We Keep Coding

Refresh the image without reloading the page

Each new image should be with different src. Untill reloading all images have single src. It is can be add location.reload(); until adding new image, then scr will change. But reloading very seen. Does it exist way to reload only scr?
var cvs;
var ctx;
cvs = document.getElementById("canvas");
ctx = cvs.getContext("2d");
var width_path_near = 80,
width_path_far = 30;
var tree1 = new Image();
var tree2 = new Image();
var tree3 = new Image();
var tree4 = new Image();
tree1.src = "https://png.pngtree.com/element_origin_min_pic/00/02/61/6156839a2a633b7.jpg";
tree2.src = "http://s02.yapfiles.ru/files/457732/derevo_1.png";
tree3.src = "http://www.grafamania.net/uploads/posts/2014-06/1401644723_1-9.jpg";
tree4.src = "http://img11.txapela.ru/e/c/c/4/f/52e052f118c7b8ff9317385f581.jpg";
var masTree=[tree1, tree2, tree3, tree4];
var randTree=Math.floor(Math.random()*masTree.length);
var tree_size = 100;
var grow = 0.2;
var gap = 100;
var forest = [];
forest[0] = {
x : cvs.width/2-width_path_near-tree_size/2,
y : cvs.height/2-tree_size+10,
size : tree_size
}
function draw() {
ctx.fillStyle = "rgb(84,209,216)";
ctx.fillRect(0, 0, 1000, 600);
for (var i=0; i<forest.length; i++){
ctx.drawImage(masTree[randTree], forest[i].x, forest[i].y, forest[i].size, forest[i].size);
if(forest[i].y == 3*cvs.height/4){
forest.push({
y : cvs.height/2-tree_size+10,
x : cvs.width/2-width_path_near-tree_size/2,
size : tree_size
});
}
forest[i].y += 0.5;
forest[i].x -= 0.4;
forest[i].size += 0.4;
}
requestAnimationFrame(draw);
}
masTree[randTree].onload = draw;
http://jsfiddle.net/Nata_Hamster/ugyb1fd0/

Images not loaded on first call in html canvas

I want to load the sorted array images in canvas in a same sequence, for that i created a load function and I am calling it from there.
Every thing works fine, but the problem is that it does not draw the images on canvas at first call.
Here is a fiddle
With my current code, it does not show you an image , but when you run it again, it will create and show the canvas image.
I am facing the same issue in my local host where i load the images with ajax.
var ImagesArray = new Array("http://s4.postimg.org/dw8aujkkd/slim_Fit.png",
"http://s27.postimg.org/l6mq3hboz/outer_collar1.png",
"http://s22.postimg.org/e7alkm44x/inner_collar11.png",
"http://s12.postimg.org/h4kgdjn4t/maincolar.png",
"http://s13.postimg.org/edabwknfr/outer_fastening1.png");
//alert(ImagesArray.length);
MainMethods(ImagesArray);
function MainMethods(responseImages) {
//alert(responseImages.length);
var canvas = document.getElementById("product-image");
canvas.height = ($(window).height()) - 120;
canvas.width = canvas.height * 0.75;
var heightscreen = ($(window).height()) - 120;
var canvasheight = heightscreen;
var canvaswidth = canvas.height * 0.75;
canvaswidthdiv4 = 0;
var widthNeeded = canvasheight * 0.75;
var context = canvas.getContext('2d');
var returnedImages = loadImages(responseImages);
for (i = 0; i < returnedImages.length; i++) {
console.log(returnedImages[i]);
context.drawImage(returnedImages[i], canvaswidthdiv4, 55, widthNeeded, canvasheight);
}
// Image loading global variables
var loadcount = 0;
var loadtotal = 0;
var preloaded = false;
// Load images
function loadImages(imagefiles) {
// Initialize variables
loadcount = 0;
loadtotal = imagefiles.length;
preloaded = false;
// Load the images
var loadedimages = [];
for (var i = 0; i < imagefiles.length; i++) {
// Create the image object
var image = new Image();
// Add onload event handler
image.onload = function() {
loadcount++;
if (loadcount == loadtotal) {
// Done loading
preloaded = true;
}
};
// Set the source url of the image
image.src = imagefiles[i];
// Save to the image array
loadedimages[i] = image;
}
// Return an array of images
return loadedimages;
}
}
<canvas id="product-image" width="700" height="823"></canvas>

