How do I make multiple moving squares on a canvas? - javascript

So far I have made a moving square that when the button is clicked in the HTML file, calls the draw() function and draws a red square in the canvas area that moves accross the canvas. How do I make it so that the same function draw() can create multiple moving sqaures?
Here's the code so far:
var x = 10;
var y = 10;
function draw(){
var can = document.getElementById("myCanvas");
var ctx = can.getContext("2d");
var x = 1;
setInterval(function(){
ctx.clearRect(0,0, can.width, can.height);
ctx.fillRect(x, 20, 75, 75);
ctx.fillStyle ="red";
x=x+5;
}, 500
);
}

Not sure that my solution is good, I'm just starting to learn js, but hope it will helpful.
// variables declaration. I suggest to use Arrays
// for store individual rectangle parameters.
// rectangle start coords x and y
var rcx = [];
var rcy = [];
// delta to move x, y
var dx = [];
var dy = [];
// rectangle size (if you want it variable)
var size =[];
// init canvas
let canvas = document.getElementById('canvas');
let ctx = canvas.getContext('2d');
// create and collect rectangles parameters
// on window load (here 100 rectangles created)
// with unique coords, deltas to move,
// and sizes for each rectangle.
window.onload = function() {
for (var i=0; i<100; i++) {
// in this solution all parameters randomized,
// but you can set whatever you want.
rcx[i]=(Math.floor(Math.random() * Math.floor(canvas.width)));
rcy[i]=(Math.floor(Math.random() * Math.floor(canvas.height)));
dx[i]= (Math.floor(Math.random() * Math.floor(3))-1);
dy[i]=(Math.floor(Math.random() * Math.floor(3))-1);
size[i] = (Math.floor(Math.random() * Math.floor(8)));
}};
// it is optional, but i decide
// made function for rectangle declaration.
// It will looks more compact when rendering.
function rect(x, y, size){
ctx.fillRect(x, y, size, size/2 );
ctx.fillStyle = "rgba(255,255,255,1)";
}
// finally all together into function draw()
function draw(){
setInterval(function(){
ctx.clearRect(0,0, canvas.width, canvas.height);
for (var j=0; j<100; j++) {
// read arrays
// render rectangle with params from arrays
rect(rcx[j],rcy[j],size[j]);
// add delta to move (x,y)
// and rewrite new coords to arrays
rcx[j]=rcx[j]+dx[j];
rcy[j]=rcy[j]+dy[j]};
}, 100
);
};
//rendering animation
draw();
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Document</title>
<style>
#canvas {
width: 500px;
height: 500px;
background-color: #ccc;
}
</style>
</head>
<body>
<canvas id="canvas"></canvas>
<script src="js1.js"></script>
</body>
</html>

