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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.
#include <memory>
#include "base/macros.h"
#include "ui/compositor/layer_animation_observer.h"
#include "ui/gfx/geometry/rect.h"
namespace gfx {
struct ShadowDetails;
} // namespace gfx
namespace ui {
class Layer;
// Simple class that draws a drop shadow around content at given bounds.
class Shadow : public ui::ImplicitAnimationObserver {
~Shadow() override;
// Initialize for the the given shadow |elevation|. This is passed to
// gfx::ShadowValue::MakeMdShadowValues() and controls the y-offset and blur
// for the shadow style.
void Init(int elevation);
// Returns |layer_.get()|. This is exposed so it can be added to the same
// layer as the content and stacked below it. SetContentBounds() should be
// used to adjust the shadow's size and position (rather than applying
// transformations to this layer).
ui::Layer* layer() const { return layer_.get(); }
// Exposed to allow setting animation parameters for bounds and opacity
// animations.
ui::Layer* shadow_layer() const { return shadow_layer_.get(); }
const gfx::Rect& content_bounds() const { return content_bounds_; }
int desired_elevation() const { return desired_elevation_; }
// Moves and resizes the shadow layer to frame |content_bounds|.
void SetContentBounds(const gfx::Rect& content_bounds);
// Sets the shadow's appearance, animating opacity as necessary.
void SetElevation(int elevation);
// Sets the radius for the rounded corners to take into account when
// adjusting the shadow layer to frame |content_bounds|. 0 or greater.
void SetRoundedCornerRadius(int rounded_corner_radius);
const gfx::ShadowDetails* details_for_testing() const { return details_; }
// ui::ImplicitAnimationObserver overrides:
void OnImplicitAnimationsCompleted() override;
// Updates the shadow layer and its image to reflect |desired_elevation_|.
void RecreateShadowLayer();
// Updates the shadow layer bounds based on the inteior inset and the current
// |content_bounds_|.
void UpdateLayerBounds();
// The goal elevation, set when the transition animation starts. The elevation
// dictates the shadow's display characteristics and is proportional to the
// size of the blur and its offset. This may not match reality if the window
// isn't big enough to support it.
int desired_elevation_ = 0;
// Rounded corners are drawn on top of the window's content layer,
// we need to exclude them from the occlusion area.
int rounded_corner_radius_ = 2;
// The details of the shadow image that's currently set on |shadow_layer_|.
// This will be null until a positive elevation has been set. Once set, it
// will always point to a global ShadowDetails instance that is guaranteed
// to outlive the Shadow instance. See ui/gfx/shadow_util.h for how these
// ShadowDetails instances are created.
const gfx::ShadowDetails* details_ = nullptr;
// The parent layer of the shadow layer. It serves as a container accessible
// from the outside to control the visibility of the shadow.
std::unique_ptr<ui::Layer> layer_;
// The actual shadow layer corresponding to a cc::NinePatchLayer.
std::unique_ptr<ui::Layer> shadow_layer_;
// When the elevation changes, the old shadow cross-fades with the new one.
// When non-null, this is an old |shadow_layer_| that's being animated out.
std::unique_ptr<ui::Layer> fading_layer_;
// Bounds of the content that the shadow encloses.
gfx::Rect content_bounds_;
} // namespace ui