pixelbattle/index.html

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2023-07-30 21:19:35 +03:00
<!DOCTYPE html>
<html>
<head>
<title>Pixel Battle</title>
<meta charset="UTF-8">
</head>
<body>
<canvas id="board" width="1920" height="1080" style="border:1px solid #000000;" display="block">
<canvas hidden id="hidden" width="1920" height="1080" style="border:1px solid #000000;" display="block">
</canvas>
<script>
var canvas = document.getElementById("board");
var canvasHidden = document.getElementById("hidden");
var ctx = canvas.getContext("2d");
var ctx2 = canvasHidden.getContext("2d");
canvas.width = 1920;
canvas.height = 1080;
var imgData = ctx2.createImageData(canvasHidden.width, canvasHidden.height)
// All the code that is making zooms and moving around cavnas is made with big help of http://phrogz.net/tmp/canvas_zoom_to_cursor.html. Thanks alot!
window.onload = function() {
var ctx = canvas.getContext("2d");
trackTransforms(ctx);
function redraw(x ,y) {
ctx.save();
ctx.setTransform(1,0,0,1,0,0);
ctx.clearRect(0,0,canvas.width,canvas.height);
ctx.restore();
for (let i = 0; i < 1000; i += 4) {
imgData.data[i+0] = 255;
imgData.data[i+1] = 0;
imgData.data[i+2] = 0;
imgData.data[i+3] = 255;
}
ctx2.putImageData(imgData, 10, 50);
ctx.drawImage(canvasHidden, 0, 0)
}
function drawPixel(x, y, color) {
let pixelNumber = y * canvas.width + x // THIS IS NOT CORRECT. MUST BE FIXED
for (let i = 0; i < 4; i ++)
imgData.data[pixelNumber+i] = color[i]
redraw();
}
redraw();
var lastX=canvas.width/2, lastY=canvas.height/2;
var dragStart,dragged;
canvas.addEventListener('mousedown',function(evt){
document.body.style.mozUserSelect = document.body.style.webkitUserSelect = document.body.style.userSelect = 'none';
lastX = evt.offsetX || (evt.pageX - canvas.offsetLeft);
lastY = evt.offsetY || (evt.pageY - canvas.offsetTop);
dragStart = ctx.transformedPoint(lastX,lastY);
dragged = false;
},false);
canvas.addEventListener('mousemove',function(evt){
lastX = evt.offsetX || (evt.pageX - canvas.offsetLeft);
lastY = evt.offsetY || (evt.pageY - canvas.offsetTop);
dragged = true;
if (dragStart){
var pt = ctx.transformedPoint(lastX,lastY);
ctx.translate(pt.x-dragStart.x,pt.y-dragStart.y);
redraw();
}
},false);
canvas.addEventListener('mouseup',function(evt){
dragStart = null;
if (!dragged) drawPixel(
Math.round(ctx.transformedPoint(lastX,lastY).x),
Math.round(ctx.transformedPoint(lastX,lastY).y)
)
// if (!dragged) zoom(evt.shiftKey ? -1 : 1 );
},false);
var scaleFactor = 1.1;
var zoom = function(clicks){
var pt = ctx.transformedPoint(lastX,lastY);
ctx.translate(pt.x,pt.y);
var factor = Math.pow(scaleFactor,clicks);
ctx.scale(factor,factor);
ctx.translate(-pt.x,-pt.y);
redraw();
}
var handleScroll = function(evt){
var delta = evt.wheelDelta ? evt.wheelDelta/40 : evt.detail ? -evt.detail : 0;
if (delta) zoom(delta);
return evt.preventDefault() && false;
};
canvas.addEventListener('DOMMouseScroll',handleScroll,false);
canvas.addEventListener('mousewheel',handleScroll,false);
};
function trackTransforms(ctx){
var svg = document.createElementNS("http://www.w3.org/2000/svg",'svg');
var xform = svg.createSVGMatrix();
ctx.getTransform = function(){ return xform; };
var savedTransforms = [];
var save = ctx.save;
ctx.save = function(){
savedTransforms.push(xform.translate(0,0));
return save.call(ctx);
};
var restore = ctx.restore;
ctx.restore = function(){
xform = savedTransforms.pop();
return restore.call(ctx);
};
var scale = ctx.scale;
ctx.scale = function(sx,sy){
xform = xform.scaleNonUniform(sx,sy);
return scale.call(ctx,sx,sy);
};
var rotate = ctx.rotate;
ctx.rotate = function(radians){
xform = xform.rotate(radians*180/Math.PI);
return rotate.call(ctx,radians);
};
var translate = ctx.translate;
ctx.translate = function(dx,dy){
xform = xform.translate(dx,dy);
return translate.call(ctx,dx,dy);
};
var transform = ctx.transform;
ctx.transform = function(a,b,c,d,e,f){
var m2 = svg.createSVGMatrix();
m2.a=a; m2.b=b; m2.c=c; m2.d=d; m2.e=e; m2.f=f;
xform = xform.multiply(m2);
return transform.call(ctx,a,b,c,d,e,f);
};
var setTransform = ctx.setTransform;
ctx.setTransform = function(a,b,c,d,e,f){
xform.a = a;
xform.b = b;
xform.c = c;
xform.d = d;
xform.e = e;
xform.f = f;
return setTransform.call(ctx,a,b,c,d,e,f);
};
var pt = svg.createSVGPoint();
ctx.transformedPoint = function(x,y){
pt.x=x; pt.y=y;
return pt.matrixTransform(xform.inverse());
}
}
</script>
</body>
</html>