Sorry, didn't mention about button. So for the btn changes are simple.
Create btn div in html,
Add listener on this div. Рut params in arrays if button is pushed. Instead of generation by random as it was in my solution before.
Read arrays and render all rectangles from it.
// variables declaration. I suggest to use Arrays for store individual rectangle parameters.
// rectangle start coords x and y
var rcx = [];
var rcy = [];
// delta to move x, y
var dx = [];
var dy = [];
// rectangle size (if you want it variable)
var size =[];
//counter for created rectangles
var i=0;
// init canvas
let canvas = document.getElementById('canvas');
let ctx = canvas.getContext('2d');
// create and collect rectangles parameters on btn push
// with unique coords, deltas to move, and sizes for each rectangle.
var btn =document.getElementById('btn');
btn.addEventListener( 'click', function() {
//count every time you push the btn and create rect
i=i+1;
//generate rect params x,y, delta x, delta y, size
rcx[i]=20;
rcy[i]=20;
dx[i]=1
dy[i]=0
size[i] = 8;
});
// it is optional, but i decide made function for rectangle declaration. It will looks more compact when rendering.
function rect(x, y, size){
ctx.fillRect(x, y, size, size/1.5);
ctx.fillStyle = "red";
}
// finally all together into function draw()
function draw(){
setInterval(function(){
ctx.clearRect(0,0, canvas.width, canvas.height);
for (var j=1; j<rcx.length; j++) {
// read arrays
// render rectangle with params from arrays
rect(rcx[j],rcy[j],size[j]);
// add delta to move (x,y) and rewrite new coords to arrays
rcx[j]=rcx[j]+dx[j];
rcy[j]=rcy[j]+dy[j]};
}, 100
);
};
//rendering animation
draw();
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Document</title>
<style>
body{
margin: 0 auto;
padding: 0;
background-color: rgb(17, 0, 28);
}
#container{
position: relative;
margin-top: 10px;
margin-left: 50px;
}
#canvas {
z-index: 0;
position:fixed;
align-self: center;
justify-self: center;
width: 80vw;
height: 50vw;
background-color: #ccc;
}
#btn {
margin: 20px 20px 20px 0px;
padding: 10px;
position:static;
top: 30px;
font-family: 'Roboto', sans-serif;
width: 65px;
background-color: brown;
cursor: pointer;
}
#btn:hover {
background-color: red;
}
#btn:active {
background-color: coral;
}
</style>
</head>
<body>
<div id="container">
<div id="btn"> Push me </div>
<canvas id="canvas"></canvas>
</div>
<script src="js1.js"></script>
</body>
</html>

