Add GM to prevent mis-drawing of LCD text in SkPictureImageFilters

gm/pictureimagefilter.cpp

 /*
  * Copyright 2013 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 "SkPictureImageFilter.h"
@@ skipping 19 matching lines @@
     SkPaint paint;
     paint.setAntiAlias(true);
     sk_tool_utils::set_portable_typeface(&paint);
     paint.setColor(0xFFFFFFFF);
     paint.setTextSize(SkIntToScalar(96));
     const char* str = "e";
     canvas->drawText(str, strlen(str), SkIntToScalar(20), SkIntToScalar(70), paint);
     return recorder.finishRecordingAsPicture();
 }
 
+// Create a picture that will draw LCD text
+static sk_sp<SkPicture> make_LCD_picture() {
+    SkPictureRecorder recorder;
+    SkCanvas* canvas = recorder.beginRecording(100, 100, nullptr, 0);
+    canvas->clear(SK_ColorTRANSPARENT);
+    SkPaint paint;
+    paint.setLCDRenderText(true);   // want LCD
+    paint.setAntiAlias(true);       // need AA for LCD
+    sk_tool_utils::set_portable_typeface(&paint);
+    paint.setColor(0xFFFFFFFF);
+    // this has to be small enough that it doesn't become a path
+    paint.setTextSize(SkIntToScalar(36));
+    const char* str = "e";
+    canvas->drawText(str, strlen(str), SkIntToScalar(20), SkIntToScalar(70), paint);
+    return recorder.finishRecordingAsPicture();
+}
+
 class PictureImageFilterGM : public skiagm::GM {
 public:
     PictureImageFilterGM() { }
 
 protected:
     SkString onShortName() override {
         return SkString("pictureimagefilter");
     }
 
     SkISize onISize() override { return SkISize::Make(600, 300); }
 
     void onOnceBeforeDraw() override {
         fPicture = make_picture();
+        fLCDPicture = make_LCD_picture();
     }
 
     void onDraw(SkCanvas* canvas) override {
-        canvas->clear(SK_ColorBLACK);
+        canvas->clear(SK_ColorGRAY);
         {
             SkRect srcRect = SkRect::MakeXYWH(20, 20, 30, 30);
             SkRect emptyRect = SkRect::MakeXYWH(20, 20, 0, 0);
             SkRect bounds = SkRect::MakeXYWH(0, 0, 100, 100);
             sk_sp<SkImageFilter> pictureSource(SkPictureImageFilter::Make(fPicture));
             sk_sp<SkImageFilter> pictureSourceSrcRect(SkPictureImageFilter::Make(fPicture,
                                                                                  srcRect));
             sk_sp<SkImageFilter> pictureSourceEmptyRect(SkPictureImageFilter::Make(fPicture,
                                                                                    emptyRect));
             sk_sp<SkImageFilter> pictureSourceResampled(SkPictureImageFilter::MakeForLocalSpace(
@@ skipping 11 matching lines @@
             canvas->translate(SkIntToScalar(100), 0);
 
             // Draw an unscaled subset of the source picture.
             fill_rect_filtered(canvas, bounds, pictureSourceSrcRect);
             canvas->translate(SkIntToScalar(100), 0);
 
             // Draw the picture to an empty rect (should draw nothing).
             fill_rect_filtered(canvas, bounds, pictureSourceEmptyRect);
             canvas->translate(SkIntToScalar(100), 0);
 
+            // Draw the LCD picture to a layer
+            {
+                SkPaint stroke;
+                stroke.setStyle(SkPaint::kStroke_Style);
+
+                canvas->drawRect(bounds, stroke);
+
+                SkPaint paint;
+                paint.setImageFilter(SkPictureImageFilter::MakeForLocalSpace(
+                                                                        fLCDPicture,
+                                                                        fPicture->cullRect(),
+                                                                        kNone_SkFilterQuality));
+
+                canvas->scale(4, 4);
+                canvas->translate(-0.9f*srcRect.fLeft, -2.45f*srcRect.fTop);
+
+                canvas->saveLayerPreserveLCDTextRequests(&bounds, &paint);
+                canvas->restore();
+            }
+
             canvas->restore();
 
             // Draw the picture scaled
             canvas->translate(0, SkIntToScalar(100));
             canvas->scale(200 / srcRect.width(), 200 / srcRect.height());
             canvas->translate(-srcRect.fLeft, -srcRect.fTop);
             fill_rect_filtered(canvas, srcRect, pictureSource);
 
             // Draw the picture scaled, but rasterized at original resolution
             canvas->translate(srcRect.width(), 0);
             fill_rect_filtered(canvas, srcRect, pictureSourceResampled);
 
             // Draw the picture scaled, pixelated
             canvas->translate(srcRect.width(), 0);
             fill_rect_filtered(canvas, srcRect, pictureSourcePixelated);
         }
     }
 
 private:
     sk_sp<SkPicture> fPicture;
+    sk_sp<SkPicture> fLCDPicture;
 
     typedef GM INHERITED;
 };
 
 ///////////////////////////////////////////////////////////////////////////////
 
 DEF_GM( return new PictureImageFilterGM; )