gfx/skia/skia/src/effects/SkMagnifierImageFilter.cpp
author Wes Kocher <wkocher@mozilla.com>
Wed, 10 May 2017 10:01:18 -0700
changeset 407965 ce2218406119c36a551e3faea4e192186ee46cc5
parent 407937 af6f19870b2a00759ac1d83dedc3db57213abfee
child 408167 0ded74baeaf23d7985401fe9bbabdb3d9385ac22
permissions -rw-r--r--
Backed out 9 changesets (bug 1340627) for graphical glitches a=backout Backed out changeset 0b1371055c7f (bug 1340627) Backed out changeset f152be1fadb7 (bug 1340627) Backed out changeset c691e2ab6a0c (bug 1340627) Backed out changeset 3cb4bceb8d79 (bug 1340627) Backed out changeset 026aadd76d06 (bug 1340627) Backed out changeset fdbd5d281287 (bug 1340627) Backed out changeset 75fb0d9858a9 (bug 1340627) Backed out changeset 0d4ec7d38a00 (bug 1340627) Backed out changeset af6f19870b2a (bug 1340627) MozReview-Commit-ID: 9dHr7xMZezY

/*
 * Copyright 2012 The Android Open Source Project
 *
 * Use of this source code is governed by a BSD-style license that can be
 * found in the LICENSE file.
 */

#include "SkMagnifierImageFilter.h"

#include "SkBitmap.h"
#include "SkColorPriv.h"
#include "SkReadBuffer.h"
#include "SkSpecialImage.h"
#include "SkWriteBuffer.h"
#include "SkValidationUtils.h"

////////////////////////////////////////////////////////////////////////////////
#if SK_SUPPORT_GPU
#include "GrContext.h"
#include "GrDrawContext.h"
#include "GrInvariantOutput.h"
#include "effects/GrSingleTextureEffect.h"
#include "glsl/GrGLSLFragmentProcessor.h"
#include "glsl/GrGLSLFragmentShaderBuilder.h"
#include "glsl/GrGLSLProgramDataManager.h"
#include "glsl/GrGLSLUniformHandler.h"

class GrMagnifierEffect : public GrSingleTextureEffect {

public:
    static sk_sp<GrFragmentProcessor> Make(GrTexture* texture,
                                           const SkRect& bounds,
                                           float xOffset,
                                           float yOffset,
                                           float xInvZoom,
                                           float yInvZoom,
                                           float xInvInset,
                                           float yInvInset) {
        return sk_sp<GrFragmentProcessor>(new GrMagnifierEffect(texture, bounds,
                                                                xOffset, yOffset,
                                                                xInvZoom, yInvZoom,
                                                                xInvInset, yInvInset));
    }

    ~GrMagnifierEffect() override {}

    const char* name() const override { return "Magnifier"; }

    const SkRect& bounds() const { return fBounds; }    // Bounds of source image.
    // Offset to apply to zoomed pixels, (srcRect position / texture size).
    float xOffset() const { return fXOffset; }
    float yOffset() const { return fYOffset; }

    // Scale to apply to zoomed pixels (srcRect size / bounds size).
    float xInvZoom() const { return fXInvZoom; }
    float yInvZoom() const { return fYInvZoom; }

    // 1/radius over which to transition from unzoomed to zoomed pixels (bounds size / inset).
    float xInvInset() const { return fXInvInset; }
    float yInvInset() const { return fYInvInset; }

private:
    GrMagnifierEffect(GrTexture* texture,
                      const SkRect& bounds,
                      float xOffset,
                      float yOffset,
                      float xInvZoom,
                      float yInvZoom,
                      float xInvInset,
                      float yInvInset)
        : INHERITED(texture, nullptr, GrCoordTransform::MakeDivByTextureWHMatrix(texture))
        , fBounds(bounds)
        , fXOffset(xOffset)
        , fYOffset(yOffset)
        , fXInvZoom(xInvZoom)
        , fYInvZoom(yInvZoom)
        , fXInvInset(xInvInset)
        , fYInvInset(yInvInset) {
        this->initClassID<GrMagnifierEffect>();
    }