Related

How do I get the Mouseover Target's X&Y for a CreateJS Shape

I am trying to change the FILL COLOR of a SHAPE on Mouseover & Mouseout. Most examples I've seen use the events StageX and StageY coordinates. However, those coordinates are the X & Y positions of the mouse at the time of the event. This forces the object to suddently move when "redrawn".
Other examples ask you to call "GetBounds"...which is not available for Shape objects.
I don't want the object to move simply because I am changing the FillColor
I see nothing resembling the top/left in the EVENT.TARGET
Q: How do I calculate or retrieve the Shapes current X/Y (top/left) coordinates?
THE HTML & JAVASCRIPT:
<style>
.dashboard { height:600px; }
.dashboard header { }
.dashboard aside { vertical-align:top; display:inline-block; }
.dashboard aside.control-bar { border: solid 1px black; border-radius: 3px; padding: 5px; height: 100%; width:10%; margin-right: 5px; }
.dashboard aside.control-bar {}
.dashboard aside.control-bar .btn { width:95%; }
.dashboard section { vertical-align:top; display:inline-block; }
.dashboard section.desktop { height:100%; min-width:80%; border:solid 1px black; border-radius: 3px; }
.dashboard section.desktop canvas { height:98%; width:99%; }
.dashboard footer { margin-top:5px; padding:5px; }
</style>
<div class="row">
<div class="col-md-12">
<main role="main" class="dashboard pb-3">
<header qwik-control="header">
<h3>Dashboard</h3>
</header>
<aside class="control-bar">
<center>
<h6>UI Controls</h6>
<a id="btnCreateNode" class="btn btn-sm btn-dark">Create Node</a>
</center>
</aside>
<section class="desktop">
<canvas id="demoCanvas"></canvas>
</section>
<footer>
<center>
<h5 style="color:#C7C9CD;">Button Controls</h5>
</center>
</footer>
</main>
</div>
</div>
<script src="https://code.createjs.com/1.0.0/createjs.min.js"></script>
<script type="text/javascript">
var stage = null,
loader = null;
// GLOBALS
var _PROPERTIES = { node: { y: 100, x: 200, fillColor: '#F9FAFB', fillOverColor: '#FCFCC2', strokeColor: '#000' } };
function node_create(){
console.log('node_create');
var top = Math.random() * 500;
var left = Math.random() * 500;
var width = _PROPERTIES.node.x;
var height = _PROPERTIES.node.y;
// Create
var node = new createjs.Shape();
node.graphics.beginStroke(_PROPERTIES.node.strokeColor);
node.graphics.beginFill(_PROPERTIES.node.fillColor);
node.graphics.setStrokeStyle(1);
node.snapToPixel = true;
node.graphics.drawRect(left, top, width, height);
node.graphics.endFill();
node.name = name;
node.overColor = _PROPERTIES.node.fillOverColor;
node.outColor = _PROPERTIES.node.fillColor;
// Events
node.on("mouseover", node_mouseover);
node.on("mouseout", node_mouseout);
// Display
stage.addChild(node);
stage.update();
};
function node_mouseover(evt) {
console.log('node_mouseover');
// COORDS is the events coordinates...not the targets Top/Left (e.g. cursor)
// How do I get the X/Y of the target? (getBounds does not exist for Shapes)
var target = evt.target;
var coords = { x: evt.stageX, y: evt.stageY };
target.graphics.clear();
target.graphics.beginStroke(_PROPERTIES.node.strokeColor);
target.graphics.beginFill(target.overColor);
target.graphics.drawRect(coords.x, coords.y, _PROPERTIES.node.x, _PROPERTIES.node.y);
target.graphics.endFill();
stage.update();
};
function node_mouseout(evt) {
console.log('node_mouseout');
// COORDS is the events coordinates...not the targets Top/Left (e.g. cursor)
// How do I get the X/Y of the target? (getBounds does not exist for Shapes)
var target = evt.target;
var coords = { x: evt.stageX, y: evt.stageY };
target.graphics.clear();
target.graphics.beginStroke(_PROPERTIES.node.strokeColor);
target.graphics.beginFill(target.outColor);
target.graphics.drawRect(coords.x, coords.y, _PROPERTIES.node.x, _PROPERTIES.node.y);
target.graphics.endFill();
stage.update();
};
$(document).ready(function () {
// Stage
stage = new createjs.Stage('demoCanvas');
stage.canvas.width = window.innerWidth;
stage.canvas.height = window.innerHeight;
// Stage - Events
stage.enableMouseOver(10);
// Queue
loader = new createjs.LoadQueue();
// DOM - EVENTS
$('#btnCreateNode').on('click', function(e){
node_create();
});
});
</script>
The solution is to put your Shapes into a Container. Shapes don't have the same properties & methods useful in determining location that other objects do: like images or bitmaps etc.
As such...Containers are the "solution" to that.
THE JAVASCRIPT:
var _PROPERTIES = { node: { y: 100, x: 200, fillColor: '#F9FAFB', fillOverColor: '#FCFCC2', strokeColor: '#000' } };
function node_create(){
console.log('node_create');
var top = Math.random() * 500;
var left = Math.random() * 500;
var width = _PROPERTIES.node.x;
var height = _PROPERTIES.node.y;
// Create
var node = new createjs.Shape();
node.graphics.beginStroke(_PROPERTIES.node.strokeColor);
node.graphics.beginFill(_PROPERTIES.node.fillColor);
node.graphics.setStrokeStyle(1);
node.snapToPixel = true;
node.graphics.drawRect(0, 0, width, height); //<-- changed
node.graphics.endFill();
node.name = name;
node.overColor = _PROPERTIES.node.fillOverColor; //<-- added
node.outColor = _PROPERTIES.node.fillColor; //<-- added
// Events
node.on("mouseover", node_mouseover);
node.on("mouseout", node_mouseout);
// Container
var container = new createjs.Container(); //<-- added
container.x = top;
container.y = left;
container.addChild(node);
// Display
stage.addChild(container); //<-- changed
stage.update();
};
function node_mouseover(evt) {
console.log('node_mouseover');
// Because of the container...you no longer need to calculate a TOP or LEFT
var target = evt.target;
target.graphics.clear();
target.graphics.beginStroke(_PROPERTIES.node.strokeColor);
target.graphics.beginFill(target.overColor);
target.graphics.drawRect(0, 0, _PROPERTIES.node.x, _PROPERTIES.node.y); //<-- changed
target.graphics.endFill();
stage.update();
};
function node_mouseout(evt) {
console.log('node_mouseout');
// Because of the container...you no longer need to calculate a TOP or LEFT
var target = evt.target;
target.graphics.clear();
target.graphics.beginStroke(_PROPERTIES.node.strokeColor);
target.graphics.beginFill(target.outColor);
target.graphics.drawRect(0, 0, _PROPERTIES.node.x, _PROPERTIES.node.y); //<-- changed
target.graphics.endFill();
stage.update();
};