The problem is that your images are not loaded yet when you try to draw it.
Wrap the drawImage part in a function and call it when preloaded becomes true, here your boolean does nothing.
I refactored your code a little bit, you also had an issue with loadtotal being reset to 0 after your call to loadImage() function. So loadcountwon't ever be === loadtotal and your useless preloaded never switched to true.
var ImagesArray = new Array ("http://s4.postimg.org/dw8aujkkd/slim_Fit.png",
"http://s27.postimg.org/l6mq3hboz/outer_collar1.png",
"http://s22.postimg.org/e7alkm44x/inner_collar11.png",
"http://s12.postimg.org/h4kgdjn4t/maincolar.png",
"http://s13.postimg.org/edabwknfr/outer_fastening1.png");
function MainMethods(responseImages) {
var canvas = document.getElementById("product-image");
canvas.height = ($(window).height()) - 120;
canvas.width = canvas.height * 0.75;
var canvasheight = ($(window).height()) - 120;
var canvaswidth = canvas.height * 0.75;
canvaswidthdiv4 = 0;
var widthNeeded = canvasheight * 0.75;
var context = canvas.getContext('2d');
// an other error, if you set loadtotal to 0 after calling loadImages(), it will be set to 0 when images are loaded.
// and loadcount won't ever be === loadtotal.
var loadcount;
var loadtotal;
function loadImages(imagefiles) {
loadcount = 0;
loadtotal = imagefiles.length;
var loadedimages = [];
for (var i=0; i<imagefiles.length; i++) {
var image = new Image();
image.onload = function () {
loadcount++;
console.log(loadcount+'/'+ loadtotal);
if (loadcount == loadtotal) {
// done loading all the images
draw(loadedimages);
}
};
image.src = imagefiles[i];
loadedimages[i] = image;
}
}
// Wrap your drawing in a function that will be called asynchronously
function draw(loadedimages){
for (var i = 0; i < loadedimages.length; i++) {
console.log(loadedimages[i]);
context.drawImage(loadedimages[i], canvaswidthdiv4, 55, widthNeeded, canvasheight);
}
}
// Once all your variables are set, you can load the images
loadImages(responseImages);
}
MainMethods(ImagesArray);
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<canvas id="product-image"></canvas>

Since it appears to be a browser specific issue, here's a hack to get it to work:
Replace : MainMethods(ImagesArray);
with : setTimeout(function () { MainMethods(ImagesArray); }, 0);
With timeout set to 0 ms, it would virtually execute instantaneously.
JsFiddle : http://jsfiddle.net/wdfrrayh/3/
Tested on IE, FF, Chrome

image src needs to be called after drawImage which i was doing before I have updated my function which is working fine,
below is working code for this
function loadImages(sources, callback, jsondata) {
var images = {};
var loadedImages = 0;
var numImages = 0;
// get num of sources
for(var src in sources) {
numImages++;
}
for(var src in sources) {
images[src] = new Image();
images[src].onload = function() {
if(++loadedImages >= numImages) {
callback(images);
}
};
images[src].src = sources[src];
}
}
var canvas = document.getElementById('product-image');
canvas.height = (jQuery(window).height()) -120;
canvas.width = canvas.height * 0.75;
var heightscreen = (jQuery(window).height()) -120;
var canvasheight = heightscreen;
var canvaswidth = canvas.height * 0.75;
canvaswidthdiv4 = 0;
var widthNeeded = canvasheight * 0.75;
var context = canvas.getContext('2d');
var sources = new Array ("http://s4.postimg.org/dw8aujkkd/slim_Fit.png",
"http://s27.postimg.org/l6mq3hboz/outer_collar1.png",
"http://s22.postimg.org/e7alkm44x/inner_collar11.png",
"http://s12.postimg.org/h4kgdjn4t/maincolar.png",
"http://s13.postimg.org/edabwknfr/outer_fastening1.png");
loadImages(sources, function(images) {
for(var i=0; i < sources.length; i++){
context.drawImage(images[i], canvaswidthdiv4, 55,widthNeeded,canvasheight);
}
});

Dynamically add multiple images from input

I have the following code:
var imageLoader = document.getElementById('imageLoader');
var patternLoader = document.getElementById("patternLoader");
var canvas = document.getElementById('imageCanvas');
var ctx = canvas.getContext('2d');
function handleImage(e) {
var reader = new FileReader();
reader.onload = function (event) {
var img = new Image();
img.onload = function () {
canvas.width = img.width;
canvas.height = img.height;
ctx.drawImage(img, 0, 0);
}
img.src = event.target.result;
}
reader.readAsDataURL(e.target.files[0]);
};
imageLoader.addEventListener("change", handleImage, false);
patternLoader.addEventListener("change", handleImage, false);
How can I load one image over another from inputs and not replace them?
I want it to be like that http://i.gyazo.com/85c8c6bdcd2efcdd6a1c1b156000f204.png

Here's a crude way to add images dynamically. Declare an array to keep track on all your images and scale the canvas based on the largest image.
Since I didn't konw what kind of DOM elements the OP used for "imageLoader" and "patternLoader", I simply used an <input>-tag.
Just keep pasting URLs for images to add images to your canvas. The images will be drawn in the order as you add them.
var c = document.getElementById("canvas");
var ctx = c.getContext("2d");
var maxWidth = 0;
var maxHeight = 0;
var images = [];
var myInput = document.getElementById("myInput");
myInput.addEventListener('change',handleImage,false);
function handleImage(e) {
var myImage = new Image();
myImage.onload = function () {
if (myImage.width > maxWidth) {
maxWidth = myImage.width;
}
if (myImage.height > maxHeight) {
maxHeight = myImage.height;
}
canvas.width = maxWidth;
canvas.height = maxHeight;
images.push(myImage);
drawImages();
}
myImage.src = e.target.value;
}
function drawImages() {
for (var i = 0; i<images.length; i++) {
ctx.drawImage(images[i],canvas.width/2-images[i].width/2,canvas.height/2-images[i].height/2);
}
}
<input type="text" id="myInput"><br />
<canvas id="canvas"></canvas>

