From 43bd48b7a26cca1803d1c1c0ffac240a9f561784 Mon Sep 17 00:00:00 2001
From: Markus Stange <mstange.moz@gmail.com>
Date: Tue, 20 Oct 2020 03:57:25 +0000
Subject: [PATCH] Bug 1672044 - Convert DrawScrollbarTrack to use DrawTarget.
 r=haik

Differential Revision: https://phabricator.services.mozilla.com/D93841
---
 widget/cocoa/nsNativeThemeCocoa.h  |  3 ++-
 widget/cocoa/nsNativeThemeCocoa.mm | 43 +++++++++++++-----------------
 2 files changed, 21 insertions(+), 25 deletions(-)

diff --git a/widget/cocoa/nsNativeThemeCocoa.h b/widget/cocoa/nsNativeThemeCocoa.h
index f970e23b4518..0da013b52496 100644
--- a/widget/cocoa/nsNativeThemeCocoa.h
+++ b/widget/cocoa/nsNativeThemeCocoa.h
@@ -502,7 +502,8 @@ class nsNativeThemeCocoa : private nsNativeTheme, public nsITheme {
   void DrawStatusBar(CGContextRef cgContext, const HIRect& inBoxRect, bool aIsMain);
   void DrawResizer(CGContextRef cgContext, const HIRect& aRect, bool aIsRTL);
   void DrawScrollbarThumb(CGContextRef cgContext, const CGRect& inBoxRect, ScrollbarParams aParams);
-  void DrawScrollbarTrack(CGContextRef cgContext, const CGRect& inBoxRect, ScrollbarParams aParams);
+  void DrawScrollbarTrack(mozilla::gfx::DrawTarget& aDT, const mozilla::gfx::Rect& aRect,
+                          ScrollbarParams aParams);
   void DrawScrollCorner(CGContextRef cgContext, const CGRect& inBoxRect, ScrollbarParams aParams);
   void DrawMultilineTextField(CGContextRef cgContext, const CGRect& inBoxRect, bool aIsFocused);
   void DrawSourceList(CGContextRef cgContext, const CGRect& inBoxRect, bool aIsActive);
diff --git a/widget/cocoa/nsNativeThemeCocoa.mm b/widget/cocoa/nsNativeThemeCocoa.mm
index ac9639b0a0f9..1d35fb9c6849 100644
--- a/widget/cocoa/nsNativeThemeCocoa.mm
+++ b/widget/cocoa/nsNativeThemeCocoa.mm
@@ -2559,7 +2559,7 @@ static ScrollbarTrackDecorationColors ComputeScrollbarTrackDecorationColors(nsco
   return result;
 }
 
-void nsNativeThemeCocoa::DrawScrollbarTrack(CGContextRef cgContext, const CGRect& inBoxRect,
+void nsNativeThemeCocoa::DrawScrollbarTrack(DrawTarget& aDT, const gfx::Rect& aRect,
                                             ScrollbarParams aParams) {
   if (aParams.overlay && !aParams.rolledOver) {
     // Non-hovered overlay scrollbars don't have a track. Draw nothing.
@@ -2578,14 +2578,14 @@ void nsNativeThemeCocoa::DrawScrollbarTrack(CGContextRef cgContext, const CGRect
     }
   }
 
-  CGFloat thickness = aParams.horizontal ? inBoxRect.size.height : inBoxRect.size.width;
+  float thickness = aParams.horizontal ? aRect.height : aRect.width;
 
   // The scrollbar track is drawn as multiple non-overlapping segments, which make up lines of
   // different widths and with slightly different shading.
   ScrollbarTrackDecorationColors colors = ComputeScrollbarTrackDecorationColors(trackColor);
   struct {
     nscolor color;
-    CGFloat thickness;
+    float thickness;
   } segments[] = {
       {colors.mInnerColor, 1.0f},
       {colors.mShadowColor, 1.0f},
@@ -2596,28 +2596,22 @@ void nsNativeThemeCocoa::DrawScrollbarTrack(CGContextRef cgContext, const CGRect
   // Iterate over the segments "from inside to outside" and fill each segment.
   // For horizontal scrollbars, iterate top to bottom.
   // For vertical scrollbars, iterate left to right or right to left based on aParams.rtl.
-  CGRect segmentRect = inBoxRect;
+  float accumulatedThickness = 0.0f;
   for (const auto& segment : segments) {
+    gfx::Rect segmentRect = aRect;
+    float startThickness = accumulatedThickness;
+    float endThickness = startThickness + segment.thickness;
     if (aParams.horizontal) {
-      segmentRect.size.height = segment.thickness;
+      segmentRect.SetBoxY(aRect.Y() + startThickness, aRect.Y() + endThickness);
     } else {
       if (aParams.rtl) {
-        CGFloat rightEdge = segmentRect.origin.x + segmentRect.size.width;
-        segmentRect.origin.x = rightEdge - segment.thickness;
-      }
-      segmentRect.size.width = segment.thickness;
-    }
-    SetCGContextFillColor(cgContext, segment.color);
-    CGContextFillRect(cgContext, segmentRect);
-    if (aParams.horizontal) {
-      segmentRect.origin.y += segment.thickness;
-    } else {
-      if (aParams.rtl) {
-        segmentRect.origin.x -= segment.thickness;
+        segmentRect.SetBoxX(aRect.XMost() - endThickness, aRect.XMost() - startThickness);
       } else {
-        segmentRect.origin.x += segment.thickness;
+        segmentRect.SetBoxX(aRect.X() + startThickness, aRect.X() + endThickness);
       }
     }
+    aDT.FillRect(segmentRect, ColorPattern(ToDeviceColor(segment.color)));
+    accumulatedThickness = endThickness;
   }
 }
 
@@ -3183,6 +3177,11 @@ void nsNativeThemeCocoa::RenderWidget(const WidgetInfo& aWidgetInfo, DrawTarget&
       aDrawTarget.FillRect(widgetRect, ColorPattern(ToDeviceColor(color)));
       break;
     }
+    case Widget::eScrollbarTrack: {
+      ScrollbarParams params = aWidgetInfo.Params<ScrollbarParams>();
+      DrawScrollbarTrack(aDrawTarget, widgetRect, params);
+      break;
+    }
     default: {
       // The remaining widgets require a CGContext.
       CGRect macRect =
@@ -3203,7 +3202,8 @@ void nsNativeThemeCocoa::RenderWidget(const WidgetInfo& aWidgetInfo, DrawTarget&
       CGContextSetBaseCTM(cgContext, CGAffineTransformMakeScale(aScale, aScale));
 
       switch (widget) {
-        case Widget::eColorFill: {
+        case Widget::eColorFill:
+        case Widget::eScrollbarTrack: {
           MOZ_CRASH("already handled in outer switch");
           break;
         }
@@ -3341,11 +3341,6 @@ void nsNativeThemeCocoa::RenderWidget(const WidgetInfo& aWidgetInfo, DrawTarget&
           DrawScrollbarThumb(cgContext, macRect, params);
           break;
         }
-        case Widget::eScrollbarTrack: {
-          ScrollbarParams params = aWidgetInfo.Params<ScrollbarParams>();
-          DrawScrollbarTrack(cgContext, macRect, params);
-          break;
-        }
         case Widget::eScrollCorner: {
           ScrollbarParams params = aWidgetInfo.Params<ScrollbarParams>();
           DrawScrollCorner(cgContext, macRect, params);