Using variable font inside WEBGL canvas, p5 js

I have a WEBGL canvas in which I am loading a 3d model. I also have a text in variable font which I create with createP. The problem is that I need the text to be between the background and the 3d model. But I can only have the text in front of the canvas (on top of 3d model). Is there any way I can achieve this?
Ps. Creating the text with text() does not allow me to have variable weight value.
let kalameh;
var cnv;
let img;
function preload(){
img = loadImage('assets/lines.png');
kalameh = loadModel('kalameh.obj');
}
function setup() {
cnv = createCanvas(700, 700, WEBGL);
var x = (windowWidth - width) / 2;
var y = (windowHeight - height) / 2;
cnv.position(x, y);
wordA = createP('my text');
}
function draw() {
background(220, 220, 220);
wordA.style('font-size', '110px');
wordA.style('font-weight', '200');
wordA.style('font-stretch', '200%');
wordA.style('align', 'center');
wordA.position(40,25);
image(img, -1*windowWidth/2, -1*windowHeight/2, windowWidth, windowHeight);
translate (0,0,100);
pointLight(255,255,255, -350,0,400);
pointLight(255,255,255, 350,0,400);
ambientMaterial(255);
noStroke();
scale (0.25);
model(kalameh);
}
You could create two sketches (and thus two canvases) and assign z-index properties of -1 and 1 to make them foreground and background sketches, respectively. You can then sandwich the paragraph element that you created between the two canvases by giving it a z-index of 0. You can then make the foreground sketch transparent by calling clear() at the beginning of the draw loop.
In the code snippet below, the 3D object is in front of the text paragraph, whereas the white square of the "background" is behind the text.
let testP;
new p5(function(p){
p.setup = function() {
const foregroundCanvas = p.createCanvas(400, 400, p.WEBGL);
foregroundCanvas.id("foregroundSketch");
foregroundCanvas.position(0, 0);
p.normalMaterial();
testP = p.createP("In front of background / behind object ")
testP.position(95, 115);
testP.id("sandwichedParagraph")
p.angleMode(p.RADIANS)
}
p.draw = function() {
p.clear();
//drag to move the world.
// p.orbitControl();
p.push();
let rotateAngle = p.sin(p.frameCount/50);
p.rotateX(rotateAngle/2);
p.rotateY(-rotateAngle);
p.rotateZ(rotateAngle);
p.box(200, 100, 40);
p.pop();
}
}, "foregroundSketch");
new p5(function(p){
p.setup = function() {
const backgroundCanvas = p.createCanvas(400, 400);
// backgroundCanvas.parent("wrapper")
backgroundCanvas.position(0, 0);
backgroundCanvas.id("backgroundSketch")
p.noStroke();
}
p.draw = function() {
p.background(200);
let shiftAmount = p.map(p.sin(p.frameCount/60), -1, 1, 80, 310);
p.rect(shiftAmount, 120, 40, 40);
}
}, "backgroundSketch");
html, body {
margin: 0;
padding: 0;
}
/* The sketch with the white square has z-index of -1 (background!) */
#backgroundSketch {
z-index: -1;
position: absolute;
}
/* The <p> has z-index of 0 (sandwiched between both sketches)*/
#sandwichedParagraph {
z-index: 0;
position: absolute;
}
/* The sketch with the object has z-index of 1 (foreground!)*/
#foregroundSketch {
z-index: 1;
position: absolute;
}
<!DOCTYPE html>
<html lang="en">
<head>
<script src="https://cdnjs.cloudflare.com/ajax/libs/p5.js/0.10.2/p5.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/p5.js/0.10.2/addons/p5.sound.min.js"></script>
<link rel="stylesheet" type="text/css" href="style.css">
<meta charset="utf-8" />
</head>
<body>
<script src="sketch.js"></script>
</body>
</html>

