Fix pixelation of tab borders when device scale changes (abandoned)

chrome/browser/ui/views/tabs/tab.cc

Index: chrome/browser/ui/views/tabs/tab.cc
diff --git a/chrome/browser/ui/views/tabs/tab.cc b/chrome/browser/ui/views/tabs/tab.cc
index 4b854bcfbe4b1bf089ab06e6bbaf58f9954d4cd4..da49b038fb0bf5b50525da9900d25a831331130a 100644
--- a/chrome/browser/ui/views/tabs/tab.cc
+++ b/chrome/browser/ui/views/tabs/tab.cc
@@ -44,6 +44,7 @@
 #include "ui/gfx/color_analysis.h"
 #include "ui/gfx/favicon_size.h"
 #include "ui/gfx/geometry/rect_conversions.h"
+#include "ui/gfx/image/canvas_image_source.h"
 #include "ui/gfx/image/image_skia_operations.h"
 #include "ui/gfx/paint_vector_icon.h"
 #include "ui/gfx/path.h"
@@ -119,19 +120,25 @@ const char kTabCloseButtonName[] = "TabCloseButton";
 // Parameters for PaintTabBackgroundUsingParams().
 struct PaintBackgroundParams {
   PaintBackgroundParams(bool is_active,
-                        gfx::ImageSkia* fill_image_ptr,
+                        gfx::ImageSkia* fill_image,
                         bool has_custom_image,
-                        gfx::Rect rect,
+                        const gfx::Rect& rect,
                         SkColor stroke_color,
                         SkColor toolbar_color,
-                        SkColor background_tab_color)
+                        SkColor background_tab_color,
+                        bool draw_hover,
+                        const gfx::Point& hover_location,
+                        SkAlpha hover_alpha)
       : is_active(is_active),
-        fill_image(fill_image_ptr ? *fill_image_ptr : gfx::ImageSkia()),
+        fill_image(fill_image ? *fill_image : gfx::ImageSkia()),
         has_custom_image(has_custom_image),
         rect(rect),
         stroke_color(stroke_color),
         toolbar_color(toolbar_color),
-        background_tab_color(background_tab_color) {}
+        background_tab_color(background_tab_color),
+        draw_hover(draw_hover),
+        hover_location(PointToSkPoint(hover_location)),
+        hover_alpha(hover_alpha) {}
 
   const bool is_active;
   const gfx::ImageSkia fill_image;
@@ -140,8 +147,61 @@ struct PaintBackgroundParams {
   const SkColor stroke_color;
   const SkColor toolbar_color;
   const SkColor background_tab_color;
+  const bool draw_hover;
+  const SkPoint hover_location;
+  const SkAlpha hover_alpha;
 };
 
+void PaintTabBackgroundUsingParams(gfx::Canvas* fill_canvas,
+                                   gfx::Canvas* stroke_canvas,
+                                   const PaintBackgroundParams& params);
+
+////////////////////////////////////////////////////////////////////////////////
+// TabImageSource
+//
+// This subclass of CanvasImageSource allows the inactive tab image to be cached
+// once and rendered correctly for all scale factors.
+class TabImageSource : public gfx::CanvasImageSource {
+ public:
+  enum UseCanvas { FILL, STROKE, BOTH };
+
+  TabImageSource(UseCanvas use_canvas, Tab* tab, int fill_id, int y_offset);
+  ~TabImageSource() override {}
+
+  // gfx::CanvasImageSource override.
+  void Draw(gfx::Canvas* canvas) override;
+
+ private:
+  const UseCanvas use_canvas_;
+  const PaintBackgroundParams params_;
+
+  DISALLOW_COPY_AND_ASSIGN(TabImageSource);
+};
+
+TabImageSource::TabImageSource(UseCanvas use_canvas,
+                               Tab* tab,
+                               int fill_id,
+                               int y_offset)
+    : gfx::CanvasImageSource(tab->size(), true),
+      use_canvas_(use_canvas),
+      params_(false,
+              tab->GetThemeProvider()->GetImageSkiaNamed(fill_id),
+              false,
+              gfx::Rect(gfx::Point(0, y_offset), tab->size()),
+              tab->controller()->GetToolbarTopSeparatorColor(),
+              tab->GetThemeProvider()->GetColor(ThemeProperties::COLOR_TOOLBAR),
+              tab->GetThemeProvider()->GetColor(
+                  ThemeProperties::COLOR_BACKGROUND_TAB),
+              false,
+              gfx::Point(),
+              255) {}
+
+void TabImageSource::Draw(gfx::Canvas* canvas) {
+  PaintTabBackgroundUsingParams(use_canvas_ != STROKE ? canvas : nullptr,

