SkMagnifierImageFilter.cpp revision 1598899975ecc85b003a59740b588d1ddbcedb09 
1/*
2 * Copyright 2012 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 "SkBitmap.h"
9#include "SkMagnifierImageFilter.h"
10#include "SkColorPriv.h"
11#include "SkReadBuffer.h"
12#include "SkWriteBuffer.h"
13#include "SkValidationUtils.h"
14
15////////////////////////////////////////////////////////////////////////////////
16#if SK_SUPPORT_GPU
17#include "effects/GrSingleTextureEffect.h"
18#include "gl/GrGLProcessor.h"
19#include "gl/builders/GrGLProgramBuilder.h"
20#include "gl/GrGLSL.h"
21#include "gl/GrGLTexture.h"
22#include "GrTBackendProcessorFactory.h"
23
24class GrGLMagnifierEffect;
25
26class GrMagnifierEffect : public GrSingleTextureEffect {
27
28public:
29    static GrFragmentProcessor* Create(GrTexture* texture,
30                                       float xOffset,
31                                       float yOffset,
32                                       float xInvZoom,
33                                       float yInvZoom,
34                                       float xInvInset,
35                                       float yInvInset) {
36        return SkNEW_ARGS(GrMagnifierEffect, (texture,
37                                              xOffset,
38                                              yOffset,
39                                              xInvZoom,
40                                              yInvZoom,
41                                              xInvInset,
42                                              yInvInset));
43    }
44
45    virtual ~GrMagnifierEffect() {};
46
47    static const char* Name() { return "Magnifier"; }
48
49    virtual const GrBackendFragmentProcessorFactory& getFactory() const SK_OVERRIDE;
50    float x_offset() const { return fXOffset; }
51    float y_offset() const { return fYOffset; }
52    float x_inv_zoom() const { return fXInvZoom; }
53    float y_inv_zoom() const { return fYInvZoom; }
54    float x_inv_inset() const { return fXInvInset; }
55    float y_inv_inset() const { return fYInvInset; }
56
57    typedef GrGLMagnifierEffect GLProcessor;
58
59private:
60    GrMagnifierEffect(GrTexture* texture,
61                      float xOffset,
62                      float yOffset,
63                      float xInvZoom,
64                      float yInvZoom,
65                      float xInvInset,
66                      float yInvInset)
67        : GrSingleTextureEffect(texture, GrCoordTransform::MakeDivByTextureWHMatrix(texture))
68        , fXOffset(xOffset)
69        , fYOffset(yOffset)
70        , fXInvZoom(xInvZoom)
71        , fYInvZoom(yInvZoom)
72        , fXInvInset(xInvInset)
73        , fYInvInset(yInvInset) {}
74
75    virtual bool onIsEqual(const GrProcessor&) const SK_OVERRIDE;
76
77    virtual void onComputeInvariantOutput(InvariantOutput* inout) const SK_OVERRIDE;
78
79    GR_DECLARE_FRAGMENT_PROCESSOR_TEST;
80
81    float fXOffset;
82    float fYOffset;
83    float fXInvZoom;
84    float fYInvZoom;
85    float fXInvInset;
86    float fYInvInset;
87
88    typedef GrSingleTextureEffect INHERITED;
89};
90
91// For brevity
92typedef GrGLProgramDataManager::UniformHandle UniformHandle;
93
94class GrGLMagnifierEffect : public GrGLFragmentProcessor {
95public:
96    GrGLMagnifierEffect(const GrBackendProcessorFactory&, const GrProcessor&);
97
98    virtual void emitCode(GrGLFPBuilder*,
99                          const GrFragmentProcessor&,
100                          const GrProcessorKey&,
101                          const char* outputColor,
102                          const char* inputColor,
103                          const TransformedCoordsArray&,
104                          const TextureSamplerArray&) SK_OVERRIDE;
105
106    virtual void setData(const GrGLProgramDataManager&, const GrProcessor&) SK_OVERRIDE;
107
108private:
109    UniformHandle       fOffsetVar;
110    UniformHandle       fInvZoomVar;
