I'm using the javascript from this older script: JavaScript: how to load all images in a folder?
However, I want to use the same javascript file to write some html code before the loop and some after the loop, all using this same javascript file.
Just putting a document.write before and after it in the javascript doesn't work.
var bCheckEnabled = true;
var bFinishCheck = false;
var img;
var imgArray = new Array();
var i = 0;
var myInterval = setInterval(loadImage, 1);
function loadImage() {
if (bFinishCheck) {
clearInterval(myInterval);
document.write('Loaded ' + i + ' image(s)');
return;
}
if (bCheckEnabled) {
bCheckEnabled = false;
img = new Image();
img.onload = fExists;
img.onerror = fDoesntExist;
img.src = 'assets/' + i + '.png';
document.write('<img src="assets/' + i + '.png" width="1016" height="813" alt="Kar" />');
}
}
function fExists() {
imgArray.push(img);
i++;
bCheckEnabled = true;
}
function fDoesntExist() {
bFinishCheck = true;
}
You may be using this example code incorrectly. Its intent appears to be to pre-load the image files in the background, not display them to the user in the HTML (yet). This is to improve apparent download speed of your page.
In short, this code doesn't actually render the image into the DOM; and that is intentional behavior.
Related
I have several canvases. I also have several picture URLs. I want to draw all pictures on the canvas. There is a problem in the drawing function. Drawing the image only works when the image loads completely, but I have to draw the image as it loads. I wrote following code:
for (var i = 2; i < length; i++) {
canvid[i] = "canv" + i;
img[i] = new Image();
img[i].src = "..\\images\\UploadImage\\"+ name + i + ".jpg";
img[i].onload = function () {
var c = document.getElementById(canvId[i]);
var cDraw = c.getContext("2d");
cDraw.drawImage(img[i], 0, 0);
};
I know this code has error, it's kind of pseudo code to show what I want.
Put your logic in
$(documet).ready(function(){
//logic
});
the answer is in following link
stack overflow link
when you want to call on click event on image variable you have to wait for it
so you couldn't use loop you have to put next call on previous image on load event .
var loadImages = function (imageURLarray) {
if (!(startPage < pages))
return;
canvid = "canv" + i;
img.src = imageURLarray[startPage];
// your top code
img.onload = function (e) {
// code, run after image load
var c = document.getElementById(canvid);
var cDraw = c.getContext("2d");
cDraw.drawImage(img, 0, 0);
startPage++;
loadImages(imageURLarray);
}
}
loadImages(imageURLarray);
I have 2 pictures for my website, and i want it to load one of them whem the website loads.
I have tried using some javascript. But i am quite new to all this.
This is how i am think i want to make it.
<div class="image">
Show one of 2 images here.
</div>
<script>
var r = Math.floor(Math.random() * 100) + 1;
if(r < 51) {
SHOW IMAGE 1
}
else {
SHOWIMAGE 2
}
</sccript>
So i was hoping someone could teach me how to actually turn this into functional code.
Thanks.
You can set the src attribute of an image directly using javascript, then use Math.random like you expected to pick between different image urls.
With an image tag with id 'random_image':
// images from wikipedia featured images/articles 2015-03-03
var img = document.getElementById('random_image');
if (Math.random() > .5) {
img.src = 'http://upload.wikimedia.org/wikipedia/en/thumb/4/45/Bradford1911.jpg/266px-Bradford1911.jpg';
} else {
img.src = 'http://upload.wikimedia.org/wikipedia/commons/thumb/a/ae/Pitta_sordida_-_Sri_Phang_Nga.jpg/720px-Pitta_sordida_-_Sri_Phang_Nga.jpg';
}
Here is a jsfiddle example: http://jsfiddle.net/8zd5509u/
1.way:
var _img = document.getElementById('id1');
var newImg = new Image;
newImg.onload = function() {
_img.src = this.src;
}
newImg.src = 'http://www.something.blabla.....';
another:
function preload(images) {
if (document.images) {
var i = 0;
var imageArray = new Array();
imageArray = images.split(',');
var imageObj = new Image();
for(i=0; i<=imageArray.length-1; i++) {
//document.write('<img src="' + imageArray[i] + '" />');// Write to page (uncomment to check images)
imageObj.src=imageArray[i];
}
}
}
Then in the of each web page, add the following code after you've called the main JavaScript file:
<script type="text/javascript">
preload('image1.jpg,image2.jpg,image3.jpg');
</script>
I have a list of images that is rendered as thumbnails after upload. The issue that I have is I need the dimensions of the fully uploaded images, so that I can run a resize function if sized incorrectly.
