ash: Better and faster text shadows.

- Add a DrawStringWithShadows that draws text with shadows to canvas skia
  and RenderText;
- Use DrawStringWithShadows in DropShadowLabel for better and faster text
  shadows;

BUG=121694
TEST=Verify fix for issue 121694.


Review URL: http://codereview.chromium.org/10008027

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@131696 0039d316-1c4b-4281-b951-d872f2087c98

3 files changed, 45 insertions, 100 deletions

diff --git a/ash/app_list/app_list_item_view.cc b/ash/app_list/app_list_item_view.cc
index 5addda1..c9e7492 100644
--- a/ash/app_list/app_list_item_view.cc
+++ b/ash/app_list/app_list_item_view.cc
@@ -17,6 +17,7 @@
 #include "ui/base/resource/resource_bundle.h"
 #include "ui/gfx/canvas.h"
 #include "ui/gfx/font.h"
+#include "ui/gfx/shadow_value.h"
 #include "ui/gfx/skbitmap_operations.h"
 #include "ui/views/controls/image_view.h"
 #include "ui/views/controls/menu/menu_item_view.h"
@@ -184,7 +185,14 @@ AppListItemView::AppListItemView(AppListModelView* list_model_view,
       ALLOW_THIS_IN_INITIALIZER_LIST(apply_shadow_factory_(this)) {
   title_->SetBackgroundColor(0);
   title_->SetEnabledColor(kTitleColor);
-  title_->SetDropShadowSize(3);
+
+  const gfx::ShadowValue kTitleShadows[] = {
+    gfx::ShadowValue(gfx::Point(0, 0), 1, SkColorSetARGB(0x66, 0, 0, 0)),
+    gfx::ShadowValue(gfx::Point(0, 0), 10, SkColorSetARGB(0x66, 0, 0, 0)),
+    gfx::ShadowValue(gfx::Point(0, 2), 2, SkColorSetARGB(0x66, 0, 0, 0)),
+    gfx::ShadowValue(gfx::Point(0, 2), 4, SkColorSetARGB(0x66, 0, 0, 0)),
+  };
+  title_->SetTextShadows(arraysize(kTitleShadows), kTitleShadows);
 
   AddChildView(icon_);
   AddChildView(title_);
diff --git a/ash/app_list/drop_shadow_label.cc b/ash/app_list/drop_shadow_label.cc
index de1c90f..c897e2a 100644
--- a/ash/app_list/drop_shadow_label.cc
+++ b/ash/app_list/drop_shadow_label.cc
@@ -8,97 +8,49 @@
 #include "third_party/skia/include/effects/SkGradientShader.h"
 #include "ui/gfx/canvas.h"
 #include "ui/gfx/color_utils.h"
+#include "ui/gfx/insets.h"
 #include "ui/gfx/skbitmap_operations.h"
 
 using views::Label;
 
 namespace ash {
 
-static const int kDefaultDropShadowSize = 2;
+DropShadowLabel::DropShadowLabel() {
+}
 
-DropShadowLabel::DropShadowLabel() : drop_shadow_size_(kDefaultDropShadowSize) {
+DropShadowLabel::~DropShadowLabel() {
 }
 
-void DropShadowLabel::SetDropShadowSize(int drop_shadow_size) {
-  if (drop_shadow_size != drop_shadow_size_) {
-    drop_shadow_size_ = drop_shadow_size;
-    invalidate_text_size();
-    SchedulePaint();
+void DropShadowLabel::SetTextShadows(int shadow_count,
+                                     const gfx::ShadowValue* shadows) {
+  text_shadows_.clear();
+
+  if (shadow_count && shadows) {
+    for (int i = 0; i < shadow_count; ++i)
+      text_shadows_.push_back(shadows[i]);
   }
 }
 