Draw rectangle over uploaded image

Once I upload an image I make 2 clicks over it. That's how (x1,y1) and (x2,y2) are obtained. Given these 4 numbers I waanna draw a rectangle over the image by means for example of P5.js. Then I should say rect(x1,y1,x2,y2) but this never happens. How can I deal with this problem (maybe not by P5)
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Vue Test</title>
<link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.4/css/bootstrap.min.css">
</head>
<body>
<div id="app">
<button v-on:click="isHidden = false">Load img</button>
<img onclick="showCoords(event)" v-if="!isHidden" v-bind:src="src[z]"></img>
</div>
<script>
var test = new Vue({
el: '#app',
data: {
src: ["cat.jpg", "dog.jpg"],
z: Math.round(Math.random()),
isHidden: true,
}
})
var k=0;
var koors = [];
var flag = false;
function showCoords(event) {
if (k===0){
koors[0] = event.clientX;
koors[1] = event.clientY;
k+=1;
} else if (k===1){
flag = true;
koors[2] = event.clientX;
koors[3] = event.clientY;
}
if ((koors[3] != 0) && (flag)){
console.log(koors)
}
}
//p5
function setup(){
}
function draw(){
console.log(koors[0],koors[1],koors[2],koors[3]);
rect(koors[0],koors[1],koors[2],koors[3])
}
</script>
<script src="p5.min.js"></script>
<script src="https://cdn.jsdelivr.net/npm/vue#2.5.13/dist/vue.js"></script>
<script src="js.js"></script>
</body>
</html>
P5 needs a canvas for rendering. If you don't initialize one, it creates it himself (and you are in trouble).
Also, P5 is powerful library, it has tools for events, image processing etc. For current example I wouldn't use any other library (vue).
I created canvas on top of the image (css) and rest is playing with P5.
var test = new Vue({
el: '#app',
data: {
src: [ "https://i.stack.imgur.com/XZ4V5.jpg", "https://i.stack.imgur.com/7bI1Y.jpg"],
z: Math.round(Math.random()),
isHidden: false,
}
})
var recStart;
var coords = {};
/*******************************************************************
* P5 setup
* run once, use for initialisation.
*
* Create a canvas, change dimensions to
* something meaningful(like image dim)
********************************************************************/
function setup(){
var canvas = createCanvas(480, 320);
canvas.parent('app');
}
/*******************************************************************
* P5 draw
* endless loop.
*
* Lets redraw rectangle until second click.
********************************************************************/
function draw(){
if(recStart)
drawRect();
}
/*******************************************************************
* drawRect
*
* Draw a rectangle. mouseX and mouseY are P5 variables
* holding mouse current position.
********************************************************************/
function drawRect(){
clear();
noFill();
stroke('red');
rect(coords.x, coords.y, mouseX-coords.x, mouseY-coords.y);
}
/*******************************************************************
* P5 mouseClicked
*
* P5 event. Again, mouseX and mouseY are used.
********************************************************************/
mouseClicked = function() {
if (mouseButton === LEFT) {
if(!recStart){ // start rectangle, give initial coords
coords.x = mouseX;
coords.y = mouseY;
recStart = true; // draw() starts to draw
} else {
recStart = false; // stop draw()
drawRect(); // draw final rectangle
coords = {}; // clear coords
}
}
};
canvas {
width: 500px;
height:500px;
z-index: 2;
border:1px solid;
position:absolute;
left: 0;
top: 0;
}
img {
z-index: 1;
position: absolute;
border: 2px solid black;
left: 0;
top: 0;
}
<script src="https://cdnjs.cloudflare.com/ajax/libs/p5.js/0.7.2/p5.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/vue/2.5.13/vue.js"></script>
<div id="app">
<img id="pilt" v-if="!isHidden" v-bind:src="src[z]"></img>
</div>
It seems that you don't call draw anywhere. You may also consider draw the image into a canvas and than draw rect in this canvas. Checking if koors[3] != 0 is really risky as user may click at 0th pixel.

