gecko/modules/libpr0n/public/imgIContainer.idl

/** -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
 *
 * ***** BEGIN LICENSE BLOCK *****
 * Version: MPL 1.1/GPL 2.0/LGPL 2.1
 *
 * The contents of this file are subject to the Mozilla Public License Version
 * 1.1 (the "License"); you may not use this file except in compliance with
 * the License. You may obtain a copy of the License at
 * http://www.mozilla.org/MPL/
 *
 * Software distributed under the License is distributed on an "AS IS" basis,
 * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
 * for the specific language governing rights and limitations under the
 * License.
 *
 * The Original Code is mozilla.org code.
 *
 * The Initial Developer of the Original Code is
 * Netscape Communications Corporation.
 * Portions created by the Initial Developer are Copyright (C) 2001
 * the Initial Developer. All Rights Reserved.
 *
 * Contributor(s):
 *   Stuart Parmenter <pavlov@netscape.com>
 *   Federico Mena-Quintero <federico@novell.com>
 *   Joe Drew <joe@drew.ca>
 *   Bobby Holley <bobbyholley@gmail.com>
 *
 * Alternatively, the contents of this file may be used under the terms of
 * either the GNU General Public License Version 2 or later (the "GPL"), or
 * the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
 * in which case the provisions of the GPL or the LGPL are applicable instead
 * of those above. If you wish to allow use of your version of this file only
 * under the terms of either the GPL or the LGPL, and not to allow others to
 * use your version of this file under the terms of the MPL, indicate your
 * decision by deleting the provisions above and replace them with the notice
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 * the provisions above, a recipient may use your version of this file under
 * the terms of any one of the MPL, the GPL or the LGPL.
 *
 * ***** END LICENSE BLOCK ***** */

#include "nsISupports.idl"

interface imgIDecoderObserver;

%{C++
#include "gfxImageSurface.h"
#include "gfxContext.h"
#include "gfxMatrix.h"
#include "gfxRect.h"
#include "gfxPattern.h"
#include "gfxASurface.h"
#include "nsRect.h"
%}

[ptr] native gfxImageSurface(gfxImageSurface);
[ptr] native gfxASurface(gfxASurface);
native gfxImageFormat(gfxASurface::gfxImageFormat);
[ptr] native gfxContext(gfxContext);
[ref] native gfxMatrix(gfxMatrix);
[ref] native gfxRect(gfxRect);
native gfxGraphicsFilter(gfxPattern::GraphicsFilter);
[ref] native nsIntRect(nsIntRect);

/**
 * imgIContainer is the interface that represents an image. It allows
 * access to frames as Thebes surfaces, and permits users to extract subregions
 * as other imgIContainers. It also allows drawing of images on to Thebes
 * contexts.
 *
 * Internally, imgIContainer also manages animation of images.
 */
[scriptable, uuid(e80ec20d-8e9c-405f-a673-cea00aa95b4d)]
interface imgIContainer : nsISupports
{
  /**
   * The width of the container rectangle.
   */
  readonly attribute PRInt32 width;

  /**
   * The height of the container rectangle.
   */
  readonly attribute PRInt32 height;

  /**
   * Whether this image is animated. You can only be guaranteed that querying
   * this will not throw if STATUS_DECODE_COMPLETE is set on the imgIRequest.
   *
   * @throws NS_ERROR_NOT_AVAILABLE if the animated state cannot be determined.
   */
  readonly attribute boolean animated;

  /**
   * Whether the current frame is opaque; that is, needs the background painted
   * behind it.
   */
  readonly attribute boolean currentFrameIsOpaque;

  /**
   * Flags for imgIContainer operations.
   *
   * Meanings:
   *
   * FLAG_NONE: Lack of flags
   *
   * FLAG_SYNC_DECODE: Forces synchronous/non-progressive decode of all
   * available data before the call returns.
   */

  const long FLAG_NONE            = 0x0;
  const long FLAG_SYNC_DECODE     = 0x1;

  /**
    * Constants for specifying various "special" frames.
    *
    * FRAME_FIRST: The first frame
    * FRAME_CURRENT: The current frame
    *
    * FRAME_MAX_VALUE should be set to the value of the maximum constant above,
    * as it is used for ensuring that a valid value was passed in.
    */
  const unsigned long FRAME_FIRST = 0;
  const unsigned long FRAME_CURRENT = 1;
  const unsigned long FRAME_MAX_VALUE = 1;

  /**
   * Get a surface for the given frame. This may be a platform-native,
   * optimized surface, so you cannot inspect its pixel data.
   *
   * @param aWhichFrame Frame specifier of the FRAME_* variety.
   * @param aFlags Flags of the FLAG_* variety
   */
  [noscript] gfxASurface getFrame(in PRUint32 aWhichFrame,
                                  in PRUint32 aFlags);

