Bug 1111944 - part 1 - Make nsLayoutUtils::DrawString (and the nsFontMetrics methods it calls) handle vertical text. r=smontagu

gfx/src/nsFontMetrics.cpp

@@ -57,6 +57,19 @@ private:
         if (aMetrics->GetTextRunRTL()) {
             flags |= gfxTextRunFactory::TEXT_IS_RTL;
         }
+        if (aMetrics->GetVertical()) {
+            switch (aMetrics->GetTextOrientation()) {
+            case NS_STYLE_TEXT_ORIENTATION_MIXED:
+                flags |= gfxTextRunFactory::TEXT_ORIENT_VERTICAL_MIXED;
+                break;
+            case NS_STYLE_TEXT_ORIENTATION_UPRIGHT:
+                flags |= gfxTextRunFactory::TEXT_ORIENT_VERTICAL_UPRIGHT;
+                break;
+            case NS_STYLE_TEXT_ORIENTATION_SIDEWAYS_RIGHT:
+                flags |= gfxTextRunFactory::TEXT_ORIENT_VERTICAL_SIDEWAYS_RIGHT;
+                break;
+            }
+        }
         return flags;
     }
 
@@ -95,6 +108,7 @@ public:
 
 nsFontMetrics::nsFontMetrics()
     : mDeviceContext(nullptr), mP2A(0), mTextRunRTL(false)
+    , mVertical(false), mTextOrientation(0)
 {
 }
 
@@ -151,9 +165,10 @@ nsFontMetrics::Destroy()
 #define ROUND_TO_TWIPS(x) (nscoord)floor(((x) * mP2A) + 0.5)
 #define CEIL_TO_TWIPS(x) (nscoord)ceil((x) * mP2A)
 
-const gfxFont::Metrics& nsFontMetrics::GetMetrics() const
+const gfxFont::Metrics&
+nsFontMetrics::GetMetrics(gfxFont::Orientation aOrientation) const
 {
-    return mFontGroup->GetFirstValidFont()->GetMetrics(mOrientation);
+    return mFontGroup->GetFirstValidFont()->GetMetrics(aOrientation);
 }
 
 nscoord
@@ -274,7 +289,14 @@ nsFontMetrics::AveCharWidth()
 nscoord
 nsFontMetrics::SpaceWidth()
 {
-    return CEIL_TO_TWIPS(GetMetrics().spaceWidth);
+    // For vertical text with mixed or sideways orientation, we want the
+    // width of a horizontal space (even if we're using vertical line-spacing
+    // metrics, as with "writing-mode:vertical-*;text-orientation:mixed").
+    return CEIL_TO_TWIPS(
+        GetMetrics(mVertical &&
+                   mTextOrientation == NS_STYLE_TEXT_ORIENTATION_UPRIGHT
+                       ? gfxFont::eVertical
+                       : gfxFont::eHorizontal).spaceWidth);
 }
 
 int32_t
@@ -334,7 +356,11 @@ nsFontMetrics::DrawString(const char *aString, uint32_t aLength,
     }
     gfxPoint pt(aX, aY);
     if (mTextRunRTL) {
-        pt.x += textRun->GetAdvanceWidth(0, aLength, &provider);
+        if (mVertical) {
+            pt.y += textRun->GetAdvanceWidth(0, aLength, &provider);
+        } else {
+            pt.x += textRun->GetAdvanceWidth(0, aLength, &provider);
+        }
     }
     textRun->Draw(aContext->ThebesContext(), pt, DrawMode::GLYPH_FILL, 0, aLength,
                   &provider, nullptr, nullptr);
@@ -356,7 +382,11 @@ nsFontMetrics::DrawString(const char16_t* aString, uint32_t aLength,
     }
     gfxPoint pt(aX, aY);
     if (mTextRunRTL) {
-        pt.x += textRun->GetAdvanceWidth(0, aLength, &provider);
+        if (mVertical) {
+            pt.y += textRun->GetAdvanceWidth(0, aLength, &provider);
+        } else {
+            pt.x += textRun->GetAdvanceWidth(0, aLength, &provider);
+        }
     }
     textRun->Draw(aContext->ThebesContext(), pt, DrawMode::GLYPH_FILL, 0, aLength,
                   &provider, nullptr, nullptr);

gfx/src/nsFontMetrics.h

@@ -169,17 +169,17 @@ public:
      * Returns the font associated with these metrics. The return value
      * is only defined after Init() has been called.
      */
-    const nsFont &Font() { return mFont; }
+    const nsFont &Font() const { return mFont; }
 
     /**
      * Returns the language associated with these metrics
      */
-    nsIAtom* Language() { return mLanguage; }
+    nsIAtom* Language() const { return mLanguage; }
 
     /**
      * Returns the orientation (horizontal/vertical) of these metrics.
      */
-    gfxFont::Orientation Orientation() { return mOrientation; }
+    gfxFont::Orientation Orientation() const { return mOrientation; }
 
     int32_t GetMaxStringLength();
 
