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 "GrInvariantOutput.h"
18#include "effects/GrSingleTextureEffect.h"
19#include "gl/GrGLProcessor.h"
20#include "gl/GrGLSL.h"
21#include "gl/GrGLTexture.h"
22#include "gl/builders/GrGLProgramBuilder.h"
23
24class GrMagnifierEffect : public GrSingleTextureEffect {
25
26public:
27    static GrFragmentProcessor* Create(GrTexture* texture,
28                                       const SkRect& bounds,
29                                       float xOffset,
30                                       float yOffset,
31                                       float xInvZoom,
32                                       float yInvZoom,
33                                       float xInvInset,
34                                       float yInvInset) {
35        return SkNEW_ARGS(GrMagnifierEffect, (texture,
36                                              bounds,
37                                              xOffset,
38                                              yOffset,
39                                              xInvZoom,
40                                              yInvZoom,
41                                              xInvInset,
42                                              yInvInset));
43    }
44
45    virtual ~GrMagnifierEffect() {};
46
47    const char* name() const override { return "Magnifier"; }
48
49    void getGLProcessorKey(const GrGLSLCaps&, GrProcessorKeyBuilder*) const override;
50
51    GrGLFragmentProcessor* createGLInstance() const override;
52
53    const SkRect& bounds() const { return fBounds; }    // Bounds of source image.
54    // Offset to apply to zoomed pixels, (srcRect position / texture size).
55    float x_offset() const { return fXOffset; }
56    float y_offset() const { return fYOffset; }
57
58    // Scale to apply to zoomed pixels (srcRect size / bounds size).
59    float x_inv_zoom() const { return fXInvZoom; }
60    float y_inv_zoom() const { return fYInvZoom; }
61
62    // 1/radius over which to transition from unzoomed to zoomed pixels (bounds size / inset).
63    float x_inv_inset() const { return fXInvInset; }
64    float y_inv_inset() const { return fYInvInset; }
65
66private:
67    GrMagnifierEffect(GrTexture* texture,
68                      const SkRect& bounds,
69                      float xOffset,
70                      float yOffset,
71                      float xInvZoom,
72                      float yInvZoom,
73                      float xInvInset,
74                      float yInvInset)
75        : GrSingleTextureEffect(texture, GrCoordTransform::MakeDivByTextureWHMatrix(texture))
76        , fBounds(bounds)
77        , fXOffset(xOffset)
78        , fYOffset(yOffset)
79        , fXInvZoom(xInvZoom)
80        , fYInvZoom(yInvZoom)
81        , fXInvInset(xInvInset)
82        , fYInvInset(yInvInset) {
83        this->initClassID<GrMagnifierEffect>();
84    }
85
86    bool onIsEqual(const GrFragmentProcessor&) const override;
87
88    void onComputeInvariantOutput(GrInvariantOutput* inout) const override;
89
90    GR_DECLARE_FRAGMENT_PROCESSOR_TEST;
91
92    SkRect fBounds;
93    float fXOffset;
94    float fYOffset;
95    float fXInvZoom;
96    float fYInvZoom;
97    float fXInvInset;
98    float fYInvInset;
99
100    typedef GrSingleTextureEffect INHERITED;
101};
102
103// For brevity
104typedef GrGLProgramDataManager::UniformHandle UniformHandle;
105
106class GrGLMagnifierEffect : public GrGLFragmentProcessor {
107public:
108    GrGLMagnifierEffect(const GrProcessor&);
109
110    virtual void emitCode(GrGLFPBuilder*,
111                          const GrFragmentProcessor&,
112                          const char* outputColor,
113                          const char* inputColor,
114                          const TransformedCoordsArray&,
115                          const TextureSamplerArray&) override;
116
117    void setData(const GrGLProgramDataManager&, const GrProcessor&) override;
118
119private:
120    UniformHandle       fOffsetVar;
121    UniformHandle       fInvZoomVar;
122    UniformHandle       fInvInsetVar;
123    UniformHandle       fBoundsVar;
124
