add local-matrix to shader::context

src/core/SkDraw.cpp

Index: src/core/SkDraw.cpp
diff --git a/src/core/SkDraw.cpp b/src/core/SkDraw.cpp
index 9347efe475b4c9ade919e40a0864f1a5ce1e8867..df599b4706fdf779000ef56794d1e8ab13a9e351 100644
--- a/src/core/SkDraw.cpp
+++ b/src/core/SkDraw.cpp
@@ -2403,7 +2403,11 @@ bool SkTriColorShader::TriColorShaderContext::setup(const SkPoint pts[], const S
     if (!m.invert(&im)) {
         return false;
     }
-    fDstToUnit.setConcat(im, this->getTotalInverse());
+    SkMatrix ctmInv;
+    if (!this->getCTM().invert(&ctmInv)) {

[scroggo, 2014/05/06 15:40:30]

So if I understand correctly, the reason this doesn't just look at
this->getTotalInverse() is because that accounts for the local matrices, and
this does not want to?

[reed1, 2014/05/06 17:04:50]

Yes. Added a comment to explain that.

+        return false;
+    }
+    fDstToUnit.setConcat(im, ctmInv);
     return true;
 }
 
@@ -2556,18 +2560,13 @@ void SkDraw::drawVertices(SkCanvas::VertexMode vmode, int count,
     VertState::Proc vertProc = state.chooseProc(vmode);
 
     if (NULL != textures || NULL != colors) {
-        SkMatrix  tempM;
-        SkMatrix  savedLocalM;
-        if (shader) {
-            savedLocalM = shader->getLocalMatrix();
-        }
-
         while (vertProc(&state)) {
             if (NULL != textures) {
+                SkMatrix tempM;
                 if (texture_to_matrix(state, vertices, textures, &tempM)) {
-                    tempM.postConcat(savedLocalM);
-                    shader->setLocalMatrix(tempM);
-                    if (!blitter->resetShaderContext(*fBitmap, p, *fMatrix)) {
+                    SkShader::ContextRec rec(*fBitmap, p, *fMatrix);
+                    rec.fLocalMatrix = &tempM;

[scroggo, 2014/05/06 15:40:30]

Why not set this in the constructor?

[reed1, 2014/05/06 17:04:50]

half dozen. At some point I find arguments harder to know what's going on, since
they are not named.

+                    if (!blitter->resetShaderContext(rec)) {
                         continue;
                     }
                 }
@@ -2603,11 +2602,6 @@ void SkDraw::drawVertices(SkCanvas::VertexMode vmode, int count,
             };
             SkScan::FillTriangle(tmp, *fRC, blitter.get());
         }
-
-        // now restore the shader's original local matrix
-        if (NULL != shader) {
-            shader->setLocalMatrix(savedLocalM);
-        }
     } else {
         // no colors[] and no texture
         HairProc hairProc = ChooseHairProc(paint.isAntiAlias());