  /**
   * Create and return a new copy of the given frame that you can write to
   * and otherwise inspect the pixels of.
   *
   * @param aWhichFrame Frame specifier of the FRAME_* variety.
   * @param aFlags Flags of the FLAG_* variety
   */
  [noscript] gfxImageSurface copyFrame(in PRUint32 aWhichFrame,
                                       in PRUint32 aFlags);

  /**
   * Create a new imgContainer that contains only a single frame, which itself
   * contains a subregion of the given frame.
   *
   * @param aWhichFrame Frame specifier of the FRAME_* variety.
   * @param aRect the area of the current frame to be duplicated in the
   *              returned imgContainer's frame.
   * @param aFlags Flags of the FLAG_* variety
   */
  [noscript] imgIContainer extractFrame(in PRUint32 aWhichFrame,
                                        [const] in nsIntRect aRect,
                                        in PRUint32 aFlags);

  /**
   * Draw the current frame on to the context specified.
   *
   * @param aContext The Thebes context to draw the image to.
   * @param aFilter The filter to be used if we're scaling the image.
   * @param aUserSpaceToImageSpace The transformation from user space (e.g.,
   *                               appunits) to image space.
   * @param aFill The area in the context to draw pixels to. Image will be
   *              automatically tiled as necessary.
   * @param aSubimage The area of the image, in pixels, that we are allowed to
   *                  sample from.
   * @param aFlags Flags of the FLAG_* variety
   */
  [noscript] void draw(in gfxContext aContext, in gfxGraphicsFilter aFilter,
                       in gfxMatrix aUserSpaceToImageSpace, in gfxRect aFill,
                       in nsIntRect aSubimage, in PRUint32 aFlags);

  /*
   * Ensures that an image is decoding. Calling this function guarantees that
   * the image will at some point fire off decode notifications. Calling draw(),
   * getFrame(), copyFrame(), or extractCurrentFrame() triggers the same
   * mechanism internally. Thus, if you want to be sure that the image will be
   * decoded but don't want to access it until then, you must call
   * requestDecode().
   */
  void requestDecode();

  /**
    * Increments the lock count on the image. An image will not be discarded
    * as long as the lock count is nonzero. Note that it is still possible for
    * the image to be undecoded if decode-on-draw is enabled and the image
    * was never drawn.
    *
    * Upon instantiation images have a lock count of zero.
    */
  void lockImage();

  /**
    * Decreases the lock count on the image. If the lock count drops to zero,
    * the image is allowed to discard its frame data to save memory.
    *
    * Upon instantiation images have a lock count of zero. It is an error to
    * call this method without first having made a matching lockImage() call.
    * In other words, the lock count is not allowed to be negative.
    */
  void unlockImage();

  /************ Internal libpr0n use only below here. *****************/

  /**
   * Flags for imgIContainer initialization.
   *
   * Meanings:
   *
   * INIT_FLAG_NONE: Lack of flags
   *
   * INIT_FLAG_DISCARDABLE: The container should be discardable
   *
   * INIT_FLAG_DECODE_ON_DRAW: The container should decode on draw rather than
   * decoding on load.
   *
   * INIT_FLAG_MULTIPART: The container will be used to display a stream of
   * images in a multipart channel. If this flag is set, INIT_FLAG_DISCARDABLE
   * and INIT_FLAG_DECODE_ON_DRAW must not be set.
   */

  const long INIT_FLAG_NONE           = 0x0;
  const long INIT_FLAG_DISCARDABLE    = 0x1;
  const long INIT_FLAG_DECODE_ON_DRAW = 0x2;
  const long INIT_FLAG_MULTIPART      = 0x4;

  /**
   * Creates a new image container.
   *
   * @param aObserver Observer to send decoder and animation notifications to.
   * @param aMimeType The mimetype of the image.
   * @param aFlags Initialization flags of the INIT_FLAG_* variety.
   */
  void init(in imgIDecoderObserver aObserver,
            in string aMimeType,
            in PRUint32 aFlags);

  /** 
   * "Disposal" method indicates how the image should be handled before the
   *  subsequent image is displayed.
   *  Don't change these without looking at the implementations using them,
   *  struct gif_struct::disposal_method and gif_write() in particular.
   */
  const long kDisposeClearAll         = -1; // Clear the whole image, revealing
                                            // what was there before the gif displayed
  const long kDisposeNotSpecified     =  0; // Leave frame, let new frame draw on top
  const long kDisposeKeep             =  1; // Leave frame, let new frame draw on top
  const long kDisposeClear            =  2; // Clear the frame's area, revealing bg
  const long kDisposeRestorePrevious  =  3; // Restore the previous (composited) frame
  
