tupali/tupale/scripts/wm.js
2017-10-25 22:36:21 -05:00

160 lines
4.2 KiB
JavaScript

/*
* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
* watermark.js - Create watermarked images with Canvas and JS
*
* Version: 1 (2011-04-04)
* Copyright (c) 2011 Patrick Wied ( http://www.patrick-wied.at )
* This code is licensed under the terms of the MIT LICENSE
*
* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
*/
(function(w){
var wm = (function(w){
var doc = w.document,
gcanvas = {},
gctx = {},
imgQueue = [],
className = "watermark",
watermark = false,
watermarkPosition = "bottom-right",
watermarkPath = "watermark.png?"+(+(new Date())),
opacity = (255/(100/50)), // 50%
initCanvas = function(){
gcanvas = doc.createElement("canvas");
gcanvas.style.cssText = "display:none;";
gctx = gcanvas.getContext("2d");
doc.body.appendChild(gcanvas);
},
initWatermark = function(){
watermark = new Image();
watermark.src = "";
watermark.src = watermarkPath;
if(opacity != 255){
if(!watermark.complete)
watermark.onload = function(){
applyTransparency();
}
else
applyTransparency();
}else{
applyWatermarks();
}
},
// function for applying transparency to the watermark
applyTransparency = function(){
var w = watermark.width || watermark.offsetWidth,
h = watermark.height || watermark.offsetHeight;
setCanvasSize(w, h);
gctx.drawImage(watermark, 0, 0);
var image = gctx.getImageData(0, 0, w, h);
var imageData = image.data,
length = imageData.length;
for(var i=3; i < length; i+=4){
imageData[i] = (imageData[i]<opacity)?imageData[i]:opacity;
}
image.data = imageData;
gctx.putImageData(image, 0, 0);
watermark.onload = null;
watermark.src = "";
watermark.src = gcanvas.toDataURL();
// assign img attributes to the transparent watermark
// because browsers recalculation doesn't work as fast as needed
watermark.width = w;
watermark.height = h;
applyWatermarks();
},
configure = function(config){
if(config["watermark"])
watermark = config["watermark"];
if(config["path"])
watermarkPath = config["path"];
if(config["position"])
watermarkPosition = config["position"];
if(config["opacity"])
opacity = (255/(100/config["opacity"]));
if(config["className"])
className = config["className"];
initCanvas();
initWatermark();
}
setCanvasSize = function(w, h){
gcanvas.width = w;
gcanvas.height = h;
},
applyWatermark = function(img){
/*
var f = image.height / image.width;
var newHeight = canvas.width * f;
*/
var proporcion = ( img.height / img.width );
var ancho = 600;
//var alto_orginal = img.height;
//var alto = (alto_original * proporcion);
//alert("hola pro"+alto);
gcanvas.width = ancho;// || img.offsetWidth;
//gcanvas.width = img.width || img.offsetWidth;
//gcanvas.height = img.height || img.offsetHeight;
gcanvas.height = (gcanvas.width * proporcion);// || img.offsetHeight;
gctx.drawImage(img, 0, 0,ancho,gcanvas.height);
var position = watermarkPosition,
x = 0,
y = 0;
if(position.indexOf("top")!=-1)
y = 20;
else if(position.indexOf("middle")!=-1)
y = (gcanvas.height -watermark.height)/2;
else
y = gcanvas.height-watermark.height-20;
if(position.indexOf("left")!=-1)
x = 20;
else if(position.indexOf("center")!=-1)
x = (gcanvas.width - watermark.width) /2;
else
x = gcanvas.width-watermark.width-20;
gctx.drawImage(watermark, x, y);
img.onload = null;
img.src = gcanvas.toDataURL();
},
applyWatermarks = function(){
setTimeout(function(){
var els = doc.getElementsByClassName(className),
len = els.length;
while(len--){
var img = els[len];
if(img.tagName.toUpperCase() != "IMG")
continue;
if(!img.complete){
img.onload = function(){
applyWatermark(this);
};
}else{
applyWatermark(img);
}
}
},10);
};
return {
init: function(config){
configure(config);
}
};
})(w);
w.wmark = wm;
})(window);