bug 674373 pt 6 - support HiDPI display in Cocoa widget code. r=roc,s…

…michaud

browser/base/content/tabbrowser.xml

@@ -3577,12 +3577,17 @@
         dt.mozCursor = "default";
 
         // Create a canvas to which we capture the current tab.
+        // Until canvas is HiDPI-aware (bug 780362), we need to scale the desired
+        // canvas size (in CSS pixels) to the window's backing resolution in order
+        // to get a full-resolution drag image for use on HiDPI displays.
+        let windowUtils = window.getInterface(Ci.nsIDOMWindowUtils);
+        let scale = windowUtils.screenPixelsPerCSSPixel / windowUtils.fullZoom;
         let canvas = document.createElementNS("http://www.w3.org/1999/xhtml", "canvas");
         canvas.mozOpaque = true;
-        canvas.width = 160;
-        canvas.height = 90;
+        canvas.width = 160 * scale;
+        canvas.height = 90 * scale;
         PageThumbs.captureToCanvas(browser.contentWindow, canvas);
-        dt.setDragImage(canvas, -16, -16);
+        dt.setDragImage(canvas, -16 * scale, -16 * scale);
 
         // _dragData.offsetX/Y give the coordinates that the mouse should be
         // positioned relative to the corner of the new window created upon

layout/style/test/test_media_queries.html

@@ -25,7 +25,7 @@
 
 var iframe;
 
-function getZoomRatio() {
+function getScreenPixelsPerCSSPixel() {
   return SpecialPowers.DOMWindowUtils.screenPixelsPerCSSPixel;
 }
 
@@ -357,9 +357,9 @@
   should_apply("not all and (max-device-aspect-ratio: " + low_dar_2 + ")");
   expression_should_not_be_parseable("max-device-aspect-ratio");
 
-  var real_dpr = 1.0 * getZoomRatio();
-  var high_dpr = 1.1 * getZoomRatio();
-  var low_dpr = 0.9 * getZoomRatio();
+  var real_dpr = 1.0 * getScreenPixelsPerCSSPixel();
+  var high_dpr = 1.1 * getScreenPixelsPerCSSPixel();
+  var low_dpr = 0.9 * getScreenPixelsPerCSSPixel();
   should_apply("all and (max--moz-device-pixel-ratio: " + real_dpr + ")");
   should_apply("all and (min--moz-device-pixel-ratio: " + real_dpr + ")");
   should_not_apply("not all and (max--moz-device-pixel-ratio: " + real_dpr + ")");

layout/xul/base/src/nsMenuPopupFrame.h

@@ -264,9 +264,9 @@ class nsMenuPopupFrame : public nsBoxFrame, public nsMenuParent
 
   void EnsureMenuItemIsVisible(nsMenuFrame* aMenuFrame);
 
-  // Move the popup to the screen coordinate (aLeft, aTop). If aUpdateAttrs
-  // is true, and the popup already has left or top attributes, then those
-  // attributes are updated to the new location.
+  // Move the popup to the screen coordinate (aLeft, aTop) in CSS pixels.
+  // If aUpdateAttrs is true, and the popup already has left or top attributes,
+  // then those attributes are updated to the new location.
   // The frame may be destroyed by this method.
   void MoveTo(int32_t aLeft, int32_t aTop, bool aUpdateAttrs);
 
@@ -302,6 +302,7 @@ class nsMenuPopupFrame : public nsBoxFrame, public nsMenuParent
   nsIContent* GetAnchor() const { return mAnchorContent; }
 
   // Return the screen coordinates of the popup, or (-1, -1) if anchored.
+  // This position is in CSS pixels.
   nsIntPoint ScreenPosition() const { return nsIntPoint(mScreenXPos, mScreenYPos); }
 
   NS_IMETHOD BuildDisplayList(nsDisplayListBuilder*   aBuilder,
@@ -387,8 +388,9 @@ class nsMenuPopupFrame : public nsBoxFrame, public nsMenuParent
   // would be before resizing. Computations are performed using this size.
   nsSize mPrefSize;
 
-  // the position of the popup. The screen coordinates, if set to values other
-  // than -1, override mXPos and mYPos.
+  // The position of the popup, in CSS pixels.
+  // The screen coordinates, if set to values other than -1,
+  // override mXPos and mYPos.
   int32_t mXPos;
   int32_t mYPos;
   int32_t mScreenXPos;

layout/xul/base/src/nsXULPopupManager.cpp

@@ -316,6 +316,11 @@ nsXULPopupManager::PopupMoved(nsIFrame* aFrame, nsIntPoint aPnt)
   if (!menuPopupFrame)
     return;
 