    GrGLSLFragmentProcessor* onCreateGLSLInstance() const override;

    void onGetGLSLProcessorKey(const GrGLSLCaps&, GrProcessorKeyBuilder*) const override;

    bool onIsEqual(const GrFragmentProcessor&) const override;

    void onComputeInvariantOutput(GrInvariantOutput* inout) const override;

    GR_DECLARE_FRAGMENT_PROCESSOR_TEST;

    SkRect fBounds;
    float fXOffset;
    float fYOffset;
    float fXInvZoom;
    float fYInvZoom;
    float fXInvInset;
    float fYInvInset;

    typedef GrSingleTextureEffect INHERITED;
};

// For brevity
typedef GrGLSLProgramDataManager::UniformHandle UniformHandle;

class GrGLMagnifierEffect : public GrGLSLFragmentProcessor {
public:
    void emitCode(EmitArgs&) override;

protected:
    void onSetData(const GrGLSLProgramDataManager&, const GrProcessor&) override;

private:
    UniformHandle       fOffsetVar;
    UniformHandle       fInvZoomVar;
    UniformHandle       fInvInsetVar;
    UniformHandle       fBoundsVar;

    typedef GrGLSLFragmentProcessor INHERITED;
};

void GrGLMagnifierEffect::emitCode(EmitArgs& args) {
    GrGLSLUniformHandler* uniformHandler = args.fUniformHandler;
    fOffsetVar = uniformHandler->addUniform(kFragment_GrShaderFlag,
                                            kVec2f_GrSLType, kDefault_GrSLPrecision,
                                            "Offset");
    fInvZoomVar = uniformHandler->addUniform(kFragment_GrShaderFlag,
                                             kVec2f_GrSLType, kDefault_GrSLPrecision,
                                             "InvZoom");
    fInvInsetVar = uniformHandler->addUniform(kFragment_GrShaderFlag,
                                              kVec2f_GrSLType, kDefault_GrSLPrecision,
                                              "InvInset");
    fBoundsVar = uniformHandler->addUniform(kFragment_GrShaderFlag,
                                            kVec4f_GrSLType, kDefault_GrSLPrecision,
                                            "Bounds");

    GrGLSLFPFragmentBuilder* fragBuilder = args.fFragBuilder;
    SkString coords2D = fragBuilder->ensureCoords2D(args.fTransformedCoords[0]);
    fragBuilder->codeAppendf("\t\tvec2 coord = %s;\n", coords2D.c_str());
    fragBuilder->codeAppendf("\t\tvec2 zoom_coord = %s + %s * %s;\n",
                             uniformHandler->getUniformCStr(fOffsetVar),
                             coords2D.c_str(),
                             uniformHandler->getUniformCStr(fInvZoomVar));
    const char* bounds = uniformHandler->getUniformCStr(fBoundsVar);
    fragBuilder->codeAppendf("\t\tvec2 delta = (coord - %s.xy) * %s.zw;\n", bounds, bounds);
    fragBuilder->codeAppendf("\t\tdelta = min(delta, vec2(1.0, 1.0) - delta);\n");
    fragBuilder->codeAppendf("\t\tdelta = delta * %s;\n",
                             uniformHandler->getUniformCStr(fInvInsetVar));

    fragBuilder->codeAppend("\t\tfloat weight = 0.0;\n");
    fragBuilder->codeAppend("\t\tif (delta.s < 2.0 && delta.t < 2.0) {\n");
    fragBuilder->codeAppend("\t\t\tdelta = vec2(2.0, 2.0) - delta;\n");
    fragBuilder->codeAppend("\t\t\tfloat dist = length(delta);\n");
    fragBuilder->codeAppend("\t\t\tdist = max(2.0 - dist, 0.0);\n");
    fragBuilder->codeAppend("\t\t\tweight = min(dist * dist, 1.0);\n");
    fragBuilder->codeAppend("\t\t} else {\n");
    fragBuilder->codeAppend("\t\t\tvec2 delta_squared = delta * delta;\n");
    fragBuilder->codeAppend("\t\t\tweight = min(min(delta_squared.x, delta_squared.y), 1.0);\n");
    fragBuilder->codeAppend("\t\t}\n");

