SkLiteDL: drawAsLayer()

src/core/SkLiteDL.h

 /*
  * Copyright 2016 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #ifndef SkLiteDL_DEFINED
 #define SkLiteDL_DEFINED
 
 #include "SkCanvas.h"
 #include "SkPaint.h"
 #include "SkPath.h"
 #include "SkDrawable.h"
 #include "SkRect.h"
 #include "SkTDArray.h"
 
 class SkLiteDL final : public SkDrawable {
 public:
     static sk_sp<SkLiteDL> New(SkRect);
     void reset(SkRect);
 
     void makeThreadsafe();
     bool empty() const { return fUsed == 0; }
 
 #ifdef SK_SUPPORT_LEGACY_DRAWFILTER
     void setDrawFilter(SkDrawFilter*);
 #endif
 
+    // Draws as if...
+    //   SkPaint p;
+    //   p.setColorFilter(cf);
+    //   p.setXfermode(xfer);
+    //   p.setAlpha(alpha);
+    //   SkRect bounds = this->getBounds();
+    //   c->saveLayer(&bounds, &p);
+    //       this->draw(c, matrix);
+    //   c->restore();
+    void drawAsLayer(SkCanvas* c, const SkMatrix* matrix

[djsollen, 2016/09/07 14:31:36]

yep, though in my current case matrix will always be a nullptr.

[reed1, 2016/09/07 15:29:55]

drawPicture has nearly this signature already:

canvas->drawPicture(picture, matrix, layerPaint)

I think this guy should take a paint* instead of separate params:
- matches drawPicture (and saveLayer for that matter)
- can be well defined (given the other layer-paint uses as to which fields are
respected)
- automatically gets other fields (not yet respected by android.. yet) like
imagefilter

[mtklein, 2016/09/08 15:20:54]

sgtm, ptal

+                                , SkColorFilter* cf
+                                , SkXfermode* xfer
+                                , U8CPU alpha);
+
     void save();
     void saveLayer(const SkRect*, const SkPaint*, const SkImageFilter*, SkCanvas::SaveLayerFlags);
     void restore();
 
     void    concat (const SkMatrix&);
     void setMatrix (const SkMatrix&);
     void translate(SkScalar, SkScalar);
     void translateZ(SkScalar);
 
     void clipPath  (const   SkPath&, SkRegion::Op, bool aa);
@@ skipping 57 matching lines @@
     template <typename Fn, typename... Args>
     void map(const Fn[], Args...);
 
     SkAutoTMalloc<uint8_t> fBytes;
     size_t                 fUsed;
     size_t                 fReserved;
     SkRect                 fBounds;
 };
 
 #endif//SkLiteDL_DEFINED