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// Copyright (c) 2017 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "ui/gfx/skia_paint_util.h"
#include "cc/paint/paint_image_builder.h"
#include "third_party/skia/include/core/SkColorFilter.h"
#include "third_party/skia/include/core/SkMaskFilter.h"
#include "third_party/skia/include/effects/SkGradientShader.h"
#include "third_party/skia/include/effects/SkLayerDrawLooper.h"
#include "ui/gfx/image/image_skia_rep.h"
namespace gfx {
sk_sp<cc::PaintShader> CreateImageRepShader(const gfx::ImageSkiaRep& image_rep,
SkShader::TileMode tile_mode,
const SkMatrix& local_matrix) {
return CreateImageRepShaderForScale(image_rep, tile_mode, local_matrix,
image_rep.scale());
}
sk_sp<cc::PaintShader> CreateImageRepShaderForScale(
const gfx::ImageSkiaRep& image_rep,
SkShader::TileMode tile_mode,
const SkMatrix& local_matrix,
SkScalar scale) {
// Unscale matrix by |scale| such that the bitmap is drawn at the
// correct density.
// Convert skew and translation to pixel coordinates.
// Thus, for |bitmap_scale| = 2:
// x scale = 2, x translation = 1 DIP,
// should be converted to
// x scale = 1, x translation = 2 pixels.
SkMatrix shader_scale = local_matrix;
shader_scale.preScale(scale, scale);
shader_scale.setScaleX(local_matrix.getScaleX() / scale);
shader_scale.setScaleY(local_matrix.getScaleY() / scale);
return cc::PaintShader::MakeImage(
cc::PaintImageBuilder::WithDefault()
.set_id(cc::PaintImage::GetNextId())
.set_image(SkImage::MakeFromBitmap(image_rep.sk_bitmap()),
cc::PaintImage::GetNextContentId())
.TakePaintImage(),
tile_mode, tile_mode, &shader_scale);
}
sk_sp<cc::PaintShader> CreateGradientShader(int start_point,
int end_point,
SkColor start_color,
SkColor end_color) {
SkColor grad_colors[2] = {start_color, end_color};
SkPoint grad_points[2];
grad_points[0].iset(0, start_point);
grad_points[1].iset(0, end_point);
return cc::PaintShader::MakeLinearGradient(grad_points, grad_colors, nullptr,
2, SkShader::kClamp_TileMode);
}
// This is copied from
// third_party/WebKit/Source/platform/graphics/skia/SkiaUtils.h
static SkScalar RadiusToSigma(double radius) {
return radius > 0 ? SkDoubleToScalar(0.288675f * radius + 0.5f) : 0;
}
sk_sp<SkDrawLooper> CreateShadowDrawLooper(
const std::vector<ShadowValue>& shadows) {
if (shadows.empty())
return nullptr;
SkLayerDrawLooper::Builder looper_builder;
looper_builder.addLayer(); // top layer of the original.
SkLayerDrawLooper::LayerInfo layer_info;
layer_info.fPaintBits |= SkLayerDrawLooper::kMaskFilter_Bit;
layer_info.fPaintBits |= SkLayerDrawLooper::kColorFilter_Bit;
layer_info.fColorMode = SkBlendMode::kSrc;
for (size_t i = 0; i < shadows.size(); ++i) {
const ShadowValue& shadow = shadows[i];
layer_info.fOffset.set(SkIntToScalar(shadow.x()),
SkIntToScalar(shadow.y()));
SkPaint* paint = looper_builder.addLayer(layer_info);
// Skia's blur radius defines the range to extend the blur from
// original mask, which is half of blur amount as defined in ShadowValue.
paint->setMaskFilter(SkMaskFilter::MakeBlur(
kNormal_SkBlurStyle, RadiusToSigma(shadow.blur() / 2)));
paint->setColorFilter(
SkColorFilter::MakeModeFilter(shadow.color(), SkBlendMode::kSrcIn));
}
return looper_builder.detach();
}
} // namespace gfx
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