gecko-dev/gfx/public/nsIImageGroup.h

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/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
*
* The contents of this file are subject to the Netscape Public License
* Version 1.0 (the "NPL"); you may not use this file except in
* compliance with the NPL. You may obtain a copy of the NPL at
* http://www.mozilla.org/NPL/
*
* Software distributed under the NPL is distributed on an "AS IS" basis,
* WITHOUT WARRANTY OF ANY KIND, either express or implied. See the NPL
* for the specific language governing rights and limitations under the
* NPL.
*
* The Initial Developer of this code under the NPL is Netscape
* Communications Corporation. Portions created by Netscape are
* Copyright (C) 1998 Netscape Communications Corporation. All Rights
* Reserved.
*/
#ifndef nsIImageGroup_h___
#define nsIImageGroup_h___
#include <stdio.h>
#include "nsISupports.h"
#include "nscore.h"
#include "nsColor.h"
class nsIImageGroupObserver;
class nsIImageRequestObserver;
class nsIImageRequest;
class nsIDeviceContext;
class nsIStreamListener;
class nsIURLGroup;
/** For important images, like backdrops. */
#define nsImageLoadFlags_kHighPriority 0x01
/** Don't throw this image out of cache. */
#define nsImageLoadFlags_kSticky 0x02
/** Don't get image out of image cache. */
#define nsImageLoadFlags_kBypassCache 0x04
/** Don't load if image cache misses. */
#define nsImageLoadFlags_kOnlyFromCache 0x08
// IID for the nsIImageGroup interface
#define NS_IIMAGEGROUP_IID \
{ 0xbe927e40, 0xaeaa, 0x11d1, \
{ 0x9b, 0xc3, 0x00, 0x60, 0x08, 0x8c, 0xa6, 0xb3 } }
/**
*
* Image group. A convenient way to group a set of image load requests
* and control them as a group.
*/
class nsIImageGroup : public nsISupports
{
public:
static const nsIID& GetIID() { static nsIID iid = NS_IIMAGEGROUP_IID; return iid; }
/**
* Initialize an image group with a device context. All images
* in this group will be decoded for the specified device context.
*/
virtual nsresult Init(nsIDeviceContext *aDeviceContext,
nsIURLGroup* aURLGroup) = 0;
/**
* Add an observers to be informed of image group notifications.
*
* @param aObserver - An observer to add to the observer list.
* @param boolean indicating whether addition was successful.
*/
virtual PRBool AddObserver(nsIImageGroupObserver *aObserver) = 0;
/**
* Remove a previously added observer from the observer list.
*
* @param aObserver - An observer to remove from the observer list.
* @param boolean indicating whether the removal was successful.
*/
virtual PRBool RemoveObserver(nsIImageGroupObserver *aObserver) = 0;
/**
* Fetch the image corresponding to the specified URL.
*
* @param aUrl - the URL of the image to be loaded.
* @param aObserver - the observer is notified at significant
* points in image loading.
* @param aWidth, aHeight - These parameters specify the target
* dimensions of the image. The image will be stretched
* horizontally, vertically or both to meet these parameters.
* If both width and height are zero, the image is decoded
* using its "natural" size. If only one of width and height
* is zero, the image is scaled to the provided dimension, with
* the unspecified dimension scaled to maintain the image's
* original aspect ratio.
* @param aBackgroundColor - If the background color is NULL, a mask
* will be generated for any transparent images. If background
* color is non-NULL, it indicates the RGB value to be painted
* into the image for "transparent" areas of the image, in which
* case no mask is created. This is intended for backdrops and
* printing.
* @param aFlags - image loading flags are specified above
*
* @return the resulting image request object.
*/
virtual nsIImageRequest* GetImage(const char* aUrl,
nsIImageRequestObserver *aObserver,
const nscolor* aBackgroundColor,
PRUint32 aWidth, PRUint32 aHeight,
PRUint32 aFlags) = 0;
/**
* Like GetImage except load the image from a live stream.
* The call returns an nsIImageRequest and an nsIStreamListener
* that should be connected to the live stream to accept
* the image data.
*/
NS_IMETHOD GetImageFromStream(const char* aURL,
nsIImageRequestObserver *aObserver,
const nscolor* aBackgroundColor,
PRUint32 aWidth, PRUint32 aHeight,
PRUint32 aFlags,
nsIImageRequest*& aResult,
nsIStreamListener*& aListenerResult) = 0;
/**
* Halt decoding of images or animation without destroying associated
* pixmap data. All ImageRequests created with this ImageGroup
* are interrupted.
*/
virtual void Interrupt(void) = 0;
};
/// Factory method for creating an image group
extern "C" NS_GFX_(nsresult)
NS_NewImageGroup(nsIImageGroup **aInstancePtrResult);
#endif