auto merge of #774 : metajack/servo/au-rounding, r=pcwalton

This fixes too narrow boxes due to flooring computations.

r? @pcwalton

src/components/gfx/font.rs

@@ -399,8 +399,8 @@ impl Font {
                 let azglyph = struct__AzGlyph {
                     mIndex: glyph.index() as uint32_t,
                     mPosition: struct__AzPoint {
-                        x: (origin.x + glyph_offset.x).to_px() as AzFloat,
-                        y: (origin.y + glyph_offset.y).to_px() as AzFloat
+                        x: (origin.x + glyph_offset.x).to_nearest_px() as AzFloat,
+                        y: (origin.y + glyph_offset.y).to_nearest_px() as AzFloat
                     }
                 };
                 origin = Point2D(origin.x + glyph_advance, origin.y);

src/components/gfx/geometry.rs

@@ -82,15 +82,15 @@ pub fn box<T:Clone + Ord + Add<T,T> + Sub<T,T>>(x: T, y: T, w: T, h: T) -> Rect<
 
 impl Au {
     pub fn scale_by(self, factor: float) -> Au {
-        Au(((*self as float) * factor) as i32)
+        Au(((*self as float) * factor).round() as i32)
     }
 
     pub fn from_px(px: int) -> Au {
         NumCast::from(px * 60)
     }
 
-    pub fn to_px(&self) -> int {
-        (**self / 60) as int
+    pub fn to_nearest_px(&self) -> int {
+        ((**self as float) / 60f).round() as int
     }
 
     pub fn to_snapped(&self) -> Au {

src/components/gfx/render_context.rs

@@ -124,8 +124,10 @@ trait ToAzureRect {
 
 impl ToAzureRect for Rect<Au> {
     fn to_azure_rect(&self) -> Rect<AzFloat> {
-        Rect(Point2D(self.origin.x.to_px() as AzFloat, self.origin.y.to_px() as AzFloat),
-             Size2D(self.size.width.to_px() as AzFloat, self.size.height.to_px() as AzFloat))
+        Rect(Point2D(self.origin.x.to_nearest_px() as AzFloat,
+                     self.origin.y.to_nearest_px() as AzFloat),
+             Size2D(self.size.width.to_nearest_px() as AzFloat,
+                    self.size.height.to_nearest_px() as AzFloat))
     }
 }
 
@@ -135,9 +137,9 @@ trait ToSideOffsetsPx {
 
 impl ToSideOffsetsPx for SideOffsets2D<Au> {
     fn to_float_px(&self) -> SideOffsets2D<AzFloat> {
-        SideOffsets2D::new(self.top.to_px() as AzFloat,
-                           self.right.to_px() as AzFloat,
-                           self.bottom.to_px() as AzFloat,
-                           self.left.to_px() as AzFloat)
+        SideOffsets2D::new(self.top.to_nearest_px() as AzFloat,
+                           self.right.to_nearest_px() as AzFloat,
+                           self.bottom.to_nearest_px() as AzFloat,
+                           self.left.to_nearest_px() as AzFloat)
     }
 }

src/components/main/layout/layout_task.rs

@@ -348,7 +348,8 @@ impl LayoutTask {
 
                 let render_layer = RenderLayer {
                     display_list: display_list.clone(),
-                    size: Size2D(root_size.width.to_px() as uint, root_size.height.to_px() as uint)
+                    size: Size2D(root_size.width.to_nearest_px() as uint,
+                                 root_size.height.to_nearest_px() as uint)
                 };
 
                 self.display_list = Some(display_list.clone());

src/components/script/dom/bindings/element.rs

@@ -223,7 +223,7 @@ extern fn HTMLImageElement_getWidth(cx: *JSContext, _argc: c_uint, vp: *mut JSVa
                 let (port, chan) = comm::stream();
                 // TODO(tkuehn): currently this just queries top-level page's layout. Need to handle subframes.
                 match (*page).query_layout(ContentBoxQuery(node, chan), port) {
-                    Ok(ContentBoxResponse(rect)) => rect.size.width.to_px(),
+                    Ok(ContentBoxResponse(rect)) => rect.size.width.to_nearest_px(),
                     Err(()) => 0
                 }
                 // TODO: if nothing is being rendered(?), return zero dimensions