HTML5的动画学习历程
一.三角学原理.
function getRadio(d){//根据角度获得弧度,
return d*Math.PI/180;
},
function getDdegree(r){//根据弧度获得角度
return r*180/Math.PI;
二.循环动画方法的浏览器判断 }
if(!window.requestAnimationFrame){
window.requestAnimationFrame=(window.webkitRequestAnimationFrame||
window.mozRequestAnimationFrame||
window.oRequestAnimationFrame||
window.msRequestionFrame||
function(callback){return window.setTimeout(callback,100/60);}
);
}
三.获得元素坐标
var captureMouse=function(element){
var mouse={x:0,y:0};
element.addEventListener('mousemove',function(event){
var x,y;
if(event.pageX||event.pageY){
x=event.pageX;y=event.pageY;
}
else{
x=event.clientX+document.body.scrollLeft+document.documentElement.scrollLeft;
y=event.clientY+document.body.scrollTop+document.documentElement.scrollTop;
}
x-=element.offsetLeft;
y-=element.offsetTop;
mouse.x=x;
mouse.y=y;
},false);
return mouse;
};
四.//将十六进制的色值转换成rgb格式
var colorToRGB=function(color,alpha){
if(typeof color==="string"&&color[0]==="#")
color=window.parseInt(color.slice(1),16);
alpha=(alpha===underfined)?1:alpha;
var r=color>>16&0xff,
g=color>>8&0xff,
b=color&0xff,
a=(alpha<0)?0:((alpha>1)?1:alpha);
if(a===1)
return "rgb("+r+","+g+","+b+")";
else
return "rgba("+r+","+g+","+b+","+a+")";
};
五//可以将一个颜色的数据值转换成十六进制,也可以将十六进制转换成数据
var parseColor=function(color,toNumber){
if(toNumber===true){
if(typeof color==='number')
return (color|0);
if(typeof color==='string'&&color[0]==='#')
color=color.slice(1);
return window.parseInt(color,16);
}
else{
if(typeof color==='number')
color='#'+('00000'+(color|0).toString(16)).substr(-6);
return color;
}
};
六.绘制箭头
(1)
function Arrow(){
this.x=0;
this.y=0;
this.color="#ffff00";
this.rotation=0;
}
Arrow.prototype.draw=function(context){
context.save();
context.translate(this.x,this.y);
context.rotate(this.rotation);
context.lineWidth=2;
context.fillStyle=this.color;
context.beginPath();
context.moveTo(-50,-25);
context.lineTo(0,-25);
context.lineTo(0,-50);
context.lineTo(50,0);
context.lineTo(0,50);
context.lineTo(0,25);
context.lineTo(-50,25);
context.lineTo(-50,-25);
context.closePath();
context.fill();
context.stroke();
context.restore();
};
绘制圆球
function Ball(radius,color){
if(radius===undefined){ radius=40;}
if(color==undefined){ color="#ff0000";}
this.x=0;this.y=0;
this.radius=radius;
this.rotation=0;
this.vx=0;//在边界和摩擦力上添加
this.vy=0;//在边界和摩擦力上添加
this.scaleX=1;
this.scaleY=1;
this.color=parseColor(color);
this.lineWidth=1;
}
Ball.prototype.draw=function(context){
context.save();
context.translate(this.x,this.y);
context.rotate(this.rotation);
context.scale(this.scaleX,this.scaleY);
context.lineWidth=this.lineWidth;
context.fillStyle=this.color;
context.beginPath();
context.arc(0,0,this.radius,0,(Math.PI*2),true);
context.closePath();
context.fill();
if(this.lineWidth>0){
context.stroke();
}
context.restore();
};
七.绘制各种基本动画
(1)window.onload=function(){
//平滑的上下运动
/*var canvas=document.getElementById("canvas"),
context=canvas.getContext('2d'),
mouse=captureMouse(canvas);
arrow=new Arrow();
arrow.x=canvas.width/2;
arrow.y=canvas.height/2;*/
/*(function drawFrame(){
window.requestAnimationFrame(drawFrame,canvas);
context.clearRect(0,0,canvas.width,canvas.height);
var dx=mouse.x-arrow.x;
var dy=mouse.x-arrow.y;
arrow.rotation=Math.atan(dy,dx);
arrow.draw(context);
}())*/
}
(2)window.onload=function(){
//线性垂直运动
/*var canvas=document.getElementById("canvas"),
context=canvas.getContext('2d'),
ball=new Ball(),
angle=0;
var centerY=200;
var range=50;
var speed=0.05;
ball.x=canvas.width/2;
ball.y=canvas.height/2;
(function drawFram(){
window.requestAnimationFrame(drawFram,'canvas');
context.clearRect(0,0,canvas.width,canvas.height);
ball.y=centerY/2+Math.sin(angle)*50;
angle+=speed;
ball.draw(context);
