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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 "SkErrorInternals.h"
#include "SkConvolver.h"
#include "SkBitmapProcState.h"
#include "SkBitmap.h"
#include "SkColor.h"
#include "SkColorPriv.h"
#include "SkConvolver.h"
#include "SkUnPreMultiply.h"
#include "SkShader.h"
#include "SkRTConf.h"
#include "SkMath.h"
// These are the per-scanline callbacks that are used when we must resort to
// resampling an image as it is blitted. Typically these are used only when
// the image is rotated or has some other complex transformation applied.
// Scaled images will usually be rescaled directly before rasterization.
void highQualityFilter(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, SkFloatToScalar(x + 0.5f),
SkFloatToScalar(y + 0.5f), &srcPt);
srcPt.fX -= SK_ScalarHalf;
srcPt.fY -= SK_ScalarHalf;
SkScalar weight = 0;
SkScalar fr = 0, fg = 0, fb = 0, fa = 0;
int y0 = SkClampMax(SkScalarCeilToInt(srcPt.fY-s.getBitmapFilter()->width()), maxY);
int y1 = SkClampMax(SkScalarFloorToInt(srcPt.fY+s.getBitmapFilter()->width()), maxY);
int x0 = SkClampMax(SkScalarCeilToInt(srcPt.fX-s.getBitmapFilter()->width()), maxX);
int x1 = SkClampMax(SkScalarFloorToInt(srcPt.fX+s.getBitmapFilter()->width()), maxX);
for (int srcY = y0; srcY <= y1; srcY++) {
SkScalar yWeight = s.getBitmapFilter()->lookupScalar((srcPt.fY - srcY));
for (int srcX = x0; srcX <= x1 ; srcX++) {
SkScalar xWeight = s.getBitmapFilter()->lookupScalar((srcPt.fX - srcX));
SkScalar combined_weight = SkScalarMul(xWeight, yWeight);
SkPMColor c = *s.fBitmap->getAddr32(srcX, srcY);
fr += combined_weight * SkGetPackedR32(c);
fg += combined_weight * SkGetPackedG32(c);
fb += combined_weight * SkGetPackedB32(c);
fa += combined_weight * SkGetPackedA32(c);
weight += combined_weight;
}
}
fr = SkScalarDiv(fr, weight);
fg = SkScalarDiv(fg, weight);
fb = SkScalarDiv(fb, weight);
fa = SkScalarDiv(fa, weight);
int a = SkClampMax(SkScalarRoundToInt(fa), 255);
int r = SkClampMax(SkScalarRoundToInt(fr), a);
int g = SkClampMax(SkScalarRoundToInt(fg), a);
int b = SkClampMax(SkScalarRoundToInt(fb), a);
*colors++ = SkPackARGB32(a, r, g, b);
x++;
}
}
SK_CONF_DECLARE(const char *, c_bitmapFilter, "bitmap.filter", "mitchell", "Which scanline bitmap filter to use [mitchell, lanczos, hamming, gaussian, triangle, box]");
SkBitmapFilter *SkBitmapFilter::Allocate() {
if (!strcmp(c_bitmapFilter, "mitchell")) {
return SkNEW_ARGS(SkMitchellFilter,(1.f/3.f,1.f/3.f));
} else if (!strcmp(c_bitmapFilter, "lanczos")) {
return SkNEW(SkLanczosFilter);
} else if (!strcmp(c_bitmapFilter, "hamming")) {
return SkNEW(SkHammingFilter);
} else if (!strcmp(c_bitmapFilter, "gaussian")) {
return SkNEW_ARGS(SkGaussianFilter,(2));
} else if (!strcmp(c_bitmapFilter, "triangle")) {
return SkNEW(SkTriangleFilter);
} else if (!strcmp(c_bitmapFilter, "box")) {
return SkNEW(SkBoxFilter);
} else {
SkDEBUGFAIL("Unknown filter type");
}
return NULL;
}
SkBitmapProcState::ShaderProc32
SkBitmapProcState::chooseBitmapFilterProc() {
if (fFilterLevel != SkPaint::kHigh_FilterLevel) {
return NULL;
}
if (fAlphaScale != 256) {
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;
}
if (fInvType & (SkMatrix::kAffine_Mask | SkMatrix::kScale_Mask)) {
fBitmapFilter = SkBitmapFilter::Allocate();
}
if (fInvType & SkMatrix::kScale_Mask) {
return highQualityFilter;
} else {
return NULL;
}
}
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