SkMagnifierImageFilter.cpp revision 1a1aa9303484106a955e5549bf8ae24950f54e7a 
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 "SkMagnifierImageFilter.h"
9
10#include "SkBitmap.h"
11#include "SkColorPriv.h"
12#include "SkReadBuffer.h"
13#include "SkSpecialImage.h"
14#include "SkWriteBuffer.h"
15#include "SkValidationUtils.h"
16
17////////////////////////////////////////////////////////////////////////////////
18#if SK_SUPPORT_GPU
19#include "GrContext.h"
20#include "GrDrawContext.h"
21#include "GrInvariantOutput.h"
22#include "effects/GrSingleTextureEffect.h"
23#include "glsl/GrGLSLFragmentProcessor.h"
24#include "glsl/GrGLSLFragmentShaderBuilder.h"
25#include "glsl/GrGLSLProgramDataManager.h"
26#include "glsl/GrGLSLUniformHandler.h"
27
28class GrMagnifierEffect : public GrSingleTextureEffect {
29
30public:
31    static sk_sp<GrFragmentProcessor> Make(GrTexture* texture,
32                                           const SkRect& bounds,
33                                           float xOffset,
34                                           float yOffset,
35                                           float xInvZoom,
36                                           float yInvZoom,
37                                           float xInvInset,
38                                           float yInvInset) {
39        return sk_sp<GrFragmentProcessor>(new GrMagnifierEffect(texture, bounds,
40                                                                xOffset, yOffset,
41                                                                xInvZoom, yInvZoom,
42                                                                xInvInset, yInvInset));
43    }
44
45    ~GrMagnifierEffect() override {};
46
47    const char* name() const override { return "Magnifier"; }
48
49    const SkRect& bounds() const { return fBounds; }    // Bounds of source image.
50    // Offset to apply to zoomed pixels, (srcRect position / texture size).
51    float xOffset() const { return fXOffset; }
52    float yOffset() const { return fYOffset; }
53
54    // Scale to apply to zoomed pixels (srcRect size / bounds size).
55    float xInvZoom() const { return fXInvZoom; }
56    float yInvZoom() const { return fYInvZoom; }
57
58    // 1/radius over which to transition from unzoomed to zoomed pixels (bounds size / inset).
59    float xInvInset() const { return fXInvInset; }
60    float yInvInset() const { return fYInvInset; }
61
62private:
63    GrMagnifierEffect(GrTexture* texture,
64                      const SkRect& bounds,
65                      float xOffset,
66                      float yOffset,
67                      float xInvZoom,
68                      float yInvZoom,
69                      float xInvInset,
70                      float yInvInset)
71        : INHERITED(texture, nullptr, GrCoordTransform::MakeDivByTextureWHMatrix(texture))
72        , fBounds(bounds)
73        , fXOffset(xOffset)
74        , fYOffset(yOffset)
75        , fXInvZoom(xInvZoom)
76        , fYInvZoom(yInvZoom)
77        , fXInvInset(xInvInset)
78        , fYInvInset(yInvInset) {
79        this->initClassID<GrMagnifierEffect>();
80    }
81
82    GrGLSLFragmentProcessor* onCreateGLSLInstance() const override;
83
84    void onGetGLSLProcessorKey(const GrGLSLCaps&, GrProcessorKeyBuilder*) const override;
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 GrGLSLProgramDataManager::UniformHandle UniformHandle;
105
106class GrGLMagnifierEffect : public GrGLSLFragmentProcessor {
107public:
108    void emitCode(EmitArgs&) override;
109
110protected:
