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// Copyright (c) 2012 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.
#ifndef UI_GFX_SHADOW_VALUE_H_
#define UI_GFX_SHADOW_VALUE_H_
#include <string>
#include <tuple>
#include <vector>
#include "third_party/skia/include/core/SkColor.h"
#include "ui/gfx/geometry/vector2d.h"
#include "ui/gfx/gfx_export.h"
namespace gfx {
class Insets;
class ShadowValue;
typedef std::vector<ShadowValue> ShadowValues;
// ShadowValue encapsulates parameters needed to define a shadow, including the
// shadow's offset, blur amount and color.
class GFX_EXPORT ShadowValue {
public:
constexpr ShadowValue() = default;
constexpr ShadowValue(const gfx::Vector2d& offset, double blur, SkColor color)
: offset_(offset), blur_(blur), color_(color) {}
constexpr int x() const { return offset_.x(); }
constexpr int y() const { return offset_.y(); }
constexpr const gfx::Vector2d& offset() const { return offset_; }
constexpr double blur() const { return blur_; }
constexpr SkColor color() const { return color_; }
constexpr bool operator==(const ShadowValue& other) const {
return offset_ == other.offset_ && blur_ == other.blur_ &&
color_ == other.color_;
}
ShadowValue Scale(float scale) const;
std::string ToString() const;
// Gets margin space needed for shadows. Note that values in returned Insets
// are negative because shadow margins are outside a boundary.
static Insets GetMargin(const ShadowValues& shadows);
// Gets the area inside a rectangle that would be affected by shadow blur.
// This is similar to the margin except it's positive (the blur region is
// inside a hypothetical rectangle) and it accounts for the blur both inside
// and outside the bounding box. The region inside the "blur region" would be
// a uniform color.
static Insets GetBlurRegion(const ShadowValues& shadows);
// Makes ShadowValues for the given elevation and color. Calls to
// MakeShadowValues that expect to fallback to MakeMdShadowValues should pass
// in the same base color for |key_shadow_color| and |ambient_shadow_color|
// until MakeMdShadowValues is refactored to remove SkColorSetA calls and also
// take in its own |key_shadow_color| and |ambient_shadow_color|.
// TODO(elainechien): crbug.com/1056950.
static ShadowValues MakeShadowValues(int elevation,
SkColor key_shadow_color,
SkColor ambient_shadow_color);
// Makes ShadowValues for MD shadows. This style is deprecated.
static ShadowValues MakeMdShadowValues(int elevation,
SkColor color = SK_ColorBLACK);
private:
gfx::Vector2d offset_;
// Blur amount of the shadow in pixels. If underlying implementation supports
// (e.g. Skia), it can have fraction part such as 0.5 pixel. The value
// defines a range from full shadow color at the start point inside the
// shadow to fully transparent at the end point outside it. The range is
// perpendicular to and centered on the shadow edge. For example, a blur
// amount of 4.0 means to have a blurry shadow edge of 4 pixels that
// transitions from full shadow color to fully transparent and with 2 pixels
// inside the shadow and 2 pixels goes beyond the edge.
double blur_ = 0.;
SkColor color_ = SK_ColorTRANSPARENT;
};
} // namespace gfx
#endif // UI_GFX_SHADOW_VALUE_H_