/*

 * Copyright (C) 2005, 2006 Alexander Kellett <lypanov@kde.org>

 * Copyright (C) 2006 Nikolas Zimmermann <zimmermann@kde.org>

 *

 * Redistribution and use in source and binary forms, with or without

 * modification, are permitted provided that the following conditions

 * are met:

 * 1. Redistributions of source code must retain the above copyright

 *    notice, this list of conditions and the following disclaimer.

 * 2. Redistributions in binary form must reproduce the above copyright

 *    notice, this list of conditions and the following disclaimer in the

 *    documentation and/or other materials provided with the distribution.

 *

 * THIS SOFTWARE IS PROVIDED BY APPLE COMPUTER, INC. ``AS IS'' AND ANY

 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE

 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR

 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE COMPUTER, INC. OR

 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,

 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,

 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR

 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY

 * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT

 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE

 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 

 */

#include "config.h"

#if ENABLE(SVG)

#import "SVGResourceMasker.h"

#import "CgSupport.h"

#import "GraphicsContext.h"

#import "ImageBuffer.h"

#import "SVGRenderStyle.h"

#import "SVGResourceFilter.h"

#import <QuartzCore/CIFilter.h>

#import <QuartzCore/CoreImage.h>

using namespace std;

namespace WebCore {

static CIImage* applyLuminanceToAlphaFilter(CIImage* inputImage)

{

    CIFilter* luminanceToAlpha = [CIFilter filterWithName:@"CIColorMatrix"];

    [luminanceToAlpha setDefaults];

    CGFloat alpha[4] = {0.2125f, 0.7154f, 0.0721f, 0.0f};

    CGFloat zero[4] = {0.0f, 0.0f, 0.0f, 0.0f};

    [luminanceToAlpha setValue:inputImage forKey:@"inputImage"];  

    [luminanceToAlpha setValue:[CIVector vectorWithValues:zero count:4] forKey:@"inputRVector"];

    [luminanceToAlpha setValue:[CIVector vectorWithValues:zero count:4] forKey:@"inputGVector"];

    [luminanceToAlpha setValue:[CIVector vectorWithValues:zero count:4] forKey:@"inputBVector"];

    [luminanceToAlpha setValue:[CIVector vectorWithValues:alpha count:4] forKey:@"inputAVector"];

    [luminanceToAlpha setValue:[CIVector vectorWithValues:zero count:4] forKey:@"inputBiasVector"];

    return [luminanceToAlpha valueForKey:@"outputImage"];

}

static CIImage* applyExpandAlphatoGrayscaleFilter(CIImage* inputImage)

{

    CIFilter* alphaToGrayscale = [CIFilter filterWithName:@"CIColorMatrix"];

    CGFloat zero[4] = {0, 0, 0, 0};

    [alphaToGrayscale setDefaults];

    [alphaToGrayscale setValue:inputImage forKey:@"inputImage"];

    [alphaToGrayscale setValue:[CIVector vectorWithValues:zero count:4] forKey:@"inputRVector"];

    [alphaToGrayscale setValue:[CIVector vectorWithValues:zero count:4] forKey:@"inputGVector"];

    [alphaToGrayscale setValue:[CIVector vectorWithValues:zero count:4] forKey:@"inputBVector"];

    [alphaToGrayscale setValue:[CIVector vectorWithX:0.0f Y:0.0f Z:0.0f W:1.0f] forKey:@"inputAVector"];

    [alphaToGrayscale setValue:[CIVector vectorWithX:1.0f Y:1.0f Z:1.0f W:0.0f] forKey:@"inputBiasVector"];

    return [alphaToGrayscale valueForKey:@"outputImage"];

}

static CIImage* transformImageIntoGrayscaleMask(CIImage* inputImage)

{

    CIFilter* blackBackground = [CIFilter filterWithName:@"CIConstantColorGenerator"];

    [blackBackground setValue:[CIColor colorWithRed:0.0f green:0.0f blue:0.0f alpha:1.0f] forKey:@"inputColor"];

    CIFilter* layerOverBlack = [CIFilter filterWithName:@"CISourceOverCompositing"];

    [layerOverBlack setValue:[blackBackground valueForKey:@"outputImage"] forKey:@"inputBackgroundImage"];  

    [layerOverBlack setValue:inputImage forKey:@"inputImage"];  

    CIImage* luminanceAlpha = applyLuminanceToAlphaFilter([layerOverBlack valueForKey:@"outputImage"]);

    CIImage* luminanceAsGrayscale = applyExpandAlphatoGrayscaleFilter(luminanceAlpha);

    CIImage* alphaAsGrayscale = applyExpandAlphatoGrayscaleFilter(inputImage);

    CIFilter* multipliedGrayscale = [CIFilter filterWithName:@"CIMultiplyCompositing"];

    [multipliedGrayscale setValue:luminanceAsGrayscale forKey:@"inputBackgroundImage"];  

    [multipliedGrayscale setValue:alphaAsGrayscale forKey:@"inputImage"];  

    return [multipliedGrayscale valueForKey:@"outputImage"];

}

void SVGResourceMasker::applyMask(GraphicsContext* context, const FloatRect& boundingBox) const

{

    if (!m_mask)

        return;

    IntSize maskSize = m_mask->size();

    // The mask we operate on is has it's top left corner at (0, 0) on the CGImage.

    // We have to translate to the current relative bbox, to get the clipping right.

    CGRect maskDestinationRect = CGRectMake(lroundf(boundingBox.x()), lroundf(boundingBox.y()),

                                            maskSize.width(), maskSize.height());

    // Create new graphics context in gray scale mode for image rendering

    auto_ptr<ImageBuffer> grayScaleImage(ImageBuffer::create(maskSize, true));

    if (!grayScaleImage.get())

        return;

    CGContextRef grayScaleContext = grayScaleImage->context()->platformContext();

    // Wrap CG context in CI context

    CIContext* ciGrayscaleContext = [CIContext contextWithCGContext:grayScaleContext options:nil];

    // Transform colorized mask to gray scale

    CIImage* grayScaleMask = transformImageIntoGrayscaleMask([CIImage imageWithCGImage:m_mask->cgImage()]);

    [ciGrayscaleContext drawImage:grayScaleMask atPoint:CGPointZero fromRect:CGRectMake(0, 0, maskSize.width(), maskSize.height())];

    // Do the actual masking!

    CGContextClipToMask(context->platformContext(), maskDestinationRect, grayScaleImage->cgImage());

}

} // namespace WebCore

#endif // ENABLE(SVG)