C++ SkImageFilter类代码示例

bool SkImageFilter::canComputeFastBounds() const {
    if (this->affectsTransparentBlack()) {
        return false;
    }
    for (int i = 0; i < fInputCount; i++) {
        SkImageFilter* input = this->getInput(i);
        if (input && !input->canComputeFastBounds()) {
            return false;
        }
    }
    return true;
}

void SkMergeImageFilter::toString(SkString* str) const {
    str->appendf("SkMergeImageFilter: (");
    
    for (int i = 0; i < this->countInputs(); ++i) {
        SkImageFilter* filter = this->getInput(i);
        str->appendf("%d: (", i);
        filter->toString(str);
        str->appendf(")");
    }

    str->append(")");
}

SkBitmap SkImageFilter::getInputResult(int index, Proxy* proxy,
                                       const SkBitmap& src, const SkMatrix& ctm,
                                       SkIPoint* loc) {
    SkASSERT(index < fInputCount);
    SkImageFilter* input = getInput(index);
    SkBitmap result;
    if (input && input->filterImage(proxy, src, ctm, &result, loc)) {
        return result;
    } else {
        return src;
    }
}

bool SkImageFilter::canHandleComplexCTM() const {
    if (!this->onCanHandleComplexCTM()) {
        return false;
    }
    const int count = this->countInputs();
    for (int i = 0; i < count; ++i) {
        SkImageFilter* input = this->getInput(i);
        if (input && !input->canHandleComplexCTM()) {
            return false;
        }
    }
    return true;
}

bool SkMergeImageFilter::onFilterImage(Proxy* proxy, const SkBitmap& src,
                                       const SkMatrix& ctm,
                                       SkBitmap* result, SkIPoint* loc) {
    if (countInputs() < 1) {
        return false;
    }

    const SkIRect srcBounds = SkIRect::MakeXYWH(loc->x(), loc->y(),
                                                src.width(), src.height());
    SkIRect bounds;
    if (!this->filterBounds(srcBounds, ctm, &bounds)) {
        return false;
    }

    const int x0 = bounds.left();
    const int y0 = bounds.top();

    SkAutoTUnref<SkDevice> dst(proxy->createDevice(bounds.width(), bounds.height()));
    if (NULL == dst) {
        return false;
    }
    SkCanvas canvas(dst);
    SkPaint paint;

    int inputCount = countInputs();
    for (int i = 0; i < inputCount; ++i) {
        SkBitmap tmp;
        const SkBitmap* srcPtr;
        SkIPoint pos = *loc;
        SkImageFilter* filter = getInput(i);
        if (filter) {
            if (!filter->filterImage(proxy, src, ctm, &tmp, &pos)) {
                return false;
            }
            srcPtr = &tmp;
        } else {
            srcPtr = &src;
        }

        if (fModes) {
            paint.setXfermodeMode((SkXfermode::Mode)fModes[i]);
        } else {
            paint.setXfermode(NULL);
        }
        canvas.drawSprite(*srcPtr, pos.x() - x0, pos.y() - y0, &paint);
    }

    loc->set(bounds.left(), bounds.top());
    *result = dst->accessBitmap(false);
    return true;
}

void SkComposeImageFilter::toString(SkString* str) const {
    SkImageFilter* outer = getInput(0);
    SkImageFilter* inner = getInput(1);

    str->appendf("SkComposeImageFilter: (");

    str->appendf("outer: ");
    outer->toString(str);

    str->appendf("inner: ");
    inner->toString(str);

    str->appendf(")");
}

bool SkMergeImageFilter::onFilterImage(Proxy* proxy, const SkBitmap& src,
                                       const Context& ctx,
                                       SkBitmap* result, SkIPoint* offset) const {
    if (countInputs() < 1) {
        return false;
    }

    SkIRect bounds;
    if (!this->applyCropRect(ctx, src, SkIPoint::Make(0, 0), &bounds)) {
        return false;
    }

    const int x0 = bounds.left();
    const int y0 = bounds.top();