}());
*/
}
(3)window.onload=function(){
//脉冲运动
/*var canvas=document.getElementById("canvas"),
context=canvas.getContext('2d'),
ball=new Ball(),
angle=0,
centerY=200,
range=50,
xspeed=1,
yspeed=0.05;
ball.x=0;
(function drawFrame(){
window.requestAnimationFrame(drawFrame,canvas);
context.clearRect(0,0,canvas.width,canvas.height);
ball.x+=xspeed;
ball.y=centerY/2+Math.sin(angle)*range;
ball.draw(context);
}());*/
/*var canvas=document.getElementById("canvas"),
context=canvas.getContext('2d'),
ball=new Ball(),
angle=0,
centerScale=1,
range=0.5,
speed=0.05;
ball.x=canvas.widt/2;
ball.y=canvas.height/2;
(function drawFrame(){
window.requestAnimationFrame(drawFrame,context);
context.clearRect(0,0,canvas.width,canvas.height);
ball.scaleX=ball.scaleY=centerScale+Math.sin(angle)*range;
angle+=speed;
ball.draw(context);
}());*/
}
(4)window.onload=function(){
//使用两鞥波个角
/*var canvas=document.getElementById("canvas"),
context=canvas.getContext('2d'),
ball=new Ball(),
angleX=0,
angleY=0,
range=50,
centerX=canvas.width/2,
centerY=canvas.height/2,
xspeed=0.07,
yspeed=0.11;
(function drawFrame(){
window.requestAnimationFrame(drawFrame,context);
context.clearRect(0,0,canvas.width,canvas.height);
ball.x=centerX+Math.sin(angleX)*range;
ball.y=centerY+Math.sin(angleY)*range;
angleX+=xspeed;
angleY+=yspeed;
ball.draw(context);
}());*/
}
(5)window.onload=function(){//圆周运动
var canvas=document.getElementById("canvas"),
context=canvas.getContext('2d');
angle=0,range=50,
centerY=canvas.height/2,
xspeed=1,yspeed=0.05,
xpos=0,ypos=centerY;
context.lineWidth=2;
(function drawFrame(){
window.requestAnimationFrame(drawFrame,canvas);
context.beginPath();
context.moveTo(xpos,ypos);
xpos+=xspeed;angle+=yspeed;
ypos=centerY+Math.sin(angle)*range;
context.lineTo(xpos,ypos);
context.stroke();
}());
}
(6) window.onload=function(){//椭圆运动
var canvas=document.getElementById("canvas"),
context=canvas.getContext('2d');
ball=new Ball(),
angle=0,
centerX=canvas.width/2,
centerY=canvas.height/2,
radius=50,
speed=0.05;
(function drawFrame(){
window.requestAnimationFrame(drawFrame,canvas);
context.clearRect(0,0,canvas.width,canvas.height);
ball.x=centerX+Math.sin(angle)*radius;
ball.y=centerY+Math.cos(angle)*radius;
angle+=speed;
ball.draw(context);
}());}
(7)勾股定律中 连个随机出现的点的距离算法1
var canvas=document.getElementById("canvas"),
context=canvas.getContext('2d');
log=document.getElementById('log');
var rect1={x:Math.random()*canvas.width,y:Math.random()*canvas.height};
context.fillStyle="#000000";
context.fillRect(rect1.x-2,rect1.y-2,4,4);
var rect2={x:Math.random()*canvas.width,y:Math.random()*canvas.height};
context.fillStyle="#ff0000";
context.fillRect(rect2.x-2,rect2.y-2,4,4);
var dx=rect1.x-rect2.x,
dy=rect1.y-rect2.y,
dist=Math.sqrt(dx*dx+dy*dy);
log.value="distance:"+dist;
(8)勾股定律 中 两个随机出现的点的距离算法2
var canvas=document.getElementById("canvas"),
context=canvas.getContext('2d'),
mouse=captureMouse(canvas),
log=document.getElementById('log');
var a=canvas.height/2;
rect={x:canvas.width/2,y:a};
(function drawFrame(){
window.requestAnimationFrame(drawFrame,canvas);
context.clearRect(0,0,canvas.width,canvas.height);
var dx=rect.x-mouse.x,
dy=rect.y-mouse.y,
dist=Math.sqrt(dx*dx-dy*dy);
context.fillStyle="#000000";
context.fillRect(rect.x-2,rect.y-2,4,4);
context.beginPath();
context.moveTo(rect.x,rect.y);
context.lineTo(mouse.x,mouse.y);
context.closePath();
context.stroke();
log.value="distance:"+dist;
}());
八,方法介绍
//strokeStyle该属性用于指定线条的颜色.该值是一个颜色值(css风格的字符串),一个渐变对象或一个模式对象,线条默认颜色黑色(#000000)
//lineWidth:指定线条在路径上的宽度,默认为1,此时会在路径的两侧分别延半个像素,
//lineCap:线条的终点将如何绘制,它可以是平的,圆形活着,一段延伸线.该属性包含butt,round,square,默认是butt
//lineJoin:决定两条相连的线段如何结合,或者连接线的弯头部分如何绘制.round,bevel,miter.默认miter.
