gecko/widget/gtk2/nsImageToPixbuf.cpp
2012-05-21 12:12:37 +01:00

140 lines
4.5 KiB
C++

/* vim:set sw=4 sts=4 et cin: */
/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
#include <gdk-pixbuf/gdk-pixbuf.h>
#include "gfxASurface.h"
#include "gfxImageSurface.h"
#include "gfxContext.h"
#include "imgIContainer.h"
#include "nsAutoPtr.h"
#include "nsImageToPixbuf.h"
NS_IMPL_ISUPPORTS1(nsImageToPixbuf, nsIImageToPixbuf)
inline unsigned char
unpremultiply (unsigned char color,
unsigned char alpha)
{
if (alpha == 0)
return 0;
// plus alpha/2 to round instead of truncate
return (color * 255 + alpha / 2) / alpha;
}
NS_IMETHODIMP_(GdkPixbuf*)
nsImageToPixbuf::ConvertImageToPixbuf(imgIContainer* aImage)
{
return ImageToPixbuf(aImage);
}
GdkPixbuf*
nsImageToPixbuf::ImageToPixbuf(imgIContainer* aImage)
{
nsRefPtr<gfxImageSurface> frame;
nsresult rv = aImage->CopyFrame(imgIContainer::FRAME_CURRENT,
imgIContainer::FLAG_SYNC_DECODE,
getter_AddRefs(frame));
// If the last call failed, it was probably because our call stack originates
// in an imgIDecoderObserver event, meaning that we're not allowed request
// a sync decode. Presumably the originating event is something sensible like
// OnStopFrame(), so we can just retry the call without a sync decode.
if (NS_FAILED(rv))
aImage->CopyFrame(imgIContainer::FRAME_CURRENT,
imgIContainer::FLAG_NONE,
getter_AddRefs(frame));
if (!frame)
return nsnull;
return ImgSurfaceToPixbuf(frame, frame->Width(), frame->Height());
}
GdkPixbuf*
nsImageToPixbuf::ImgSurfaceToPixbuf(gfxImageSurface* aImgSurface, PRInt32 aWidth, PRInt32 aHeight)
{
GdkPixbuf* pixbuf = gdk_pixbuf_new(GDK_COLORSPACE_RGB, TRUE, 8,
aWidth, aHeight);
if (!pixbuf)
return nsnull;
PRUint32 rowstride = gdk_pixbuf_get_rowstride (pixbuf);
guchar* pixels = gdk_pixbuf_get_pixels (pixbuf);
long cairoStride = aImgSurface->Stride();
unsigned char* cairoData = aImgSurface->Data();
gfxASurface::gfxImageFormat format = aImgSurface->Format();
for (PRInt32 row = 0; row < aHeight; ++row) {
for (PRInt32 col = 0; col < aWidth; ++col) {
guchar* pixel = pixels + row * rowstride + 4 * col;
PRUint32* cairoPixel = reinterpret_cast<PRUint32*>
((cairoData + row * cairoStride + 4 * col));
if (format == gfxASurface::ImageFormatARGB32) {
const PRUint8 a = (*cairoPixel >> 24) & 0xFF;
const PRUint8 r = unpremultiply((*cairoPixel >> 16) & 0xFF, a);
const PRUint8 g = unpremultiply((*cairoPixel >> 8) & 0xFF, a);
const PRUint8 b = unpremultiply((*cairoPixel >> 0) & 0xFF, a);
*pixel++ = r;
*pixel++ = g;
*pixel++ = b;
*pixel++ = a;
} else {
NS_ASSERTION(format == gfxASurface::ImageFormatRGB24,
"unexpected format");
const PRUint8 r = (*cairoPixel >> 16) & 0xFF;
const PRUint8 g = (*cairoPixel >> 8) & 0xFF;
const PRUint8 b = (*cairoPixel >> 0) & 0xFF;
*pixel++ = r;
*pixel++ = g;
*pixel++ = b;
*pixel++ = 0xFF; // A
}
}
}
return pixbuf;
}
GdkPixbuf*
nsImageToPixbuf::SurfaceToPixbuf(gfxASurface* aSurface, PRInt32 aWidth, PRInt32 aHeight)
{
if (aSurface->CairoStatus()) {
NS_ERROR("invalid surface");
return nsnull;
}
nsRefPtr<gfxImageSurface> imgSurface;
if (aSurface->GetType() == gfxASurface::SurfaceTypeImage) {
imgSurface = static_cast<gfxImageSurface*>
(static_cast<gfxASurface*>(aSurface));
} else {
imgSurface = new gfxImageSurface(gfxIntSize(aWidth, aHeight),
gfxImageSurface::ImageFormatARGB32);
if (!imgSurface)
return nsnull;
nsRefPtr<gfxContext> context = new gfxContext(imgSurface);
if (!context)
return nsnull;
context->SetOperator(gfxContext::OPERATOR_SOURCE);
context->SetSource(aSurface);
context->Paint();
}
return ImgSurfaceToPixbuf(imgSurface, aWidth, aHeight);
}