SkScalerContext::getMetrics to not request metrics it will ignore.

Before this change SkScalerContext::getMetrics always calls
generateMetrics to force the subclass to create full metrics. However,
if the SkScalerContext is going to draw from outlines then there is no
reason to do so since it is immediately going to overwrite those metrics
by computing its own from the path. This also puts off other decisions
being made based on the glyph metrics until after the metrics are fully
computed.

The logic in SkScalerContext::getImage is updated to be similar to the
logic in the new SkScalerContext::getMetrics.

Change-Id: I1798c9244277fab85595fb39fc3a85ef7eb33620
Reviewed-on: https://skia-review.googlesource.com/117085
Reviewed-by: Herb Derby <herb@google.com>
Commit-Queue: Ben Wagner <bungeman@google.com>

1 files changed, 31 insertions, 30 deletions

diff --git a/src/core/SkScalerContext.cpp b/src/core/SkScalerContext.cpp
index 6302a80dc1..96a0f80d7d 100644
--- a/src/core/SkScalerContext.cpp
+++ b/src/core/SkScalerContext.cpp
@@ -71,38 +71,20 @@ void SkScalerContext::getAdvance(SkGlyph* glyph) {
 }
 
 void SkScalerContext::getMetrics(SkGlyph* glyph) {
-    generateMetrics(glyph);
-
-    // for now we have separate cache entries for devkerning on and off
-    // in the future we might share caches, but make our measure/draw
-    // code make the distinction. Thus we zap the values if the caller
-    // has not asked for them.
-    if ((fRec.fFlags & SkScalerContext::kDevKernText_Flag) == 0) {
-        // no devkern, so zap the fields
-        glyph->fLsbDelta = glyph->fRsbDelta = 0;
-    }
-
-    // if either dimension is empty, zap the image bounds of the glyph
-    if (0 == glyph->fWidth || 0 == glyph->fHeight) {
-        glyph->fWidth   = 0;
-        glyph->fHeight  = 0;
-        glyph->fTop     = 0;
-        glyph->fLeft    = 0;
-        glyph->fMaskFormat = 0;
-        return;
-    }
-
     bool generatingImageFromPath = fGenerateImageFromPath;
-    if (fGenerateImageFromPath) {
+    if (!generatingImageFromPath) {
+        generateMetrics(glyph);
+    } else {
         SkPath      devPath, fillPath;
         SkMatrix    fillToDevMatrix;
-
-        if (!this->internalGetPath(glyph->getPackedID(), &fillPath, &devPath, &fillToDevMatrix)) {
-            generatingImageFromPath = false;
+        generatingImageFromPath = this->internalGetPath(glyph->getPackedID(), &fillPath, &devPath,
+                                                        &fillToDevMatrix);
+        if (!generatingImageFromPath) {
+            generateMetrics(glyph);
         } else {
-            // just use devPath
-            const SkIRect ir = devPath.getBounds().roundOut();
+            generateAdvance(glyph);
 
+            const SkIRect ir = devPath.getBounds().roundOut();
             if (ir.isEmpty() || !ir.is16Bit()) {
                 goto SK_ERROR;
             }
@@ -124,6 +106,25 @@ void SkScalerContext::getMetrics(SkGlyph* glyph) {
         }
     }
 
+    // for now we have separate cache entries for devkerning on and off
+    // in the future we might share caches, but make our measure/draw
+    // code make the distinction. Thus we zap the values if the caller
+    // has not asked for them.
+    if ((fRec.fFlags & SkScalerContext::kDevKernText_Flag) == 0) {
+        // no devkern, so zap the fields
+        glyph->fLsbDelta = glyph->fRsbDelta = 0;
+    }
+
+    // if either dimension is empty, zap the image bounds of the glyph
+    if (0 == glyph->fWidth || 0 == glyph->fHeight) {
+        glyph->fWidth   = 0;
+        glyph->fHeight  = 0;
+        glyph->fTop     = 0;
+        glyph->fLeft    = 0;
+        glyph->fMaskFormat = 0;
+        return;
+    }
+
     if (SkMask::kARGB32_Format != glyph->fMaskFormat) {
         glyph->fMaskFormat = fRec.fMaskFormat;
     }
@@ -428,7 +429,9 @@ void SkScalerContext::getImage(const SkGlyph& origGlyph) {
         glyph = &tmpGlyph;
     }
 
-    if (fGenerateImageFromPath) {
+    if (!fGenerateImageFromPath) {
+        generateImage(*glyph);
+    } else {
         SkPath      devPath, fillPath;
         SkMatrix    fillToDevMatrix;
         SkMask      mask;
@@ -441,8 +444,6 @@ void SkScalerContext::getImage(const SkGlyph& origGlyph) {
             SkASSERT(SkMask::kARGB32_Format != mask.fFormat);
             generateMask(mask, devPath, fPreBlend);
         }
-    } else {
-        generateImage(*glyph);
     }
 
     if (fMaskFilter) {