+gfx::Insets DropShadowLabel::GetInsets() const {
+  gfx::Insets insets = views::Label::GetInsets();
+  gfx::Insets shadow_margin = gfx::ShadowValue::GetMargin(text_shadows_);
+  // Negate |shadow_margin| to convert it to a padding insets needed inside
+  // the bounds and combine with label's insets.
+  insets += -shadow_margin;
+  return insets;
+}
+
 void DropShadowLabel::PaintText(gfx::Canvas* canvas,
                                 const string16& text,
                                 const gfx::Rect& text_bounds,
                                 int flags) {
   SkColor text_color = enabled() ? enabled_color() : disabled_color();
-  if (drop_shadow_size_ > 0) {
-    // To properly render shadow with elliding fade effect, text and shadow
-    // is rendered to this canvas first with elliding disable so that underlying
-    // code would not mix shadow color into text area because of elliding fade.
-    // When that is done and if we need elliding fade, an alpha mask is applied
-    // when transfering contents on this canvas to target canvas.
-    gfx::Size canvas_size(text_bounds.width() + drop_shadow_size_,
-                          text_bounds.height() + drop_shadow_size_);
-    gfx::Canvas text_canvas(canvas_size, false);
-
-    const double kShadowOpacity = 0.2;
-    const SkColor shadow_color =
-        SkColorSetA(SK_ColorBLACK, kShadowOpacity * SkColorGetA(text_color));
-    gfx::Size text_size = GetTextSize();
-    for (int i = 0; i < drop_shadow_size_; i++) {
-      text_canvas.DrawStringInt(text, font(), shadow_color, i, 0,
-                                text_size.width(), text_size.height(),
-                                flags | gfx::Canvas::NO_ELLIPSIS);
-      text_canvas.DrawStringInt(text, font(), shadow_color, i, i,
-                                text_size.width(), text_size.height(),
-                                flags | gfx::Canvas::NO_ELLIPSIS);
-      text_canvas.DrawStringInt(text, font(), shadow_color, 0, i,
-                                text_size.width(), text_size.height(),
-                                flags | gfx::Canvas::NO_ELLIPSIS);
-    }
-    text_canvas.DrawStringInt(text, font(), text_color, 0, 0,
-                              text_size.width(), text_size.height(),
-                              flags | gfx::Canvas::NO_ELLIPSIS);
-
-    const SkBitmap& text_bitmap = const_cast<SkBitmap&>(
-        skia::GetTopDevice(*text_canvas.sk_canvas())->accessBitmap(false));
-
-    if (text_size.width() > text_bounds.width() &&
-        !(flags & gfx::Canvas::NO_ELLIPSIS)) {
-      // Apply an gradient alpha mask for elliding fade effect.
-      const double kFadeWidthFactor = 1.5;
-      int fade_width = std::min(text_size.width() / 2,
-          static_cast<int>(text_size.height() * kFadeWidthFactor));
-
-      const SkColor kColors[] = { SK_ColorWHITE, 0 };
-      const SkScalar kPoints[] = { SkIntToScalar(0), SkIntToScalar(1) };
-      SkPoint p[2];
-      p[0].set(SkIntToScalar(text_bounds.width() - fade_width),
-               SkIntToScalar(0));
-      p[1].set(SkIntToScalar(text_bounds.width()),
-               SkIntToScalar(0));
-      SkShader* s = SkGradientShader::CreateLinear(
-          p, kColors, kPoints, 2, SkShader::kClamp_TileMode, NULL);
-
-      SkPaint paint;
-      paint.setShader(s)->unref();
-
-      gfx::Canvas alpha_canvas(canvas_size, false);
-      alpha_canvas.DrawRect(gfx::Rect(canvas_size), paint);
-
-      const SkBitmap& alpha_bitmap = const_cast<SkBitmap&>(
-          skia::GetTopDevice(*alpha_canvas.sk_canvas())->accessBitmap(false));
-      SkBitmap blended = SkBitmapOperations::CreateMaskedBitmap(text_bitmap,
-          alpha_bitmap);
-      canvas->DrawBitmapInt(blended, text_bounds.x(), text_bounds.y());
-    } else {
-      canvas->DrawBitmapInt(text_bitmap, text_bounds.x(), text_bounds.y());
-    }
-  } else {
-    canvas->DrawStringInt(text, font(), text_color, text_bounds.x(),
-        text_bounds.y(), text_bounds.width(), text_bounds.height(), flags);
-  }
+  canvas->DrawStringWithShadows(text,
+                                font(),
+                                text_color,
+                                text_bounds,
+                                flags,
+                                text_shadows_);
 
   if (HasFocus() || paint_as_focused()) {
     gfx::Rect focus_bounds = text_bounds;
@@ -108,11 +60,4 @@ void DropShadowLabel::PaintText(gfx::Canvas* canvas,
   }
 }
 
-gfx::Size DropShadowLabel::GetTextSize() const {
-  gfx::Size text_size = Label::GetTextSize();
-  text_size.SetSize(text_size.width() + drop_shadow_size_,
-                    text_size.height() + drop_shadow_size_);
-  return text_size;
-}
-
 }  // namespace ash
diff --git a/ash/app_list/drop_shadow_label.h b/ash/app_list/drop_shadow_label.h
index 2a7ce5d..25a24e1 100644
--- a/ash/app_list/drop_shadow_label.h
+++ b/ash/app_list/drop_shadow_label.h
@@ -1,4 +1,4 @@
-// Copyright (c) 2011 The Chromium Authors. All rights reserved.
+// 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.
 
@@ -6,7 +6,9 @@
 #define ASH_APP_LIST_DROP_SHADOW_LABEL_H_
 #pragma once
 
-#include "ui/gfx/font.h"
+#include <vector>
+
+#include "ui/gfx/shadow_value.h"
 #include "ui/views/controls/label.h"
 
 namespace ash {
@@ -22,29 +24,19 @@ namespace ash {
 class DropShadowLabel : public views::Label  {
  public:
   DropShadowLabel();
+  virtual ~DropShadowLabel();
 
-  // Sets the size of the drop shadow drawn under the text.
-  // Defaults to two.  Note that this is a really simplistic drop
-  // shadow -- it gets more expensive to draw the larger it gets,
-  // since it simply draws more copies of the string.  For instance,
-  // for a value of two, the string is draw seven times.  In general,
-  // it is drawn three extra times for each increment of |size|.
-  void SetDropShadowSize(int size);
-
-  // Return the size of the drop shadow in pixels.
-  int drop_shadow_size() const { return drop_shadow_size_; }
+  void SetTextShadows(int shadow_count, const gfx::ShadowValue* shadows);
 
-  // Overridden to paint the text differently from the base class.
+ private:
+  // Overridden from views::Label:
+  virtual gfx::Insets GetInsets() const OVERRIDE;
   virtual void PaintText(gfx::Canvas* canvas,
                          const string16& text,
                          const gfx::Rect& text_bounds,
                          int flags) OVERRIDE;
 
- protected:
-  virtual gfx::Size GetTextSize() const OVERRIDE;
-
- private:
-  int drop_shadow_size_;
+  std::vector<gfx::ShadowValue> text_shadows_;
 
   DISALLOW_COPY_AND_ASSIGN(DropShadowLabel);
 };