    fragBuilder->codeAppend("\t\tvec2 mix_coord = mix(coord, zoom_coord, weight);\n");
    fragBuilder->codeAppend("\t\tvec4 output_color = ");
    fragBuilder->appendTextureLookup(args.fTexSamplers[0], "mix_coord");
    fragBuilder->codeAppend(";\n");

    fragBuilder->codeAppendf("\t\t%s = output_color;", args.fOutputColor);
    SkString modulate;
    GrGLSLMulVarBy4f(&modulate, args.fOutputColor, args.fInputColor);
    fragBuilder->codeAppend(modulate.c_str());
}

void GrGLMagnifierEffect::onSetData(const GrGLSLProgramDataManager& pdman,
                                    const GrProcessor& effect) {
    const GrMagnifierEffect& zoom = effect.cast<GrMagnifierEffect>();
    pdman.set2f(fOffsetVar, zoom.xOffset(), zoom.yOffset());
    pdman.set2f(fInvZoomVar, zoom.xInvZoom(), zoom.yInvZoom());
    pdman.set2f(fInvInsetVar, zoom.xInvInset(), zoom.yInvInset());
    pdman.set4f(fBoundsVar, zoom.bounds().x(), zoom.bounds().y(),
                            zoom.bounds().width(), zoom.bounds().height());
}

/////////////////////////////////////////////////////////////////////

void GrMagnifierEffect::onGetGLSLProcessorKey(const GrGLSLCaps& caps,
                                              GrProcessorKeyBuilder* b) const {
    GrGLMagnifierEffect::GenKey(*this, caps, b);
}

GrGLSLFragmentProcessor* GrMagnifierEffect::onCreateGLSLInstance() const {
    return new GrGLMagnifierEffect;
}

GR_DEFINE_FRAGMENT_PROCESSOR_TEST(GrMagnifierEffect);

sk_sp<GrFragmentProcessor> GrMagnifierEffect::TestCreate(GrProcessorTestData* d) {
    GrTexture* texture = d->fTextures[0];
    const int kMaxWidth = 200;
    const int kMaxHeight = 200;
    const int kMaxInset = 20;
    uint32_t width = d->fRandom->nextULessThan(kMaxWidth);
    uint32_t height = d->fRandom->nextULessThan(kMaxHeight);
    uint32_t x = d->fRandom->nextULessThan(kMaxWidth - width);
    uint32_t y = d->fRandom->nextULessThan(kMaxHeight - height);
    uint32_t inset = d->fRandom->nextULessThan(kMaxInset);

    sk_sp<GrFragmentProcessor> effect(GrMagnifierEffect::Make(
        texture,
        SkRect::MakeWH(SkIntToScalar(kMaxWidth), SkIntToScalar(kMaxHeight)),
        (float) width / texture->width(),
        (float) height / texture->height(),
        texture->width() / (float) x,
        texture->height() / (float) y,
        (float) inset / texture->width(),
        (float) inset / texture->height()));
    SkASSERT(effect);
    return effect;
}

///////////////////////////////////////////////////////////////////////////////

bool GrMagnifierEffect::onIsEqual(const GrFragmentProcessor& sBase) const {
    const GrMagnifierEffect& s = sBase.cast<GrMagnifierEffect>();
    return (this->fBounds == s.fBounds &&
            this->fXOffset == s.fXOffset &&
            this->fYOffset == s.fYOffset &&
            this->fXInvZoom == s.fXInvZoom &&
            this->fYInvZoom == s.fYInvZoom &&
            this->fXInvInset == s.fXInvInset &&
            this->fYInvInset == s.fYInvInset);
}

void GrMagnifierEffect::onComputeInvariantOutput(GrInvariantOutput* inout) const {
    this->updateInvariantOutputForModulation(inout);
}

