DragImageChromiumMac.cpp   [plain text]


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#include "config.h"
#include "DragImage.h"

#include "Image.h"
#include "NotImplemented.h"
#include <wtf/RetainPtr.h>

#include <CoreGraphics/CGBitmapContext.h>
#include <CoreGraphics/CGImage.h>

namespace WebCore {

IntSize dragImageSize(DragImageRef image)
{
    if (!image)
        return IntSize();
    return IntSize(CGImageGetWidth(image), CGImageGetHeight(image));
}

void deleteDragImage(DragImageRef image)
{
    CGImageRelease(image);
}

DragImageRef scaleDragImage(DragImageRef image, FloatSize scale)
{
    if (!image)
        return 0;
    size_t width = roundf(CGImageGetWidth(image) * scale.width());
    size_t height = roundf(CGImageGetHeight(image) * scale.height());

    RetainPtr<CGColorSpaceRef> deviceRGB(WTF::AdoptCF, CGColorSpaceCreateWithName(kCGColorSpaceGenericRGB));
    CGContextRef context = CGBitmapContextCreate(0, width, height, 8, width * 4, deviceRGB.get(), kCGImageAlphaPremultipliedFirst | kCGBitmapByteOrder32Host);

    if (!context)
        return 0;
    CGContextDrawImage(context, CGRectMake(0, 0, width, height), image);
    CGImageRelease(image);

    CGImageRef scaledImage = CGBitmapContextCreateImage(context);
    CGContextRelease(context);
    return scaledImage;
}

DragImageRef dissolveDragImageToFraction(DragImageRef image, float delta)
{
    if (!image)
        return 0;
    size_t width = CGImageGetWidth(image);
    size_t height = CGImageGetHeight(image);

    RetainPtr<CGColorSpaceRef> deviceRGB(WTF::AdoptCF, CGColorSpaceCreateWithName(kCGColorSpaceGenericRGB));
    CGContextRef context = CGBitmapContextCreate(0, width, height, 8, width * 4, deviceRGB.get(), kCGImageAlphaPremultipliedFirst | kCGBitmapByteOrder32Host);

    if (!context)
        return 0;
    // From CGContext.h:
    //     The Porter-Duff "source over" mode is called `kCGBlendModeNormal':
    //       R = S + D*(1 - Sa)
    //  This is the same as NSCompositeSourceOver, which is what -[NSImage dissolveToPoint:fraction:] uses.
    CGContextSetAlpha(context, delta);
    CGContextSetBlendMode(context, kCGBlendModeNormal);
    CGContextDrawImage(context, CGRectMake(0, 0, width, height), image);
    CGImageRelease(image);

    CGImageRef dissolvedImage = CGBitmapContextCreateImage(context);
    CGContextRelease(context);
    return dissolvedImage;
}

DragImageRef createDragImageFromImage(Image* image)
{
    if (!image)
        return 0;
    return CGImageCreateCopy(image->nativeImageForCurrentFrame());
}

DragImageRef createDragImageIconForCachedImage(CachedImage*)
{
    notImplemented();
    return 0;
}

} // namespace WebCore