michael@0: /* -*- Mode: Java; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
michael@0: // Helper file for shared image functionality
michael@0: // 
michael@0: // Note that this is use by tests elsewhere in the source tree. When in doubt,
michael@0: // check mxr before removing or changing functionality.
michael@0: 
michael@0: // Helper function to clear the image cache of content images
michael@0: function clearImageCache()
michael@0: {
michael@0:   var tools = SpecialPowers.Cc["@mozilla.org/image/tools;1"]
michael@0:                              .getService(SpecialPowers.Ci.imgITools);
michael@0:   var imageCache = tools.getImgCacheForDocument(window.document);
michael@0:   imageCache.clearCache(false); // true=chrome, false=content
michael@0: }
michael@0: 
michael@0: // Helper function to determine if the frame is decoded for a given image id
michael@0: function isFrameDecoded(id)
michael@0: {
michael@0:   return (getImageStatus(id) &
michael@0:           SpecialPowers.Ci.imgIRequest.STATUS_FRAME_COMPLETE)
michael@0:          ? true : false;
michael@0: }
michael@0: 
michael@0: // Helper function to determine if the image is loaded for a given image id
michael@0: function isImageLoaded(id)
michael@0: {
michael@0:   return (getImageStatus(id) &
michael@0:           SpecialPowers.Ci.imgIRequest.STATUS_LOAD_COMPLETE)
michael@0:          ? true : false;
michael@0: }
michael@0: 
michael@0: // Helper function to get the status flags of an image
michael@0: function getImageStatus(id)
michael@0: {
michael@0:   // Get the image
michael@0:   var img = SpecialPowers.wrap(document.getElementById(id));
michael@0: 
michael@0:   // QI the image to nsImageLoadingContent
michael@0:   img.QueryInterface(SpecialPowers.Ci.nsIImageLoadingContent);
michael@0: 
michael@0:   // Get the request
michael@0:   var request = img.getRequest(SpecialPowers.Ci
michael@0:                                          .nsIImageLoadingContent
michael@0:                                          .CURRENT_REQUEST);
michael@0: 
michael@0:   // Return the status
michael@0:   return request.imageStatus;
michael@0: }
michael@0: 
michael@0: // Forces a synchronous decode of an image by drawing it to a canvas. Only
michael@0: // really meaningful if the image is fully loaded first
michael@0: function forceDecode(id)
michael@0: {
michael@0:   // Get the image
michael@0:   var img = document.getElementById(id);
michael@0: 
michael@0:   // Make a new canvas
michael@0:   var canvas = document.createElement("canvas");
michael@0: 
michael@0:   // Draw the image to the canvas. This forces a synchronous decode
michael@0:   var ctx = canvas.getContext("2d");
michael@0:   ctx.drawImage(img, 0, 0);
michael@0: }
michael@0: 
michael@0: 
michael@0: // Functions to facilitate getting/setting various image-related prefs
michael@0: //
michael@0: // If you change a pref in a mochitest, Don't forget to reset it to its 
michael@0: // original value!
michael@0: //
michael@0: // Null indicates no pref set
michael@0: 
michael@0: const DISCARD_ENABLED_PREF = {name: "discardable", branch: "image.mem.", type: "bool"};
michael@0: const DECODEONDRAW_ENABLED_PREF = {name: "decodeondraw", branch: "image.mem.", type: "bool"};
michael@0: const DISCARD_TIMEOUT_PREF = {name: "min_discard_timeout_ms", branch: "image.mem.", type: "int"};
michael@0: 
michael@0: function setImagePref(pref, val)
michael@0: {
michael@0:   var prefService = SpecialPowers.Cc["@mozilla.org/preferences-service;1"]
michael@0:                                  .getService(SpecialPowers.Ci.nsIPrefService);
michael@0:   var branch = prefService.getBranch(pref.branch);
michael@0:   if (val != null) {
michael@0:     switch(pref.type) {
michael@0:       case "bool":
michael@0:         branch.setBoolPref(pref.name, val);
michael@0:         break;
michael@0:       case "int":
michael@0:         branch.setIntPref(pref.name, val);
michael@0:         break;
michael@0:       default:
michael@0:         throw new Error("Unknown pref type");
michael@0:     }
michael@0:   }
michael@0:   else if (branch.prefHasUserValue(pref.name))
michael@0:     branch.clearUserPref(pref.name);
michael@0: }
michael@0: 
michael@0: function getImagePref(pref)
michael@0: {
michael@0:   var prefService = SpecialPowers.Cc["@mozilla.org/preferences-service;1"]
michael@0:                                  .getService(SpecialPowers.Ci.nsIPrefService);
michael@0:   var branch = prefService.getBranch(pref.branch);
michael@0:   if (branch.prefHasUserValue(pref.name)) {
michael@0:     switch (pref.type) {
michael@0:       case "bool":
michael@0:         return branch.getBoolPref(pref.name);
michael@0:       case "int":
michael@0:         return branch.getIntPref(pref.name);
michael@0:       default:
michael@0:         throw new Error("Unknown pref type");
michael@0:     }
michael@0:   }
michael@0:   else
michael@0:     return null;
michael@0: }
michael@0: 
michael@0: // JS implementation of imgIScriptedNotificationObserver with stubs for all of its methods.
michael@0: function ImageDecoderObserverStub()
michael@0: {
michael@0:   this.sizeAvailable = function sizeAvailable(aRequest)   {}
michael@0:   this.frameComplete = function frameComplete(aRequest)   {}
michael@0:   this.decodeComplete = function decodeComplete(aRequest) {}
michael@0:   this.loadComplete = function loadComplete(aRequest)     {}
michael@0:   this.frameUpdate = function frameUpdate(aRequest)       {}
michael@0:   this.discard = function discard(aRequest)               {}
michael@0:   this.isAnimated = function isAnimated(aRequest)         {}
michael@0: }