  /*
   * "Blend" method indicates how the current image is combined with the
   * previous image.
   */
  const long kBlendSource             =  0; // All color components of the frame, including alpha, 
                                            // overwrite the current contents of the frame's 
                                            // output buffer region
  const long kBlendOver               =  1; // The frame should be composited onto the output buffer 
                                            // based on its alpha, using a simple OVER operation
  
  /**
   * Animation mode Constants
   *   0 = normal
   *   1 = don't animate
   *   2 = loop once
   */
  const short kNormalAnimMode   = 0;
  const short kDontAnimMode     = 1;
  const short kLoopOnceAnimMode = 2;

  attribute unsigned short animationMode;

  /**
   * The rectangle defining the location and size of the currently displayed frame.
   * Should be an attribute, but can't be because of reference/pointer
   * conflicts with native types in xpidl.
   */
  [noscript] void getCurrentFrameRect(in nsIntRect aFrameRect);

  /**
   * The index of the current frame that would be drawn if the image was to be
   * drawn now.
   */
  readonly attribute unsigned long currentFrameIndex;

  /**
   * The total number of frames in this image.
   */
  readonly attribute unsigned long numFrames;

  /**
   * The size, in bytes, occupied by the significant data portions of the image.
   * This includes both compressed source data and decoded frames.
   */
  readonly attribute unsigned long dataSize;

  void setFrameDisposalMethod(in unsigned long framenumber, in PRInt32 aDisposalMethod);
  void setFrameBlendMethod(in unsigned long framenumber, in PRInt32 aBlendMethod);
  void setFrameTimeout(in unsigned long framenumber, in PRInt32 aTimeout);
  void setFrameHasNoAlpha(in unsigned long framenumber);

  /**
   * Sets the size of the container. This should only be called by the decoder. This function may be called multiple
   * times, but will throw an error if subsequent calls do not match the first.
   */
  [noscript] void setSize(in long aWidth, in long aHeight);

  /**
   * Create or re-use a frame at index aFrameNum. It is an error to call this with aFrameNum not in the range [0, numFrames].
   */
  [noscript] void ensureCleanFrame(in unsigned long aFramenum, in PRInt32 aX, in PRInt32 aY, in PRInt32 aWidth, in PRInt32 aHeight, in gfxImageFormat aFormat,
                                   [array, size_is(imageLength)] out PRUint8 imageData, out unsigned long imageLength);

  /**
   * Adds to the end of the list of frames.
   */
  [noscript] void appendFrame(in PRInt32 aX, in PRInt32 aY, in PRInt32 aWidth, in PRInt32 aHeight, in gfxImageFormat aFormat,
                              [array, size_is(imageLength)] out PRUint8 imageData, out unsigned long imageLength);
  [noscript] void appendPalettedFrame(in PRInt32 aX, in PRInt32 aY, in PRInt32 aWidth, in PRInt32 aHeight, in gfxImageFormat aFormat, in PRUint8 aPaletteDepth, 
                                      [array, size_is(imageLength)] out PRUint8 imageData, out unsigned long imageLength,
                                      [array, size_is(paletteLength)] out PRUint32 paletteData, out unsigned long paletteLength);

  [noscript] void frameUpdated(in unsigned long framenum, in nsIntRect aNewRect);

  /* notification when the current frame is done decoding */
  void endFrameDecode(in unsigned long framenumber);
  
  /* notification that the entire image has been decoded */
  void decodingComplete();
  
  void startAnimation();

  void stopAnimation();

  void resetAnimation();

  /**
   * number of times to loop the image.
   * @note -1 means forever.
   */
  attribute long loopCount;

  /* Add compressed source data to the imgContainer.
   *
   * The decoder will use this data, either immediately or at draw time, do
   * decode the image.
   */
  [noscript] void addSourceData([array, size_is(aCount), const] in char data,
                                 in unsigned long aCount);

  /* Called after the all the source data has been added with addSourceData. */
  [noscript] void sourceDataComplete();

  /* Called for multipart images when there's a new source image to add. */
  [noscript] void newSourceData();

  /**
   * A hint of the number of bytes of source data that the image contains. If
   * called early on, this can help reduce copying and reallocations by
   * appropriately preallocating the source data buffer.
   *
   * We take this approach rather than having the source data management code do
   * something more complicated (like chunklisting) because HTTP is by far the
   * dominant source of images, and the Content-Length header is quite reliable.
   * Thus, pre-allocation simplifies code and reduces the total number of
   * allocations.
   */
  void setSourceSizeHint(in unsigned long sizeHint);
};