[Peter Kasting, 2016/08/11 22:51:15]

Nit: Prefer "use_canvas_ == STROKE ? nullptr : canvas", so the "else" portion of
the ?: doesn't read mentally like a double-negative.

[Greg Levin, 2016/08/12 19:48:15]

Obsolete due to other change.

+                                use_canvas_ != FILL ? canvas : nullptr,
+                                params_);
+}
+
 ////////////////////////////////////////////////////////////////////////////////
 // ImageCacheEntryMetadata
 //
@@ -151,7 +211,6 @@ struct ImageCacheEntryMetadata {
                           SkColor fill_color,
                           SkColor stroke_color,
                           bool use_fill_and_stroke_images,
-                          ui::ScaleFactor scale_factor,
                           const gfx::Size& size);
 
   ~ImageCacheEntryMetadata();
@@ -162,7 +221,6 @@ struct ImageCacheEntryMetadata {
   SkColor fill_color;  // Both colors only needed by MD
   SkColor stroke_color;
   bool use_fill_and_stroke_images;
-  ui::ScaleFactor scale_factor;
   gfx::Size size;
 };
 
@@ -171,16 +229,12 @@ ImageCacheEntryMetadata::ImageCacheEntryMetadata(
     SkColor fill_color,
     SkColor stroke_color,
     bool use_fill_and_stroke_images,
-    ui::ScaleFactor scale_factor,
     const gfx::Size& size)
     : resource_id(resource_id),
       fill_color(fill_color),
       stroke_color(stroke_color),
       use_fill_and_stroke_images(use_fill_and_stroke_images),
-      scale_factor(scale_factor),
       size(size) {
-  DCHECK_NE(ui::SCALE_FACTOR_NONE, scale_factor);
-
   // Some fields are only relevant for pre-MD vs. MD.  Erase the irrelevant ones
   // so they don't cause incorrect cache misses.
   // TODO(pkasting): Remove |resource_id| field when non-MD code is deleted.
@@ -197,7 +251,7 @@ bool ImageCacheEntryMetadata::operator==(
   return resource_id == rhs.resource_id && fill_color == rhs.fill_color &&
          stroke_color == rhs.stroke_color &&
          use_fill_and_stroke_images == rhs.use_fill_and_stroke_images &&
-         scale_factor == rhs.scale_factor && size == rhs.size;
+         size == rhs.size;
 }
 
 ////////////////////////////////////////////////////////////////////////////////
@@ -206,8 +260,9 @@ bool ImageCacheEntryMetadata::operator==(
 // A cached image and the metadata used to generate it.
 struct ImageCacheEntry {
   ImageCacheEntry(const ImageCacheEntryMetadata& metadata,
-                  const gfx::ImageSkia& fill_image,
-                  const gfx::ImageSkia& stroke_image);
+                  Tab* tab,
+                  int fill_id,
+                  int y_offset);
   ~ImageCacheEntry();
 
   ImageCacheEntryMetadata metadata;
@@ -216,9 +271,21 @@ struct ImageCacheEntry {
 };
 
