Switch SkMagnifierImageFilter over to new onFilterImage interface

gm/imagemagnifier.cpp

 /*
  * Copyright 2012 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "gm.h"
+#include "SkImageSource.h"
 #include "SkMagnifierImageFilter.h"
 #include "SkRandom.h"
+#include "SkSurface.h"
 
 #define WIDTH 500
 #define HEIGHT 500
 
 DEF_SIMPLE_GM_BG(imagemagnifier, canvas, WIDTH, HEIGHT, SK_ColorBLACK) {
         SkPaint filterPaint;
         filterPaint.setImageFilter(
             SkMagnifierImageFilter::Make(
                 SkRect::MakeXYWH(SkIntToScalar(100), SkIntToScalar(100),
                                  SkIntToScalar(WIDTH / 2),
                                  SkIntToScalar(HEIGHT / 2)),
                 100, nullptr));
         canvas->saveLayer(nullptr, &filterPaint);
         const char* str = "The quick brown fox jumped over the lazy dog.";
         SkRandom rand;
         for (int i = 0; i < 25; ++i) {
             int x = rand.nextULessThan(WIDTH);
             int y = rand.nextULessThan(HEIGHT);
             SkPaint paint;
             sk_tool_utils::set_portable_typeface(&paint);
             paint.setColor(sk_tool_utils::color_to_565(rand.nextBits(24) | 0xFF000000));
             paint.setTextSize(rand.nextRangeScalar(0, 300));
             paint.setAntiAlias(true);
             canvas->drawText(str, strlen(str), SkIntToScalar(x),
                              SkIntToScalar(y), paint);
         }
         canvas->restore();
 }
+
+////////////////////////////////////////////////////////////////////////////////
+#define WIDTH_HEIGHT 256
+
+static sk_sp<SkImage> make_img() {
+    const SkImageInfo info = SkImageInfo::MakeN32Premul(WIDTH_HEIGHT, WIDTH_HEIGHT);
+
+    sk_sp<SkSurface> surf(SkSurface::MakeRaster(info));
+
+    SkCanvas* canvas = surf->getCanvas();
+
+    canvas->clear(0x0);
+
+    SkPaint paint;
+    paint.setColor(SK_ColorBLUE);
+
+    for (float pos = 0; pos < WIDTH_HEIGHT; pos += 16) {
+        canvas->drawLine(0, pos, SkIntToScalar(WIDTH_HEIGHT), pos, paint);
+        canvas->drawLine(pos, 0, pos, SkIntToScalar(WIDTH_HEIGHT), paint);
+    }
+
+    return surf->makeImageSnapshot();
+}
+
+DEF_SIMPLE_GM_BG(imagemagnifier_cropped, canvas, WIDTH_HEIGHT, WIDTH_HEIGHT, SK_ColorBLACK) {
+
+    sk_sp<SkImage> image(make_img());
+
+    sk_sp<SkImageFilter> imageSource(SkImageSource::Make(std::move(image)));
+
+    SkRect srcRect = SkRect::MakeWH(SkIntToScalar(WIDTH_HEIGHT-32),
+                                    SkIntToScalar(WIDTH_HEIGHT-32));
+    srcRect.inset(64.0f, 64.0f);
+
+    static const SkScalar kInset = 64.0f;
+
+    // Crop out a 16 pixel ring around the result
+    const SkRect rect = SkRect::MakeXYWH(16, 16, WIDTH_HEIGHT-32, WIDTH_HEIGHT-32);
+    SkImageFilter::CropRect cropRect(rect);
+
+    SkPaint filterPaint;
+    filterPaint.setImageFilter(SkMagnifierImageFilter::Make(srcRect, kInset,
+                                                            std::move(imageSource),
+                                                            &cropRect));
+
+    canvas->saveLayer(nullptr, &filterPaint);
+    canvas->restore();
+}