111    UniformHandle       fInvInsetVar;
112
113    typedef GrGLFragmentProcessor INHERITED;
114};
115
116GrGLMagnifierEffect::GrGLMagnifierEffect(const GrBackendProcessorFactory& factory,
117                                         const GrProcessor&)
118    : INHERITED(factory) {
119}
120
121void GrGLMagnifierEffect::emitCode(GrGLFPBuilder* builder,
122                                   const GrFragmentProcessor&,
123                                   const GrProcessorKey& key,
124                                   const char* outputColor,
125                                   const char* inputColor,
126                                   const TransformedCoordsArray& coords,
127                                   const TextureSamplerArray& samplers) {
128    fOffsetVar = builder->addUniform(
129        GrGLProgramBuilder::kFragment_Visibility |
130        GrGLProgramBuilder::kVertex_Visibility,
131        kVec2f_GrSLType, "Offset");
132    fInvZoomVar = builder->addUniform(
133        GrGLProgramBuilder::kFragment_Visibility |
134        GrGLProgramBuilder::kVertex_Visibility,
135        kVec2f_GrSLType, "InvZoom");
136    fInvInsetVar = builder->addUniform(
137        GrGLProgramBuilder::kFragment_Visibility |
138        GrGLProgramBuilder::kVertex_Visibility,
139        kVec2f_GrSLType, "InvInset");
140
141    GrGLFPFragmentBuilder* fsBuilder = builder->getFragmentShaderBuilder();
142    SkString coords2D = fsBuilder->ensureFSCoords2D(coords, 0);
143    fsBuilder->codeAppendf("\t\tvec2 coord = %s;\n", coords2D.c_str());
144    fsBuilder->codeAppendf("\t\tvec2 zoom_coord = %s + %s * %s;\n",
145                           builder->getUniformCStr(fOffsetVar),
146                           coords2D.c_str(),
147                           builder->getUniformCStr(fInvZoomVar));
148
149    fsBuilder->codeAppend("\t\tvec2 delta = min(coord, vec2(1.0, 1.0) - coord);\n");
150
151    fsBuilder->codeAppendf("\t\tdelta = delta * %s;\n", builder->getUniformCStr(fInvInsetVar));
152
153    fsBuilder->codeAppend("\t\tfloat weight = 0.0;\n");
154    fsBuilder->codeAppend("\t\tif (delta.s < 2.0 && delta.t < 2.0) {\n");
155    fsBuilder->codeAppend("\t\t\tdelta = vec2(2.0, 2.0) - delta;\n");
156    fsBuilder->codeAppend("\t\t\tfloat dist = length(delta);\n");
157    fsBuilder->codeAppend("\t\t\tdist = max(2.0 - dist, 0.0);\n");
158    fsBuilder->codeAppend("\t\t\tweight = min(dist * dist, 1.0);\n");
159    fsBuilder->codeAppend("\t\t} else {\n");
160    fsBuilder->codeAppend("\t\t\tvec2 delta_squared = delta * delta;\n");
161    fsBuilder->codeAppend("\t\t\tweight = min(min(delta_squared.x, delta_squared.y), 1.0);\n");
162    fsBuilder->codeAppend("\t\t}\n");
163
164    fsBuilder->codeAppend("\t\tvec2 mix_coord = mix(coord, zoom_coord, weight);\n");
165    fsBuilder->codeAppend("\t\tvec4 output_color = ");
166    fsBuilder->appendTextureLookup(samplers[0], "mix_coord");
167    fsBuilder->codeAppend(";\n");
168
169    fsBuilder->codeAppendf("\t\t%s = output_color;", outputColor);
170    SkString modulate;
171    GrGLSLMulVarBy4f(&modulate, outputColor, inputColor);
172    fsBuilder->codeAppend(modulate.c_str());
173}
174
175void GrGLMagnifierEffect::setData(const GrGLProgramDataManager& pdman,
176                                  const GrProcessor& effect) {
177    const GrMagnifierEffect& zoom = effect.cast<GrMagnifierEffect>();
178    pdman.set2f(fOffsetVar, zoom.x_offset(), zoom.y_offset());
179    pdman.set2f(fInvZoomVar, zoom.x_inv_zoom(), zoom.y_inv_zoom());
180    pdman.set2f(fInvInsetVar, zoom.x_inv_inset(), zoom.y_inv_inset());
181}
182
183/////////////////////////////////////////////////////////////////////
184
185GR_DEFINE_FRAGMENT_PROCESSOR_TEST(GrMagnifierEffect);
186
187GrFragmentProcessor* GrMagnifierEffect::TestCreate(SkRandom* random,
188                                                   GrContext* context,
189                                                   const GrDrawTargetCaps&,
