Revert of Hide SkCanvas::LayerIter

samplecode/SampleLayers.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 "SampleCode.h"
 #include "SkView.h"
 #include "SkCanvas.h"
 #include "SkBlurMaskFilter.h"
 #include "SkCamera.h"
 #include "SkColorFilter.h"
 #include "SkColorPriv.h"
+#include "SkDevice.h"
 #include "SkGradientShader.h"
 #include "SkImage.h"
 #include "SkInterpolator.h"
 #include "SkMaskFilter.h"
 #include "SkPath.h"
 #include "SkRegion.h"
 #include "SkShader.h"
 #include "SkTime.h"
 #include "SkTypeface.h"
 #include "SkUtils.h"
 #include "SkKey.h"
 #include "SkXfermode.h"
 #include "SkDrawFilter.h"
 
 static void make_paint(SkPaint* paint, const SkMatrix& localMatrix) {
     SkColor colors[] = { 0, SK_ColorWHITE };
     SkPoint pts[] = { { 0, 0 }, { 0, SK_Scalar1*20 } };
     paint->setShader(SkGradientShader::MakeLinear(pts, colors, nullptr, 2,
                                                   SkShader::kClamp_TileMode, 0, &localMatrix));
     paint->setXfermodeMode(SkXfermode::kDstIn_Mode);
 }
 
+static void dump_layers(const char label[], SkCanvas* canvas) {
+    SkDebugf("Dump Layers(%s)\n", label);
+
+    SkCanvas::LayerIter iter(canvas, true);
+    int index = 0;
+    while (!iter.done()) {
+        SkImageInfo info = iter.device()->imageInfo();
+        const SkIRect& clip = iter.clip().getBounds();
+        SkDebugf("Layer[%d] bitmap [%d %d] X=%d Y=%d clip=[%d %d %d %d] alpha=%d\n", index++,
+                 info.width(), info.height(), iter.x(), iter.y(),
+                 clip.fLeft, clip.fTop, clip.fRight, clip.fBottom,
+                 iter.paint().getAlpha());
+        iter.next();
+    }
+}
+
 // test drawing with strips of fading gradient above and below
 static void test_fade(SkCanvas* canvas) {
     SkAutoCanvasRestore ar(canvas, true);
 
     SkRect r;
 
     SkPaint p;
     p.setAlpha(0x88);
 
     SkAutoCanvasRestore ar2(canvas, false);
@@ skipping 15 matching lines @@
     if (true) {
         r.set(0, 0, SkIntToScalar(100), SkIntToScalar(100));
 
         canvas->saveLayerAlpha(&r, 0x80);
 
         SkPaint p;
         p.setColor(SK_ColorRED);
         p.setAntiAlias(true);
         canvas->drawOval(r, p);
 
+        dump_layers("inside layer alpha", canvas);
+
         canvas->restore();
     } else {
         r.set(0, 0, SkIntToScalar(100), SkIntToScalar(100));
 
         SkPaint p;
         p.setColor(SK_ColorRED);
         p.setAntiAlias(true);
         canvas->drawOval(r, p);
     }
 
 //    return;
 
+    dump_layers("outside layer alpha", canvas);
+
     // now apply an effect
     SkMatrix m;
     m.setScale(SK_Scalar1, -SK_Scalar1);
     m.postTranslate(0, SkIntToScalar(100));
 
     SkPaint paint;
     make_paint(&paint, m);
     r.set(0, 0, SkIntToScalar(100), SkIntToScalar(20));
 //    SkDebugf("--------- draw top grad\n");
     canvas->drawRect(r, paint);
@@ skipping 184 matching lines @@
     bool onClick(Click* click) override {
         this->inval(nullptr);
         fCenter = click->fCurr;
         return this->INHERITED::onClick(click);
     }
 
 private:
     typedef SampleView INHERITED;
 };
 DEF_SAMPLE( return new BackdropView; )