111    void onSetData(const GrGLSLProgramDataManager&, const GrProcessor&) override;
112
113private:
114    UniformHandle       fOffsetVar;
115    UniformHandle       fInvZoomVar;
116    UniformHandle       fInvInsetVar;
117    UniformHandle       fBoundsVar;
118
119    typedef GrGLSLFragmentProcessor INHERITED;
120};
121
122void GrGLMagnifierEffect::emitCode(EmitArgs& args) {
123    GrGLSLUniformHandler* uniformHandler = args.fUniformHandler;
124    fOffsetVar = uniformHandler->addUniform(kFragment_GrShaderFlag,
125                                            kVec2f_GrSLType, kDefault_GrSLPrecision,
126                                            "Offset");
127    fInvZoomVar = uniformHandler->addUniform(kFragment_GrShaderFlag,
128                                             kVec2f_GrSLType, kDefault_GrSLPrecision,
129                                             "InvZoom");
130    fInvInsetVar = uniformHandler->addUniform(kFragment_GrShaderFlag,
131                                              kVec2f_GrSLType, kDefault_GrSLPrecision,
132                                              "InvInset");
133    fBoundsVar = uniformHandler->addUniform(kFragment_GrShaderFlag,
134                                            kVec4f_GrSLType, kDefault_GrSLPrecision,
135                                            "Bounds");
136
137    GrGLSLFPFragmentBuilder* fragBuilder = args.fFragBuilder;
138    SkString coords2D = fragBuilder->ensureCoords2D(args.fTransformedCoords[0]);
139    fragBuilder->codeAppendf("\t\tvec2 coord = %s;\n", coords2D.c_str());
140    fragBuilder->codeAppendf("\t\tvec2 zoom_coord = %s + %s * %s;\n",
141                             uniformHandler->getUniformCStr(fOffsetVar),
142                             coords2D.c_str(),
143                             uniformHandler->getUniformCStr(fInvZoomVar));
144    const char* bounds = uniformHandler->getUniformCStr(fBoundsVar);
145    fragBuilder->codeAppendf("\t\tvec2 delta = (coord - %s.xy) * %s.zw;\n", bounds, bounds);
146    fragBuilder->codeAppendf("\t\tdelta = min(delta, vec2(1.0, 1.0) - delta);\n");
147    fragBuilder->codeAppendf("\t\tdelta = delta * %s;\n",
148                             uniformHandler->getUniformCStr(fInvInsetVar));
149
150    fragBuilder->codeAppend("\t\tfloat weight = 0.0;\n");
151    fragBuilder->codeAppend("\t\tif (delta.s < 2.0 && delta.t < 2.0) {\n");
152    fragBuilder->codeAppend("\t\t\tdelta = vec2(2.0, 2.0) - delta;\n");
153    fragBuilder->codeAppend("\t\t\tfloat dist = length(delta);\n");
154    fragBuilder->codeAppend("\t\t\tdist = max(2.0 - dist, 0.0);\n");
155    fragBuilder->codeAppend("\t\t\tweight = min(dist * dist, 1.0);\n");
156    fragBuilder->codeAppend("\t\t} else {\n");
157    fragBuilder->codeAppend("\t\t\tvec2 delta_squared = delta * delta;\n");
158    fragBuilder->codeAppend("\t\t\tweight = min(min(delta_squared.x, delta_squared.y), 1.0);\n");
159    fragBuilder->codeAppend("\t\t}\n");
160
161    fragBuilder->codeAppend("\t\tvec2 mix_coord = mix(coord, zoom_coord, weight);\n");
162    fragBuilder->codeAppend("\t\tvec4 output_color = ");
163    fragBuilder->appendTextureLookup(args.fTexSamplers[0], "mix_coord");
164    fragBuilder->codeAppend(";\n");
165
166    fragBuilder->codeAppendf("\t\t%s = output_color;", args.fOutputColor);
167    SkString modulate;
168    GrGLSLMulVarBy4f(&modulate, args.fOutputColor, args.fInputColor);
169    fragBuilder->codeAppend(modulate.c_str());
170}
171
172void GrGLMagnifierEffect::onSetData(const GrGLSLProgramDataManager& pdman,
173                                    const GrProcessor& effect) {