//miterLimit:当lineJoin属性设置问miter时,该属性可用于控制两条相交线外侧交点与内侧交点的距离,它必须是大于0的有限数,默认为10.
//context.save()
和context.restore()实现不同样式的转换,context.save()方法将canvas的当时状态存入栈中,包含各种样式,例
如:strokeStyle,fillStyle以及应用于canvas的变换效果.额外的样式变化会影响到后续的绘制指令.调用
context.restore()可以使得当时的canvas状态出栈而使用下一个状态,也就是上一个状态.//context.beginPath()即可表示想开始绘制一条新的路径,一条路劲只不过是构成一条线的一系列坐标位置,为了将它渲染到canvas上,需要调用contxt.stroke();
九:绘制宇宙飞船
function Ship(){
this.x=0;
this.y=0;
this.width=25;
this.height=20;
this.rotation=0;
this.showFlame=false;
}
Ship.prototype.draw=function(context){
context.save();
context.translate(this.x,this.y);
context.lineWidth=1;
context.strokeStyle="#ffffff";
context.beginPath();
context.moveTo(10,0);
context.lineTo(-10,0);
context.lineTo(-5,0);
context.lineTo(-10,-10);
context.lineTo(10,0);
context.stroke();
if(this.showFlame){
context.beginPath();
context.moveTo(-7.5,-5);
context.lineTo(-15,0);
context.lineTo(-7.5,0);
context.stroke();
}
context.restore();
};
十: 使用鼠标绘制路径
var canvas=document.getElementById("canvas"),
context=canvas.getContext('2d'),
mouse=captureMouse(canvas);
function onMouseMove(){
context.lineTo(mouse.x,mouse.y);
context.stroke();
}
canvas.addEventListener('mousedown',function(){
context.beginPath();
context.moveTo(mouse.x,mouse.y);
canvas.addEventListener('mousemove',onMouseMove,false);
},false);
canvas.addEventListener('mouseup',function(){
canvas.removeEventListener('mousemove',onMouseMove,false)
},false);
十一,使用quadraticCurveTo绘制弯线,不会穿过控制点
var canvas=document.getElementById("canvas"),
context=canvas.getContext('2d'),
mouse=captureMouse(canvas),
x0=100,y0=200,x2=300,y2=200;
canvas.addEventListener('mousemove',function(){
context.clearRect(0,0,canvas.width,canvas.height);
var x1=mouse.x,y1=mouse.y;
context.beginPath();
context.moveTo(x0,y0);
context.quadraticCurveTo(x1,y1,x2,y2);
context.stroke();
},false);
十二:使用quadraticCurveTo绘制弯线,穿过控制点
var canvas=document.getElementById("canvas"),
context=canvas.getContext('2d'),
mouse=captureMouse(canvas),
x0=100,y0=200,x2=300,y2=200;
canvas.addEventListener('mousemove',function(){
context.clearRect(0,0,canvas.width,canvas.height);
var x1=mouse.x*2-(x0+y2)/2,y1=mouse.y*2-(x0+y2)/2;
context.beginPath();
context.moveTo(x0,y0);
context.quadraticCurveTo(x1,y1,x2,y2);
context.stroke();
},false);
十三:色值渐变色:线性渐变
var canvas=document.getElementById("canvas"),
context=canvas.getContext('2d'),
pt1={x:0,y:0},pt2={x:100,y:100},
gradient=context.createLinearGradient(pt1.x,pt2.y,pt2.x,pt2.y);
gradient.addColorStop(0,"#ffffff");//为渐变色添加颜色
gradient.addColorStop(0.5,"#0000ff")
gradient.addColorStop(1,"#ff0000");
context.fillStyle=gradient;
context.fillRect(0,0,100,100);//绘制并填充一个矩
十四:色值渐变色:线性渐变
var canvas=document.getElementById("canvas"),
context=canvas.getContext('2d'),
c1={x:150,y:150,radius:0},c2={x:150,y:150,radius:50},
gradient=context.createRadialGradient(c1.x,c1.y,c1.radius,c2.x,c2.y,c2.radius);
gradient.addColorStop(0,"#ffffff");//为渐变色添加颜色
