap->getAddr32(x1, y1);
SkPMColor s21 = *s.fBitmap->getAddr32(x2, y1);
SkPMColor s31 = *s.fBitmap->getAddr32(x3, y1);
SkPMColor s1 = cubicBlend(coeffX, s01, s11, s21, s31);
SkPMColor s02 = *s.fBitmap->getAddr32(x0, y2);
SkPMColor s12 = *s.fBitmap->getAddr32(x1, y2);
SkPMColor s22 = *s.fBitmap->getAddr32(x2, y2);
SkPMColor s32 = *s.fBitmap->getAddr32(x3, y2);
SkPMColor s2 = cubicBlend(coeffX, s02, s12, s22, s32);
SkPMColor s03 = *s.fBitmap->getAddr32(x0, y3);
SkPMColor s13 = *s.fBitmap->getAddr32(x1, y3);
SkPMColor s23 = *s.fBitmap->getAddr32(x2, y3);
SkPMColor s33 = *s.fBitmap->getAddr32(x3, y3);
SkPMColor s3 = cubicBlend(coeffX, s03, s13, s23, s33);
*colors++ = cubicBlend(coeffY, s0, s1, s2, s3);
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;
}
return bicubicFilter;
}
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