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guacamole-client/guacamole/web-client/web/javascript/layer.js

129 lines
3.3 KiB
JavaScript

/*
* Guacamole - Clientless Remote Desktop
* Copyright (C) 2010 Michael Jumper
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU Affero General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Affero General Public License for more details.
*
* You should have received a copy of the GNU Affero General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
function Layer(width, height) {
// Off-screen buffer
var display = document.createElement("canvas");
display.style.position = "absolute";
display.style.left = "0px";
display.style.right = "0px";
display.width = width;
display.height = height;
var displayContext = display.getContext("2d");
var nextUpdateToDraw = 0;
var currentUpdate = 0;
var updates = new Array();
// Given an update ID, either call the provided update callback, or
// schedule the update for later.
function setUpdate(updateId, update) {
// If this update is the next to draw...
if (updateId == nextUpdateToDraw) {
// Call provided update handler.
update();
// Draw all pending updates.
var updateCallback;
while (updateCallback = updates[++nextUpdateToDraw]) {
updateCallback();
delete updates[nextUpdateToDraw];
}
}
// If not next to draw, set callback and wait.
else
updates[updateId] = update;
}
display.drawImage = function(x, y, image) {
var updateId = currentUpdate++;
setUpdate(updateId, function() {
displayContext.drawImage(image, x, y);
});
}
display.draw = function(x, y, url) {
var updateId = currentUpdate++;
var image = new Image();
image.onload = function() {
setUpdate(updateId, function() {
displayContext.drawImage(image, x, y);
});
};
image.src = url;
};
display.copyRect = function(srcx, srcy, w, h, x, y) {
var updateId = currentUpdate++;
setUpdate(updateId, function() {
displayContext.drawImage(display, srcx, srcy, w, h, x, y, w, h);
});
};
display.drawRect = function(x, y, w, h, color) {
var updateId = currentUpdate++;
setUpdate(updateId, function() {
displayContext.fillStyle = color;
displayContext.fillRect(x, y, w, h);
});
};
display.clearRect = function(x, y, w, h) {
var updateId = currentUpdate++;
setUpdate(updateId, function() {
displayContext.clearRect(x, y, w, h);
});
};
display.filter = function(filter) {
var updateId = currentUpdate++;
setUpdate(updateId, function() {
var imageData = displayContext.getImageData(0, 0, width, height);
filter(imageData.data, width, height);
displayContext.putImageData(imageData, 0, 0);
});
};
return display;
}