chrome/browser/chromeos/ui/focus_ring_layer.cc

   1 // Copyright 2013 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #include "chrome/browser/chromeos/ui/focus_ring_layer.h"
   6
   7 #include "base/bind.h"
   8 #include "ui/aura/window.h"
   9 #include "ui/compositor/layer.h"
  10 #include "ui/compositor/paint_recorder.h"
  11 #include "ui/gfx/canvas.h"
  12
  13 namespace chromeos {
  14
  15 namespace {
  16
  17 const int kShadowRadius = 10;
  18 const int kShadowAlpha = 90;
  19 const SkColor kShadowColor = SkColorSetRGB(77, 144, 254);
  20
  21 }  // namespace
  22
  23 FocusRingLayerDelegate::~FocusRingLayerDelegate() {}
  24
  25 FocusRingLayer::FocusRingLayer(FocusRingLayerDelegate* delegate)
  26     : delegate_(delegate),
  27       root_window_(NULL) {
  28 }
  29
  30 FocusRingLayer::~FocusRingLayer() {}
  31
  32 void FocusRingLayer::Set(aura::Window* root_window, const gfx::Rect& bounds) {
  33   focus_ring_ = bounds;
  34   CreateOrUpdateLayer(root_window, "FocusRing");
  35
  36   // Update the layer bounds.
  37   gfx::Rect layer_bounds = bounds;
  38   int inset = -(kShadowRadius + 2);
  39   layer_bounds.Inset(inset, inset, inset, inset);
  40   layer_->SetBounds(layer_bounds);
  41 }
  42
  43 void FocusRingLayer::CreateOrUpdateLayer(
  44     aura::Window* root_window, const char* layer_name) {
  45   if (!layer_ || root_window != root_window_) {
  46     root_window_ = root_window;
  47     ui::Layer* root_layer = root_window->layer();
  48     layer_.reset(new ui::Layer(ui::LAYER_TEXTURED));
  49     layer_->set_name(layer_name);
  50     layer_->set_delegate(this);
  51     layer_->SetFillsBoundsOpaquely(false);
  52     root_layer->Add(layer_.get());
  53   }
  54
  55   // Keep moving it to the top in case new layers have been added
  56   // since we created this layer.
  57   layer_->parent()->StackAtTop(layer_.get());
  58 }
  59
  60 void FocusRingLayer::OnPaintLayer(const ui::PaintContext& context) {
  61   if (!root_window_ || focus_ring_.IsEmpty())
  62     return;
  63
  64   ui::PaintRecorder recorder(context, layer_->size());
  65
  66   SkPaint paint;
  67   paint.setColor(kShadowColor);
  68   paint.setFlags(SkPaint::kAntiAlias_Flag);
  69   paint.setStyle(SkPaint::kStroke_Style);
  70   paint.setStrokeWidth(2);
  71
  72   gfx::Rect bounds = focus_ring_ - layer_->bounds().OffsetFromOrigin();
  73   int r = kShadowRadius;
  74   for (int i = 0; i < r; i++) {
  75     // Fade out alpha quadratically.
  76     paint.setAlpha((kShadowAlpha * (r - i) * (r - i)) / (r * r));
  77     gfx::Rect outsetRect = bounds;
  78     outsetRect.Inset(-i, -i, -i, -i);
  79     recorder.canvas()->DrawRect(outsetRect, paint);
  80   }
  81 }
  82
  83 void FocusRingLayer::OnDelegatedFrameDamage(
  84     const gfx::Rect& damage_rect_in_dip) {
  85 }
  86
  87 void FocusRingLayer::OnDeviceScaleFactorChanged(float device_scale_factor) {
  88   if (delegate_)
  89     delegate_->OnDeviceScaleFactorChanged();
  90 }
  91
  92 base::Closure FocusRingLayer::PrepareForLayerBoundsChange() {
  93   return base::Bind(&base::DoNothing);
  94 }
  95
  96 }  // namespace chromeos