image/imgITools.idl
author Jed Davis <jld@mozilla.com>
Thu, 02 Aug 2018 14:18:01 -0600
changeset 430152 1e65391c7583a32fdefea325dc37b476cfbe2b5c
parent 418172 85d61067345b4ba153ae793eb43bdffdaa062def
permissions -rw-r--r--
Bug 1480401 - Avoid heap-allocated closures in async signal safe part of LaunchApp. r=froydnj MozReview-Commit-ID: 4LYtBGbqtVh

/* -*- 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 nsIEventTarget;
interface nsIInputStream;
interface imgIContainer;
interface imgILoader;
interface imgICache;
interface imgIScriptedNotificationObserver;
interface imgINotificationObserver;
interface imgIContainerCallback;

webidl Document;

[scriptable, builtinclass, uuid(4c2383a4-931c-484d-8c4a-973590f66e3f)]
interface imgITools : nsISupports
{
    /**
     * decodeImageFromBuffer
     * Caller provides an buffer, a buffer size and a mimetype. We read from
     * the stream and decompress it (according to the specified mime type) and
     * return the resulting imgIContainer.
     *
     * @param aBuffer
     *        Data in memory.
     * @param aSize
     *        Buffer size.
     * @param aMimeType
     *        Type of image in the stream.
     */
    imgIContainer decodeImageFromBuffer(in string aBuffer,
                                        in unsigned long aSize,
                                        in ACString aMimeType);

    /**
     * decodeImageFromArrayBuffer
     * Caller provides an ArrayBuffer and a mimetype. We read from
     * the stream and decompress it (according to the specified mime type) and
     * return the resulting imgIContainer.
     *
     * @param aArrayBuffer
     *        An ArrayBuffer.
     * @param aMimeType
     *        Type of image in the stream.
     */
    [implicit_jscontext]
    imgIContainer decodeImageFromArrayBuffer(in jsval aArrayBuffer,
                                             in ACString aMimeType);

    /**
     * decodeImageAsync
     * See decodeImage. The main difference between this method and decodeImage
     * is that here the operation is done async on a thread from the decode
     * pool. When the operation is completed, the callback is executed with the
     * result.
     *
     * @param aStream
     *        An input stream for an encoded image file.
     * @param aMimeType
     *        Type of image in the stream.
     * @param aCallback
     *        The callback is executed when the imgContainer is fully created.
     * @param aEventTarget
     *        This eventTarget is used to execute aCallback
     */
    void decodeImageAsync(in nsIInputStream aStream,
                          in ACString aMimeType,
                          in imgIContainerCallback aCallback,
                          in nsIEventTarget aEventTarget);

    /**
     * encodeImage
     * Caller provides an image container, and the mime type it should be
     * encoded to. We return an input stream for the encoded image data.
     *
     * @param aContainer
     *        An image container.
     * @param aMimeType
     *        Type of encoded image desired (eg "image/png").
     * @param outputOptions
     *        Encoder-specific output options.
     */
    nsIInputStream encodeImage(in imgIContainer aContainer,
                               in ACString aMimeType,
                               [optional] in AString outputOptions);

    /**
     * encodeScaledImage
     * Caller provides an image container, and the mime type it should be
     * encoded to. We return an input stream for the encoded image data.
     * The encoded image is scaled to the specified dimensions.
     *
     * @param aContainer
     *        An image container.
     * @param aMimeType
     *        Type of encoded image desired (eg "image/png").
     * @param aWidth, aHeight
     *        The size (in pixels) desired for the resulting image. Specify 0 to
     *        use the given image's width or height. Values must be >= 0.
     * @param outputOptions
     *        Encoder-specific output options.
     */
    nsIInputStream encodeScaledImage(in imgIContainer aContainer,
                                     in ACString aMimeType,
                                     in long aWidth,
                                     in long aHeight,
                                     [optional] in AString outputOptions);

    /**
     * getImgLoaderForDocument
     * Retrieve an image loader that reflects the privacy status of the given
     * document.
     *
     * @param doc
     *        A document. Must not be null.
     */
    imgILoader getImgLoaderForDocument(in Document doc);

    /**
     * getImgLoaderForDocument
     * Retrieve an image cache that reflects the privacy status of the given
     * document.
     *
     * @param doc
     *        A document. Null is allowed, but must _only_ be passed
     *        when there is no way to obtain a relevant document for
     *        the current context in which a cache is desired.
     */
    imgICache getImgCacheForDocument(in Document doc);

    /**
     * encodeCroppedImage
     * Caller provides an image container, and the mime type it should be
     * encoded to. We return an input stream for the encoded image data.
     * The encoded image is cropped to the specified dimensions.
     *
     * The given offset and size must not exceed the image bounds.
     *
     * @param aContainer
     *        An image container.
     * @param aMimeType
     *        Type of encoded image desired (eg "image/png").
     * @param aOffsetX, aOffsetY
     *        The crop offset (in pixels). Values must be >= 0.
     * @param aWidth, aHeight
     *        The size (in pixels) desired for the resulting image. Specify 0 to
     *        use the given image's width or height. Values must be >= 0.
     * @param outputOptions
     *        Encoder-specific output options.
     */
    nsIInputStream encodeCroppedImage(in imgIContainer aContainer,
                                      in ACString aMimeType,
                                      in long aOffsetX,
                                      in long aOffsetY,
                                      in long aWidth,
                                      in long aHeight,
                                      [optional] in AString outputOptions);

    /**
     * Create a wrapper around a scripted notification observer (ordinarily
     * imgINotificationObserver cannot be implemented from scripts).
     *
     * @param aObserver The scripted observer to wrap
     */
    imgINotificationObserver
    createScriptedObserver(in imgIScriptedNotificationObserver aObserver);
};

/**
 * This is a companion interface for nsIAsyncInputStream::asyncWait.
 */
[function, scriptable, uuid(f195772c-a4c0-47ae-80ca-211e001c67be)]
interface imgIContainerCallback : nsISupports
{
    /* If the operation fails, aStatus will contain the error value */
    void onImageReady(in imgIContainer aImage, in nsresult aStatus);
};