174    const GrMagnifierEffect& zoom = effect.cast<GrMagnifierEffect>();
175    pdman.set2f(fOffsetVar, zoom.xOffset(), zoom.yOffset());
176    pdman.set2f(fInvZoomVar, zoom.xInvZoom(), zoom.yInvZoom());
177    pdman.set2f(fInvInsetVar, zoom.xInvInset(), zoom.yInvInset());
178    pdman.set4f(fBoundsVar, zoom.bounds().x(), zoom.bounds().y(),
179                            zoom.bounds().width(), zoom.bounds().height());
180}
181
182/////////////////////////////////////////////////////////////////////
183
184void GrMagnifierEffect::onGetGLSLProcessorKey(const GrGLSLCaps& caps,
185                                              GrProcessorKeyBuilder* b) const {
186    GrGLMagnifierEffect::GenKey(*this, caps, b);
187}
188
189GrGLSLFragmentProcessor* GrMagnifierEffect::onCreateGLSLInstance() const {
190    return new GrGLMagnifierEffect;
191}
192
193GR_DEFINE_FRAGMENT_PROCESSOR_TEST(GrMagnifierEffect);
194
195sk_sp<GrFragmentProcessor> GrMagnifierEffect::TestCreate(GrProcessorTestData* d) {
196    GrTexture* texture = d->fTextures[0];
197    const int kMaxWidth = 200;
198    const int kMaxHeight = 200;
199    const int kMaxInset = 20;
200    uint32_t width = d->fRandom->nextULessThan(kMaxWidth);
201    uint32_t height = d->fRandom->nextULessThan(kMaxHeight);
202    uint32_t x = d->fRandom->nextULessThan(kMaxWidth - width);
203    uint32_t y = d->fRandom->nextULessThan(kMaxHeight - height);
204    uint32_t inset = d->fRandom->nextULessThan(kMaxInset);
205
206    sk_sp<GrFragmentProcessor> effect(GrMagnifierEffect::Make(
207        texture,
208        SkRect::MakeWH(SkIntToScalar(kMaxWidth), SkIntToScalar(kMaxHeight)),
209        (float) width / texture->width(),
210        (float) height / texture->height(),
211        texture->width() / (float) x,
212        texture->height() / (float) y,
213        (float) inset / texture->width(),
214        (float) inset / texture->height()));
215    SkASSERT(effect);
216    return effect;
217}
218
219///////////////////////////////////////////////////////////////////////////////
220
221bool GrMagnifierEffect::onIsEqual(const GrFragmentProcessor& sBase) const {
222    const GrMagnifierEffect& s = sBase.cast<GrMagnifierEffect>();
223    return (this->fBounds == s.fBounds &&
224            this->fXOffset == s.fXOffset &&
225            this->fYOffset == s.fYOffset &&
226            this->fXInvZoom == s.fXInvZoom &&
227            this->fYInvZoom == s.fYInvZoom &&
228            this->fXInvInset == s.fXInvInset &&
229            this->fYInvInset == s.fYInvInset);
230}
231
232void GrMagnifierEffect::onComputeInvariantOutput(GrInvariantOutput* inout) const {
233    this->updateInvariantOutputForModulation(inout);
234}
235
236#endif
237
238////////////////////////////////////////////////////////////////////////////////
239
240sk_sp<SkImageFilter> SkMagnifierImageFilter::Make(const SkRect& srcRect, SkScalar inset,
241                                                  sk_sp<SkImageFilter> input,
242                                                  const CropRect* cropRect) {
243
244    if (!SkScalarIsFinite(inset) || !SkIsValidRect(srcRect)) {
245        return nullptr;
246    }
247    // Negative numbers in src rect are not supported
248    if (srcRect.fLeft < 0 || srcRect.fTop < 0) {
249        return nullptr;
250    }
251    return sk_sp<SkImageFilter>(new SkMagnifierImageFilter(srcRect, inset,
252                                                           std::move(input),
253                                                           cropRect));
254}
255
256
