1/*
2 * Copyright 2012 Google Inc.
3 *
4 * Use of this source code is governed by a BSD-style license that can be
5 * found in the LICENSE file.
6 */
7
8#include "SkBitmapDevice.h"
9#include "SkCanvas.h"
10#include "SkData.h"
11#include "SkNoSaveLayerCanvas.h"
12#include "SkPictureUtils.h"
13#include "SkPixelRef.h"
14#include "SkRRect.h"
15#include "SkShader.h"
16
17class PixelRefSet {
18public:
19    PixelRefSet(SkTDArray<SkPixelRef*>* array) : fArray(array) {}
20
21    // This does a linear search on existing pixelrefs, so if this list gets big
22    // we should use a more complex sorted/hashy thing.
23    //
24    void add(SkPixelRef* pr) {
25        uint32_t genID = pr->getGenerationID();
26        if (fGenID.find(genID) < 0) {
27            *fArray->append() = pr;
28            *fGenID.append() = genID;
29//            SkDebugf("--- adding [%d] %x %d\n", fArray->count() - 1, pr, genID);
30        } else {
31//            SkDebugf("--- already have %x %d\n", pr, genID);
32        }
33    }
34
35private:
36    SkTDArray<SkPixelRef*>* fArray;
37    SkTDArray<uint32_t>     fGenID;
38};
39
40static void not_supported() {
41    SkDEBUGFAIL("this method should never be called");
42}
43
44static void nothing_to_do() {}
45
46/**
47 *  This device will route all bitmaps (primitives and in shaders) to its PRSet.
48 *  It should never actually draw anything, so there need not be any pixels
49 *  behind its device.
50 */
51class GatherPixelRefDevice : public SkBaseDevice {
52public:
53    SK_DECLARE_INST_COUNT(GatherPixelRefDevice)
54
55    GatherPixelRefDevice(int width, int height, PixelRefSet* prset) {
56        fSize.set(width, height);
57        fEmptyBitmap.setInfo(SkImageInfo::MakeUnknown(width, height));
58        fPRSet = prset;
59    }
60
61    virtual SkImageInfo imageInfo() const SK_OVERRIDE {
62        return SkImageInfo::MakeUnknown(fSize.width(), fSize.height());
63    }
64    virtual GrRenderTarget* accessRenderTarget() SK_OVERRIDE { return NULL; }
65    virtual bool filterTextFlags(const SkPaint& paint, TextFlags*) SK_OVERRIDE {
66        return false;
67    }
68    // TODO: allow this call to return failure, or move to SkBitmapDevice only.
69    virtual const SkBitmap& onAccessBitmap() SK_OVERRIDE {
70        return fEmptyBitmap;
71    }
72    virtual void lockPixels() SK_OVERRIDE { nothing_to_do(); }
73    virtual void unlockPixels() SK_OVERRIDE { nothing_to_do(); }
74    virtual bool allowImageFilter(const SkImageFilter*) SK_OVERRIDE { return false; }
75    virtual bool canHandleImageFilter(const SkImageFilter*) SK_OVERRIDE { return false; }
76    virtual bool filterImage(const SkImageFilter*, const SkBitmap&, const SkImageFilter::Context&,
77                             SkBitmap* result, SkIPoint* offset) SK_OVERRIDE {
78        return false;
79    }
80
81    virtual void clear(SkColor color) SK_OVERRIDE {
82        nothing_to_do();
83    }
84
85    virtual void drawPaint(const SkDraw&, const SkPaint& paint) SK_OVERRIDE {
86        this->addBitmapFromPaint(paint);
87    }
88    virtual void drawPoints(const SkDraw&, SkCanvas::PointMode mode, size_t count,
89                            const SkPoint[], const SkPaint& paint) SK_OVERRIDE {
90        this->addBitmapFromPaint(paint);
91    }
92    virtual void drawRect(const SkDraw&, const SkRect&,
93                          const SkPaint& paint) SK_OVERRIDE {
94        this->addBitmapFromPaint(paint);
95    }
96    virtual void drawRRect(const SkDraw&, const SkRRect&,
97                           const SkPaint& paint) SK_OVERRIDE {
98        this->addBitmapFromPaint(paint);
99    }
100    virtual void drawOval(const SkDraw&, const SkRect&,
101                          const SkPaint& paint) SK_OVERRIDE {
102        this->addBitmapFromPaint(paint);
103    }
104    virtual void drawPath(const SkDraw&, const SkPath& path,
105                          const SkPaint& paint, const SkMatrix* prePathMatrix,
106                          bool pathIsMutable) SK_OVERRIDE {
107        this->addBitmapFromPaint(paint);
108    }
109    virtual void drawBitmap(const SkDraw&, const SkBitmap& bitmap,
110                            const SkMatrix&, const SkPaint& paint) SK_OVERRIDE {
111        this->addBitmap(bitmap);
112        if (kAlpha_8_SkColorType == bitmap.colorType()) {
113            this->addBitmapFromPaint(paint);
114        }
115    }