 ImageCacheEntry::ImageCacheEntry(const ImageCacheEntryMetadata& metadata,
-                                 const gfx::ImageSkia& fill_image,
-                                 const gfx::ImageSkia& stroke_image)
-    : metadata(metadata), fill_image(fill_image), stroke_image(stroke_image) {}
+                                 Tab* tab,
+                                 int fill_id,
+                                 int y_offset)
+    : metadata(metadata) {
+  if (metadata.use_fill_and_stroke_images) {
+    fill_image = gfx::ImageSkia(
+        new TabImageSource(TabImageSource::FILL, tab, fill_id, y_offset),
+        tab->size());
+  }
+  TabImageSource::UseCanvas use = metadata.use_fill_and_stroke_images
+                                      ? TabImageSource::STROKE
+                                      : TabImageSource::BOTH;
+  stroke_image = gfx::ImageSkia(new TabImageSource(use, tab, fill_id, y_offset),
+                                tab->size());
+}
 
 ImageCacheEntry::~ImageCacheEntry() {}
 
@@ -483,17 +550,13 @@ void PaintTabFill(gfx::Canvas* canvas,
 
 void PaintTabBackgroundUsingParams(gfx::Canvas* fill_canvas,
                                    gfx::Canvas* stroke_canvas,
-                                   views::GlowHoverController* hc,
                                    const PaintBackgroundParams& params) {
   const gfx::Rect& rect = params.rect;
   const SkScalar kMinHoverRadius = 16;
   const SkScalar radius =
       std::max(SkFloatToScalar(rect.width() / 4.f), kMinHoverRadius);
-  const bool draw_hover = !params.is_active && hc;
-  SkPoint hover_location(
-      gfx::PointToSkPoint(draw_hover ? hc->location() : gfx::Point()));
   const SkColor hover_color =
-      SkColorSetA(params.toolbar_color, draw_hover ? hc->GetAlpha() : 255);
+      SkColorSetA(params.toolbar_color, params.hover_alpha);
 
   if (ui::MaterialDesignController::IsModeMaterial()) {
     gfx::Path fill;
@@ -501,7 +564,7 @@ void PaintTabBackgroundUsingParams(gfx::Canvas* fill_canvas,
     paint.setAntiAlias(true);
 
     // Draw the fill.
-    {
+    if (fill_canvas) {
       gfx::ScopedCanvas scoped_canvas(fill_canvas);
       const float scale = fill_canvas->UndoDeviceScaleFactor();
 
@@ -521,16 +584,15 @@ void PaintTabBackgroundUsingParams(gfx::Canvas* fill_canvas,
               gfx::ScaleToEnclosingRect(gfx::Rect(rect.size()), scale),
               paint);
         }
-        if (draw_hover) {
-          hover_location.scale(SkFloatToScalar(scale));
-          DrawHighlight(fill_canvas, hover_location, radius * scale,
-                        hover_color);
+        if (params.draw_hover) {
+          DrawHighlight(fill_canvas, params.hover_location * scale,
+                        radius * scale, hover_color);
         }
       }
     }
 
     // Draw the stroke.
-    {
+    if (stroke_canvas) {
       gfx::ScopedCanvas scoped_canvas(stroke_canvas);
       const float scale = stroke_canvas->UndoDeviceScaleFactor();
 
@@ -547,7 +609,7 @@ void PaintTabBackgroundUsingParams(gfx::Canvas* fill_canvas,
     }
   } else {
     gfx::Canvas* canvas = stroke_canvas;
-    if (draw_hover) {
+    if (params.draw_hover) {
       // Draw everything to a temporary canvas so we can extract an image for
       // use in masking the hover glow.
       gfx::Canvas background_canvas(rect.size(), canvas->image_scale(), false);
@@ -557,7 +619,7 @@ void PaintTabBackgroundUsingParams(gfx::Canvas* fill_canvas,
       canvas->DrawImageInt(background_image, 0, 0);
 