+  // Convert desired point to CSS pixels for comparison
+  nsPresContext* presContext = menuPopupFrame->PresContext();
+  aPnt.x = presContext->DevPixelsToIntCSSPixels(aPnt.x);
+  aPnt.y = presContext->DevPixelsToIntCSSPixels(aPnt.y);
+
   // Don't do anything if the popup is already at the specified location. This
   // prevents recursive calls when a popup is positioned.
   nsIntPoint currentPnt = menuPopupFrame->ScreenPosition();
@@ -346,13 +351,20 @@ nsXULPopupManager::PopupResized(nsIFrame* aFrame, nsIntSize aSize)
   nsPresContext* presContext = menuPopupFrame->PresContext();
 
   nsSize currentSize = menuPopupFrame->GetSize();
-  if (aSize.width != presContext->AppUnitsToDevPixels(currentSize.width) ||
-      aSize.height != presContext->AppUnitsToDevPixels(currentSize.height)) {
+
+  // convert both current and new sizes to integer CSS pixels for comparison;
+  // we won't set attributes if there is only a sub-CSS-pixel discrepancy
+  nsIntSize currCSS(nsPresContext::AppUnitsToIntCSSPixels(currentSize.width),
+                    nsPresContext::AppUnitsToIntCSSPixels(currentSize.height));
+  nsIntSize newCSS(presContext->DevPixelsToIntCSSPixels(aSize.width),
+                   presContext->DevPixelsToIntCSSPixels(aSize.height));
+
+  if (newCSS.width != currCSS.width || newCSS.height != currCSS.height) {
     // for resizes, we just set the width and height attributes
     nsIContent* popup = menuPopupFrame->GetContent();
     nsAutoString width, height;
-    width.AppendInt(aSize.width);
-    height.AppendInt(aSize.height);
+    width.AppendInt(newCSS.width);
+    height.AppendInt(newCSS.height);
     popup->SetAttr(kNameSpaceID_None, nsGkAtoms::width, width, false);
     popup->SetAttr(kNameSpaceID_None, nsGkAtoms::height, height, true);
   }

modules/libpref/src/init/all.js

@@ -186,6 +186,14 @@ pref("media.autoplay.enabled", true);
 // nsBuiltinDecoderReader's mVideoQueue.
 pref("media.video-queue.default-size", 10);
 
+#ifdef XP_MACOSX
+// Whether to run in native HiDPI mode on machines with "Retina"/HiDPI display;
+//   <= 0 : hidpi mode disabled, display will just use pixel-based upscaling
+//   == 1 : hidpi supported if all screens share the same backingScaleFactor
+//   >= 2 : hidpi supported even with mixed backingScaleFactors (currently broken)
+pref("gfx.hidpi.enabled", 1);
+#endif
+
 // 0 = Off, 1 = Full, 2 = Tagged Images Only. 
 // See eCMSMode in gfx/thebes/gfxPlatform.h
 pref("gfx.color_management.mode", 2);
@@ -1588,9 +1596,7 @@ pref("layout.css.dpi", -1);
 // automatically based on user settings for the platform (e.g., "UI scale factor"
 // on Mac). A positive value is used as-is. This effectively controls the size
 // of a CSS "px". This is only used for windows on the screen, not for printing.
-// XXX the default value here should be 0, but before we can set it to 0,
-// we have to get this feature working on all platforms.
-pref("layout.css.devPixelsPerPx", "1.0");
+pref("layout.css.devPixelsPerPx", "-1.0");
 
 // Is support for the the @supports rule enabled?
 pref("layout.css.supports-rule.enabled", true);

widget/cocoa/nsChildView.h

@@ -411,6 +411,16 @@ class nsChildView : public nsBaseWidget,
   NS_IMETHOD              SetFocus(bool aRaise);
   NS_IMETHOD              GetBounds(nsIntRect &aRect);
 
+  // Returns the "backing scale factor" of the view's window, which is the
+  // ratio of pixels in the window's backing store to Cocoa points. Prior to
+  // HiDPI support in OS X 10.7, this was always 1.0, but in HiDPI mode it
+  // will be 2.0 (and might potentially other values as screen resolutions
+  // evolve). This gives the relationship between what Gecko calls "device
+  // pixels" and the Cocoa "points" coordinate system.
+  CGFloat                 BackingScaleFactor();
+
+  virtual double          GetDefaultScale();
+
   NS_IMETHOD              Invalidate(const nsIntRect &aRect);
 
   virtual void*           GetNativeData(uint32_t aDataType);
@@ -516,6 +526,20 @@ class nsChildView : public nsBaseWidget,
     return mTextInputHandler;
   }
 
+  // unit conversion convenience functions
+  nsIntPoint        CocoaPointsToDevPixels(const NSPoint& aPt) {
+    return nsCocoaUtils::CocoaPointsToDevPixels(aPt, BackingScaleFactor());
+  }
+  nsIntRect         CocoaPointsToDevPixels(const NSRect& aRect) {
+    return nsCocoaUtils::CocoaPointsToDevPixels(aRect, BackingScaleFactor());
+  }
+  CGFloat           DevPixelsToCocoaPoints(int32_t aPixels) {
+    return nsCocoaUtils::DevPixelsToCocoaPoints(aPixels, BackingScaleFactor());
+  }
+  NSRect            DevPixelsToCocoaPoints(const nsIntRect& aRect) {
+    return nsCocoaUtils::DevPixelsToCocoaPoints(aRect, BackingScaleFactor());
+  }
+
 protected:
 
   void              ReportMoveEvent();
@@ -552,6 +576,12 @@ class nsChildView : public nsBaseWidget,
   nsRefPtr<gfxASurface> mTempThebesSurface;
   nsRefPtr<mozilla::gl::TextureImage> mResizerImage;
 
+  // Cached value of [mView backingScaleFactor], to avoid sending two obj-c
+  // messages (respondsToSelector, backingScaleFactor) every time we need to
+  // use it.
+  // ** We'll need to reinitialize this if the backing resolution changes. **
+  CGFloat               mBackingScaleFactor;
+
   bool                  mVisible;
   bool                  mDrawing;
   bool                  mPluginDrawing;