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/gfx/canvas.h"
  11
  12 namespace chromeos {
  13
  14 namespace {
  15
  16 const int kShadowRadius = 10;
  17 const int kShadowAlpha = 90;
  18 const SkColor kShadowColor = SkColorSetRGB(77, 144, 254);
  19
  20 }  // namespace
  21
  22 FocusRingLayerDelegate::~FocusRingLayerDelegate() {}
  23
  24 FocusRingLayer::FocusRingLayer(FocusRingLayerDelegate* delegate)
  25     : delegate_(delegate),
  26       root_window_(NULL) {
  27 }
  28
  29 FocusRingLayer::~FocusRingLayer() {}
  30
  31 void FocusRingLayer::Set(aura::Window* root_window, const gfx::Rect& bounds) {
  32   focus_ring_ = bounds;
  33   CreateOrUpdateLayer(root_window, "FocusRing");
  34
  35   // Update the layer bounds.
  36   gfx::Rect layer_bounds = bounds;
  37   int inset = -(kShadowRadius + 2);
  38   layer_bounds.Inset(inset, inset, inset, inset);
  39   layer_->SetBounds(layer_bounds);
  40 }
  41
  42 void FocusRingLayer::CreateOrUpdateLayer(
  43     aura::Window* root_window, const char* layer_name) {
  44   if (!layer_ || root_window != root_window_) {
  45     root_window_ = root_window;
  46     ui::Layer* root_layer = root_window->layer();
  47     layer_.reset(new ui::Layer(ui::LAYER_TEXTURED));
  48     layer_->set_name(layer_name);
  49     layer_->set_delegate(this);
  50     layer_->SetFillsBoundsOpaquely(false);
  51     root_layer->Add(layer_.get());
  52   }
  53
  54   // Keep moving it to the top in case new layers have been added
  55   // since we created this layer.
  56   layer_->parent()->StackAtTop(layer_.get());
  57 }
  58
  59 void FocusRingLayer::OnPaintLayer(gfx::Canvas* canvas) {
  60   if (!root_window_ || focus_ring_.IsEmpty())
  61     return;
  62
  63   gfx::Rect bounds = focus_ring_ - layer_->bounds().OffsetFromOrigin();
  64   SkPaint paint;
  65   paint.setColor(kShadowColor);
  66   paint.setFlags(SkPaint::kAntiAlias_Flag);
  67   paint.setStyle(SkPaint::kStroke_Style);
  68   paint.setStrokeWidth(2);
  69   int r = kShadowRadius;
  70   for (int i = 0; i < r; i++) {
  71     // Fade out alpha quadratically.
  72     paint.setAlpha((kShadowAlpha * (r - i) * (r - i)) / (r * r));
  73     gfx::Rect outsetRect = bounds;
  74     outsetRect.Inset(-i, -i, -i, -i);
  75     canvas->DrawRect(outsetRect, paint);
  76   }
  77 }
  78
  79 void FocusRingLayer::OnDelegatedFrameDamage(
  80     const gfx::Rect& damage_rect_in_dip) {
  81 }
  82
  83 void FocusRingLayer::OnDeviceScaleFactorChanged(float device_scale_factor) {
  84   if (delegate_)
  85     delegate_->OnDeviceScaleFactorChanged();
  86 }
  87
  88 base::Closure FocusRingLayer::PrepareForLayerBoundsChange() {
  89   return base::Bind(&base::DoNothing);
  90 }
  91
  92 }  // namespace chromeos