125    typedef GrGLFragmentProcessor INHERITED;
126};
127
128GrGLMagnifierEffect::GrGLMagnifierEffect(const GrProcessor&) {
129}
130
131void GrGLMagnifierEffect::emitCode(GrGLFPBuilder* builder,
132                                   const GrFragmentProcessor&,
133                                   const char* outputColor,
134                                   const char* inputColor,
135                                   const TransformedCoordsArray& coords,
136                                   const TextureSamplerArray& samplers) {
137    fOffsetVar = builder->addUniform(
138        GrGLProgramBuilder::kFragment_Visibility |
139        GrGLProgramBuilder::kVertex_Visibility,
140        kVec2f_GrSLType, kDefault_GrSLPrecision, "Offset");
141    fInvZoomVar = builder->addUniform(
142        GrGLProgramBuilder::kFragment_Visibility |
143        GrGLProgramBuilder::kVertex_Visibility,
144        kVec2f_GrSLType, kDefault_GrSLPrecision, "InvZoom");
145    fInvInsetVar = builder->addUniform(
146        GrGLProgramBuilder::kFragment_Visibility |
147        GrGLProgramBuilder::kVertex_Visibility,
148        kVec2f_GrSLType, kDefault_GrSLPrecision, "InvInset");
149    fBoundsVar = builder->addUniform(
150        GrGLProgramBuilder::kFragment_Visibility |
151        GrGLProgramBuilder::kVertex_Visibility,
152        kVec4f_GrSLType, kDefault_GrSLPrecision, "Bounds");
153
154    GrGLFragmentBuilder* fsBuilder = builder->getFragmentShaderBuilder();
155    SkString coords2D = fsBuilder->ensureFSCoords2D(coords, 0);
156    fsBuilder->codeAppendf("\t\tvec2 coord = %s;\n", coords2D.c_str());
157    fsBuilder->codeAppendf("\t\tvec2 zoom_coord = %s + %s * %s;\n",
158                           builder->getUniformCStr(fOffsetVar),
159                           coords2D.c_str(),
160                           builder->getUniformCStr(fInvZoomVar));
161    const char* bounds = builder->getUniformCStr(fBoundsVar);
162    fsBuilder->codeAppendf("\t\tvec2 delta = (coord - %s.xy) * %s.zw;\n", bounds, bounds);
163    fsBuilder->codeAppendf("\t\tdelta = min(delta, vec2(1.0, 1.0) - delta);\n");
164    fsBuilder->codeAppendf("\t\tdelta = delta * %s;\n", builder->getUniformCStr(fInvInsetVar));
165
166    fsBuilder->codeAppend("\t\tfloat weight = 0.0;\n");
167    fsBuilder->codeAppend("\t\tif (delta.s < 2.0 && delta.t < 2.0) {\n");
168    fsBuilder->codeAppend("\t\t\tdelta = vec2(2.0, 2.0) - delta;\n");
169    fsBuilder->codeAppend("\t\t\tfloat dist = length(delta);\n");
170    fsBuilder->codeAppend("\t\t\tdist = max(2.0 - dist, 0.0);\n");
171    fsBuilder->codeAppend("\t\t\tweight = min(dist * dist, 1.0);\n");
172    fsBuilder->codeAppend("\t\t} else {\n");
173    fsBuilder->codeAppend("\t\t\tvec2 delta_squared = delta * delta;\n");
174    fsBuilder->codeAppend("\t\t\tweight = min(min(delta_squared.x, delta_squared.y), 1.0);\n");
175    fsBuilder->codeAppend("\t\t}\n");
176
177    fsBuilder->codeAppend("\t\tvec2 mix_coord = mix(coord, zoom_coord, weight);\n");
178    fsBuilder->codeAppend("\t\tvec4 output_color = ");
179    fsBuilder->appendTextureLookup(samplers[0], "mix_coord");
180    fsBuilder->codeAppend(";\n");
181
182    fsBuilder->codeAppendf("\t\t%s = output_color;", outputColor);
183    SkString modulate;
184    GrGLSLMulVarBy4f(&modulate, outputColor, inputColor);
185    fsBuilder->codeAppend(modulate.c_str());
186}
187
188void GrGLMagnifierEffect::setData(const GrGLProgramDataManager& pdman,
189                                  const GrProcessor& effect) {
190    const GrMagnifierEffect& zoom = effect.cast<GrMagnifierEffect>();
191    pdman.set2f(fOffsetVar, zoom.x_offset(), zoom.y_offset());
192    pdman.set2f(fInvZoomVar, zoom.x_inv_zoom(), zoom.y_inv_zoom());
193    pdman.set2f(fInvInsetVar, zoom.x_inv_inset(), zoom.y_inv_inset());
194    pdman.set4f(fBoundsVar, zoom.bounds().x(), zoom.bounds().y(),
195                            zoom.bounds().width(), zoom.bounds().height());
196}
197
198/////////////////////////////////////////////////////////////////////
199
200void GrMagnifierEffect::getGLProcessorKey(const GrGLSLCaps& caps,
201                                          GrProcessorKeyBuilder* b) const {
