-1
でパンだから私は現在、ミニプロジェクトに取り組んで、私がズームイン、ズームアウトやHTMLキャンバスの周りにパンし使用していたコードを少し助けが必要です。HTMLキャンバス：ズームと制限
私は制限を追加したい：
あなたが（オブジェクトのための最小と最大のサイズ）でズームイン、ズームアウトすることができますどのくらい遠くまで- 。あなたは、画面の周りにパンすることができますどのくらい遠くまで
- 。ここでは（限度として、画面の初期エッジ）
は私が
var canvas = document.querySelector('canvas'); // selecting the canvas element in html file, the assigning to a variable
canvas.width = window.innerWidth;
canvas.height = window.innerHeight;
var ctx = canvas.getContext('2d');
window.onload = function(){ \t \t
\t \t
trackTransforms(ctx);
function Object (x, y, radius, color) {
this.x = x;
this.y = y;
this.radius = radius;
this.color = color;
this.draw = function() {
ctx.beginPath();
ctx.arc(this.x, this.y, this.radius, 0, Math.PI*2, false);
ctx.fillStyle = this.color;
ctx.fill();
ctx.closePath();
};
}
function init(x, systemRadi, systemColor, scaleVal){
var y = canvas.height/2
var planets = [];
for (var i= 0; i< systemRadi.length; i++){
planets.push(new Object(x[i], y, systemRadi[i]*scaleVal, systemColor[i]))
}
animate(planets);
}
function animate(planets){
planets.forEach(function(Object) {
Object.draw();
}, this);
}
function main(){
var scaleVal = 100;
var r = [0.6957,0.0049,0.0121,0.0128,0.0068,0.143,0.1205,0.0511,0.0495,0.0028];
var x =[-r[0]*scaleVal/4,11.6 + r[0]*scaleVal,21.6 + r[0]*scaleVal,29.9 + r[0]*scaleVal,45.6 + r[0]*scaleVal,155.8 + r[0]*scaleVal,286 + r[0]*scaleVal,574 + r[0]*scaleVal,899 + r[0]*scaleVal,1300 + r[0]*scaleVal];
var col = ['rgb(242, 181, 50)','rgb(40, 8, 8)', 'rgb(124, 175, 35)','rgb(32, 32, 155)', 'rgb(196, 70, 39)', 'rgb(219, 125, 43)','rgb(219, 182, 37)', 'rgb(37, 140, 219)', 'rgb(37, 185, 219)', 'rgb(5, 10, 20)']
init(x, r, col, scaleVal);
}
\t \t
function redraw(){
// Clear the entire canvas
var p1 = ctx.transformedPoint(0,0);
var p2 = ctx.transformedPoint(canvas.width,canvas.height);
ctx.clearRect(p1.x,p1.y,p2.x-p1.x,p2.y-p1.y);
ctx.save();
ctx.setTransform(1,0,0,1,0,0);
ctx.clearRect(0,0,canvas.width,canvas.height);
ctx.restore();
main(); // create image
}
redraw(); // redraw the image upon transformation
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) 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);
\t };
\t
\t // Adds ctx.getTransform() - returns an SVGMatrix
\t // Adds ctx.transformedPoint(x,y) - returns an SVGPoint
\t 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);
\t \t };
var scale = ctx.scale;
ctx.scale = function(sx,sy){
xform = xform.scaleNonUniform(sx,sy);
return scale.call(ctx,sx,sy);
\t \t };
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());
}
}<!DOCTYPE html>
<html>
<head>
<style type="text/css">
canvas {
border: thin solid black;
}
body{
margin: 0;
}
</style>
</head>
<body>
<canvas></canvas>
<script src="tester.js"></script>
</body>
</html>を使用しています、私はJavaScriptに非常に新しいですが、コードので、任意で助けてくださいです方法は可能です。可能であれば、自分が何をしているのか、そして、なぜ私はコードを理解したいのですか？何かがうまくいくかどうかを説明してください。
非常に高く評価されています。