116    virtual void drawBitmapRect(const SkDraw&, const SkBitmap& bitmap,
117                                const SkRect* srcOrNull, const SkRect& dst,
118                                const SkPaint& paint,
119                                SkCanvas::DrawBitmapRectFlags flags) SK_OVERRIDE {
120        this->addBitmap(bitmap);
121        if (kAlpha_8_SkColorType == bitmap.colorType()) {
122            this->addBitmapFromPaint(paint);
123        }
124    }
125    virtual void drawSprite(const SkDraw&, const SkBitmap& bitmap,
126                            int x, int y, const SkPaint& paint) SK_OVERRIDE {
127        this->addBitmap(bitmap);
128    }
129    virtual void drawText(const SkDraw&, const void* text, size_t len,
130                          SkScalar x, SkScalar y,
131                          const SkPaint& paint) SK_OVERRIDE {
132        this->addBitmapFromPaint(paint);
133    }
134    virtual void drawPosText(const SkDraw&, const void* text, size_t len,
135                             const SkScalar pos[], SkScalar constY,
136                             int, const SkPaint& paint) SK_OVERRIDE {
137        this->addBitmapFromPaint(paint);
138    }
139    virtual void drawTextOnPath(const SkDraw&, const void* text, size_t len,
140                                const SkPath& path, const SkMatrix* matrix,
141                                const SkPaint& paint) SK_OVERRIDE {
142        this->addBitmapFromPaint(paint);
143    }
144    virtual void drawVertices(const SkDraw&, SkCanvas::VertexMode, int vertexCount,
145                              const SkPoint verts[], const SkPoint texs[],
146                              const SkColor colors[], SkXfermode* xmode,
147                              const uint16_t indices[], int indexCount,
148                              const SkPaint& paint) SK_OVERRIDE {
149        this->addBitmapFromPaint(paint);
150    }
151    virtual void drawDevice(const SkDraw&, SkBaseDevice*, int x, int y,
152                            const SkPaint&) SK_OVERRIDE {
153        nothing_to_do();
154    }
155
156protected:
157    virtual void replaceBitmapBackendForRasterSurface(const SkBitmap&) SK_OVERRIDE {
158        not_supported();
159    }
160    virtual SkBaseDevice* onCreateDevice(const SkImageInfo& info, Usage usage) SK_OVERRIDE {
161        // we expect to only get called via savelayer, in which case it is fine.
162        SkASSERT(kSaveLayer_Usage == usage);
163        return SkNEW_ARGS(GatherPixelRefDevice, (info.width(), info.height(), fPRSet));
164    }
165    virtual void flush() SK_OVERRIDE {}
166
167private:
168    PixelRefSet*  fPRSet;
169    SkBitmap fEmptyBitmap;  // legacy -- need to remove the need for this guy
170    SkISize fSize;
171
172    void addBitmap(const SkBitmap& bm) {
173      fPRSet->add(bm.pixelRef());
174    }
175
176    void addBitmapFromPaint(const SkPaint& paint) {
177      SkShader* shader = paint.getShader();
178      if (shader) {
179          SkBitmap bm;
180          // Check whether the shader is a gradient in order to short-circuit
181          // call to asABitmap to prevent generation of bitmaps from
182          // gradient shaders, which implement asABitmap.
183          if (SkShader::kNone_GradientType == shader->asAGradient(NULL) &&
184              shader->asABitmap(&bm, NULL, NULL)) {
185              fPRSet->add(bm.pixelRef());
186          }
187      }
188    }
189
190    typedef SkBaseDevice INHERITED;
191};
192
193SkData* SkPictureUtils::GatherPixelRefs(SkPicture* pict, const SkRect& area) {
194    if (NULL == pict) {
195        return NULL;
196    }
197
198    // this test also handles if either area or pict's width/height are empty
199    if (!SkRect::Intersects(area,
200                            SkRect::MakeWH(SkIntToScalar(pict->width()),
201                                           SkIntToScalar(pict->height())))) {
202        return NULL;
203    }
204
205    SkTDArray<SkPixelRef*> array;
206    PixelRefSet prset(&array);
207
208    GatherPixelRefDevice device(pict->width(), pict->height(), &prset);
209    SkNoSaveLayerCanvas canvas(&device);
210
211    canvas.clipRect(area, SkRegion::kIntersect_Op, false);
212    canvas.drawPicture(pict);
213
214    SkData* data = NULL;
215    int count = array.count();
216    if (count > 0) {
217        data = SkData::NewFromMalloc(array.detach(), count * sizeof(SkPixelRef*));
218    }
219    return data;
220}
221