Converting images to base64 within a loop before adding to jspdf - javascript

I have researched issues with the base64 conversion and jspdf function quite a bit. ( PS this is my first question on stackoverflow, please bare with any rookie mistakes ).
All seems to work fine with the below code except that the pdf is generated and saved before the loop where the images are converted to base64 and placed to the document is finished. I added a couple alerts to check timing. Would the solution be to check when the loop is finished, the images placed before continuing with the pdf function? if so, how? please help.
$(document).ready(function(){
$("a#getdoc").click(function(){
var doc = new jsPDF('landscape, in, legal');
var myimages = 'img1.jpg|img2.jpg|img3.png';
var myimgarray = myimages.split('|');
function convertImgToBase64(url, callback, outputFormat){
var canvas = document.createElement("canvas");
canvas.width = img.width;
canvas.height = img.height;
var ctx = canvas.getContext("2d");
ctx.drawImage(img, 0, 0);
return canvas.toDataURL("image/jpeg");
var dataURL = canvas.toDataURL("image/jpeg");
callback(dataURL);
canvas = null;
}
for(var i = 0; i < myimgarray.length; i++)
{
icount.count = i;
var img = new Image();
alert(checkoutimgarray);
img.src = '/Portals/0/repair-images/' + myimgarray[i];
img.onload = function(){
newData = convertImgToBase64(img);
alert(newData);
doc.addImage(newData, 'JPEG', (icount * 100), 10, 70, 15); // would doc be undefined here? out of scope?
};
}
doc.setFontSize(20);
doc.text(100, 20, "This is a test to see if images will show");
doc.save('My_file.pdf');
});
});

var canvas = document.createElement("canvas");
var ctx = canvas.getContext("2d");
function convertImgToBase64(img, outputFormat){
// clear canvas
canvas.width = img.width;
canvas.height = img.height;
// draw image
ctx.drawImage(img, 0, 0);
// get data url of output format or defaults to jpeg if not set
return canvas.toDataURL("image/" + (outputFormat || "jpeg"));
}
var images = [];
for(var i = 0; i < myimgarray.length; i++) {
var img = new Image();
img.onload = function() {
images.push({
base64: convertImgToBase64(this),
width: this.width,
height: this.height
});
// all images loaded
if(images.length === myimgarray.length) {
for(var j = 0; j < images.length; j++) {
doc.addImage(images[j].base64, 'JPEG', (j * 100), 10, 70, 15);
}
doc.setFontSize(20);
doc.text(100, 20, "This is a test to see if images will show");
doc.save('My_file.pdf');
}
};
img.src = '/Portals/0/repair-images/' + myimgarray[i];
}

fill image with other image javascript/html5

I need help with the following resource http://www.filmfans.cz/test/index2.html
I don't know how to change the colours of the pinquen after the click on the sample.
I would like to do something similar as in the following link http://www.pixelbox.sk/fileadmin/Flash/cosmo_2.swf
Here is my code
$(window).load(function(){
var width = $(window).width();
var height = $(window).height();
var c = document.getElementById("a");
var ctx = c.getContext("2d");
var can2 = document.createElement('canvas');
document.body.appendChild(can2)
can2.width = c.width;
can2.height= c.height;
var ctx2 = can2.getContext("2d");
var test= new Image();
test.src = "tux.png";
test.onload = function() {
ctx2.drawImage(test, 0, 0);
}
var img = new Image();
img.src = "2.png";
img.onload = function(){
ctx2.globalCompositeOperation = "source-in";
var pattern = ctx2.createPattern(img, "repeat");
ctx2.fillStyle=pattern;
ctx2.fillRect(0,0,300,300);
}
});
$(document).ready(function () {
$('.klik').click(function() {
var adresa = $(this).children('img').attr('src');
var canvas = document.getElementById("a");
canvas.width = canvas.width;//blanks the canvas
var c = canvas.getContext("2d");
var img = new Image();
img.src = adresa;
img.onload = function(){
var pattern = c.createPattern(img, "repeat");
//c.globalCompositeOperation = "source-in";
c.fillStyle=pattern;
c.fillRect(0,0,300,300);
}
// c.drawImage(img, 0, 0);
//}
//return false;
});
});
</code>
</pre>
Problem solved !

Using a second, temporary canvas with source-in is the right idea:
ctx2.drawImage(test, 0, 0);
ctx2.globalCompositeOperation = 'source-in';
var ptrn = ctx2.createPattern(pattern,'repeat');
ctx2.fillStyle = ptrn;
ctx2.fillRect(0,0,300,300);
ctx.drawImage(can2,0,0)
live example:
http://jsfiddle.net/UcGrC/