*/
Guacamole.Layer = function(width, height) {
- // Reference to this Layer
+ /**
+ * Reference to this Layer.
+ * @private
+ */
var layer = this;
- // Off-screen buffer (canvas element) and corresponding
- // context.
+ /**
+ * The canvas element backing this Layer.
+ * @private
+ */
var display = document.createElement("canvas");
+
+ /**
+ * The 2D display context of the canvas element backing this Layer.
+ * @private
+ */
var displayContext = display.getContext("2d");
+ var tasks = new Array();
+
+ var compositeOperation = {
+ /* 0x0 NOT IMPLEMENTED */
+ 0x1: "destination-in",
+ 0x2: "destination-out",
+ /* 0x3 NOT IMPLEMENTED */
+ 0x4: "source-in",
+ /* 0x5 NOT IMPLEMENTED */
+ 0x6: "source-atop",
+ /* 0x7 NOT IMPLEMENTED */
+ 0x8: "source-out",
+ 0x9: "destination-atop",
+ 0xA: "xor",
+ 0xB: "destination-over",
+ 0xC: "copy",
+ /* 0xD NOT IMPLEMENTED */
+ 0xE: "source-over",
+ 0xF: "lighter"
+ };
+
/**
* Returns the canvas element backing this Layer.
* @returns {Element} The canvas element backing this Layer.
}
- // Initialize canvas dimensions
- resize(width, height);
-
/**
* Set to true if this Layer should resize itself to accomodate the
* dimensions of any drawing operation, and false (the default) otherwise.
*/
this.autosize = false;
- var updates = new Array();
-
- function Update(updateHandler) {
-
- this.setHandler = function(handler) {
- updateHandler = handler;
- };
-
- this.hasHandler = function() {
- return updateHandler != null;
- };
-
- this.handle = function() {
- updateHandler();
- };
-
+ /**
+ * A container for an task handler. Each operation which must be ordered
+ * is associated with a Task that goes into a task queue. Tasks in this
+ * queue are executed in order once their handlers are set, while Tasks
+ * without handlers block themselves and any following Tasks from running.
+ *
+ * @constructor
+ * @private
+ * @param {function} taskHandler The function to call when this task
+ * runs, if any.
+ */
+ function Task(taskHandler) {
+
+ /**
+ * The handler this Task is associated with, if any.
+ *
+ * @type function
+ */
+ this.handler = taskHandler;
+
}
- function reserveJob(handler) {
+ function scheduleTask(handler) {
- // If no pending updates, just call (if available) and exit
+ // If no pending tasks, just call (if available) and exit
if (layer.isReady() && handler != null) {
handler();
return null;
}
- // If updates are pending/executing, schedule a pending update
+ // If tasks are pending/executing, schedule a pending task
// and return a reference to it.
- var update = new Update(handler);
- updates.push(update);
- return update;
+ var task = new Task(handler);
+ tasks.push(task);
+ return task;
}
- function handlePendingUpdates() {
+ function handlePendingTasks() {
- // Draw all pending updates.
- var update;
- while ((update = updates[0]) != null && update.hasHandler()) {
- update.handle();
- updates.shift();
+ // Draw all pending tasks.
+ var task;
+ while ((task = tasks[0]) != null && task.handler) {
+ task.handler();
+ tasks.shift();
}
}
* @returns {Boolean} true if this Layer is ready, false otherwise.
*/
this.isReady = function() {
- return updates.length == 0;
+ return tasks.length == 0;
};
/**
* object - not a URL.
*/
this.drawImage = function(x, y, image) {
- reserveJob(function() {
+ scheduleTask(function() {
if (autosize != 0) fitRect(x, y, image.width, image.height);
displayContext.drawImage(image, x, y);
});
* @param {String} url The URL of the image to draw.
*/
this.draw = function(x, y, url) {
- var update = reserveJob(null);
+ var task = scheduleTask(null);
var image = new Image();
image.onload = function() {
- update.setHandler(function() {
+ task.handler = function() {
if (autosize != 0) fitRect(x, y, image.width, image.height);
displayContext.drawImage(image, x, y);
- });
+ };
- // As this update originally had no handler and may have blocked
- // other updates, handle any blocked updates.
- handlePendingUpdates();
+ // As this task originally had no handler and may have blocked
+ // other tasks, handle any blocked tasks.
+ handlePendingTasks();
};
image.src = url;
* pending operations are complete.
*/
this.sync = function(handler) {
- reserveJob(handler);
+ scheduleTask(handler);
};
/**
// If we ARE the source layer, no need to sync.
// Syncing would result in deadlock.
if (layer === srcLayer)
- reserveJob(doCopyRect);
+ scheduleTask(doCopyRect);
// Otherwise synchronize copy operation with source layer
else {
- var update = reserveJob(null);
+ var task = scheduleTask(null);
srcLayer.sync(function() {
- update.setHandler(doCopyRect);
+ task.handler = doCopyRect;
- // As this update originally had no handler and may have blocked
- // other updates, handle any blocked updates.
- handlePendingUpdates();
+ // As this task originally had no handler and may have blocked
+ // other tasks, handle any blocked tasks.
+ handlePendingTasks();
});
}
};
this.clearRect = function(x, y, w, h) {
- reserveJob(function() {
+ scheduleTask(function() {
if (autosize != 0) fitRect(x, y, w, h);
displayContext.clearRect(x, y, w, h);
});
};
this.filter = function(filter) {
- reserveJob(function() {
+ scheduleTask(function() {
var imageData = displayContext.getImageData(0, 0, width, height);
filter(imageData.data, width, height);
displayContext.putImageData(imageData, 0, 0);
});
};
- var compositeOperation = {
- /* 0x0 NOT IMPLEMENTED */
- 0x1: "destination-in",
- 0x2: "destination-out",
- /* 0x3 NOT IMPLEMENTED */
- 0x4: "source-in",
- /* 0x5 NOT IMPLEMENTED */
- 0x6: "source-atop",
- /* 0x7 NOT IMPLEMENTED */
- 0x8: "source-out",
- 0x9: "destination-atop",
- 0xA: "xor",
- 0xB: "destination-over",
- 0xC: "copy",
- /* 0xD NOT IMPLEMENTED */
- 0xE: "source-over",
- 0xF: "lighter"
- };
-
this.setChannelMask = function(mask) {
- reserveJob(function() {
+ scheduleTask(function() {
displayContext.globalCompositeOperation = compositeOperation[mask];
});
};
+ // Initialize canvas dimensions
+ resize(width, height);
+
}
projects / guacamole-common-js.git / commitdiff