190                                                   GrTexture** textures) {
191    GrTexture* texture = textures[0];
192    const int kMaxWidth = 200;
193    const int kMaxHeight = 200;
194    const int kMaxInset = 20;
195    uint32_t width = random->nextULessThan(kMaxWidth);
196    uint32_t height = random->nextULessThan(kMaxHeight);
197    uint32_t x = random->nextULessThan(kMaxWidth - width);
198    uint32_t y = random->nextULessThan(kMaxHeight - height);
199    uint32_t inset = random->nextULessThan(kMaxInset);
200
201    GrFragmentProcessor* effect = GrMagnifierEffect::Create(
202        texture,
203        (float) width / texture->width(),
204        (float) height / texture->height(),
205        texture->width() / (float) x,
206        texture->height() / (float) y,
207        (float) inset / texture->width(),
208        (float) inset / texture->height());
209    SkASSERT(effect);
210    return effect;
211}
212
213///////////////////////////////////////////////////////////////////////////////
214
215const GrBackendFragmentProcessorFactory& GrMagnifierEffect::getFactory() const {
216    return GrTBackendFragmentProcessorFactory<GrMagnifierEffect>::getInstance();
217}
218
219bool GrMagnifierEffect::onIsEqual(const GrProcessor& sBase) const {
220    const GrMagnifierEffect& s = sBase.cast<GrMagnifierEffect>();
221    return (this->texture(0) == s.texture(0) &&
222            this->fXOffset == s.fXOffset &&
223            this->fYOffset == s.fYOffset &&
224            this->fXInvZoom == s.fXInvZoom &&
225            this->fYInvZoom == s.fYInvZoom &&
226            this->fXInvInset == s.fXInvInset &&
227            this->fYInvInset == s.fYInvInset);
228}
229
230void GrMagnifierEffect::onComputeInvariantOutput(InvariantOutput* inout) const {
231    this->updateInvariantOutputForModulation(inout);
232    inout->fIsSingleComponent = false;
233}
234
235#endif
236
237////////////////////////////////////////////////////////////////////////////////
238
239SkImageFilter* SkMagnifierImageFilter::Create(const SkRect& srcRect, SkScalar inset,
240                                              SkImageFilter* input) {
241
242    if (!SkScalarIsFinite(inset) || !SkIsValidRect(srcRect)) {
243        return NULL;
244    }
245    // Negative numbers in src rect are not supported
246    if (srcRect.fLeft < 0 || srcRect.fTop < 0) {
247        return NULL;
248    }
249    return SkNEW_ARGS(SkMagnifierImageFilter, (srcRect, inset, input));
250}
251
252
253#ifdef SK_SUPPORT_LEGACY_DEEPFLATTENING
254SkMagnifierImageFilter::SkMagnifierImageFilter(SkReadBuffer& buffer)
255  : INHERITED(1, buffer) {
256    float x = buffer.readScalar();
257    float y = buffer.readScalar();
258    float width = buffer.readScalar();
259    float height = buffer.readScalar();
260    fSrcRect = SkRect::MakeXYWH(x, y, width, height);
261    fInset = buffer.readScalar();
262
263    buffer.validate(SkScalarIsFinite(fInset) && SkIsValidRect(fSrcRect) &&
264                    // Negative numbers in src rect are not supported
265                    (fSrcRect.fLeft >= 0) && (fSrcRect.fTop >= 0));
266}
267#endif
268
269SkMagnifierImageFilter::SkMagnifierImageFilter(const SkRect& srcRect, SkScalar inset,
270                                               SkImageFilter* input)
271    : INHERITED(1, &input), fSrcRect(srcRect), fInset(inset) {
272    SkASSERT(srcRect.x() >= 0 && srcRect.y() >= 0 && inset >= 0);
273}
274
275#if SK_SUPPORT_GPU
276bool SkMagnifierImageFilter::asFragmentProcessor(GrFragmentProcessor** fp, GrTexture* texture,
277                                                 const SkMatrix&, const SkIRect&) const {
278    if (fp) {
279        SkScalar yOffset = (texture->origin() == kTopLeft_GrSurfaceOrigin) ? fSrcRect.y() :
280                           (texture->height() - (fSrcRect.y() + fSrcRect.height()));
281        SkScalar invInset = fInset > 0 ? SkScalarInvert(fInset) : SK_Scalar1;
