From be2284de556e7ec29489693093d42dc86b762645 Mon Sep 17 00:00:00 2001
From: bungeman <bungeman@google.com>
Date: Tue, 25 Nov 2014 08:08:09 -0800
Subject: [PATCH] Use text size on Mac.

The current code assumes that text on Mac is freely scalable,
or at least that the text size is just a part of the transform.
However, it appears that application of the 'trak' table,
as well as other optical adjustments, may rely on the text size
directly.

This change passes the text size requested directly to CoreText.

BUG=chromium:427528

Review URL: https://codereview.chromium.org/752183002
---
 src/core/SkScalerContext.cpp | 13 +++++++++++++
 src/core/SkScalerContext.h   |  2 ++
 src/ports/SkFontHost_mac.cpp | 25 +++++++++++++++++++------
 3 files changed, 34 insertions(+), 6 deletions(-)

diff --git a/src/core/SkScalerContext.cpp b/src/core/SkScalerContext.cpp
index 20413a7..b7409ff 100644
--- a/src/core/SkScalerContext.cpp
+++ b/src/core/SkScalerContext.cpp
@@ -700,6 +700,10 @@ void SkScalerContextRec::getLocalMatrix(SkMatrix* m) const {
     SkPaint::SetTextMatrix(m, fTextSize, fPreScaleX, fPreSkewX);
 }
 
+void SkScalerContextRec::getLocalMatrixWithoutTextSize(SkMatrix* m) const {
+    SkPaint::SetTextMatrix(m, SK_Scalar1, fPreScaleX, fPreSkewX);
+}
+
 void SkScalerContextRec::getSingleMatrix(SkMatrix* m) const {
     this->getLocalMatrix(m);
 
@@ -709,6 +713,15 @@ void SkScalerContextRec::getSingleMatrix(SkMatrix* m) const {
     m->postConcat(deviceMatrix);
 }
 
+void SkScalerContextRec::getSingleMatrixWithoutTextSize(SkMatrix* m) const {
+    this->getLocalMatrixWithoutTextSize(m);
+
+    //  now concat the device matrix
+    SkMatrix    deviceMatrix;
+    this->getMatrixFrom2x2(&deviceMatrix);
+    m->postConcat(deviceMatrix);
+}
+
 SkAxisAlignment SkComputeAxisAlignmentForHText(const SkMatrix& matrix) {
     SkASSERT(!matrix.hasPerspective());
 
diff --git a/src/core/SkScalerContext.h b/src/core/SkScalerContext.h
index 3ebaa59..b78efef 100644
--- a/src/core/SkScalerContext.h
+++ b/src/core/SkScalerContext.h
@@ -82,7 +82,9 @@ struct SkScalerContextRec {
 
     void    getMatrixFrom2x2(SkMatrix*) const;
     void    getLocalMatrix(SkMatrix*) const;
+    void    getLocalMatrixWithoutTextSize(SkMatrix*) const;
     void    getSingleMatrix(SkMatrix*) const;
+    void    getSingleMatrixWithoutTextSize(SkMatrix*) const;
 
     inline SkPaint::Hinting getHinting() const;
     inline void setHinting(SkPaint::Hinting);
diff --git a/src/ports/SkFontHost_mac.cpp b/src/ports/SkFontHost_mac.cpp
index 7fd645b..dea72c7 100755
--- a/src/ports/SkFontHost_mac.cpp
+++ b/src/ports/SkFontHost_mac.cpp
@@ -717,8 +717,9 @@ SkScalerContext_Mac::SkScalerContext_Mac(SkTypeface_Mac* typeface,
     SkASSERT(numGlyphs >= 1 && numGlyphs <= 0xFFFF);
     fGlyphCount = SkToU16(numGlyphs);
 
-    fRec.getSingleMatrix(&fFUnitMatrix);
-    CGAffineTransform transform = MatrixToCGAffineTransform(fFUnitMatrix);
+    SkMatrix skTransform;
+    fRec.getSingleMatrixWithoutTextSize(&skTransform);
+    CGAffineTransform transform = MatrixToCGAffineTransform(skTransform);
 
     AutoCFRelease<CTFontDescriptorRef> ctFontDesc;
     if (fVertical) {
@@ -734,15 +735,27 @@ SkScalerContext_Mac::SkScalerContext_Mac(SkTypeface_Mac* typeface,
             ctFontDesc.reset(CTFontDescriptorCreateWithAttributes(cfAttributes));
         }
     }
-    // Since our matrix includes everything, we pass 1 for size.
-    fCTFont.reset(CTFontCreateCopyWithAttributes(ctFont, 1, &transform, ctFontDesc));
+
+    // The transform contains everything except the requested text size.
+    // Some properties, like 'trak', are based on the text size (before applying the matrix).
+    CGFloat textSize = ScalarToCG(fRec.fTextSize);
+
+    // If a text size of 0 is requested, CoreGraphics will use 12 instead.
+    // If the text size is 0, set it to something tiny.
+    if (textSize < CGFLOAT_MIN) {
+        textSize = CGFLOAT_MIN;
+    }
+
+    fCTFont.reset(CTFontCreateCopyWithAttributes(ctFont, textSize, &transform, ctFontDesc));
     fCGFont.reset(CTFontCopyGraphicsFont(fCTFont, NULL));
     if (fVertical) {
         CGAffineTransform rotateLeft = CGAffineTransformMake(0, -1, 1, 0, 0, 0);
         transform = CGAffineTransformConcat(rotateLeft, transform);
-        fCTVerticalFont.reset(CTFontCreateCopyWithAttributes(ctFont, 1, &transform, NULL));
+        fCTVerticalFont.reset(CTFontCreateCopyWithAttributes(ctFont, textSize, &transform, NULL));
     }
 
+    // The fUnitMatrix includes the text size (and em) as it is used to scale the raw font data.
+    fRec.getSingleMatrix(&fFUnitMatrix);
     SkScalar emPerFUnit = SkScalarInvert(SkIntToScalar(CGFontGetUnitsPerEm(fCGFont)));
     fFUnitMatrix.preScale(emPerFUnit, -emPerFUnit);
 }
@@ -793,7 +806,7 @@ CGRGBPixel* Offscreen::getCG(const SkScalerContext_Mac& context, const SkGlyph&
 
         CGContextSetTextDrawingMode(fCG, kCGTextFill);
         CGContextSetFont(fCG, context.fCGFont);
-        CGContextSetFontSize(fCG, 1 /*CTFontGetSize(context.fCTFont)*/);
+        CGContextSetFontSize(fCG, CTFontGetSize(context.fCTFont));
         CGContextSetTextMatrix(fCG, CTFontGetMatrix(context.fCTFont));
 
         // Because CG always draws from the horizontal baseline,
-- 
2.7.4