202    GrGLMagnifierEffect::GenKey(*this, caps, b);
203}
204
205GrGLFragmentProcessor* GrMagnifierEffect::createGLInstance() const {
206    return SkNEW_ARGS(GrGLMagnifierEffect, (*this));
207}
208
209GR_DEFINE_FRAGMENT_PROCESSOR_TEST(GrMagnifierEffect);
210
211GrFragmentProcessor* GrMagnifierEffect::TestCreate(SkRandom* random,
212                                                   GrContext* context,
213                                                   const GrDrawTargetCaps&,
214                                                   GrTexture** textures) {
215    GrTexture* texture = textures[0];
216    const int kMaxWidth = 200;
217    const int kMaxHeight = 200;
218    const int kMaxInset = 20;
219    uint32_t width = random->nextULessThan(kMaxWidth);
220    uint32_t height = random->nextULessThan(kMaxHeight);
221    uint32_t x = random->nextULessThan(kMaxWidth - width);
222    uint32_t y = random->nextULessThan(kMaxHeight - height);
223    uint32_t inset = random->nextULessThan(kMaxInset);
224
225    GrFragmentProcessor* effect = GrMagnifierEffect::Create(
226        texture,
227        SkRect::MakeWH(SkIntToScalar(kMaxWidth), SkIntToScalar(kMaxHeight)),
228        (float) width / texture->width(),
229        (float) height / texture->height(),
230        texture->width() / (float) x,
231        texture->height() / (float) y,
232        (float) inset / texture->width(),
233        (float) inset / texture->height());
234    SkASSERT(effect);
235    return effect;
236}
237
238///////////////////////////////////////////////////////////////////////////////
239
240bool GrMagnifierEffect::onIsEqual(const GrFragmentProcessor& sBase) const {
241    const GrMagnifierEffect& s = sBase.cast<GrMagnifierEffect>();
242    return (this->fBounds == s.fBounds &&
243            this->fXOffset == s.fXOffset &&
244            this->fYOffset == s.fYOffset &&
245            this->fXInvZoom == s.fXInvZoom &&
246            this->fYInvZoom == s.fYInvZoom &&
247            this->fXInvInset == s.fXInvInset &&
248            this->fYInvInset == s.fYInvInset);
249}
250
251void GrMagnifierEffect::onComputeInvariantOutput(GrInvariantOutput* inout) const {
252    this->updateInvariantOutputForModulation(inout);
253}
254
255#endif
256
257////////////////////////////////////////////////////////////////////////////////
258
259SkImageFilter* SkMagnifierImageFilter::Create(const SkRect& srcRect, SkScalar inset,
260                                              SkImageFilter* input) {
261
262    if (!SkScalarIsFinite(inset) || !SkIsValidRect(srcRect)) {
263        return NULL;
264    }
265    // Negative numbers in src rect are not supported
266    if (srcRect.fLeft < 0 || srcRect.fTop < 0) {
267        return NULL;
268    }
269    return SkNEW_ARGS(SkMagnifierImageFilter, (srcRect, inset, input));
270}
271
272
273SkMagnifierImageFilter::SkMagnifierImageFilter(const SkRect& srcRect, SkScalar inset,
274                                               SkImageFilter* input)
275    : INHERITED(1, &input), fSrcRect(srcRect), fInset(inset) {
276    SkASSERT(srcRect.x() >= 0 && srcRect.y() >= 0 && inset >= 0);
277}
278
279#if SK_SUPPORT_GPU
280bool SkMagnifierImageFilter::asFragmentProcessor(GrFragmentProcessor** fp, GrTexture* texture,
281                                                 const SkMatrix&, const SkIRect&bounds) const {
282    if (fp) {
283        SkScalar yOffset = texture->origin() == kTopLeft_GrSurfaceOrigin ? fSrcRect.y() :
284           texture->height() - fSrcRect.height() * texture->height() / bounds.height()
285                             - fSrcRect.y();
286        int boundsY = (texture->origin() == kTopLeft_GrSurfaceOrigin) ? bounds.y() :
287                      (texture->height() - bounds.height());
288        SkRect effectBounds = SkRect::MakeXYWH(
289            SkIntToScalar(bounds.x()) / texture->width(),
290            SkIntToScalar(boundsY) / texture->height(),
291            SkIntToScalar(texture->width()) / bounds.width(),
292            SkIntToScalar(texture->height()) / bounds.height());
293        SkScalar invInset = fInset > 0 ? SkScalarInvert(fInset) : SK_Scalar1;
294        *fp = GrMagnifierEffect::Create(texture,
