In a javascript script I need to superimpose two png images into one and then save the new image as a single file. My script does not work inside a webpage but completely batch.
The function that I imagined was something like this:
newPng = mergePng(png1, png2);
I have long searched for a javascript library that would allow me to get the result I wanted, but I did not find it. I've also tried among the previous questions here on Stackoverflow, but I have not found any solutions.
Does anyone know if the function I'm looking for exists?
Thank you.
You can draw png files inside a canvas like this:
drawing = new Image();
drawing2 = new Image();
drawing2.src = "draw2.png";
drawing.src = "draw.png";
drawing.onload = function() {
context.drawImage(drawing,0,0);
context.drawImage(drawing2,0,0);
};
Related
ive ventured into the world of PIXI and JS, new programming language for me, liking the way it is right now but i have an issue.
I am a bit confused with the TextureCache and the loader. If you look at part of my code i try to add 3 different images to the screen. Ive been following the 'Get Started section' of the pixi website. I wanted to add their cat image, which i have, the tileset image (all of it)* and then a tile of the tileset image.
The issue is, i create 3 new sprite instances and the tileset image shows the area ive set for the tile(rocket) when i want it to show the whole tileset. Ive loaded in the tileset iin the cahce and the loader.
Why does tile show the cropped image and not the whole image?
Am i using the cache correctly to just store images?
Am i using the resources method properly to locate the image FROM the cache or the loader?
Is there any point of the cache?
my thoughts**
when you use the rectangle method, it destroys the original image and the cropped version is now tileset1 (the name of my image)?
<html>
<body>
<script src="pixi.js"></script>
<script>
//Aliases
let Application = PIXI.Application,
loader = PIXI.loader,
resources = PIXI.loader.resources,
Sprite = PIXI.Sprite,
Rectangle = PIXI.Rectangle,
TextureCache = PIXI.utils.TextureCache;
let app = new PIXI.Application({
width: 1000,
height: 600,
antialias: true,
transparent: false,
resolution: 1
}
);
//Add the canvas that Pixi automatically created for you to the HTML document
document.body.appendChild(app.view);
TextureCache["tileset1.png","images/3.png"];
//load an image and run the `setup` function when it's done
loader.add(["images/3.png","tileset1.png"]).load(setup);
//This `setup` function will run when the image has loaded
function setup() {
let texture = TextureCache["tileset1.png"];
let rectangle = new Rectangle(96,64,32,32);
texture.frame = rectangle;
//Create the cat sprite, use a texture from the loader
let card = new Sprite(resources["images/3.png"].texture);
let tile = new Sprite(resources["tileset1.png"].texture);
let rocket = new Sprite(texture);
card.scale.set(0.06,0.06);
tile.x=400;
tile.y=400;
rocket.x=100;
rocket.y=100;
//Add the cat to the stage
app.stage.addChild(card);
app.stage.addChild(tile);
app.stage.addChild(rocket);
app.renderer.render(app.stage);
}
</script>
</body>
</html>
<script src="https://cdnjs.cloudflare.com/ajax/libs/pixi.js/5.2.4/pixi.js"></script>
Is there any point of the cache? - this question seems to be most important from your questions :)
Searching around about "pixi.js" and "TextureCache" gives following answers for example:
https://github.com/pixijs/pixi.js/issues/4053
MySecret commented on May 23, 2017:
the docs has no specs about PIXI.utils.TextureCache
...
englercj commented on May 26, 2017
This is intentional, it is not meant as a public-facing API. It is an internal cache used by some texture creation methods.
https://www.html5gamedevs.com/topic/17788-loader-and-texturecache-tutorial-anywhere/
xerver - Pixi.js Moderator:
Here is the loader: https://github.com/englercj/resource-loader
The code is really well documented, and there are examples on the readme. The pixi examples also use the loader a few times: http://pixijs.github.io/examples/
The TextureCache is an internal mechanism, there is rarely any reason you should even know it exists.
https://www.html5gamedevs.com/topic/25575-pixiloaderresources-or-texturecache/
xerver - Pixi.js Moderator:
Dont do this:
let e = PIXI.utils.TextureCache[player.img];
Instead use the resources the loader loaded for you:
let e = PIXI.loader.resources[player.img].texture;
...