257SkMagnifierImageFilter::SkMagnifierImageFilter(const SkRect& srcRect,
258                                               SkScalar inset,
259                                               sk_sp<SkImageFilter> input,
260                                               const CropRect* cropRect)
261    : INHERITED(&input, 1, cropRect)
262    , fSrcRect(srcRect)
263    , fInset(inset) {
264    SkASSERT(srcRect.x() >= 0 && srcRect.y() >= 0 && inset >= 0);
265}
266
267sk_sp<SkFlattenable> SkMagnifierImageFilter::CreateProc(SkReadBuffer& buffer) {
268    SK_IMAGEFILTER_UNFLATTEN_COMMON(common, 1);
269    SkRect src;
270    buffer.readRect(&src);
271    return Make(src, buffer.readScalar(), common.getInput(0), &common.cropRect());
272}
273
274void SkMagnifierImageFilter::flatten(SkWriteBuffer& buffer) const {
275    this->INHERITED::flatten(buffer);
276    buffer.writeRect(fSrcRect);
277    buffer.writeScalar(fInset);
278}
279
280sk_sp<SkSpecialImage> SkMagnifierImageFilter::onFilterImage(SkSpecialImage* source,
281                                                            const Context& ctx,
282                                                            SkIPoint* offset) const {
283    SkIPoint inputOffset = SkIPoint::Make(0, 0);
284    sk_sp<SkSpecialImage> input(this->filterInput(0, source, ctx, &inputOffset));
285    if (!input) {
286        return nullptr;
287    }
288
289    const SkIRect inputBounds = SkIRect::MakeXYWH(inputOffset.x(), inputOffset.y(),
290                                                  input->width(), input->height());
291
292    SkIRect bounds;
293    if (!this->applyCropRect(ctx, inputBounds, &bounds)) {
294        return nullptr;
295    }
296
297    SkScalar invInset = fInset > 0 ? SkScalarInvert(fInset) : SK_Scalar1;
298
299    SkScalar invXZoom = fSrcRect.width() / bounds.width();
300    SkScalar invYZoom = fSrcRect.height() / bounds.height();
301
302
303#if SK_SUPPORT_GPU
304    if (source->isTextureBacked()) {
305        GrContext* context = source->getContext();
306
307        sk_sp<GrTexture> inputTexture(input->asTextureRef(context));
308        SkASSERT(inputTexture);
309
310        offset->fX = bounds.left();
311        offset->fY = bounds.top();
312        bounds.offset(-inputOffset);
313
314        SkScalar yOffset = inputTexture->origin() == kTopLeft_GrSurfaceOrigin
315            ? fSrcRect.y()
316            : inputTexture->height() -
317                      fSrcRect.height() * inputTexture->height() / bounds.height() - fSrcRect.y();
318        int boundsY = inputTexture->origin() == kTopLeft_GrSurfaceOrigin
319            ? bounds.y()
320            : inputTexture->height() - bounds.height();
321        SkRect effectBounds = SkRect::MakeXYWH(
322            SkIntToScalar(bounds.x()) / inputTexture->width(),
323            SkIntToScalar(boundsY) / inputTexture->height(),
324            SkIntToScalar(inputTexture->width()) / bounds.width(),
325            SkIntToScalar(inputTexture->height()) / bounds.height());
326        // SRGBTODO: Handle sRGB here
327        sk_sp<GrFragmentProcessor> fp(GrMagnifierEffect::Make(
328                                                        inputTexture.get(),
329                                                        effectBounds,
330                                                        fSrcRect.x() / inputTexture->width(),
331                                                        yOffset / inputTexture->height(),
332                                                        invXZoom,
333                                                        invYZoom,