How can I check if an attractor is strange?

Lately I learned a bit about strange attractors, and I created the following programm in JS:
var ctx, clock, width, height, pixSize;
var x,y,a,b,c,d;
window.onload = function(){
start();
};
function start(random=true){
window.cancelAnimationFrame(clock);
if(random){
a = 6*Math.random()-3;
b = 6*Math.random()-3;
c = 2*Math.random()-0.5;
d = 2*Math.random()-0.5;
}
canvasSetup();
clearCanvas();
x = Math.random()-Math.random();
y = Math.random()-Math.random();
clock = requestAnimationFrame(main);
}
function save(){
var text = JSON.stringify({
a:a,
b:b,
c:c,
d:d
});
window.prompt("Copy to clipboard: Ctrl+C", text);
}
function load(){
var input = JSON.parse(window.prompt("Import Save:"));
a = input.a;
b = input.b;
c = input.c;
d = input.d;
start(false);
}
function canvasSetup(){
canvas = document.getElementById('canvas');
width = window.innerWidth-5;
height = window.innerHeight-5;
canvas.width = width;
canvas.height = height;
ctx = canvas.getContext('2d');
var min = Math.min(width,height);
var scale = min/4;
ctx.translate(width/2, height/2);
ctx.scale(scale, scale);
pixSize = 1/scale/2;
ctx.globalCompositeOperation = "lighter";
}
function clearCanvas(){
ctx.save();
ctx.setTransform(1, 0, 0, 1, 0, 0);
ctx.clearRect(0,0,width,height);
ctx.restore();
}
function main(){
for(var i=0;i<10000;i++){
var xnew = Math.sin(y*b)+c*Math.sin(x*b);
var ynew = Math.sin(x*a)+d*Math.sin(y*a);
x = xnew;
y = ynew;
plot(x,y,"rgb(50,5,1)");
}
clock = requestAnimationFrame(main);
}
function plot(x,y,color="white"){
ctx.fillStyle = color;
ctx.fillRect(x,-y,pixSize,pixSize);
}
body {
background-color: black;
color: white;
font-family: Consolas;
font-size: 13px;
margin: 0;
padding: 0;
}
#buttons{
position: absolute;
top: 0;
left: 0;
}
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>Strange Attractor</title>
<link rel="stylesheet" href="style.css">
<script src="rules.js"></script>
<script src="script.js"></script>
</head>
<body>
<div align="center">
<canvas id="canvas"></canvas>
</div>
<div id="buttons">
<button onclick="start()">New Attractor</button><br>
<button onclick="save()">Save</button><br>
<button onclick="load()">Load</button>
</div>
</body>
</html>
It's taking 4 random Parameters (a,b,c,d) and uses the formular
var xnew = Math.sin(y*b)+c*Math.sin(x*b);
var ynew = Math.sin(x*a)+d*Math.sin(y*a);
x = xnew;
y = ynew;
for the new point. In some cases this indeed creates a fancy strange sttractor:
But in other cases I only get a single line or a few points. Is there a simple way to look at the parameters and find out, if the attrator they create will be strange?
I know, that I could save a bunch of values, compare them with each other and test in that way, if the picture might be intresting, but I'd love a different solution...
I hope you can help :)
EDIT:
To look at speccific values you can simply use the save and load buttons in the js sketch above...