//gradient.addColorStop(0.5,"#0000ff")
gradient.addColorStop(1,"#ff0000");
context.fillStyle=gradient;
context.fillRect(0,0,100,100);//绘制并填充一个矩形
十五: 绘制图片
1 var canvas=document.getElementById("canvas"), 2 context=canvas.getContext('2d'), 3 image=new Image(); 4 5 image.src='1.jpg'; 6 image.onload=function(){ 7 //context.drawImage(image,0,0);//图片左上角位置0,0 8 //context.drawImage(image,0,0,400,400);//图片左上角位置0,0,图片尺寸400,400 9 context.drawImage(image,50,50,450,450,50,50,300,300);//(image,sx,sy,sw,sh,dx,dy,dw,dh),将图片裁剪到矩形内(sx,xy,sw,sh)中,并缩放至(dh,dw),在绘制到(dx,dy)坐标 10 };
十六:绘制canvas中的图片
1 var canvas=document.getElementById("canvas"), 2 context=canvas.getContext('2d'), 3 image=document.getElementById("picture");//<canvas id="canvas" width="400px" height="400px" style="border:1px solid red; position:absolute; left:200px; top:50px;"><img src="1.jpg" id="picture" /></canvas> 4 context.drawImage(image,0,0);
十七:速度向量,双轴上的圆运动
1 var canvas=document.getElementById("canvas"), 2 context=canvas.getContext("2d"), 3 ball=new Ball(), 4 vx=1,vy=1; 5 ball.x=50,ball.y=100; 6 7 (function drawFrame(){ 8 window.requestAnimationFrame(drawFrame,canvas); 9 context.clearRect(0,0,canvas.width,canvas.height); 10 ball.x+=vx; 11 ball.y+=vy; 12 ball.draw(context); 13 }());
十八:角速度
var canvas=document.getElementById("canvas"), context=canvas.getContext("2d"), ball=new Ball(), angle=45,speed=1; ball.x=50,ball.y=100; (function drawFrame(){ window.requestAnimationFrame(drawFrame,canvas); context.clearRect(0,0,canvas.width,canvas.height); var radians=angle*Math.PI/180, vx=Math.cos(radians)*speed,vy=Math.sin(radians)*speed; ball.x+=vx;ball.y+=vy; ball.draw(context); }())
十九:鼠标追随者
1 var canvas=document.getElementById("canvas"), 2 context=canvas.getContext("2d"), 3 mouse=captureMouse(canvas), 4 arrow=new Arrow(), 5 speed=3; 6 (function drawFrame(){ 7 window.requestAnimationFrame(drawFrame,canvas); 8 context.clearRect(0,0,canvas.width,canvas.height); 9 var dx=mouse.x-arrow.x, 10 dy=mouse.y-arrow.y, 11 angle=Math.atan2(dy,dx), 12 vx=Math.cos(angle)*speed, 13 vy=Math.sin(angle)*speed; 14 15 arrow.rotation=angle;arrow.x+=vx;arrow.y+=vy; 16 arrow.draw(context); 17 }());
二十:速度向量扩展
1 var canvas=document.getElementById("canvas"), 2 context=canvas.getContext('2d'), 3 mouse=captureMouse(canvas), 4 arrow=new Arrow(), 5 vr=2; 6 arrow.x=canvas.width/2; 7 arrow.y=canvas.height/2; 8 9 (function drawFrame(){ 10 window.requestAnimationFrame(drawFrame,canvas); 11 context.clearRect(0,0,canvas.width,canvas.height/2); 12 arrow.rotation+=vr*Math.PI/180; 13 arrow.draw(context); 14 }());
二十一: 键盘的左右键控制圆的运动
