Merge pull request #430 from ivmartel/412-cancel-load

Fixes #412.

src/app/application.js

@@ -550,6 +550,16 @@ dwv.App = function ()
      */
     function loadImageData(data, loader, options)
     {
+        // allow to cancel
+        var previousOnKeyDown = window.onkeydown;
+        window.onkeydown = function (event) {
+            if (event.ctrlKey && event.keyCode === 88 ) // crtl-x
+            {
+                console.log("crtl-x pressed!");
+                loader.abort();
+            }
+        };
+
         // clear variables
         self.reset();
         // first data name
@@ -575,7 +585,9 @@ dwv.App = function ()
             postLoadInit(data);
         };
         loader.onerror = function (error) { handleError(error); };
+        loader.onabort = function (error) { handleAbort(error); };
         loader.onloadend = function (/*event*/) {
+            window.onkeydown = previousOnKeyDown;
             if ( drawController ) {
                 drawController.activateDrawLayer(viewController);
             }
@@ -1234,7 +1246,7 @@ dwv.App = function ()
     {
         // alert window
         if ( error.name && error.message) {
-            alert(error.name+": "+error.message+".");
+            alert(error.name+": "+error.message);
         }
         else {
             alert("Error: "+error+".");
@@ -1247,6 +1259,24 @@ dwv.App = function ()
         dwv.gui.displayProgress(100);
     }
 
+    /**
+     * Handle an abort: display it to the user.
+     * @param {Object} error The error to handle.
+     * @private
+     */
+    function handleAbort(error)
+    {
+        // log
+        if ( error.message ) {
+            console.warn(error.message);
+        }
+        else {
+            console.warn("Abort called.");
+        }
+        // stop progress
+        dwv.gui.displayProgress(100);
+    }
+
     /**
      * Handle a load progress.
      * @private

src/image/decoder.js

@@ -43,6 +43,14 @@ dwv.image.AsynchPixelBufferDecoder = function (script)
         // add it the queue and run it
         pool.addWorkerTask(workerTask);
     };
+
+    /**
+     * Abort decoding.
+     */
+    this.abort = function () {
+        // abort the thread pool
+        pool.abort();
+    };
 };
 
 /**
@@ -72,12 +80,12 @@ dwv.image.SynchPixelBufferDecoder = function (algoName)
      * @param {Array} pixelBuffer The pixel buffer.
      * @param {Number} bitsAllocated The bits allocated per element in the buffer.
      * @param {Boolean} isSigned Is the data signed.
-     * @return {Array} The decoded pixel buffer.
+     * @param {Function} callback Callback function to handle decoded data.
      * @external jpeg
      * @external JpegImage
      * @external JpxImage
      */
-    this.decode = function (pixelBuffer, bitsAllocated, isSigned) {
+    this.decode = function (pixelBuffer, bitsAllocated, isSigned, callback) {
         var decoder = null;
         var decodedBuffer = null;
         if( algoName === "jpeg-lossless" ) {
@@ -127,8 +135,15 @@ dwv.image.SynchPixelBufferDecoder = function (algoName)
         // send events
         this.ondecoded();
         this.ondecodeend();
-        // return result as array
-        return [decodedBuffer];
+        // call callback with decoded buffer as array
+        callback({data: [decodedBuffer]});
+    };
+
+    /**
+     * Abort decoding.
+     */
+    this.abort = function () {
+        // nothing to do in the synchronous case.
     };
 };
 
@@ -155,20 +170,22 @@ dwv.image.SynchPixelBufferDecoder.prototype.ondecoded = function ()
  * If the 'dwv.image.decoderScripts' variable does not contain the desired algorythm,
  * the decoder will switch to the synchronous mode.
  */
-dwv.image.PixelBufferDecoder = function (algoName, asynch)
+dwv.image.PixelBufferDecoder = function (algoName)
 {
     /**
-     * Asynchronous decoder.
+     * Pixel decoder.
      * Defined only once.
      * @private
      * @type Object
      */
-    var asynchDecoder = null;
+    var pixelDecoder = null;
 
     // initialise the asynch decoder (if possible)
     if (typeof dwv.image.decoderScripts !== "undefined" &&
             typeof dwv.image.decoderScripts[algoName] !== "undefined") {
-        asynchDecoder = new dwv.image.AsynchPixelBufferDecoder(dwv.image.decoderScripts[algoName]);
+        pixelDecoder = new dwv.image.AsynchPixelBufferDecoder(dwv.image.decoderScripts[algoName]);
+    } else {
+        pixelDecoder = new dwv.image.SynchPixelBufferDecoder(algoName);
     }
 