Function that builds the image list
function buildEditList(json, galleryID)
{
//Hide the list
$sortable = $('#sortable');
$sortable.hide();
for(i = 0, j = json.revision_images.length; i < j; i++) {
$sortable.append(
"<li id='image_" + json.revision_images[i].id + "'><a class=\"ui-lightbox\" href=\"../data/gallery/"
+ galleryID
+ "/images/album/"
+ json.revision_images[i].OrgImageName
+ "\"><img id=\""
+ json.revision_images[i].id
+ "\" alt=\"\" src=\"../data/gallery/"
+ galleryID
+ "/images/album/"
+ json.revision_images[i].OrgImageName
+ "\"/></a></li>"
).hide();
}
//Set first and last li to 50% so that it fits the format
$('#sortable li img').first().css('width','50%');
$('#sortable li img').last().css('width', '50%');
//Fade images back in
$sortable.fadeIn("fast",function(){
var img = $("#703504"); // Get my img elem -- hard coded at the moment
var pic_real_width, pic_real_height;
$("<img/>") // Make in memory copy of image to avoid css issues
.attr("src", $(img).attr("src"))
.load(function() {
pic_real_width = this.width; // Note: $(this).width() will not
pic_real_height = this.height; // work for in memory images.
});
alert(pic_real_height);
});
}
I have been trying to use the solution from this stackoverflow post, but have yet to get it to work, or it may just be my code. if you have any ideas on this I could use the help. Currently the alert is coming back undefined.
There's a newer js method called naturalHeight or naturalWidth that will return the information you're looking for. Unfortunately it wont work in older IE versions. Here's a function I created a few months back that may work for you. I added a bit of your code below it for an example:
function getNatural($mainImage) {
var mainImage = $mainImage[0],
d = {};
if (mainImage.naturalWidth === undefined) {
var i = new Image();
i.src = mainImage.src;
d.oWidth = i.width;
d.oHeight = i.height;
} else {
d.oWidth = mainImage.naturalWidth;
d.oHeight = mainImage.naturalHeight;
}
return d;
}
var img = $("#703504");
var naturalDimension = getNatural(img);
alert(naturalDimension.oWidth, naturalDimension.oHeight)
I'm building a navigation bar where the images should be swapped out on mouseover; normally I use CSS for this but this time I'm trying to figure out javascript. This is what I have right now:
HTML:
<li class="bio"><img src="images/nav/bio.jpg" name="bio" /></li>
Javascript:
if (document.images) {
var bio_up = new Image();
bio_up.src = "images/nav/bio.jpg";
var bio_over = new Image();
bio_over.src = "images/nav/bio-ov.jpg";
}
function over_bio() {
if (document.images) {
document["bio"].src = bio_over.src
}
}
function up_bio() {
if (document.images) {
document["bio"].src = bio_up.src
}
}
However, all of the images have names of the form "xyz.jpg" and "xyz-ov.jpg", so I would prefer to just have a generic function that works for every image in the navbar, rather than a separate function for each image.
A quick-fire solution which should be robust enough provided all your images are of the same type:
$("li.bio a").hover(function() {
var $img = $(this).find("img");
$img[0].src = $img[0].src.replace(".jpg", "") + "-ov.jpg";
}, function() {
var $img = $(this).find("img");
$img[0].src = $img[0].src.replace("-ov.jpg", "") + ".jpg";
});
This should work will all image formats as long as the extension is between 2 and 4 characters long IE. png, jpeg, jpg, gif etc.
var images = document.getElementById('navbar').getElementsByTagName('img'), i;
for(i = 0; i < images.length; i++){
images[i].onmouseover = function(){
this.src = this.src.replace(/^(.*)(\.\w{2,4})$/, '$1'+'-ov'+'$2');
}
images[i].onmouseout = function(){
this.src = this.src.replace(/^(.*)-ov(\.\w{2,4})$/, '$1'+'$2');
}
}
Here's an idea in plain javascript (no jQuery):
function onMouseOverSwap(e) {
e.src = e.src.replace(/\.jpg$/", "-ov.jpg"); // add -ov onto end
}
function onMouseOutSwap(e) {
e.src = e.src.replace(/(-ov)+\.jpg$/, ".jpg"); // remove -ov
}
How do you implement a preloader for a processingjs canvas element?
Two cases - assets have loaded, but js still calculating/rendering the view; assets have not loaded
P.S. Someone create the processingjs tag! Users with rep lt 1500 can't do that yet :(
May be this very old snippet helps you, after loading all images a callback is called. The folder param was used to load low or highres pics.
pics = {
'Trans100' : "trans100.png",
'Trans101' : "trans101.png",
'TransPanel' : "transPanel.png"
}
function oAttrs(o) { var a, out = ""; for (a in o){ out += a + " ";} return trim(out);}
function imageLoader(pics, folder, onready){
this.nextPic = 0;
this.pics = pics;
this.folder = folder;
this.names = oAttrs(pics).split(" ");
this.onReady = onready;
this.loadNext();
}
imageLoader.prototype.loadNext = function (){
if (this.nextPic === this.names.length) {
this.onReady();
} else {
this.loadImage(this.pics[this.names[this.nextPic]]);
}
};
imageLoader.prototype.loadImage = function (file){
this.nextPic += 1;
var pic = new Image();
pic.onload = this.loadNext.bind(this);
pic.onerror = function(){console.error("ERROR: " + file);};
pic.src = this.folder + file;
};
// example:
new imageLoader(pics, "images", function(){
console.log("Images loaded");
})