Merging javascript code with canvas animation

I’m trying to ‘merge’ some javascript code that changes pictures with a canvas that has also animation to it, without them cancelling eachother out. In this canvas there are some clouds that move and I want to throw kittens into it.
I understand this this might be a basic HTML5 canvas question but I’m terrible using canvas though. This is the first time I’m really working with it. Whenever I try to implement the code that applies to the kittens, the canvas screen just goes white and nothing shows.
I want to stick with most of the code that I have. I really want to keep the canvas the way it is and change nothing there but add those kittens in there too. Can someone puzzle out for me how to appropiately do this?
I'm guessing I would need to tweak the animation function somehow?
function animate(){
ctx.save();
ctx.clearRect(0, 0, cW, cH);
background.render();
foreground.render();
ctx.restore();
}
var animateInterval = setInterval(animate, 30);
}
The code is all in a FIDDLE, because it’s too much to show it on here.
EDIT: To be clear, I'm asking for the pictures of the kittens to be laid over the canvas, but I want the clouds in the canvas to overlay the kittens.
What you need to know is that the canvas element is transparent by default. So notice the minor change I made here :
body{
background:#667;
}
canvas {
width:50vw;
height:50vh;
margin-left: 20%;
}
#image {
border:#000 1px solid;
padding-left: 0;
padding-right: 0;
margin-left: auto;
margin-right: auto;
display: block;
width: 33%;
height: 100%;
position: relative;
top:140px;
z-index: -1;
}
#my_canvas{
border:#000 1px solid;
padding-left: 0;
padding-right: 0;
margin-left: auto;
margin-right: auto;
display: block;
width: 33%;
height: 100%;
}
<link href="css.css" rel="stylesheet" type="text/css">
<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.11.1/jquery.min.js"></script>
<img src="" id="image"/>
<script>
var bg = new Image();
bg.src = "http://proverum.ru/templates/oblaka/img/cloud.png";
var fg = new Image();
fg.src = "http://www.tourisme-fumel.com/img_interf/meteo/cloudy.png";
function initCanvas(){
var lastTick = 0;
var position = { x:0, y:0 };
var rain = document.getElementById('rain');
var ctx = document.getElementById('my_canvas').getContext('2d');
var canvas_container = document.getElementById('my_canvas2');
var cW = ctx.canvas.width, cH = ctx.canvas.height;
function Background(){
this.x = 0, this.y = 0, this.w = bg.width, this.h = bg.height;
this.render = function(){
ctx.drawImage(bg, this.x--, 0);
if(this.x <= -250){
this.x = 0;
}
}
}
var background = new Background();
var image1 = "http://www.catsofaustralia.com/images/three_kittens.jpg";
var image2 = "http://thecatpalace.com.au/wp-content/uploads/2015/05/kitten1.jpg";
var image3 = "http://www.keepingkittens.com/images/cute-little-kitten-minka-rose-the-real-cinderella-story-21652512.jpg";
$(function() {
$("#image").prop("src", image1);
setInterval(function() {
$("#image").prop("src", image2);
setTimeout(function() {
$("#image").prop("src", image2);
setTimeout(function() {
$("#image").prop("src", image3);
}, 50);
setTimeout(function() {
$("#image").prop("src", image1);
}, 500);
}, 10);
}, 5000);
});
function Foreground(){
this.x = 0, this.y = 0, this.w = fg.width, this.h = fg.height;
this.render = function(){
ctx.drawImage(fg, this.x--, 0);
if(this.x <= -499){
this.x = 0;
}
}
}
var foreground = new Foreground();
function animate(){
ctx.save();
ctx.clearRect(0, 0, cW, cH);
background.render();
foreground.render();
ctx.restore();
}
var animateInterval = setInterval(animate, 30);
}
window.addEventListener('load', function(event) {
initCanvas();
});
</script>
</head>
<body>
<canvas id="my_canvas" width="611" height="864"></canvas>
<h1 id="status"></h1>
</body>
</html>
I just removed the
background:#FFF;
from the canvas css and the canvas became transparent.
How you will line up the canvas over the kittens is up to you, I just quickly used position:relative and z-index to prove my point.

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