282        *fp = GrMagnifierEffect::Create(texture,
283                                        fSrcRect.x() / texture->width(),
284                                        yOffset / texture->height(),
285                                        fSrcRect.width() / texture->width(),
286                                        fSrcRect.height() / texture->height(),
287                                        texture->width() * invInset,
288                                        texture->height() * invInset);
289    }
290    return true;
291}
292#endif
293
294SkFlattenable* SkMagnifierImageFilter::CreateProc(SkReadBuffer& buffer) {
295    SK_IMAGEFILTER_UNFLATTEN_COMMON(common, 1);
296    SkRect src;
297    buffer.readRect(&src);
298    return Create(src, buffer.readScalar(), common.getInput(0));
299}
300
301void SkMagnifierImageFilter::flatten(SkWriteBuffer& buffer) const {
302    this->INHERITED::flatten(buffer);
303    buffer.writeRect(fSrcRect);
304    buffer.writeScalar(fInset);
305}
306
307bool SkMagnifierImageFilter::onFilterImage(Proxy*, const SkBitmap& src,
308                                           const Context&, SkBitmap* dst,
309                                           SkIPoint* offset) const {
310    SkASSERT(src.colorType() == kN32_SkColorType);
311    SkASSERT(fSrcRect.width() < src.width());
312    SkASSERT(fSrcRect.height() < src.height());
313
314    if ((src.colorType() != kN32_SkColorType) ||
315        (fSrcRect.width() >= src.width()) ||
316        (fSrcRect.height() >= src.height())) {
317      return false;
318    }
319
320    SkAutoLockPixels alp(src);
321    SkASSERT(src.getPixels());
322    if (!src.getPixels() || src.width() <= 0 || src.height() <= 0) {
323      return false;
324    }
325
326    if (!dst->tryAllocPixels(src.info())) {
327        return false;
328    }
329
330    SkScalar inv_inset = fInset > 0 ? SkScalarInvert(fInset) : SK_Scalar1;
331
332    SkScalar inv_x_zoom = fSrcRect.width() / src.width();
333    SkScalar inv_y_zoom = fSrcRect.height() / src.height();
334
335    SkColor* sptr = src.getAddr32(0, 0);
336    SkColor* dptr = dst->getAddr32(0, 0);
337    int width = src.width(), height = src.height();
338    for (int y = 0; y < height; ++y) {
339        for (int x = 0; x < width; ++x) {
340            SkScalar x_dist = SkMin32(x, width - x - 1) * inv_inset;
341            SkScalar y_dist = SkMin32(y, height - y - 1) * inv_inset;
342            SkScalar weight = 0;
343
344            static const SkScalar kScalar2 = SkScalar(2);
345
346            // To create a smooth curve at the corners, we need to work on
347            // a square twice the size of the inset.
348            if (x_dist < kScalar2 && y_dist < kScalar2) {
349                x_dist = kScalar2 - x_dist;
350                y_dist = kScalar2 - y_dist;
351
352                SkScalar dist = SkScalarSqrt(SkScalarSquare(x_dist) +
353                                             SkScalarSquare(y_dist));
354                dist = SkMaxScalar(kScalar2 - dist, 0);
355                weight = SkMinScalar(SkScalarSquare(dist), SK_Scalar1);
356            } else {
357                SkScalar sqDist = SkMinScalar(SkScalarSquare(x_dist),
358                                              SkScalarSquare(y_dist));
359                weight = SkMinScalar(sqDist, SK_Scalar1);
360            }
361
362            SkScalar x_interp = SkScalarMul(weight, (fSrcRect.x() + x * inv_x_zoom)) +
363                           (SK_Scalar1 - weight) * x;
364            SkScalar y_interp = SkScalarMul(weight, (fSrcRect.y() + y * inv_y_zoom)) +
365                           (SK_Scalar1 - weight) * y;
366
367            int x_val = SkPin32(SkScalarFloorToInt(x_interp), 0, width - 1);
368            int y_val = SkPin32(SkScalarFloorToInt(y_interp), 0, height - 1);
369
370            *dptr = sptr[y_val * width + x_val];
371            dptr++;
372        }
373    }
374    return true;
375}
376