    SkAutoTUnref<SkBaseDevice> dst(proxy->createDevice(bounds.width(), bounds.height()));
    if (NULL == dst) {
        return false;
    }
    SkCanvas canvas(dst);
    SkPaint paint;

    int inputCount = countInputs();
    for (int i = 0; i < inputCount; ++i) {
        SkBitmap tmp;
        const SkBitmap* srcPtr;
        SkIPoint pos = SkIPoint::Make(0, 0);
        SkImageFilter* filter = getInput(i);
        if (filter) {
            if (!filter->filterImage(proxy, src, ctx, &tmp, &pos)) {
                return false;
            }
            srcPtr = &tmp;
        } else {
            srcPtr = &src;
        }

        if (fModes) {
            paint.setXfermodeMode((SkXfermode::Mode)fModes[i]);
        } else {
            paint.setXfermode(NULL);
        }
        canvas.drawSprite(*srcPtr, pos.x() - x0, pos.y() - y0, &paint);
    }

    offset->fX = bounds.left();
    offset->fY = bounds.top();
    *result = dst->accessBitmap(false);
    return true;
}

bool SkXfermodeImageFilter::onFilterImage(Proxy* proxy,
                                            const SkBitmap& src,
                                            const SkMatrix& ctm,
                                            SkBitmap* dst,
                                            SkIPoint* offset) {
    SkBitmap background = src, foreground = src;
    SkImageFilter* backgroundInput = getInput(0);
    SkImageFilter* foregroundInput = getInput(1);
    SkIPoint backgroundOffset = SkIPoint::Make(0, 0);
    if (backgroundInput &&
        !backgroundInput->filterImage(proxy, src, ctm, &background, &backgroundOffset)) {
        return false;
    }
    SkIPoint foregroundOffset = SkIPoint::Make(0, 0);
    if (foregroundInput &&
        !foregroundInput->filterImage(proxy, src, ctm, &foreground, &foregroundOffset)) {
        return false;
    }

    SkIRect bounds, foregroundBounds;
    background.getBounds(&bounds);
    bounds.offset(backgroundOffset);
    foreground.getBounds(&foregroundBounds);
    foregroundBounds.offset(foregroundOffset);
    bounds.join(foregroundBounds);
    if (!applyCropRect(&bounds, ctm)) {
        return false;
    }

    SkAutoTUnref<SkBaseDevice> device(proxy->createDevice(bounds.width(), bounds.height()));
    if (NULL == device.get()) {
        return false;
    }
    SkCanvas canvas(device);
    canvas.translate(SkIntToScalar(-bounds.left()), SkIntToScalar(-bounds.top()));
    SkPaint paint;
    paint.setXfermodeMode(SkXfermode::kSrc_Mode);
    canvas.drawBitmap(background, SkIntToScalar(backgroundOffset.fX),
                      SkIntToScalar(backgroundOffset.fY), &paint);
    paint.setXfermode(fMode);
    canvas.drawBitmap(foreground, SkIntToScalar(foregroundOffset.fX),
                      SkIntToScalar(foregroundOffset.fY), &paint);
    canvas.clipRect(SkRect::Make(foregroundBounds), SkRegion::kDifference_Op);
    paint.setColor(SK_ColorTRANSPARENT);
    canvas.drawPaint(paint);
    *dst = device->accessBitmap(false);
    offset->fX += bounds.left();
    offset->fY += bounds.top();
    return true;
}

sk_sp<SkSpecialImage> SkImageFilter::filterInput(int index,
                                                 SkSpecialImage* src,
                                                 const Context& ctx,
                                                 SkIPoint* offset) const {
    SkImageFilter* input = this->getInput(index);
    if (!input) {
        return sk_sp<SkSpecialImage>(SkRef(src));
    }

    sk_sp<SkSpecialImage> result(input->filterImage(src, this->mapContext(ctx), offset));

