Bug 1255214 - Only repaint GTK scrollbar button if its enablement actually changed. r=mstange

MozReview-Commit-ID: ITLeksQzvVM

--HG--
extra : rebase_source : 1a3779ab7154282388c2e57251886863e818b168

gfx/src/nsITheme.h

@@ -15,6 +15,7 @@
 #include "Units.h"
 
 struct nsRect;
+class nsAttrValue;
 class nsPresContext;
 class nsRenderingContext;
 class nsDeviceContext;
@@ -128,7 +129,8 @@ public:
   { return eUnknownTransparency; }
 
   NS_IMETHOD WidgetStateChanged(nsIFrame* aFrame, uint8_t aWidgetType, 
-                                nsIAtom* aAttribute, bool* aShouldRepaint)=0;
+                                nsIAtom* aAttribute, bool* aShouldRepaint,
+                                const nsAttrValue* aOldValue)=0;
 
   NS_IMETHOD ThemeChanged()=0;
 

layout/base/RestyleManager.cpp

@@ -1191,7 +1191,7 @@ RestyleManager::ContentStateChanged(nsIContent* aContent,
         if (theme && theme->ThemeSupportsWidget(mPresContext,
                                                 primaryFrame, app)) {
           bool repaint = false;
-          theme->WidgetStateChanged(primaryFrame, app, nullptr, &repaint);
+          theme->WidgetStateChanged(primaryFrame, app, nullptr, &repaint, nullptr);
           if (repaint) {
             NS_UpdateHint(hint, nsChangeHint_RepaintFrame);
           }
@@ -1320,7 +1320,8 @@ RestyleManager::AttributeChanged(Element* aElement,
       nsITheme *theme = mPresContext->GetTheme();
       if (theme && theme->ThemeSupportsWidget(mPresContext, primaryFrame, disp->mAppearance)) {
         bool repaint = false;
-        theme->WidgetStateChanged(primaryFrame, disp->mAppearance, aAttribute, &repaint);
+        theme->WidgetStateChanged(primaryFrame, disp->mAppearance, aAttribute,
+            &repaint, aOldValue);
         if (repaint)
           NS_UpdateHint(hint, nsChangeHint_RepaintFrame);
       }

layout/xul/nsScrollbarFrame.cpp

@@ -249,6 +249,9 @@ nsScrollbarFrame::MoveToNewPosition()
   // get the max pos
   int32_t maxpos = nsSliderFrame::GetMaxPosition(content);
 
+  // save the old curpos
+  int32_t oldCurpos = curpos;
+
   // increment the given amount
   if (mIncrement) {
     curpos += mIncrement;
@@ -297,7 +300,10 @@ nsScrollbarFrame::MoveToNewPosition()
     nsITheme *theme = presContext->GetTheme();
     if (theme && theme->ThemeSupportsWidget(presContext, this, disp->mAppearance)) {
       bool repaint;
-      theme->WidgetStateChanged(this, disp->mAppearance, nsGkAtoms::curpos, &repaint);
+      nsAttrValue oldValue;
+      oldValue.SetTo(oldCurpos);
+      theme->WidgetStateChanged(this, disp->mAppearance, nsGkAtoms::curpos,
+          &repaint, &oldValue);
     }
   }
   content->UnsetAttr(kNameSpaceID_None, nsGkAtoms::smooth, false);

widget/cocoa/nsNativeThemeCocoa.h

@@ -69,7 +69,8 @@ public:
                                   uint8_t aWidgetType,
                                   mozilla::LayoutDeviceIntSize* aResult, bool* aIsOverridable) override;
   NS_IMETHOD WidgetStateChanged(nsIFrame* aFrame, uint8_t aWidgetType, 
-                                nsIAtom* aAttribute, bool* aShouldRepaint) override;
+                                nsIAtom* aAttribute, bool* aShouldRepaint,
+                                const nsAttrValue* aOldValue) override;
   NS_IMETHOD ThemeChanged() override;
   bool ThemeSupportsWidget(nsPresContext* aPresContext, nsIFrame* aFrame, uint8_t aWidgetType) override;
   bool WidgetIsContainer(uint8_t aWidgetType) override;

widget/cocoa/nsNativeThemeCocoa.mm

@@ -3588,7 +3588,8 @@ nsNativeThemeCocoa::GetMinimumWidgetSize(nsPresContext* aPresContext,
 
 NS_IMETHODIMP
 nsNativeThemeCocoa::WidgetStateChanged(nsIFrame* aFrame, uint8_t aWidgetType, 
-                                     nsIAtom* aAttribute, bool* aShouldRepaint)
+                                       nsIAtom* aAttribute, bool* aShouldRepaint,
+                                       const nsAttrValue* aOldValue)
 {
   // Some widget types just never change state.
   switch (aWidgetType) {

widget/gtk/nsNativeThemeGTK.cpp

@@ -23,6 +23,7 @@
 #include "nsIDOMHTMLInputElement.h"
 #include "nsRenderingContext.h"
 #include "nsGkAtoms.h"
+#include "nsAttrValueInlines.h"
 
 #include "mozilla/EventStates.h"
 #include "mozilla/Services.h"
@@ -176,6 +177,15 @@ nsNativeThemeGTK::GetTabMarginPixels(nsIFrame* aFrame)
                        aFrame->PresContext()->AppUnitsToDevPixels(-margin)));
 }
 