@@ -211,26 +211,53 @@ public:
                                                     nsRenderingContext *aContext);
 
     void SetTextRunRTL(bool aIsRTL) { mTextRunRTL = aIsRTL; }
-    bool GetTextRunRTL() { return mTextRunRTL; }
+    bool GetTextRunRTL() const { return mTextRunRTL; }
 
-    gfxFontGroup* GetThebesFontGroup() { return mFontGroup; }
-    gfxUserFontSet* GetUserFontSet() { return mFontGroup->GetUserFontSet(); }
+    void SetVertical(bool aVertical) { mVertical = aVertical; }
+    bool GetVertical() const { return mVertical; }
 
-    int32_t AppUnitsPerDevPixel() { return mP2A; }
+    void SetTextOrientation(uint8_t aTextOrientation)
+    {
+      mTextOrientation = aTextOrientation;
+    }
+    uint8_t GetTextOrientation() const { return mTextOrientation; }
+
+    gfxFontGroup* GetThebesFontGroup() const { return mFontGroup; }
+    gfxUserFontSet* GetUserFontSet() const
+    {
+      return mFontGroup->GetUserFontSet();
+    }
+
+    int32_t AppUnitsPerDevPixel() const { return mP2A; }
 
 private:
     // Private destructor, to discourage deletion outside of Release():
     ~nsFontMetrics();
 
-    const gfxFont::Metrics& GetMetrics() const;
+    const gfxFont::Metrics& GetMetrics() const {
+      return GetMetrics(mOrientation);
+    }
+
+    const gfxFont::Metrics&
+    GetMetrics(const gfxFont::Orientation aFontOrientation) const;
 
     nsFont mFont;
     nsRefPtr<gfxFontGroup> mFontGroup;
     nsCOMPtr<nsIAtom> mLanguage;
     nsDeviceContext *mDeviceContext;
     int32_t mP2A;
-    bool mTextRunRTL;
+
+    // The font orientation (horizontal or vertical) for which these metrics
+    // have been initialized. This determines which line metrics (ascent and
+    // descent) they will return.
     gfxFont::Orientation mOrientation;
+
+    // These fields may be set by clients to control the behavior of methods
+    // like GetWidth and DrawString according to the writing mode, direction
+    // and text-orientation desired.
+    bool mTextRunRTL;
+    bool mVertical;
+    uint8_t mTextOrientation;
 };
 
 #endif /* NSFONTMETRICS__H__ */

layout/base/nsBidiPresUtils.cpp

@@ -2090,10 +2090,16 @@ public:
                                                *mTextRunConstructionContext);
   }
 
-  virtual void DrawText(nscoord aXOffset,
+  virtual void DrawText(nscoord aIOffset,
                         nscoord) MOZ_OVERRIDE
   {
-    mFontMetrics->DrawString(mText, mLength, mPt.x + aXOffset, mPt.y,
+    nsPoint pt(mPt);
+    if (mFontMetrics->GetVertical()) {
+      pt.y += aIOffset;
+    } else {
+      pt.x += aIOffset;
+    }
+    mFontMetrics->DrawString(mText, mLength, pt.x, pt.y,
                              mCtx, mTextRunConstructionContext);
   }
 

layout/base/nsLayoutUtils.cpp

@@ -5115,6 +5115,8 @@ nsLayoutUtils::AppUnitWidthOfStringBidi(const char16_t* aString,
                                              aFontMetrics);
   }
   aFontMetrics.SetTextRunRTL(false);
+  aFontMetrics.SetVertical(aFrame->GetWritingMode().IsVertical());
+  aFontMetrics.SetTextOrientation(aFrame->StyleVisibility()->mTextOrientation);
   return nsLayoutUtils::AppUnitWidthOfString(aString, aLength, aFontMetrics,
                                              aContext);
 }
@@ -5156,11 +5158,19 @@ nsLayoutUtils::DrawString(const nsIFrame*       aFrame,
                           nsStyleContext*       aStyleContext)
 {
   nsresult rv = NS_ERROR_FAILURE;
+
+  // If caller didn't pass a style context, use the frame's.
+  if (!aStyleContext) {
+    aStyleContext = aFrame->StyleContext();
+  }
+  aFontMetrics.SetVertical(WritingMode(aStyleContext).IsVertical());
+  aFontMetrics.SetTextOrientation(
+    aStyleContext->StyleVisibility()->mTextOrientation);
+
   nsPresContext* presContext = aFrame->PresContext();
   if (presContext->BidiEnabled()) {
     nsBidiLevel level =
-      nsBidiPresUtils::BidiLevelFromStyle(aStyleContext ?
-                                          aStyleContext : aFrame->StyleContext());
+      nsBidiPresUtils::BidiLevelFromStyle(aStyleContext);
     rv = nsBidiPresUtils::RenderText(aString, aLength, level,
                                      presContext, *aContext, *aContext,
                                      aFontMetrics,