#endif

////////////////////////////////////////////////////////////////////////////////

sk_sp<SkImageFilter> SkMagnifierImageFilter::Make(const SkRect& srcRect, SkScalar inset,
                                                  sk_sp<SkImageFilter> input,
                                                  const CropRect* cropRect) {

    if (!SkScalarIsFinite(inset) || !SkIsValidRect(srcRect)) {
        return nullptr;
    }
    // Negative numbers in src rect are not supported
    if (srcRect.fLeft < 0 || srcRect.fTop < 0) {
        return nullptr;
    }
    return sk_sp<SkImageFilter>(new SkMagnifierImageFilter(srcRect, inset,
                                                           std::move(input),
                                                           cropRect));
}


SkMagnifierImageFilter::SkMagnifierImageFilter(const SkRect& srcRect,
                                               SkScalar inset,
                                               sk_sp<SkImageFilter> input,
                                               const CropRect* cropRect)
    : INHERITED(&input, 1, cropRect)
    , fSrcRect(srcRect)
    , fInset(inset) {
    SkASSERT(srcRect.x() >= 0 && srcRect.y() >= 0 && inset >= 0);
}

sk_sp<SkFlattenable> SkMagnifierImageFilter::CreateProc(SkReadBuffer& buffer) {
    SK_IMAGEFILTER_UNFLATTEN_COMMON(common, 1);
    SkRect src;
    buffer.readRect(&src);
    return Make(src, buffer.readScalar(), common.getInput(0), &common.cropRect());
}

void SkMagnifierImageFilter::flatten(SkWriteBuffer& buffer) const {
    this->INHERITED::flatten(buffer);
    buffer.writeRect(fSrcRect);
    buffer.writeScalar(fInset);
}

sk_sp<SkSpecialImage> SkMagnifierImageFilter::onFilterImage(SkSpecialImage* source,
                                                            const Context& ctx,
                                                            SkIPoint* offset) const {
    SkIPoint inputOffset = SkIPoint::Make(0, 0);
    sk_sp<SkSpecialImage> input(this->filterInput(0, source, ctx, &inputOffset));
    if (!input) {
        return nullptr;
    }

    const SkIRect inputBounds = SkIRect::MakeXYWH(inputOffset.x(), inputOffset.y(),
                                                  input->width(), input->height());

    SkIRect bounds;
    if (!this->applyCropRect(ctx, inputBounds, &bounds)) {
        return nullptr;
    }

    SkScalar invInset = fInset > 0 ? SkScalarInvert(fInset) : SK_Scalar1;

    SkScalar invXZoom = fSrcRect.width() / bounds.width();
    SkScalar invYZoom = fSrcRect.height() / bounds.height();


#if SK_SUPPORT_GPU
    if (source->isTextureBacked()) {
        GrContext* context = source->getContext();

        sk_sp<GrTexture> inputTexture(input->asTextureRef(context));
        SkASSERT(inputTexture);

        offset->fX = bounds.left();
        offset->fY = bounds.top();
        bounds.offset(-inputOffset);

        SkScalar yOffset = inputTexture->origin() == kTopLeft_GrSurfaceOrigin
            ? fSrcRect.y()
            : inputTexture->height() -
                      fSrcRect.height() * inputTexture->height() / bounds.height() - fSrcRect.y();
        int boundsY = inputTexture->origin() == kTopLeft_GrSurfaceOrigin
            ? bounds.y()
            : inputTexture->height() - bounds.height();
        SkRect effectBounds = SkRect::MakeXYWH(
            SkIntToScalar(bounds.x()) / inputTexture->width(),
            SkIntToScalar(boundsY) / inputTexture->height(),
            SkIntToScalar(inputTexture->width()) / bounds.width(),
            SkIntToScalar(inputTexture->height()) / bounds.height());
        // SRGBTODO: Handle sRGB here
        sk_sp<GrFragmentProcessor> fp(GrMagnifierEffect::Make(
                                                        inputTexture.get(),
                                                        effectBounds,
                                                        fSrcRect.x() / inputTexture->width(),
                                                        yOffset / inputTexture->height(),
                                                        invXZoom,
                                                        invYZoom,
                                                        bounds.width() * invInset,
                                                        bounds.height() * invInset));
        if (!fp) {
            return nullptr;
        }

        return DrawWithFP(context, std::move(fp), bounds, ctx.outputProperties());
    }
#endif

