Implement an SkPicture image filter source. This is required for the external-SVG reference feature of feImage. It simply plays back an SkPicture to a given destination rect.

R=reed@google.com

Review URL: https://codereview.chromium.org/114263002

git-svn-id: http://skia.googlecode.com/svn/trunk@12661 2bbb7eff-a529-9590-31e7-b0007b416f81

gm/pictureimagefilter.cpp

@@ -0,0 +1,82 @@
+/*
+ * 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"
+
+// This GM exercises the SkPictureImageFilter ImageFilter class.
+
+class PictureImageFilterGM : public skiagm::GM {
+public:
+    PictureImageFilterGM() {
+    }
+
+protected:
+    virtual SkString onShortName() SK_OVERRIDE {
+        return SkString("pictureimagefilter");
+    }
+
+    void makePicture() {
+        SkCanvas* canvas = fPicture.beginRecording(100, 100);
+        canvas->clear(0x00000000);
+        SkPaint paint;
+        paint.setAntiAlias(true);
+        paint.setColor(0xFFFFFFFF);
+        paint.setTextSize(SkIntToScalar(96));
+        const char* str = "e";
+        canvas->drawText(str, strlen(str), SkIntToScalar(20), SkIntToScalar(70), paint);
+        fPicture.endRecording();
+    }
+
+    virtual SkISize onISize() SK_OVERRIDE { return SkISize::Make(500, 150); }
+
+    virtual void onOnceBeforeDraw() SK_OVERRIDE {
+        this->makePicture();
+    }
+
+    static void fillRectFiltered(SkCanvas* canvas, const SkRect& clipRect, SkImageFilter* filter) {
+        SkPaint paint;
+        paint.setImageFilter(filter);
+        canvas->save();
+        canvas->clipRect(clipRect);
+        canvas->drawPaint(paint);
+        canvas->restore();
+    }
+
+    virtual void onDraw(SkCanvas* canvas) SK_OVERRIDE {
+        canvas->clear(0x00000000);
+        {
+            SkRect srcRect = SkRect::MakeXYWH(20, 20, 30, 30);
+            SkRect emptyRect = SkRect::MakeXYWH(20, 20, 0, 0);
+            SkRect bounds = SkRect::MakeXYWH(0, 0, 100, 100);
+            SkAutoTUnref<SkImageFilter> pictureSource(new SkPictureImageFilter(&fPicture));
+            SkAutoTUnref<SkImageFilter> pictureSourceSrcRect(new SkPictureImageFilter(&fPicture, srcRect));
+            SkAutoTUnref<SkImageFilter> pictureSourceEmptyRect(new SkPictureImageFilter(&fPicture, emptyRect));
+
+            // Draw the picture unscaled.
+            fillRectFiltered(canvas, bounds, pictureSource);
+            canvas->translate(SkIntToScalar(100), 0);
+
+            // Draw an unscaled subset of the source picture.
+            fillRectFiltered(canvas, bounds, pictureSourceSrcRect);
+            canvas->translate(SkIntToScalar(100), 0);
+
+            // Draw the picture to an empty rect (should draw nothing).
+            fillRectFiltered(canvas, bounds, pictureSourceEmptyRect);
+            canvas->translate(SkIntToScalar(100), 0);
+        }
+    }
+
+private:
+    SkPicture fPicture;
+    typedef GM INHERITED;
+};
+
+///////////////////////////////////////////////////////////////////////////////
+
+DEF_GM( return new PictureImageFilterGM; )

gyp/effects.gypi

@@ -48,6 +48,7 @@
     '<(skia_src_path)/effects/SkOffsetImageFilter.cpp',
     '<(skia_src_path)/effects/SkPaintFlagsDrawFilter.cpp',
     '<(skia_src_path)/effects/SkPerlinNoiseShader.cpp',
+    '<(skia_src_path)/effects/SkPictureImageFilter.cpp',
     '<(skia_src_path)/effects/SkPixelXorXfermode.cpp',
     '<(skia_src_path)/effects/SkPorterDuff.cpp',
     '<(skia_src_path)/effects/SkRectShaderImageFilter.cpp',

gyp/gmslides.gypi

@@ -105,6 +105,7 @@
     '../gm/pathopsskpclip.cpp',
     '../gm/pathreverse.cpp',
     '../gm/perlinnoise.cpp',
+    '../gm/pictureimagefilter.cpp',
     '../gm/points.cpp',
     '../gm/poly2poly.cpp',
     '../gm/polygons.cpp',