+static bool ShouldScrollbarButtonBeDisabled(int32_t aCurpos, int32_t aMaxpos,
+                                            uint8_t aWidgetType)
+{
+  return ((aCurpos == 0 && (aWidgetType == NS_THEME_SCROLLBAR_BUTTON_UP ||
+                            aWidgetType == NS_THEME_SCROLLBAR_BUTTON_LEFT))
+      || (aCurpos == aMaxpos && (aWidgetType == NS_THEME_SCROLLBAR_BUTTON_DOWN ||
+                                 aWidgetType == NS_THEME_SCROLLBAR_BUTTON_RIGHT)));
+}
+
 bool
 nsNativeThemeGTK::GetGtkWidgetAndState(uint8_t aWidgetType, nsIFrame* aFrame,
                                        GtkThemeWidgetType& aGtkWidgetType,
@@ -308,12 +318,9 @@ nsNativeThemeGTK::GetGtkWidgetAndState(uint8_t aWidgetType, nsIFrame* aFrame,
           // the beginning or the end, depending on the button type.
           int32_t curpos = CheckIntAttr(aFrame, nsGkAtoms::curpos, 0);
           int32_t maxpos = CheckIntAttr(aFrame, nsGkAtoms::maxpos, 100);
-          if ((curpos == 0 && (aWidgetType == NS_THEME_SCROLLBAR_BUTTON_UP ||
+          if (ShouldScrollbarButtonBeDisabled(curpos, maxpos, aWidgetType)) {
-                aWidgetType == NS_THEME_SCROLLBAR_BUTTON_LEFT)) ||
-              (curpos == maxpos &&
-               (aWidgetType == NS_THEME_SCROLLBAR_BUTTON_DOWN ||
-                aWidgetType == NS_THEME_SCROLLBAR_BUTTON_RIGHT)))
             aState->disabled = true;
+          }
 
           // In order to simulate native GTK scrollbar click behavior,
           // we set the active attribute on the element to true if it's
@@ -1644,7 +1651,8 @@ nsNativeThemeGTK::GetMinimumWidgetSize(nsPresContext* aPresContext,
 
 NS_IMETHODIMP
 nsNativeThemeGTK::WidgetStateChanged(nsIFrame* aFrame, uint8_t aWidgetType, 
-                                     nsIAtom* aAttribute, bool* aShouldRepaint)
+                                     nsIAtom* aAttribute, bool* aShouldRepaint,
+                                     const nsAttrValue* aOldValue)
 {
   // Some widget types just never change state.
   if (aWidgetType == NS_THEME_TOOLBOX ||
@@ -1679,7 +1687,25 @@ nsNativeThemeGTK::WidgetStateChanged(nsIFrame* aFrame, uint8_t aWidgetType,
        aWidgetType == NS_THEME_SCROLLBAR_BUTTON_RIGHT) &&
       (aAttribute == nsGkAtoms::curpos ||
        aAttribute == nsGkAtoms::maxpos)) {
-    *aShouldRepaint = true;
+    // If 'curpos' has changed and we are passed its old value, we can
+    // determine whether the button's enablement actually needs to change.
+    if (aAttribute == nsGkAtoms::curpos && aOldValue) {
+      int32_t curpos = CheckIntAttr(aFrame, nsGkAtoms::curpos, 0);
+      int32_t maxpos = CheckIntAttr(aFrame, nsGkAtoms::maxpos, 0);
+      nsAutoString str;
+      aOldValue->ToString(str);
+      nsresult err;
+      int32_t oldCurpos = str.ToInteger(&err);
+      if (str.IsEmpty() || NS_FAILED(err)) {
+        *aShouldRepaint = true;
+      } else {
+        bool disabledBefore = ShouldScrollbarButtonBeDisabled(oldCurpos, maxpos, aWidgetType);
+        bool disabledNow = ShouldScrollbarButtonBeDisabled(curpos, maxpos, aWidgetType);
+        *aShouldRepaint = (disabledBefore != disabledNow);
+      }
+    } else {
+      *aShouldRepaint = true;
+    }
     return NS_OK;
   }
 

widget/gtk/nsNativeThemeGTK.h

@@ -50,7 +50,8 @@ public:
 
   NS_IMETHOD WidgetStateChanged(nsIFrame* aFrame, uint8_t aWidgetType, 
                                 nsIAtom* aAttribute,
-                                bool* aShouldRepaint) override;
+                                bool* aShouldRepaint,
+                                const nsAttrValue* aOldValue) override;
 
   NS_IMETHOD ThemeChanged() override;
 

widget/windows/nsNativeThemeWin.cpp

@@ -2574,7 +2574,8 @@ nsNativeThemeWin::GetMinimumWidgetSize(nsPresContext* aPresContext, nsIFrame* aF
 
 NS_IMETHODIMP
 nsNativeThemeWin::WidgetStateChanged(nsIFrame* aFrame, uint8_t aWidgetType, 
-                                     nsIAtom* aAttribute, bool* aShouldRepaint)
+                                     nsIAtom* aAttribute, bool* aShouldRepaint,
+                                     const nsAttrValue* aOldValue)
 {
   // Some widget types just never change state.
   if (aWidgetType == NS_THEME_TOOLBOX ||

widget/windows/nsNativeThemeWin.h

@@ -56,7 +56,8 @@ public:
   virtual Transparency GetWidgetTransparency(nsIFrame* aFrame, uint8_t aWidgetType) override;
 
   NS_IMETHOD WidgetStateChanged(nsIFrame* aFrame, uint8_t aWidgetType, 
-                                nsIAtom* aAttribute, bool* aShouldRepaint) override;
+                                nsIAtom* aAttribute, bool* aShouldRepaint,
+                                const nsAttrValue* aOldValue) override;
 
   NS_IMETHOD ThemeChanged() override;