    SkBitmap inputBM;

    if (!input->getROPixels(&inputBM)) {
        return nullptr;
    }

    if ((inputBM.colorType() != kN32_SkColorType) ||
        (fSrcRect.width() >= inputBM.width()) || (fSrcRect.height() >= inputBM.height())) {
        return nullptr;
    }

    SkAutoLockPixels alp(inputBM);
    SkASSERT(inputBM.getPixels());
    if (!inputBM.getPixels() || inputBM.width() <= 0 || inputBM.height() <= 0) {
        return nullptr;
    }

    const SkImageInfo info = SkImageInfo::MakeN32Premul(bounds.width(), bounds.height());

    SkBitmap dst;
    if (!dst.tryAllocPixels(info)) {
        return nullptr;
    }

    SkAutoLockPixels dstLock(dst);

    SkColor* dptr = dst.getAddr32(0, 0);
    int dstWidth = dst.width(), dstHeight = dst.height();
    for (int y = 0; y < dstHeight; ++y) {
        for (int x = 0; x < dstWidth; ++x) {
            SkScalar x_dist = SkMin32(x, dstWidth - x - 1) * invInset;
            SkScalar y_dist = SkMin32(y, dstHeight - y - 1) * invInset;
            SkScalar weight = 0;

            static const SkScalar kScalar2 = SkScalar(2);

            // To create a smooth curve at the corners, we need to work on
            // a square twice the size of the inset.
            if (x_dist < kScalar2 && y_dist < kScalar2) {
                x_dist = kScalar2 - x_dist;
                y_dist = kScalar2 - y_dist;

                SkScalar dist = SkScalarSqrt(SkScalarSquare(x_dist) +
                                             SkScalarSquare(y_dist));
                dist = SkMaxScalar(kScalar2 - dist, 0);
                weight = SkMinScalar(SkScalarSquare(dist), SK_Scalar1);
            } else {
                SkScalar sqDist = SkMinScalar(SkScalarSquare(x_dist),
                                              SkScalarSquare(y_dist));
                weight = SkMinScalar(sqDist, SK_Scalar1);
            }

            SkScalar x_interp = SkScalarMul(weight, (fSrcRect.x() + x * invXZoom)) +
                           (SK_Scalar1 - weight) * x;
            SkScalar y_interp = SkScalarMul(weight, (fSrcRect.y() + y * invYZoom)) +
                           (SK_Scalar1 - weight) * y;

            int x_val = SkTPin(bounds.x() + SkScalarFloorToInt(x_interp), 0, inputBM.width() - 1);
            int y_val = SkTPin(bounds.y() + SkScalarFloorToInt(y_interp), 0, inputBM.height() - 1);

            *dptr = *inputBM.getAddr32(x_val, y_val);
            dptr++;
        }
    }

    offset->fX = bounds.left();
    offset->fY = bounds.top();
    return SkSpecialImage::MakeFromRaster(SkIRect::MakeWH(bounds.width(), bounds.height()),
                                          dst);
}

#ifndef SK_IGNORE_TO_STRING
void SkMagnifierImageFilter::toString(SkString* str) const {
    str->appendf("SkMagnifierImageFilter: (");
    str->appendf("src: (%f,%f,%f,%f) ",
                 fSrcRect.fLeft, fSrcRect.fTop, fSrcRect.fRight, fSrcRect.fBottom);
    str->appendf("inset: %f", fInset);
    str->append(")");
}
#endif