[Chrome OS MD] Draw a 1px separator between 2 tray items

ash/common/system/tray/tray_background_view.cc

Index: ash/common/system/tray/tray_background_view.cc
diff --git a/ash/common/system/tray/tray_background_view.cc b/ash/common/system/tray/tray_background_view.cc
index e6393764d72dda2bf251ca1f66e52c3359dffb96..afd779b94cf880b009eb09251c7a6763818c4c3f 100644
--- a/ash/common/system/tray/tray_background_view.cc
+++ b/ash/common/system/tray/tray_background_view.cc
@@ -9,6 +9,7 @@
 #include "ash/common/shelf/wm_shelf.h"
 #include "ash/common/shelf/wm_shelf_util.h"
 #include "ash/common/shell_window_ids.h"
+#include "ash/common/system/status_area_widget.h"
 #include "ash/common/system/tray/system_tray.h"
 #include "ash/common/system/tray/tray_constants.h"
 #include "ash/common/system/tray/tray_event_filter.h"
@@ -25,9 +26,11 @@
 #include "ui/gfx/animation/tween.h"
 #include "ui/gfx/canvas.h"
 #include "ui/gfx/geometry/rect.h"
+#include "ui/gfx/geometry/size.h"
 #include "ui/gfx/image/image_skia.h"
 #include "ui/gfx/image/image_skia_operations.h"
 #include "ui/gfx/nine_image_painter.h"
+#include "ui/gfx/scoped_canvas.h"
 #include "ui/gfx/skia_util.h"
 #include "ui/gfx/transform.h"
 #include "ui/views/background.h"
@@ -101,15 +104,31 @@ class TrayBackground : public views::Background {
     SkPaint background_paint;
     background_paint.setFlags(SkPaint::kAntiAlias_Flag);
     background_paint.setColor(SkColorSetA(kShelfBaseColor, alpha_));
-    canvas->DrawRoundRect(view->GetLocalBounds(), kTrayRoundedBorderRadius,
-                          background_paint);
+    gfx::Rect bounds;
+
+    // The hit region are padded to the |view| as insets, so they are included
+    // in the local bounds. Remove these regions from view because hit region is
+    // invisible.
+    if (IsHorizontalAlignment(GetShelf()->GetAlignment())) {
+      bounds = gfx::Rect(view->GetLocalBounds().x() + kHitRegionPadding,

[James Cook, 2016/08/19 00:55:50]

nit: cache the result of view->GetLocalBounds() in a local variable so you don't
call it so many times

[yiyix, 2016/08/19 19:07:56]

Thanks! After i finally get it working after many many trials, I somehow failed
to see this repetitive calling.

+                         view->GetLocalBounds().y(),
+                         view->GetLocalBounds().width() - kHitRegionPadding -
+                             kHitRegionPadding - kSeparatorWidth,
+                         view->GetLocalBounds().height());
+    } else {
+      bounds = gfx::Rect(view->GetLocalBounds().x(),
+                         view->GetLocalBounds().y() + kHitRegionPadding,
+                         view->GetLocalBounds().width(),
+                         view->GetLocalBounds().height() - kHitRegionPadding -
+                             kHitRegionPadding - kSeparatorWidth);
+    }
+    canvas->DrawRoundRect(bounds, kTrayRoundedBorderRadius, background_paint);
 
     if (tray_background_view_->draw_background_as_active()) {
       SkPaint highlight_paint;
       highlight_paint.setFlags(SkPaint::kAntiAlias_Flag);
       highlight_paint.setColor(kShelfButtonActivatedHighlightColor);
-      canvas->DrawRoundRect(view->GetLocalBounds(), kTrayRoundedBorderRadius,
-                            highlight_paint);
+      canvas->DrawRoundRect(bounds, kTrayRoundedBorderRadius, highlight_paint);
     }
   }
 
@@ -207,15 +226,23 @@ void TrayBackgroundView::TrayContainer::UpdateLayout() {
       IsHorizontalAlignment(alignment_) ? views::BoxLayout::kHorizontal
                                         : views::BoxLayout::kVertical;
 
+  gfx::Insets insets;
   if (!ash::MaterialDesignController::IsShelfMaterial()) {
     // Additional padding used to adjust the user-visible size of status tray
     // dark background.
     const int padding = 3;

[varkha, 2016/08/19 16:33:39]

nit: can you declare the constant in anonymous namespace above and then use
something like:
const Insets insets(MDC::IsShelfMaterial ? gfx::Insets(...) :
gfx::Insets(kStatusTrayBackgroundPadding);
?

