Bug 1113684 - part 1 - Handle vertical writing modes when displaying alt-text alongside a broken-image icon. r=smontagu

layout/generic/nsImageFrame.cpp

@@ -1100,14 +1100,23 @@ nsImageFrame::DisplayAltText(nsPresContext*      aPresContext,
 
   nscoord maxAscent = fm->MaxAscent();
   nscoord maxDescent = fm->MaxDescent();
-  nscoord height = fm->MaxHeight();
+  nscoord lineHeight = fm->MaxHeight(); // line-relative, so an x-coordinate
+                                        // length if writing mode is vertical
+
+  WritingMode wm = GetWritingMode();
+  bool isVertical = wm.IsVertical();
+
+  fm->SetVertical(isVertical);
+  fm->SetTextOrientation(StyleVisibility()->mTextOrientation);
 
   // XXX It would be nice if there was a way to have the font metrics tell
   // use where to break the text given a maximum width. At a minimum we need
   // to be able to get the break character...
   const char16_t* str = aAltText.get();
-  int32_t          strLen = aAltText.Length();
-  nscoord          y = aRect.y;
+  int32_t strLen = aAltText.Length();
+  nsPoint pt = wm.IsVerticalRL() ? aRect.TopRight() - nsPoint(lineHeight, 0)
+                                 : aRect.TopLeft();
+  nscoord iSize = isVertical ? aRect.height : aRect.width;
 
   if (!aPresContext->BidiEnabled() && HasRTLChars(aAltText)) {
     aPresContext->SetBidiEnabled();
@@ -1115,38 +1124,71 @@ nsImageFrame::DisplayAltText(nsPresContext*      aPresContext,
 
   // Always show the first line, even if we have to clip it below
   bool firstLine = true;
-  while ((strLen > 0) && (firstLine || (y + maxDescent) < aRect.YMost())) {
+  while (strLen > 0) {
+    if (!firstLine) {
+      // If we've run out of space, break out of the loop
+      if ((!isVertical && (pt.y + maxDescent) >= aRect.YMost()) ||
+          (wm.IsVerticalRL() && (pt.x + maxDescent < aRect.x)) ||
+          (wm.IsVerticalLR() && (pt.x + maxDescent >= aRect.XMost()))) {
+        break;
+      }
+    }
+
     // Determine how much of the text to display on this line
     uint32_t  maxFit;  // number of characters that fit
-    nscoord strWidth = MeasureString(str, strLen, aRect.width, maxFit,
+    nscoord strWidth = MeasureString(str, strLen, iSize, maxFit,
                                      aRenderingContext, *fm);
-    
+
     // Display the text
     nsresult rv = NS_ERROR_FAILURE;
 
     if (aPresContext->BidiEnabled()) {
-      const nsStyleVisibility* vis = StyleVisibility();
-      if (vis->mDirection == NS_STYLE_DIRECTION_RTL)
-        rv = nsBidiPresUtils::RenderText(str, maxFit, NSBIDI_RTL,
-                                         aPresContext, aRenderingContext,
-                                         aRenderingContext, *fm,
-                                         aRect.XMost() - strWidth, y + maxAscent);
-      else
-        rv = nsBidiPresUtils::RenderText(str, maxFit, NSBIDI_LTR,
-                                         aPresContext, aRenderingContext,
-                                         aRenderingContext, *fm,
-                                         aRect.x, y + maxAscent);
+      nsBidiDirection dir;
+      nscoord x, y;
+
+      if (isVertical) {
+        x = pt.x + maxDescent; // XXX will need update for sideways-left
+        if (wm.IsBidiLTR()) {
+          y = aRect.y;
+          dir = NSBIDI_LTR;
+        } else {
+          y = aRect.YMost() - strWidth;
+          dir = NSBIDI_RTL;
+        }
+      } else {
+        y = pt.y + maxAscent;
+        if (wm.IsBidiLTR()) {
+          x = aRect.x;
+          dir = NSBIDI_LTR;
+        } else {
+          x = aRect.XMost() - strWidth;
+          dir = NSBIDI_RTL;
+        }
+      }
+
+      rv = nsBidiPresUtils::RenderText(str, maxFit, dir,
+                                       aPresContext, aRenderingContext,
+                                       aRenderingContext, *fm, x, y);
     }
     if (NS_FAILED(rv)) {
       nsLayoutUtils::DrawUniDirString(str, maxFit,
-                                      nsPoint(aRect.x, y + maxAscent), *fm,
-                                      aRenderingContext);
+                                      isVertical
+                                        ? nsPoint(pt.x + maxDescent, pt.y)
+                                        : nsPoint(pt.x, pt.y + maxAscent),
+                                      *fm, aRenderingContext);
     }
 