include/effects/SkPictureImageFilter.h

@@ -0,0 +1,42 @@
+/*
+ * Copyright 2013 The Android Open Source Project
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#ifndef SkPictureImageFilter_DEFINED
+#define SkPictureImageFilter_DEFINED
+
+#include "SkImageFilter.h"
+#include "SkPicture.h"
+
+class SK_API SkPictureImageFilter : public SkImageFilter {
+public:
+    /**
+     *  Refs the passed-in picture.
+     */
+    explicit SkPictureImageFilter(SkPicture* picture);
+
+    /**
+     *  Refs the passed-in picture. rect can be used to crop or expand the destination rect when
+     *  the picture is drawn. (No scaling is implied by the dest rect; only the CTM is applied.)
+     */
+    SkPictureImageFilter(SkPicture* picture, const SkRect& rect);
+
+    SK_DECLARE_PUBLIC_FLATTENABLE_DESERIALIZATION_PROCS(SkPictureImageFilter)
+
+protected:
+    virtual ~SkPictureImageFilter();
+    explicit SkPictureImageFilter(SkFlattenableReadBuffer& buffer);
+    virtual void flatten(SkFlattenableWriteBuffer&) const SK_OVERRIDE;
+    virtual bool onFilterImage(Proxy*, const SkBitmap& src, const SkMatrix&,
+                               SkBitmap* result, SkIPoint* offset) SK_OVERRIDE;
+
+private:
+    SkPicture* fPicture;
+    SkRect     fRect;
+    typedef SkImageFilter INHERITED;
+};
+
+#endif

src/effects/SkPictureImageFilter.cpp

@@ -0,0 +1,77 @@
+/*
+ * Copyright 2013 The Android Open Source Project
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#include "SkPictureImageFilter.h"
+#include "SkDevice.h"
+#include "SkCanvas.h"
+#include "SkFlattenableBuffers.h"
+#include "SkValidationUtils.h"
+
+SkPictureImageFilter::SkPictureImageFilter(SkPicture* picture)
+  : INHERITED(0, 0),
+    fPicture(picture),
+    fRect(SkRect::MakeWH(picture ? SkIntToScalar(picture->width()) : 0,
+                         picture ? SkIntToScalar(picture->height()) : 0)) {
+    SkSafeRef(fPicture);
+}
+
+SkPictureImageFilter::SkPictureImageFilter(SkPicture* picture, const SkRect& rect)
+  : INHERITED(0, 0),
+    fPicture(picture),
+    fRect(rect) {
+    SkSafeRef(fPicture);
+}
+
+SkPictureImageFilter::~SkPictureImageFilter() {
+    SkSafeUnref(fPicture);
+}
+
+SkPictureImageFilter::SkPictureImageFilter(SkFlattenableReadBuffer& buffer)
+  : INHERITED(0, buffer),
+    fPicture(NULL) {
+    // FIXME: unflatten picture here.
+    buffer.readRect(&fRect);
+}
+
+void SkPictureImageFilter::flatten(SkFlattenableWriteBuffer& buffer) const {
+    this->INHERITED::flatten(buffer);
+    // FIXME: flatten picture here.
+    buffer.writeRect(fRect);
+}
+
+bool SkPictureImageFilter::onFilterImage(Proxy* proxy, const SkBitmap&, const SkMatrix& matrix,
+                                   SkBitmap* result, SkIPoint* offset) {
+    if (!fPicture) {
+        return true;
+    }
+
+    SkRect floatBounds;
+    SkIRect bounds;
+    matrix.mapRect(&floatBounds, fRect);
+    floatBounds.roundOut(&bounds);
+
+    if (bounds.isEmpty()) {
+        return true;
+    }
+
+    SkAutoTUnref<SkBaseDevice> device(proxy->createDevice(bounds.width(), bounds.height()));
+    if (NULL == device.get()) {
+        return false;
+    }
+
+    SkCanvas canvas(device.get());
+    SkPaint paint;
+
+    canvas.translate(-SkIntToScalar(bounds.fLeft), -SkIntToScalar(bounds.fTop));
+    canvas.concat(matrix);
+    canvas.drawPicture(*fPicture);
+
+    *result = device.get()->accessBitmap(false);
+    offset->fX += bounds.fLeft;
+    offset->fY += bounds.fTop;
+    return true;
+}