gm/distantclip.cpp

   1
   2 /*
   3  * Copyright 2012 Google Inc.
   4  *
   5  * Use of this source code is governed by a BSD-style license that can be
   6  * found in the LICENSE file.
   7  */
   8
   9 #include "gm.h"
  10 #include "SkCanvas.h"
  11 #include "SkPath.h"
  12 #include "SkPicture.h"
  13 #include "SkPictureRecorder.h"
  14
  15 namespace skiagm {
  16
  17 class DistantClipGM : public GM {
  18 public:
  19     DistantClipGM() { }
  20
  21 protected:
  22
  23     SkString onShortName() {
  24         return SkString("distantclip");
  25     }
  26
  27     SkISize onISize() { return SkISize::Make(100, 100); }
  28
  29     virtual void onDraw(SkCanvas* canvas) {
  30         constexpr SkScalar kOffset = 35000.0f;
  31         constexpr SkScalar kExtents = 1000.0f;
  32
  33         SkPictureRecorder recorder;
  34         // We record a picture of huge vertical extents in which we clear the canvas to red, create
  35         // a 'extents' by 'extents' round rect clip at a vertical offset of 'offset', then draw
  36         // green into that.
  37         SkCanvas* rec = recorder.beginRecording(kExtents, kOffset + kExtents, nullptr, 0);
  38         rec->drawColor(SK_ColorRED);
  39         rec->save();
  40         SkRect r = SkRect::MakeXYWH(-kExtents, kOffset - kExtents, 2 * kExtents, 2 * kExtents);
  41         SkPath p;
  42         p.addRoundRect(r, 5, 5);
  43         rec->clipPath(p, true);
  44         rec->drawColor(SK_ColorGREEN);
  45         rec->restore();
  46         sk_sp<SkPicture> pict(recorder.finishRecordingAsPicture());
  47
  48         // Next we play that picture into another picture of the same size.
  49         pict->playback(recorder.beginRecording(pict->cullRect().width(),
  50                                                pict->cullRect().height(),
  51                                                nullptr, 0));
  52         sk_sp<SkPicture> pict2(recorder.finishRecordingAsPicture());
  53
  54         // Finally we play the part of that second picture that should be green into the canvas.
  55         canvas->save();
  56         canvas->translate(kExtents / 2, -(kOffset - kExtents / 2));
  57         pict2->playback(canvas);
  58         canvas->restore();
  59
  60         // If the image is red, we erroneously decided the clipPath was empty and didn't record
  61         // the green drawColor, if it's green we're all good.
  62     }
  63
  64 private:
  65     typedef GM INHERITED;
  66 };
  67
  68 ///////////////////////////////////////////////////////////////////////////////
  69
  70 static GM* MyFactory(void*) { return new DistantClipGM; }
  71 static GMRegistry reg(MyFactory);
  72
  73 }