change tooBitForLCD to compare against linear size of the text, not the area

src/core/SkPaint.cpp

 
 /*
  * Copyright 2006 The Android Open Source Project
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkPaint.h"
 #include "SkAnnotation.h"
@@ skipping 1534 matching lines @@
 
 #define assert_byte(x)  SkASSERT(0 == ((x) >> 8))
 
 // Beyond this size, LCD doesn't appreciably improve quality, but it always
 // cost more RAM and draws slower, so we set a cap.
 #ifndef SK_MAX_SIZE_FOR_LCDTEXT
     #define SK_MAX_SIZE_FOR_LCDTEXT    48
 #endif
 
 static bool tooBigForLCD(const SkScalerContext::Rec& rec) {
-    SkScalar area = SkScalarMul(rec.fPost2x2[0][0], rec.fPost2x2[1][1]) -
-                    SkScalarMul(rec.fPost2x2[1][0], rec.fPost2x2[0][1]);
-    SkScalar size = SkScalarMul(area, rec.fTextSize);
-    return SkScalarAbs(size) > SkIntToScalar(SK_MAX_SIZE_FOR_LCDTEXT);
+    SkScalar area = rec.fPost2x2[0][0] * rec.fPost2x2[1][1] -
+                    rec.fPost2x2[1][0] * rec.fPost2x2[0][1];
+    SkScalar size = SkScalarSqrt(SkScalarAbs(area)) * rec.fTextSize;
+    return size > SkIntToScalar(SK_MAX_SIZE_FOR_LCDTEXT);
 }
 
 /*
  *  Return the scalar with only limited fractional precision. Used to consolidate matrices
  *  that vary only slightly when we create our key into the font cache, since the font scaler
  *  typically returns the same looking resuts for tiny changes in the matrix.
  */
 static SkScalar sk_relax(SkScalar x) {
     int n = sk_float_round2int(x * 1024);
     return n / 1024.0f;
@@ skipping 1088 matching lines @@
     }
 #ifdef SK_BUILD_FOR_ANDROID
     if (dirty & kPaintOptionsAndroid_DirtyBit) {
         SkPaintOptionsAndroid options;
         options.unflatten(buffer);
         paint->setPaintOptionsAndroid(options);
     }
 #endif
     SkASSERT(dirty == paint->fDirtyBits);
 }