gecko-dev/image/public/imgIContainer.idl

/** -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
 *
 * 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 "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"
#include "nsSize.h"
#include "limits.h"

namespace mozilla {
namespace layers {
class LayerManager;
class ImageContainer;
}
}

class nsIFrame;

namespace mozilla {
class TimeStamp;
}

%}

[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);
[ref] native nsIntSize(nsIntSize);
[ptr] native nsIFrame(nsIFrame);
[ptr] native ImageContainer(mozilla::layers::ImageContainer);
[ptr] native LayerManager(mozilla::layers::LayerManager);
[ref] native TimeStamp(mozilla::TimeStamp);


/**
 * 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(d6c58749-ceb6-4afe-ab72-ff3086433e1f)]
interface imgIContainer : nsISupports
{
  /**
   * The width of the container rectangle.  In the case of any error,
   * zero is returned, and an exception will be thrown.
   */
  readonly attribute int32_t width;

  /**
   * The height of the container rectangle.  In the case of any error,
   * zero is returned, and an exception will be thrown.
   */
  readonly attribute int32_t height;

  /**
    * Enumerated values for the 'type' attribute (below).
    */
  const unsigned short TYPE_RASTER = 0;
  const unsigned short TYPE_VECTOR = 1;

  /**
   * The type of this image (one of the TYPE_* values above).
   */
  readonly attribute unsigned short type;

  /**
   * Direct C++ accessor for 'type' attribute, for convenience.
   */
  [noscript, notxpcom] uint16_t GetType();

  /**
   * 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. It is an error to pass this flag
   * from a call stack that originates in a decoder (ie, from a decoder
   * observer event).
   *
   * FLAG_DECODE_NO_PREMULTIPLY_ALPHA: Do not premultiply alpha if
   * it's not already premultiplied in the image data.
   *
   * FLAG_DECODE_NO_COLORSPACE_CONVERSION: Do not do any colorspace conversion;
   * ignore any embedded profiles, and don't convert to any particular destination
   * space.
   *
   * FLAG_CLAMP: Extend the image to the fill area by clamping image sample
   * coordinates instead of by tiling. This only affects 'draw'.
   */

  const long FLAG_NONE            = 0x0;
  const long FLAG_SYNC_DECODE     = 0x1;
  const long FLAG_DECODE_NO_PREMULTIPLY_ALPHA = 0x2;
  const long FLAG_DECODE_NO_COLORSPACE_CONVERSION = 0x4;
  const long FLAG_CLAMP           = 0x8;

  /**
    * 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 uint32_t aWhichFrame,
                                  in uint32_t aFlags);

  /**
   * Attempts to create an ImageContainer (and Image) containing the current
   * frame. Only valid for RASTER type images.
   */
  [noscript] ImageContainer getImageContainer();

  /**
   * 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 uint32_t aWhichFrame,
                                       in uint32_t 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 uint32_t aWhichFrame,
                                        [const] in nsIntRect aRect,
                                        in uint32_t 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. When aFlags includes
   *              FLAG_CLAMP, the image will be extended to this area by clampling
   *              image sample coordinates. Otherwise, the image will be
   *              automatically tiled as necessary.
   * @param aSubimage The area of the image, in pixels, that we are allowed to
   *                  sample from.
   * @param aViewportSize
   *          The size (in CSS pixels) of the viewport that would be available
   *          for the full image to occupy, if we were drawing the full image.
   *          (Note that we might not actually be drawing the full image -- we
   *          might be restricted by aSubimage -- but we still need the full
   *          image's viewport-size in order for SVG images with the "viewBox"
   *          attribute to position their content correctly.)
   * @param aFlags Flags of the FLAG_* variety
   */
  [noscript] void draw(in gfxContext aContext,
                       in gfxGraphicsFilter aFilter,
                       [const] in gfxMatrix aUserSpaceToImageSpace,
                       [const] in gfxRect aFill,
                       [const] in nsIntRect aSubimage,
                       [const] in nsIntSize aViewportSize,
                       in uint32_t aFlags);

  /**
   * If this image is TYPE_VECTOR, i.e. is really an embedded SVG document,
   * this method returns a pointer to the root nsIFrame of that document. If
   * not (or if the root nsIFrame isn't available for some reason), this method
   * returns nullptr.
   *
   * "notxpcom" for convenience, since we have no need for nsresult return-val.
   */
  [notxpcom] nsIFrame GetRootLayoutFrame();

  /*
   * 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();

  /*
   * This is equivalent to requestDecode() but it also decodes some of the image.
   */
  [noscript] void startDecoding();

  /**
    * 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();

  /**
   * If this image is unlocked, discard its decoded data.  If the image is
   * locked or has already been discarded, do nothing.
   */
  void requestDiscard();

  /**
    * Indicates that this imgIContainer has been triggered to update
    * its internal animation state. Likely this should only be called
    * from within nsImageFrame or objects of similar type.
    */
  [notxpcom] void requestRefresh([const] in TimeStamp aTime);

  /**
   * 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;

  /* Methods to control animation */
  void resetAnimation();
};