334                                                        bounds.width() * invInset,
335                                                        bounds.height() * invInset));
336        if (!fp) {
337            return nullptr;
338        }
339
340        return DrawWithFP(context, std::move(fp), bounds, sk_ref_sp(input->getColorSpace()));
341    }
342#endif
343
344    SkBitmap inputBM;
345
346    if (!input->getROPixels(&inputBM)) {
347        return nullptr;
348    }
349
350    if ((inputBM.colorType() != kN32_SkColorType) ||
351        (fSrcRect.width() >= inputBM.width()) || (fSrcRect.height() >= inputBM.height())) {
352        return nullptr;
353    }
354
355    SkAutoLockPixels alp(inputBM);
356    SkASSERT(inputBM.getPixels());
357    if (!inputBM.getPixels() || inputBM.width() <= 0 || inputBM.height() <= 0) {
358        return nullptr;
359    }
360
361    const SkImageInfo info = SkImageInfo::MakeN32Premul(bounds.width(), bounds.height());
362
363    SkBitmap dst;
364    if (!dst.tryAllocPixels(info)) {
365        return nullptr;
366    }
367
368    SkAutoLockPixels dstLock(dst);
369
370    SkColor* dptr = dst.getAddr32(0, 0);
371    int dstWidth = dst.width(), dstHeight = dst.height();
372    for (int y = 0; y < dstHeight; ++y) {
373        for (int x = 0; x < dstWidth; ++x) {
374            SkScalar x_dist = SkMin32(x, dstWidth - x - 1) * invInset;
375            SkScalar y_dist = SkMin32(y, dstHeight - y - 1) * invInset;
376            SkScalar weight = 0;
377
378            static const SkScalar kScalar2 = SkScalar(2);
379
380            // To create a smooth curve at the corners, we need to work on
381            // a square twice the size of the inset.
382            if (x_dist < kScalar2 && y_dist < kScalar2) {
383                x_dist = kScalar2 - x_dist;
384                y_dist = kScalar2 - y_dist;
385
386                SkScalar dist = SkScalarSqrt(SkScalarSquare(x_dist) +
387                                             SkScalarSquare(y_dist));
388                dist = SkMaxScalar(kScalar2 - dist, 0);
389                weight = SkMinScalar(SkScalarSquare(dist), SK_Scalar1);
390            } else {
391                SkScalar sqDist = SkMinScalar(SkScalarSquare(x_dist),
392                                              SkScalarSquare(y_dist));
393                weight = SkMinScalar(sqDist, SK_Scalar1);
394            }
395
396            SkScalar x_interp = SkScalarMul(weight, (fSrcRect.x() + x * invXZoom)) +
397                           (SK_Scalar1 - weight) * x;
398            SkScalar y_interp = SkScalarMul(weight, (fSrcRect.y() + y * invYZoom)) +
399                           (SK_Scalar1 - weight) * y;
400
401            int x_val = SkTPin(bounds.x() + SkScalarFloorToInt(x_interp), 0, inputBM.width() - 1);
402            int y_val = SkTPin(bounds.y() + SkScalarFloorToInt(y_interp), 0, inputBM.height() - 1);
403
404            *dptr = *inputBM.getAddr32(x_val, y_val);
405            dptr++;
406        }
407    }
408
409    offset->fX = bounds.left();
410    offset->fY = bounds.top();
411    return SkSpecialImage::MakeFromRaster(SkIRect::MakeWH(bounds.width(), bounds.height()),
412                                          dst);
413}
414
415#ifndef SK_IGNORE_TO_STRING
416void SkMagnifierImageFilter::toString(SkString* str) const {
417    str->appendf("SkMagnifierImageFilter: (");
418    str->appendf("src: (%f,%f,%f,%f) ",
419                 fSrcRect.fLeft, fSrcRect.fTop, fSrcRect.fRight, fSrcRect.fBottom);
420    str->appendf("inset: %f", fInset);
421    str->append(")");
422}
423#endif
424