295                                        effectBounds,
296                                        fSrcRect.x() / texture->width(),
297                                        yOffset / texture->height(),
298                                        fSrcRect.width() / bounds.width(),
299                                        fSrcRect.height() / bounds.height(),
300                                        bounds.width() * invInset,
301                                        bounds.height() * invInset);
302    }
303    return true;
304}
305#endif
306
307SkFlattenable* SkMagnifierImageFilter::CreateProc(SkReadBuffer& buffer) {
308    SK_IMAGEFILTER_UNFLATTEN_COMMON(common, 1);
309    SkRect src;
310    buffer.readRect(&src);
311    return Create(src, buffer.readScalar(), common.getInput(0));
312}
313
314void SkMagnifierImageFilter::flatten(SkWriteBuffer& buffer) const {
315    this->INHERITED::flatten(buffer);
316    buffer.writeRect(fSrcRect);
317    buffer.writeScalar(fInset);
318}
319
320bool SkMagnifierImageFilter::onFilterImage(Proxy*, const SkBitmap& src,
321                                           const Context&, SkBitmap* dst,
322                                           SkIPoint* offset) const {
323    if ((src.colorType() != kN32_SkColorType) ||
324        (fSrcRect.width() >= src.width()) ||
325        (fSrcRect.height() >= src.height())) {
326      return false;
327    }
328
329    SkAutoLockPixels alp(src);
330    SkASSERT(src.getPixels());
331    if (!src.getPixels() || src.width() <= 0 || src.height() <= 0) {
332      return false;
333    }
334
335    if (!dst->tryAllocPixels(src.info())) {
336        return false;
337    }
338
339    SkScalar inv_inset = fInset > 0 ? SkScalarInvert(fInset) : SK_Scalar1;
340
341    SkScalar inv_x_zoom = fSrcRect.width() / src.width();
342    SkScalar inv_y_zoom = fSrcRect.height() / src.height();
343
344    SkColor* sptr = src.getAddr32(0, 0);
345    SkColor* dptr = dst->getAddr32(0, 0);
346    int width = src.width(), height = src.height();
347    for (int y = 0; y < height; ++y) {
348        for (int x = 0; x < width; ++x) {
349            SkScalar x_dist = SkMin32(x, width - x - 1) * inv_inset;
350            SkScalar y_dist = SkMin32(y, height - y - 1) * inv_inset;
351            SkScalar weight = 0;
352
353            static const SkScalar kScalar2 = SkScalar(2);
354
355            // To create a smooth curve at the corners, we need to work on
356            // a square twice the size of the inset.
357            if (x_dist < kScalar2 && y_dist < kScalar2) {
358                x_dist = kScalar2 - x_dist;
359                y_dist = kScalar2 - y_dist;
360
361                SkScalar dist = SkScalarSqrt(SkScalarSquare(x_dist) +
362                                             SkScalarSquare(y_dist));
363                dist = SkMaxScalar(kScalar2 - dist, 0);
364                weight = SkMinScalar(SkScalarSquare(dist), SK_Scalar1);
365            } else {
366                SkScalar sqDist = SkMinScalar(SkScalarSquare(x_dist),
367                                              SkScalarSquare(y_dist));
368                weight = SkMinScalar(sqDist, SK_Scalar1);
369            }
370
371            SkScalar x_interp = SkScalarMul(weight, (fSrcRect.x() + x * inv_x_zoom)) +
372                           (SK_Scalar1 - weight) * x;
373            SkScalar y_interp = SkScalarMul(weight, (fSrcRect.y() + y * inv_y_zoom)) +
374                           (SK_Scalar1 - weight) * y;
375
376            int x_val = SkPin32(SkScalarFloorToInt(x_interp), 0, width - 1);
377            int y_val = SkPin32(SkScalarFloorToInt(y_interp), 0, height - 1);
378
379            *dptr = sptr[y_val * width + x_val];
380            dptr++;
381        }
382    }
383    return true;
384}
385
386#ifndef SK_IGNORE_TO_STRING
387void SkMagnifierImageFilter::toString(SkString* str) const {
388    str->appendf("SkMagnifierImageFilter: (");
389    str->appendf("src: (%f,%f,%f,%f) ",
390                 fSrcRect.fLeft, fSrcRect.fTop, fSrcRect.fRight, fSrcRect.fBottom);
391    str->appendf("inset: %f", fInset);
392    str->append(")");
393}
394#endif
395