     /**
@@ -177,31 +194,23 @@ dwv.image.PixelBufferDecoder = function (algoName, asynch)
      * @param {Number} bitsAllocated The bits allocated per element in the buffer.
      * @param {Boolean} isSigned Is the data signed.
      * @param {Object} callback The callback on the conversion.
-     * @param {Boolean} asynch Should the decoder run asynchronously, default to true.
      */
     this.decode = function (pixelBuffer, bitsAllocated, isSigned, callback)
     {
-        // default to asynch
-        asynch = (typeof asynch === 'undefined') ? true : asynch;
-
-        // run asynchronous if asked and we have scripts
-        if (asynch && asynchDecoder !== null) {
-            // (re)set event handler
-            asynchDecoder.ondecodeend = this.ondecodeend;
-            asynchDecoder.ondecoded = this.ondecoded;
-            // decode and call the callback
-            asynchDecoder.decode(pixelBuffer, bitsAllocated, isSigned, callback);
-        }
-        else {
-            // create the decoder
-            var synchDecoder = new dwv.image.SynchPixelBufferDecoder(algoName);
-            synchDecoder.ondecodeend = this.ondecodeend;
-            synchDecoder.ondecoded = this.ondecoded;
-            // decode
-            var decodedBuffer = synchDecoder.decode(pixelBuffer, bitsAllocated, isSigned);
-            // call the callback
-            callback({data: decodedBuffer});
-        }
+        // set event handler
+        pixelDecoder.ondecodeend = this.ondecodeend;
+        pixelDecoder.ondecoded = this.ondecoded;
+        // decode and call the callback
+        pixelDecoder.decode(pixelBuffer, bitsAllocated, isSigned, callback);
+    };
+
+    /**
+     * Abort decoding.
+     */
+    this.abort = function ()
+    {
+        // decoder classes should define an abort
+        pixelDecoder.abort();
     };
 };
 

src/image/dicomBufferToView.js

@@ -135,6 +135,15 @@ dwv.image.DicomBufferToView = function ()
             self.onloadend();
         }
     };
+
+    /**
+     * Abort a conversion.
+     */
+    this.abort = function () {
+        if ( pixelDecoder ) {
+            pixelDecoder.abort();
+        }
+    };
 };
 
 /**

src/io/dicomDataLoader.js

@@ -17,6 +17,13 @@ dwv.io.DicomDataLoader = function ()
      */
     var options = {};
 
+    /**
+     * Loading flag.
+     * @private
+     * @type Boolean
+     */
+    var isLoading = false;
+
     /**
      * Set the loader options.
      * @param {Object} opt The input options.
@@ -25,6 +32,14 @@ dwv.io.DicomDataLoader = function ()
         options = opt;
     };
 
+    /**
+     * Is the load ongoing?
+     * @return {Boolean} True if loading.
+     */
+    this.isLoading = function () {
+        return isLoading;
+    };
+
     /**
      * DICOM buffer to dwv.image.View (asynchronous)
      */
@@ -37,22 +52,43 @@ dwv.io.DicomDataLoader = function ()
      * @param {Number} index The data index.
      */
     this.load = function (buffer, origin, index) {
+        // set loading flag
+        isLoading = true;
         // set character set
         if (typeof options.defaultCharacterSet !== "undefined") {
             db2v.setDefaultCharacterSet(options.defaultCharacterSet);
         }
         // connect handlers
         db2v.onload = self.onload;
-        db2v.onloadend = self.onloadend;
+        db2v.onloadend = function () {
+            // reset loading flag
+            isLoading = false;
+            // call listeners
+            self.onloadend();
+        };
         db2v.onprogress = self.onprogress;
         // convert
         try {
             db2v.convert( buffer, index );
         } catch (error) {
+            // TODO: error will be for individual file, isLoading is global...
+            //isLoading = false;
             self.onerror(error);
         }
     };
 
+    /**
+     * Abort load.
+     */
+    this.abort = function () {
+        // abort conversion
+        db2v.abort();
+        // reset loading flag
+        isLoading = false;
+        // call listeners
+        self.onabort({message: "Abort while loading DICOM data."});
+    };
+
     /**
      * Get a file load handler.
      * @param {Object} file The file to load.
@@ -87,25 +123,6 @@ dwv.io.DicomDataLoader = function ()
         };
     };
 
-    /**
-     * Get an error handler.
-     * @param {String} origin The file.name/url at the origin of the error.
-     * @return {Function} An error handler.
-     */
-    this.getErrorHandler = function (origin) {
-        return function (event) {
-            var message = "";
-            if (typeof event.getMessage !== "undefined") {
-                message = event.getMessage();
-            } else if (typeof this.status !== "undefined") {
-                message = "http status: " + this.status;
-            }
-            self.onerror( {'name': "RequestError",
-                'message': "An error occurred while reading '" + origin +
-                "' (" + message + ") [DicomDataLoader]" } );
-        };
-    };
-
 }; // class DicomDataLoader
 
 /**
@@ -169,19 +186,26 @@ dwv.io.DicomDataLoader.prototype.onload = function (/*event*/) {};
  * Default does nothing.
  */
 dwv.io.DicomDataLoader.prototype.onloadend = function () {};
+/**
+ * Handle a progress event.
+ * @param {Object} event The progress event.
+ * Default does nothing.
+ */
+dwv.io.DicomDataLoader.prototype.onprogress = function (/*event*/) {};
 /**
  * Handle an error event.
- * @param {Object} event The error event, 'event.message'
- *  should be the error message.
+ * @param {Object} event The error event with an
+ *  optional 'event.message'.
  * Default does nothing.
  */
 dwv.io.DicomDataLoader.prototype.onerror = function (/*event*/) {};
 /**
- * Handle a progress event.
- * @param {Object} event The progress event.
+ * Handle an abort event.
+ * @param {Object} event The abort event with an
+ *  optional 'event.message'.
  * Default does nothing.
  */
-dwv.io.DicomDataLoader.prototype.onprogress = function (/*event*/) {};
+dwv.io.DicomDataLoader.prototype.onabort = function (/*event*/) {};
 
 /**
  * Add to Loader list.