[yiyix, 2016/08/19 19:07:56]

Done.

-    SetBorder(views::Border::CreateEmptyBorder(gfx::Insets(padding) + margin_));
+    insets = gfx::Insets(padding);
   } else {
-    SetBorder(views::Border::CreateEmptyBorder(margin_));
+    // Extend hit region horizontally or vertically depending on shelf
+    // alignment.
+    insets =
+        gfx::Insets(IsHorizontalAlignment(alignment_)
+                        ? gfx::Insets(0, kHitRegionPadding, 0,
+                                      kHitRegionPadding + kSeparatorWidth)
+                        : gfx::Insets(kHitRegionPadding, 0,
+                                      kHitRegionPadding + kSeparatorWidth, 0));
   }
-
+  SetBorder(views::Border::CreateEmptyBorder(insets + margin_));
   views::BoxLayout* layout = new views::BoxLayout(orientation, 0, 0, 0);
   layout->SetDefaultFlex(1);
   views::View::SetLayoutManager(layout);
@@ -231,6 +258,7 @@ TrayBackgroundView::TrayBackgroundView(WmShelf* wm_shelf)
       shelf_alignment_(SHELF_ALIGNMENT_BOTTOM),
       background_(NULL),
       draw_background_as_active_(false),
+      is_separator_visible_(false),
       widget_observer_(new TrayWidgetObserver(this)) {
   DCHECK(wm_shelf_);
   set_notify_enter_exit_on_child(true);
@@ -314,6 +342,7 @@ void TrayBackgroundView::SetVisible(bool visible) {
     layer()->SetVisible(false);
     HideTransformation();
   }
+  wm_shelf_->GetStatusAreaWidget()->OnTrayVisibilityChanged(this);
 }
 
 const char* TrayBackgroundView::GetClassName() const {
@@ -508,4 +537,37 @@ void TrayBackgroundView::UpdateShelfItemBackground(int alpha) {
   }
 }
 
+void TrayBackgroundView::SetSeparatorVisibility(bool is_shown) {
+  is_separator_visible_ = is_shown;
+  SchedulePaint();
+}
+
+void TrayBackgroundView::OnPaint(gfx::Canvas* canvas) {
+  if (!MaterialDesignController::IsShelfMaterial() ||
+      shelf()->GetBackgroundType() ==
+          ShelfBackgroundType::SHELF_BACKGROUND_DEFAULT ||
+      !is_separator_visible_) {
+    return;
+  }
+  // In the given |canvas|, draws a 1x32px separator line 4 pixel to the right
+  // of the TrayBackgroundView.
+  const bool horizontal_shelf = IsHorizontalAlignment(shelf()->GetAlignment());

[James Cook, 2016/08/19 00:55:50]

I would use IsHorizontalAlignment(shelf_alignment_) here. It's bad that this
class caches its own copy of the shelf alignment (I would like to eliminate
that) but I think the same value should be used everywhere for consistency.

[yiyix, 2016/08/19 19:07:56]

Done.

+  const int height = kTrayItemSize;
+  const int width = kSeparatorWidth;
+  const int x = horizontal_shelf ? GetLocalBounds().width() - kSeparatorWidth
+                                 : GetLocalBounds().height() - kSeparatorWidth;

[varkha, 2016/08/19 16:33:39]

nit: can you shorten code to (pseudocode):
const int x = (horizontal ? width : height) - kSeparatorWidth;
?

[yiyix, 2016/08/19 19:07:56]

Done.

+  const int y = (GetShelfConstant(SHELF_SIZE) - kTrayItemSize) / 2;
+  gfx::ScopedCanvas scoped_canvas(canvas);
+  const float scale = canvas->UndoDeviceScaleFactor();
+  SkPaint paint;
+  paint.setColor(kSeparatorColor);
+  paint.setAntiAlias(true);
+
+  const gfx::Rect bounds = horizontal_shelf ? gfx::Rect(x, y, width, height)
+                                            : gfx::Rect(y, x, height, width);
+  gfx::RectF rect(gfx::ScaleRect(gfx::RectF(bounds), scale));
+  canvas->DrawLine(horizontal_shelf ? rect.top_right() : rect.bottom_left(),
+                   rect.bottom_right(), paint);
+}
+
 }  // namespace ash