    SkASSERT(!result || src->isTextureBacked() == result->isTextureBacked());

    return result;
}

SkRect SkImageFilter::computeFastBounds(const SkRect& src) const {
    if (0 == this->countInputs()) {
        return src;
    }
    SkRect combinedBounds = this->getInput(0) ? this->getInput(0)->computeFastBounds(src) : src;
    for (int i = 1; i < this->countInputs(); i++) {
        SkImageFilter* input = this->getInput(i);
        if (input) {
            combinedBounds.join(input->computeFastBounds(src));
        } else {
            combinedBounds.join(src);
        }
    }
    return combinedBounds;
}

bool SkImageFilter::filterInput(int index, Proxy* proxy, const SkBitmap& src,
                                const Context& origCtx,
                                SkBitmap* result, SkIPoint* offset,
                                bool relaxSizeConstraint) const {
    SkImageFilter* input = this->getInput(index);
    if (!input) {
        return true;
    }

    SizeConstraint constraint = origCtx.sizeConstraint();
    if (relaxSizeConstraint && (kExact_SizeConstraint == constraint)) {
        constraint = kApprox_SizeConstraint;
    }
    Context ctx(origCtx.ctm(), origCtx.clipBounds(), origCtx.cache(), constraint);

    return input->filterImage(proxy, src, this->mapContext(ctx), result, offset);
}

bool SkComposeImageFilter::onFilterBounds(const SkIRect& src,
                                          const SkMatrix& ctm,
                                          SkIRect* dst) {
    SkImageFilter* outer = getInput(0);
    SkImageFilter* inner = getInput(1);

    if (!outer && !inner) {
        return false;
    }

    if (!outer || !inner) {
        return (outer ? outer : inner)->filterBounds(src, ctm, dst);
    }

    SkIRect tmp;
    return inner->filterBounds(src, ctm, &tmp) &&
           outer->filterBounds(tmp, ctm, dst);
}

SkIRect SkImageFilter::onFilterBounds(const SkIRect& src, const SkMatrix& ctm,
                                      MapDirection direction) const {
    if (this->countInputs() < 1) {
        return src;
    }

    SkIRect totalBounds;
    for (int i = 0; i < this->countInputs(); ++i) {
        SkImageFilter* filter = this->getInput(i);
        SkIRect rect = filter ? filter->filterBounds(src, ctm, direction) : src;
        if (0 == i) {
            totalBounds = rect;
        } else {
            totalBounds.join(rect);
        }
    }

    return totalBounds;
}

void SkImageFilter::computeFastBounds(const SkRect& src, SkRect* dst) const {
    if (0 == fInputCount) {
        *dst = src;
        return;
    }
    if (this->getInput(0)) {
        this->getInput(0)->computeFastBounds(src, dst);
    } else {
        *dst = src;
    }
    for (int i = 1; i < fInputCount; i++) {
        SkImageFilter* input = this->getInput(i);
        if (input) {
            SkRect bounds;
            input->computeFastBounds(src, &bounds);
            dst->join(bounds);
        } else {
            dst->join(src);
        }
    }
}

void SkBaseDevice::drawBitmapAsSprite(const SkDraw& draw, const SkBitmap& bitmap, int x, int y,
                                      const SkPaint& paint) {
    SkImageFilter* filter = paint.getImageFilter();
    if (filter && !this->canHandleImageFilter(filter)) {
        SkImageFilter::DeviceProxy proxy(this);
        SkBitmap dst;
        SkIPoint offset = SkIPoint::Make(0, 0);
        SkMatrix matrix = *draw.fMatrix;
        matrix.postTranslate(SkIntToScalar(-x), SkIntToScalar(-y));
        const SkIRect clipBounds = draw.fClip->getBounds().makeOffset(-x, -y);
        SkAutoTUnref<SkImageFilter::Cache> cache(this->getImageFilterCache());
        SkImageFilter::Context ctx(matrix, clipBounds, cache.get());
        if (filter->filterImageDeprecated(&proxy, bitmap, ctx, &dst, &offset)) {
            SkPaint tmpUnfiltered(paint);
            tmpUnfiltered.setImageFilter(nullptr);
            this->drawSprite(draw, dst, x + offset.x(), y + offset.y(), tmpUnfiltered);
        }
    } else {
        this->drawSprite(draw, bitmap, x, y, paint);
    }
}