     // Move to the next line
     str += maxFit;
     strLen -= maxFit;
-    y += height;
+    if (wm.IsVerticalRL()) {
+      pt.x -= lineHeight;
+    } else if (wm.IsVerticalLR()) {
+      pt.x += lineHeight;
+    } else {
+      pt.y += lineHeight;
+    }
+
     firstLine = false;
   }
 }
@@ -1247,7 +1289,6 @@ nsImageFrame::DisplayAltFeedback(nsRenderingContext& aRenderingContext,
 
   // Check if we should display image placeholders
   if (gIconLoad->mPrefShowPlaceholders) {
-    const nsStyleVisibility* vis = StyleVisibility();
     nscoord size = nsPresContext::CSSPixelsToAppUnits(ICON_SIZE);
 
     bool iconUsed = false;
@@ -1260,6 +1301,9 @@ nsImageFrame::DisplayAltFeedback(nsRenderingContext& aRenderingContext,
       mDisplayingIcon = true;
     }
 
+    WritingMode wm = GetWritingMode();
+    bool flushRight =
+      (!wm.IsVertical() && !wm.IsBidiLTR()) || wm.IsVerticalRL();
 
     // If the icon in question is loaded and decoded, draw it
     uint32_t imageStatus = 0;
@@ -1269,8 +1313,7 @@ nsImageFrame::DisplayAltFeedback(nsRenderingContext& aRenderingContext,
       nsCOMPtr<imgIContainer> imgCon;
       aRequest->GetImage(getter_AddRefs(imgCon));
       MOZ_ASSERT(imgCon, "Load complete, but no image container?");
-      nsRect dest((vis->mDirection == NS_STYLE_DIRECTION_RTL) ?
-                  inner.XMost() - size : inner.x,
+      nsRect dest(flushRight ? inner.XMost() - size : inner.x,
                   inner.y, size, size);
       nsLayoutUtils::DrawSingleImage(*gfx, PresContext(), imgCon,
         nsLayoutUtils::GetGraphicsFilterForFrame(this), dest, aDirtyRect,
@@ -1283,8 +1326,7 @@ nsImageFrame::DisplayAltFeedback(nsRenderingContext& aRenderingContext,
     if (!iconUsed) {
       ColorPattern color(ToDeviceColor(Color(1.f, 0.f, 0.f, 1.f)));
 
-      nscoord iconXPos = (vis->mDirection ==   NS_STYLE_DIRECTION_RTL) ?
-                         inner.XMost() - size : inner.x;
+      nscoord iconXPos = flushRight ? inner.XMost() - size : inner.x;
 
       // stroked rect:
       nsRect rect(iconXPos, inner.y, size, size);
@@ -1306,10 +1348,17 @@ nsImageFrame::DisplayAltFeedback(nsRenderingContext& aRenderingContext,
 
     // Reduce the inner rect by the width of the icon, and leave an
     // additional ICON_PADDING pixels for padding
-    int32_t iconWidth = nsPresContext::CSSPixelsToAppUnits(ICON_SIZE + ICON_PADDING);
-    if (vis->mDirection != NS_STYLE_DIRECTION_RTL)
-      inner.x += iconWidth;
-    inner.width -= iconWidth;
+    int32_t paddedIconSize =
+      nsPresContext::CSSPixelsToAppUnits(ICON_SIZE + ICON_PADDING);
+    if (wm.IsVertical()) {
+      inner.y += paddedIconSize;
+      inner.height -= paddedIconSize;
+    } else {
+      if (!flushRight) {
+        inner.x += paddedIconSize;
+      }
+      inner.width -= paddedIconSize;
+    }
   }
 
   // If there's still room, display the alt-text