SkTextBlob shader space workaround.

src/core/SkDevice.cpp

 /*
  * Copyright 2011 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkDevice.h"
 #include "SkDraw.h"
 #include "SkMetaData.h"
 #include "SkPatchUtils.h"
+#include "SkShader.h"
 #include "SkTextBlob.h"
 
 SkBaseDevice::SkBaseDevice()
     : fLeakyProperties(SkDeviceProperties::MakeDefault())
 #ifdef SK_DEBUG
     , fAttachedToCanvas(false)
 #endif
 {
     fOrigin.setZero();
     fMetaData = NULL;
@@ skipping 69 matching lines @@
     if (SkPatchUtils::getVertexData(&data, cubics, colors, texCoords, lod.width(), lod.height())) {
         this->drawVertices(draw, SkCanvas::kTriangles_VertexMode, data.fVertexCount, data.fPoints,
                            data.fTexCoords, data.fColors, xmode, data.fIndices, data.fIndexCount,
                            paint);
     }
 }
 
 void SkBaseDevice::drawTextBlob(const SkDraw& draw, const SkTextBlob* blob, SkScalar x, SkScalar y,
                                 const SkPaint &paint) {
 
+    SkPaint runPaint = paint;
     SkMatrix localMatrix;
     SkDraw localDraw(draw);
 
     if (x || y) {
         localMatrix = *draw.fMatrix;
         localMatrix.preTranslate(x, y);
         localDraw.fMatrix = &localMatrix;
+
+        if (paint.getShader()) {

[reed1, 2014/09/19 16:47:19]

Tricky, but seems fine for now.

Perhaps a TODO to consider passing x,y to the other methods, so they could
handle the additional translate w/o needing to allocate a new shader.

[f(malita), 2014/09/19 17:55:53]

Done.

+            // FIXME: We need to compensate for the translate above. This is suboptimal but
+            // temporary -- until we get proper derived class drawTextBlob implementations.
+            SkMatrix shaderMatrix;
+            shaderMatrix.setTranslate(-x, -y);
+            SkAutoTUnref<SkShader> wrapper(
+                SkShader::CreateLocalMatrixShader(paint.getShader(), shaderMatrix));
+            runPaint.setShader(wrapper);
+        }
     }
 
-    SkPaint runPaint = paint;
     SkTextBlob::RunIterator it(blob);
     while (!it.done()) {
         size_t textLen = it.glyphCount() * sizeof(uint16_t);
         const SkPoint& offset = it.offset();
         // applyFontToPaint() always overwrites the exact same attributes,
         // so it is safe to not re-seed the paint.
         it.applyFontToPaint(&runPaint);
 
         switch (it.positioning()) {
         case SkTextBlob::kDefault_Positioning:
@@ skipping 67 matching lines @@
 
 void SkBaseDevice::EXPERIMENTAL_optimize(const SkPicture* picture) {
     // The base class doesn't perform any analysis but derived classes may
 }
 
 bool SkBaseDevice::EXPERIMENTAL_drawPicture(SkCanvas*, const SkPicture*, const SkMatrix*,
                                             const SkPaint*) {
     // The base class doesn't perform any accelerated picture rendering
     return false;
 }