       gfx::Canvas hover_canvas(rect.size(), canvas->image_scale(), false);
-      DrawHighlight(&hover_canvas, hover_location, radius, hover_color);
+      DrawHighlight(&hover_canvas, params.hover_location, radius, hover_color);
       gfx::ImageSkia result = gfx::ImageSkiaOperations::CreateMaskedImage(
           gfx::ImageSkia(hover_canvas.ExtractImageRep()), background_image);
       canvas->DrawImageInt(result, 0, 0);
@@ -1522,26 +1584,12 @@ void Tab::PaintInactiveTabBackground(gfx::Canvas* canvas,
   const ImageCacheEntryMetadata metadata(
       fill_id, tp->GetColor(ThemeProperties::COLOR_BACKGROUND_TAB),
       controller_->GetToolbarTopSeparatorColor(), use_fill_and_stroke_images,
-      ui::GetSupportedScaleFactor(canvas->image_scale()), size());
+      size());
   auto it = std::find_if(
       g_image_cache->begin(), g_image_cache->end(),
       [&metadata](const ImageCacheEntry& e) { return e.metadata == metadata; });
   if (it == g_image_cache->end()) {
-    gfx::Canvas tmp_canvas(size(), canvas->image_scale(), false);
-    if (use_fill_and_stroke_images) {
-      gfx::Canvas tmp_fill_canvas(size(), canvas->image_scale(), false);
-      PaintTabBackgroundUsingFillId(&tmp_fill_canvas, &tmp_canvas, false,
-                                    fill_id, false, y_offset);
-      g_image_cache->emplace_front(
-          metadata, gfx::ImageSkia(tmp_fill_canvas.ExtractImageRep()),
-          gfx::ImageSkia(tmp_canvas.ExtractImageRep()));
-    } else {
-      PaintTabBackgroundUsingFillId(&tmp_canvas, &tmp_canvas, false, fill_id,
-                                    false, y_offset);
-      g_image_cache->emplace_front(
-          metadata, gfx::ImageSkia(),
-          gfx::ImageSkia(tmp_canvas.ExtractImageRep()));
-    }
+    g_image_cache->emplace_front(metadata, this, fill_id, y_offset);
     if (g_image_cache->size() > kMaxImageCacheSize)
       g_image_cache->pop_back();
     it = g_image_cache->begin();
@@ -1562,8 +1610,6 @@ void Tab::PaintTabBackgroundUsingFillId(gfx::Canvas* fill_canvas,
                                         int fill_id,
                                         bool has_custom_image,
                                         int y_offset) {
-  views::GlowHoverController* hc =
-      hover_controller_.ShouldDraw() ? &hover_controller_ : nullptr;
   gfx::ImageSkia* fill_image =
       has_custom_image || !ui::MaterialDesignController::IsModeMaterial()
           ? GetThemeProvider()->GetImageSkiaNamed(fill_id)
@@ -1577,9 +1623,11 @@ void Tab::PaintTabBackgroundUsingFillId(gfx::Canvas* fill_canvas,
       is_active, fill_image, has_custom_image, rect,
       controller_->GetToolbarTopSeparatorColor(),
       GetThemeProvider()->GetColor(ThemeProperties::COLOR_TOOLBAR),
-      GetThemeProvider()->GetColor(ThemeProperties::COLOR_BACKGROUND_TAB));
+      GetThemeProvider()->GetColor(ThemeProperties::COLOR_BACKGROUND_TAB),
+      !is_active && hover_controller_.ShouldDraw(),
+      hover_controller_.location(), hover_controller_.GetAlpha());
 
-  PaintTabBackgroundUsingParams(fill_canvas, stroke_canvas, hc, params);
+  PaintTabBackgroundUsingParams(fill_canvas, stroke_canvas, params);
 }
 
 void Tab::PaintPinnedTabTitleChangedIndicatorAndIcon(