avoid extra math work in MackRec

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"
 #include "SkAutoKern.h"
@@ skipping 1461 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 = 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);
+const SkScalar gMaxSize2ForLCDText = SK_MAX_SIZE_FOR_LCDTEXT * SK_MAX_SIZE_FOR_LCDTEXT;
+

[robertphillips, 2014/10/01 19:58:41]

too_big_for_lcd ?

+static bool tooBigForLCD(const SkScalerContext::Rec& rec, bool checkPost2x2) {
+    SkScalar size = rec.fTextSize;
+    if (checkPost2x2) {
+        SkScalar area = rec.fPost2x2[0][0] * rec.fPost2x2[1][1] -
+                        rec.fPost2x2[1][0] * rec.fPost2x2[0][1];
+        size *= SkScalarAbs(area);
+    }
+    return size > gMaxSize2ForLCDText;
 }
 
 /*
  *  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;
 }
 
 void SkScalerContext::MakeRec(const SkPaint& paint,
                               const SkDeviceProperties* deviceProperties,
                               const SkMatrix* deviceMatrix,
                               Rec* rec) {
     SkASSERT(deviceMatrix == NULL || !deviceMatrix->hasPerspective());
 
     SkTypeface* typeface = paint.getTypeface();
     if (NULL == typeface) {
         typeface = SkTypeface::GetDefaultTypeface();
     }
     rec->fFontID = typeface->uniqueID();
     rec->fTextSize = paint.getTextSize();
     rec->fPreScaleX = paint.getTextScaleX();
     rec->fPreSkewX  = paint.getTextSkewX();
 
+    bool checkPost2x2 = false;
+
     if (deviceMatrix) {
-        rec->fPost2x2[0][0] = sk_relax(deviceMatrix->getScaleX());
-        rec->fPost2x2[0][1] = sk_relax(deviceMatrix->getSkewX());
-        rec->fPost2x2[1][0] = sk_relax(deviceMatrix->getSkewY());
-        rec->fPost2x2[1][1] = sk_relax(deviceMatrix->getScaleY());
+        const SkMatrix::TypeMask mask = deviceMatrix->getType();
+        if (mask & SkMatrix::kScale_Mask) {
+            rec->fPost2x2[0][0] = sk_relax(deviceMatrix->getScaleX());
+            rec->fPost2x2[1][1] = sk_relax(deviceMatrix->getScaleY());
+            checkPost2x2 = true;
+        } else {
+            rec->fPost2x2[0][0] = rec->fPost2x2[1][1] = SK_Scalar1;
+        }
+        if (mask & SkMatrix::kAffine_Mask) {
+            rec->fPost2x2[0][1] = sk_relax(deviceMatrix->getSkewX());
+            rec->fPost2x2[1][0] = sk_relax(deviceMatrix->getSkewY());
+            checkPost2x2 = true;
+        } else {
+            rec->fPost2x2[0][1] = rec->fPost2x2[1][0] = 0;
+        }
     } else {
         rec->fPost2x2[0][0] = rec->fPost2x2[1][1] = SK_Scalar1;
         rec->fPost2x2[0][1] = rec->fPost2x2[1][0] = 0;
     }
 
     SkPaint::Style  style = paint.getStyle();
     SkScalar        strokeWidth = paint.getStrokeWidth();
 
     unsigned flags = 0;
 
@@ skipping 30 matching lines @@
         }
     } else {
         rec->fFrameWidth = 0;
         rec->fMiterLimit = 0;
         rec->fStrokeJoin = 0;
     }
 
     rec->fMaskFormat = SkToU8(computeMaskFormat(paint));
 
     if (SkMask::kLCD16_Format == rec->fMaskFormat || SkMask::kLCD32_Format == rec->fMaskFormat) {
-        if (tooBigForLCD(*rec)) {
+        if (tooBigForLCD(*rec, checkPost2x2)) {
             rec->fMaskFormat = SkMask::kA8_Format;
             flags |= SkScalerContext::kGenA8FromLCD_Flag;
         } else {
             SkPixelGeometry geometry = deviceProperties
                                      ? deviceProperties->fPixelGeometry
                                      : SkSurfacePropsDefaultPixelGeometry();
             switch (geometry) {
                 case kUnknown_SkPixelGeometry:
                     // eeek, can't support LCD
                     rec->fMaskFormat = SkMask::kA8_Format;
@@ skipping 977 matching lines @@
                 return 0 == this->getAlpha();
             case SkXfermode::kDst_Mode:
                 return true;
             default:
                 break;
         }
     }
     return false;
 }