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Bug 455364. Add Thebes API to extract a subimage of an image into a new image. r=vlad

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This commit is contained in:
Zack Weinberg 2009-02-05 21:14:07 +13:00
parent ccff0d2450
commit a66146acfe
3 changed files with 92 additions and 9 deletions
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15
gfx/public/nsIImage.h
View File

@ -74,10 +74,10 @@ typedef enum {
#define nsImageUpdateFlags_kBitsChanged 0x2
// IID for the nsIImage interface
// 455fc276-01de-488f-9f8f-19b85a6b112d
// c942f66c-97d0-470e-99de-a1efb4586afd
#define NS_IIMAGE_IID \
{ 0x455fc276, 0x01de, 0x488f, \
{ 0x9f, 0x8f, 0x19, 0xb8, 0x5a, 0x6b, 0x11, 0x2d } }
{ 0xc942f66c, 0x97d0, 0x470e, \
{ 0x99, 0xde, 0xa1, 0xef, 0xb4, 0x58, 0x6a, 0xfd } }
// Interface to Images
class nsIImage : public nsISupports
@ -289,6 +289,15 @@ public:
* the original format requested a 1-bit or 8-bit alpha mask
*/
virtual void SetHasNoAlpha() = 0;
/**
* Extract a rectangular region of the nsIImage and return it as a new
* nsIImage.
* @param aSubimage the region to extract
* @param aResult the extracted image
*/
NS_IMETHOD Extract(const nsIntRect& aSubimage,
nsIImage** aResult NS_OUTPARAM) = 0;
};
NS_DEFINE_STATIC_IID_ACCESSOR(nsIImage, NS_IIMAGE_IID)

82
gfx/src/thebes/nsThebesImage.cpp
View File

@ -67,6 +67,8 @@ nsThebesImage::nsThebesImage()
mImageComplete(PR_FALSE),
mSinglePixel(PR_FALSE),
mFormatChanged(PR_FALSE),
mNeverUseDeviceSurface(PR_FALSE),
mSinglePixelColor(0),
mAlphaDepth(0)
{
static PRBool hasCheckedOptimize = PR_FALSE;
@ -122,19 +124,25 @@ nsThebesImage::Init(PRInt32 aWidth, PRInt32 aHeight, PRInt32 aDepth, nsMaskRequi
mFormat = format;
// For Windows, we must create the device surface first (if we're
// going to) so that the image surface can wrap it. Can't be done
// the other way around.
#ifdef XP_WIN
if (!ShouldUseImageSurfaces()) {
if (!mNeverUseDeviceSurface && !ShouldUseImageSurfaces()) {
mWinSurface = new gfxWindowsSurface(gfxIntSize(mWidth, mHeight), format);
if (mWinSurface && mWinSurface->CairoStatus() == 0) {
// no error
mImageSurface = mWinSurface->GetImageSurface();
} else {
mWinSurface = nsnull;
}
}
if (!mImageSurface)
mWinSurface = nsnull;
#endif
// For other platforms we create the image surface first and then
// possibly wrap it in a device surface. This branch is also used
// on Windows if we're not using device surfaces or if we couldn't
// create one.
if (!mImageSurface)
mImageSurface = new gfxImageSurface(gfxIntSize(mWidth, mHeight), format);
@ -145,7 +153,9 @@ nsThebesImage::Init(PRInt32 aWidth, PRInt32 aHeight, PRInt32 aDepth, nsMaskRequi
}
#ifdef XP_MACOSX
mQuartzSurface = new gfxQuartzImageSurface(mImageSurface);
if (!mNeverUseDeviceSurface && !ShouldUseImageSurfaces()) {
mQuartzSurface = new gfxQuartzImageSurface(mImageSurface);
}
#endif
mStride = mImageSurface->Stride();
@ -301,7 +311,7 @@ nsThebesImage::Optimize(nsIDeviceContext* aContext)
// if we're being forced to use image surfaces due to
// resource constraints, don't try to optimize beyond same-pixel.
if (ShouldUseImageSurfaces())
if (mNeverUseDeviceSurface || ShouldUseImageSurfaces())
return NS_OK;
mOptSurface = nsnull;
@ -690,6 +700,66 @@ nsThebesImage::Draw(gfxContext* aContext,
}
}
nsresult
nsThebesImage::Extract(const nsIntRect& aRegion,
nsIImage** aResult)
{
nsRefPtr<nsThebesImage> subImage(new nsThebesImage());
if (!subImage)
return NS_ERROR_OUT_OF_MEMORY;
// The scaling problems described in bug 468496 are especially
// likely to be visible for the sub-image, as at present the only
// user is the border-image code and border-images tend to get
// stretched a lot. At the same time, the performance concerns
// that prevent us from just using Cairo's fallback scaler when
// accelerated graphics won't cut it are less relevant to such
// images, since they also tend to be small. Thus, we forcibly
// disable the use of anything other than a client-side image
// surface for the sub-image; this ensures that the correct
// (albeit slower) Cairo fallback scaler will be used.
subImage->mNeverUseDeviceSurface = PR_TRUE;
// ->Init() is just going to convert this back, bleah.
nsMaskRequirements maskReq;
switch (mAlphaDepth) {
case 0: maskReq = nsMaskRequirements_kNoMask; break;
case 1: maskReq = nsMaskRequirements_kNeeds1Bit; break;
case 8: maskReq = nsMaskRequirements_kNeeds8Bit; break;
default:
NS_NOTREACHED("impossible alpha depth");
maskReq = nsMaskRequirements_kNeeds8Bit; // safe
}
nsresult rv = subImage->Init(aRegion.width, aRegion.height,
8 /* ignored */, maskReq);
NS_ENSURE_SUCCESS(rv, rv);
{ // scope to destroy ctx
gfxContext ctx(subImage->ThebesSurface());
ctx.SetOperator(gfxContext::OPERATOR_SOURCE);
if (mSinglePixel) {
ctx.SetDeviceColor(mSinglePixelColor);
} else {
// SetSource() places point (0,0) of its first argument at
// the coordinages given by its second argument. We want
// (x,y) of the image to be (0,0) of source space, so we
// put (0,0) of the image at (-x,-y).
ctx.SetSource(this->ThebesSurface(),
gfxPoint(-aRegion.x, -aRegion.y));
}
ctx.Rectangle(gfxRect(0, 0, aRegion.width, aRegion.height));
ctx.Fill();
}
nsIntRect filled(0, 0, aRegion.width, aRegion.height);
subImage->ImageUpdated(nsnull, nsImageUpdateFlags_kBitsChanged, &filled);
subImage->Optimize(nsnull);
NS_ADDREF(*aResult = subImage);
return NS_OK;
}
PRBool
nsThebesImage::ShouldUseImageSurfaces()
{

4
gfx/src/thebes/nsThebesImage.h
View File

@ -116,6 +116,9 @@ public:
void SetHasNoAlpha();
NS_IMETHOD Extract(const nsIntRect& aSubimage,
nsIImage** aResult NS_OUTPARAM);
protected:
static PRBool AllowedImageSize(PRInt32 aWidth, PRInt32 aHeight) {
NS_ASSERTION(aWidth > 0, "invalid image width");
@ -156,6 +159,7 @@ protected:
PRPackedBool mImageComplete;
PRPackedBool mSinglePixel;
PRPackedBool mFormatChanged;
PRPackedBool mNeverUseDeviceSurface;
#ifdef XP_WIN
PRPackedBool mIsDDBSurface;
#endif