1/*
2 * Copyright 2013 The Android Open Source Project
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 "SkXfermodeImageFilter.h"
9#include "SkCanvas.h"
10#include "SkDevice.h"
11#include "SkColorPriv.h"
12#include "SkReadBuffer.h"
13#include "SkWriteBuffer.h"
14#include "SkXfermode.h"
15#if SK_SUPPORT_GPU
16#include "GrContext.h"
17#include "effects/GrSimpleTextureEffect.h"
18#include "SkGr.h"
19#endif
20
21///////////////////////////////////////////////////////////////////////////////
22
23SkXfermodeImageFilter::SkXfermodeImageFilter(SkXfermode* mode,
24                                             SkImageFilter* background,
25                                             SkImageFilter* foreground,
26                                             const CropRect* cropRect)
27  : INHERITED(background, foreground, cropRect), fMode(mode) {
28    SkSafeRef(fMode);
29}
30
31SkXfermodeImageFilter::~SkXfermodeImageFilter() {
32    SkSafeUnref(fMode);
33}
34
35SkXfermodeImageFilter::SkXfermodeImageFilter(SkReadBuffer& buffer)
36  : INHERITED(2, buffer) {
37    fMode = buffer.readXfermode();
38}
39
40void SkXfermodeImageFilter::flatten(SkWriteBuffer& buffer) const {
41    this->INHERITED::flatten(buffer);
42    buffer.writeFlattenable(fMode);
43}
44
45bool SkXfermodeImageFilter::onFilterImage(Proxy* proxy,
46                                            const SkBitmap& src,
47                                            const Context& ctx,
48                                            SkBitmap* dst,
49                                            SkIPoint* offset) const {
50    SkBitmap background = src, foreground = src;
51    SkImageFilter* backgroundInput = getInput(0);
52    SkImageFilter* foregroundInput = getInput(1);
53    SkIPoint backgroundOffset = SkIPoint::Make(0, 0);
54    if (backgroundInput &&
55        !backgroundInput->filterImage(proxy, src, ctx, &background, &backgroundOffset)) {
56        background.reset();
57    }
58    SkIPoint foregroundOffset = SkIPoint::Make(0, 0);
59    if (foregroundInput &&
60        !foregroundInput->filterImage(proxy, src, ctx, &foreground, &foregroundOffset)) {
61        foreground.reset();
62    }
63
64    SkIRect bounds, foregroundBounds;
65    if (!applyCropRect(ctx, foreground, foregroundOffset, &foregroundBounds)) {
66        foregroundBounds.setEmpty();
67        foreground.reset();
68    }
69    if (!applyCropRect(ctx, background, backgroundOffset, &bounds)) {
70        bounds.setEmpty();
71        background.reset();
72    }
73    bounds.join(foregroundBounds);
74    if (bounds.isEmpty()) {
75        return false;
76    }
77
78    SkAutoTUnref<SkBaseDevice> device(proxy->createDevice(bounds.width(), bounds.height()));
79    if (NULL == device.get()) {
80        return false;
81    }
82    SkCanvas canvas(device);
83    canvas.translate(SkIntToScalar(-bounds.left()), SkIntToScalar(-bounds.top()));
84    SkPaint paint;
85    paint.setXfermodeMode(SkXfermode::kSrc_Mode);
86    canvas.drawBitmap(background, SkIntToScalar(backgroundOffset.fX),
87                      SkIntToScalar(backgroundOffset.fY), &paint);
88    paint.setXfermode(fMode);
89    canvas.drawBitmap(foreground, SkIntToScalar(foregroundOffset.fX),
90                      SkIntToScalar(foregroundOffset.fY), &paint);
91    canvas.clipRect(SkRect::Make(foregroundBounds), SkRegion::kDifference_Op);
92    paint.setColor(SK_ColorTRANSPARENT);
93    canvas.drawPaint(paint);
94    *dst = device->accessBitmap(false);
95    offset->fX = bounds.left();
96    offset->fY = bounds.top();
97    return true;
98}
99
100#if SK_SUPPORT_GPU
101
102bool SkXfermodeImageFilter::canFilterImageGPU() const {
103    return fMode && fMode->asNewEffect(NULL, NULL) && !cropRectIsSet();
104}
105
106bool SkXfermodeImageFilter::filterImageGPU(Proxy* proxy,
107                                           const SkBitmap& src,
108                                           const Context& ctx,
109                                           SkBitmap* result,
110                                           SkIPoint* offset) const {
111    SkBitmap background = src;
112    SkIPoint backgroundOffset = SkIPoint::Make(0, 0);
113    if (getInput(0) && !getInput(0)->getInputResultGPU(proxy, src, ctx, &background,
114                                                       &backgroundOffset)) {
115        return onFilterImage(proxy, src, ctx, result, offset);
116    }
117    GrTexture* backgroundTex = background.getTexture();
118    SkBitmap foreground = src;
119    SkIPoint foregroundOffset = SkIPoint::Make(0, 0);
120    if (getInput(1) && !getInput(1)->getInputResultGPU(proxy, src, ctx, &foreground,
121                                                       &foregroundOffset)) {
122        return onFilterImage(proxy, src, ctx, result, offset);
123    }
124    GrTexture* foregroundTex = foreground.getTexture();
125    GrContext* context = foregroundTex->getContext();
126
127    GrEffectRef* xferEffect = NULL;
128
129    GrTextureDesc desc;
130    desc.fFlags = kRenderTarget_GrTextureFlagBit | kNoStencil_GrTextureFlagBit;
131    desc.fWidth = src.width();
132    desc.fHeight = src.height();
133    desc.fConfig = kSkia8888_GrPixelConfig;
134
135    GrAutoScratchTexture ast(context, desc);
136    SkAutoTUnref<GrTexture> dst(ast.detach());
137
138    GrContext::AutoRenderTarget art(context, dst->asRenderTarget());
139
140    if (!fMode || !fMode->asNewEffect(&xferEffect, backgroundTex)) {
141        // canFilterImageGPU() should've taken care of this
142        SkASSERT(false);
143        return false;
144    }
145
146    SkMatrix foregroundMatrix = GrEffect::MakeDivByTextureWHMatrix(foregroundTex);
147    foregroundMatrix.preTranslate(SkIntToScalar(backgroundOffset.fX-foregroundOffset.fX),
148                                  SkIntToScalar(backgroundOffset.fY-foregroundOffset.fY));
149
150
151    SkRect srcRect;
152    src.getBounds(&srcRect);
153
154    GrPaint paint;
155    paint.addColorTextureEffect(foregroundTex, foregroundMatrix);
156    paint.addColorEffect(xferEffect)->unref();
157    context->drawRect(paint, srcRect);
158
159    offset->fX = backgroundOffset.fX;
160    offset->fY = backgroundOffset.fY;
161    WrapTexture(dst, src.width(), src.height(), result);
162    return true;
163}
164
165#endif
166