Use SkTypeface::getBounds() in bounding-box calculations.

src/core/SkRecordDraw.cpp

Index: src/core/SkRecordDraw.cpp
diff --git a/src/core/SkRecordDraw.cpp b/src/core/SkRecordDraw.cpp
index 5981245c018700e8ed969e7abc75e1d76c63b7ba..6dcb9b8a4976d633b93b37cc82da12f477b02a00 100644
--- a/src/core/SkRecordDraw.cpp
+++ b/src/core/SkRecordDraw.cpp
@@ -7,6 +7,7 @@
 
 #include "SkRecordDraw.h"
 #include "SkPatchUtils.h"
+#include "SkTypeface.h"
 
 void SkRecordDraw(const SkRecord& record,
                   SkCanvas* canvas,
@@ -444,15 +445,13 @@ private:
     Bounds bounds(const DrawTextOnPath& op) const {
         SkRect dst = op.path.getBounds();
 
-        // Pad all sides by the maximum padding in any direction we'd normally apply.
+        // We don't know how the text will curve aroudn the path, so
+        // pad all sides by the maximum padding in any direction we'd normally apply.
         SkRect pad = { 0, 0, 0, 0};
         AdjustTextForFontMetrics(&pad, op.paint);
-
-        // That maximum padding happens to always be the right pad today.
-        SkASSERT(pad.fLeft == -pad.fRight);
-        SkASSERT(pad.fTop  == -pad.fBottom);
-        SkASSERT(pad.fRight > pad.fBottom);
-        dst.outset(pad.fRight, pad.fRight);
+        SkScalar max = SkTMax(SkTMax(-pad.fLeft, pad.fRight),
+                              SkTMax(-pad.fTop, pad.fBottom));
+        dst.outset(max, max);
 
         return this->adjustAndMap(dst, &op.paint);
     }
@@ -464,26 +463,39 @@ private:
     }
 
     static void AdjustTextForFontMetrics(SkRect* rect, const SkPaint& paint) {
-#ifdef SK_DEBUG
-        SkRect correct = *rect;
-#endif
-        // crbug.com/373785 ~~> xPad = 4x yPad
-        // crbug.com/424824 ~~> bump yPad from 2x text size to 2.5x
-        const SkScalar yPad = 2.5f * paint.getTextSize(),
-                       xPad = 4.0f * yPad;
-        rect->outset(xPad, yPad);
+        // rect was built from only the text's origin points, so we need
+        // to outset it by the worst-case bounds of the typeface.
+        SkAutoTUnref<SkTypeface> au;
+        SkTypeface* tf = paint.getTypeface();
+        if (!tf) {
+            au.reset(SkTypeface::RefDefault());
+            tf = au.get();
+        }
+        const SkScalar size = paint.getTextSize();
+        const SkRect tb = tf->getBounds();
+        rect->fLeft   += size * tb.fLeft;
+        rect->fRight  += size * tb.fRight;
+        rect->fTop    += size * tb.fTop;
+        rect->fBottom += size * tb.fBottom;
 #ifdef SK_DEBUG
         SkPaint::FontMetrics metrics;
         paint.getFontMetrics(&metrics);
-        correct.fLeft   += metrics.fXMin;
-        correct.fTop    += metrics.fTop;
-        correct.fRight  += metrics.fXMax;
-        correct.fBottom += metrics.fBottom;
+        // Our numbers are so close to correct now that we're sometimes _slightly_ under.  Add
+        // a little fudge factor here to make sure the assert just catches really bad failures.
+        const SkScalar kFudge = 0.0625f;
+        SkRect fudged = {
+            size * (tb.fLeft   - kFudge),
+            size * (tb.fTop    - kFudge),
+            size * (tb.fRight  + kFudge),
+            size * (tb.fBottom + kFudge),
+        };
+        SkRect correct = { metrics.fXMin, metrics.fTop, metrics.fXMax, metrics.fBottom };
         // See skia:2862 for why we ignore small text sizes.
-        SkASSERTF(paint.getTextSize() < 0.001f || rect->contains(correct),
-                  "%f %f %f %f vs. %f %f %f %f\n",
-                  -xPad, -yPad, +xPad, +yPad,
-                  metrics.fXMin, metrics.fTop, metrics.fXMax, metrics.fBottom);
+        SkASSERTF(paint.getTextSize() < 0.001f || fudged.contains(correct),
+                  "%f %f %f %f vs. %f %f %f %f, text size %f\n",
+                  size*tb.fLeft, size*tb.fTop, size*tb.fRight, size*tb.fBottom,
+                  metrics.fXMin, metrics.fTop, metrics.fXMax,  metrics.fBottom,
+                  paint.getTextSize());
 #endif
     }