TLDR: Usually TextureCache shouldnt be used directly :)
See also:
this explanation: https://www.html5gamedevs.com/topic/9255-pixijs-caching/?tab=comments#comment-55233
http://pixijs.download/release/docs/PIXI.BaseTexture.html#.addToCache
^ example of usage: https://jsfiddle.net/themoonrat/br35x20j/
i am making a game based on draw images and clear it every some part of second.
i started with:
var peng = new Image();
and then:
peng.onload = function() {
context.drawImage(peng, pengXPosition, pengYPosition, pengWidth, pengHight);
};
and in the loop:
var i=0;
function pengMoveRight(){ i++;if(i==1){peng.src = 'images/1.png';}else if(i==2)
{peng.src = 'images/2.png';} else if(i==3){peng.src = 'images/3.png';}else if(i==4){
peng.src = 'images/4.png';}else if(i==5){peng.src = 'images/5.png';}else if(i==6){
peng.src = 'images/6.png';i-=6;}}
when i run it it works well on IE but on chrome and mozilla it`s too slow and the character is about to disappear .. i used setinterval(); once and window.requestAnimationFrame(); once and both of them cause the same problem.
what should i do to make it smooth move?
here is the full script http://mark-tec.com/custom%20game/
Instead of changing the source, try to create several Image objects instead. That way, the drawImage call can always use a pre-loaded image.
You need to preload all the images or use the sprite method (all images packed into a single sprite) in order to avoid the initial delay caused by the image loading only when it's needed.
However, after that initial problem, your example should run fine once all the images are cached.
Sorry, maybe not correct title..
I have the next question: I want to make preloading with progress bar. And I stuck on one problem.
[CODE 1]:
//Preloader code
var img = [];
img[0] = new Image();
img[0].src = 'test0.jpg';
img[0].onload = function(){
//some code
}
//.....
img[100] = new Image();
img[100].src = 'test100.jpg';
img[100].onload = function(){
//some code
}
//.....
// all images loaded
//.....
/*
for expample in this part of code I need put my image 'test0.jpg' into html
*/
var temp_img = new Image();
temp_img.src = 'test0.jpg';
The question is : will it download 'test0.jpg' again or just take it from cache?
or better to do like this [CODE 2]:
//Preloader code
var img = [];
img['test0'] = new Image();
img['test0'].src = 'test0.jpg';
img['test0'].onload = function(){
//some code
}
//.....
img['test100'] = new Image();
img['test100'].src = 'test100.jpg';
img['test100'].onload = function(){
//some code
}
//.....
// all images loaded
//.....
/*
for expample in this part of code I need put my image 'test0.jpg' into html
*/
var temp_img = img['test0'];
// draw temp_img
I want to use CODE 1. But will it slow down my app? Or better to use CODE 2? Thanks in advance.
Both methods have benefits and drawbacks.
The first method is much lighter on image elements and as a general rule, the fewer DOM elements you generate, the better. There is a chance, though, that the browser will not serve the image from the cache depending on how much information is being loaded. Worst case, you will need to fetch from the network again if the browser has removed the image from the cache.
The second method is much safer and will keep the image held in memory, meaning even if the browser doesn't cache it, it's still available. It's heavier on image elements, though.
Which solution is better depends on your situation. If you're not loading a large amount of images, I'd say solution 1 is the better choice as it leverages the browser's cache. If you really can't afford to reload images off the network, though, solution 2 is safer.
TL;DR
Solution 1 shouldn't slow down your application, but solution 2 will ensure you don't fetch from the network again.
With code 1, your preloader would be useless right? I'd go with 2
Im playing around with a particle emitter (all creds: scurker.com)
Fiddle here: http://jsfiddle.net/4REVD/
Im trying to create my own image object that can be used with the framework. Im supposed to be a able to do this with:
particles.update(myObject);
What ive tried so far is:
var myImage = new Image();
myImage.src = "images/_cloud.gif";
particles.update(myImage);
However that doesnt seem to do anything - besides ruining the current default flame animation
Any suggestions?
I'm working on a web app with which users can construct a mesh containing simple objects (rectangular shaped) that can hold text and/or images. Users can create as many of these objects as they like, and in each object that can hold an image, upload one of their own. The app is online if you'd like to test it: goalcandy.com (use demo#demo.com / demo for the email and pswd fields to log in).
Once they finalize their work, they can convert that mesh to PNG. This is done by first drawing everything that's on the mesh on an HTML canvas, which is afterward converted to a PNG image, locally.
When needing to draw the array of existing images onto the canvas, I first have to preload them, which I do like this:
query = []; // array with paths to the image
var count = query.length,
images = [],
loaded = 0;
for (i=0; i<count; i++) {
images[i] = new Image();
images[i].onload = function(){
loaded++;
if (loaded == count)
drawOnCanvas();
};
images[i].src = query[i];
}
function drawOnCanvas() {
// draw the images onto the canvas
}
The problem with all of this is that on a slow, "tired" computer, the PNG sometimes turns out blank in the spaces where some user-uploaded images are supposed to be, because the images don't get drawn onto the canvas. As if they haven't finished downloading. On a good, fast computer, this doesn't happen. How can I solve this, and why does it happen? Considering that I've already attached a handler for the "load" event, I don't see the logic...