1 var canvas=document.getElementById("canvas"), 2 context=canvas.getContext("2d"), 3 ball=new Ball(), 4 vx=0,ax=0,ay=0,vy=0; 5 6 ball.x=canvas.width/2; 7 ball.y=canvas.height/2; 8 9 window.addEventListener('keydown',function(event){ 10 if(event.keyCode==37){//左 11 ax=-0.1; 12 } 13 else if(event.keyCode==39){//右 14 ax=0.1; 15 } 16 else if(event.keyCode==38){ay=-0.1;}//上 17 else if(event.keyCode==40){ay=0.1;}//下 18 },false); 19 20 21 window.addEventListener('keyup',function(){ 22 ax=0; 23 ay=0; 24 },false); 25 26 (function drawFrame(){ 27 window.requestAnimationFrame(drawFrame,canvas); 28 context.clearRect(0,0,canvas.width,canvas.height); 29 30 vx+=ax;vy+=ay; 31 ball.x+=vx; 32 ball.y+=vy; 33 ball.draw(context); 34 }());
二十二:单轴加速度
1 var canvas=document.getElementById('canvas'), 2 context=canvas.getContext('2d'), 3 ball=new Ball(), 4 vx=0,ax=0.1; 5 ball.x=50;ball.y=100; 6 7 (function drawFrame(){ 8 window.requestAnimationFrame(drawFrame,canvas); 9 context.clearRect(0,0,canvas.width,canvas.height); 10 vx+=ax; 11 ball.x+=vx; 12 ball.draw(context); 13 }());
1 双轴加速度 2 var canvas=document.getElementById("canvas"), 3 context=canvas.getContext('2d'), 4 ball=new Ball(), 5 vx=0,vy=0,ax=0,ay=0; 6 ball.x=canvas.width/2; 7 ball.y=canvas.height/2; 8 window.addEventListener('keydown',function(){ 9 switch(event.keyCode){ 10 case 37://left 11 ax=-0.1; 12 break; 13 case 39://right 14 ax=0.1; 15 break; 16 case 38: 17 ay=-0.1; 18 break; 19 case 40: 20 ay=0.1; 21 break; 22 } 23 },false); 24 window.addEventListener('keyup',function(){ 25 ax=0; ay=0; 26 },false); 27 (function drawFrame(){ 28 window.requestAnimationFrame(drawFrame,canvas); 29 context.clearRect(0,0,canvas.width,canvas.height); 30 vx+=ax; 31 vy+=ay; 32 ball.x+=vx; 33 ball.y+=vy; 34 ball.draw(context); 35 }()); 36 37 重力加速度 38 var canvas=document.getElementById("canvas"), 39 context=canvas.getContext('2d'), 40 ball=new Ball(), 41 vx=0,vy=0,ax=0,ay=0; 42 ball.x=canvas.width/2; 43 ball.y=canvas.height/2; 44 var gravity=0.02; 45 46 window.addEventListener('keydown',function(){ 47 switch(event.keyCode){ 48 case 37://left 49 ax=-0.1; 50 break; 51 case 39://right 52 ax=0.1; 53 break; 54 case 38: 55 ay=-0.1; 56 break; 57 case 40: 58 ay=0.1; 59 break; 60 } 61 },false); 62 window.addEventListener('keyup',function(){ 63 ax=0; ay=0; 64 },false); 65 (function drawFrame(){ 66 window.requestAnimationFrame(drawFrame,canvas); 67 context.clearRect(0,0,canvas.width,canvas.height); 68 69 vx+=ax; 70 vy+=ay; 71 vy+=gravity; 72 ball.x+=vx; 73 ball.y+=vy; 74 75 ball.draw(context); 76 }()); 77 78 79 角加速度 80 var canvas=document.getElementById("canvas"), 81 context=canvas.getContext('2d'), 82 mouse=captureMouse(canvas), 83 arrow=new Arrow(), 84 vx=0,vy=0,force=0.05; 85 (function drawFrame(){ 86 window.requestAnimationFrame(drawFrame,canvas); 87 context.clearRect(0,0,canvas.width,canvas.height); 88 var dx=mouse.x-arrow.x, 89 dy=mouse.x-arrow.y, 90 angle=Math.atan2(dy,dx), 91 ax=Math.cos(angle)*force, 92 ay=Math.sin(angle)*force; 93 arrow.roation=angle; 94 vx+=ax;vy+=ay; 95 arrow.x+=vx;arrow.y+=vy; 96 arrow.draw(context); 97 }()); 98 99 100 制作飞船 101 var canvas=document.getElementById("canvas"), 102 context=canvas.getContext("2d"); 103 var ship=new Ship(), 104 vr=0,vx=0,vy=0,thrust=0; 105 106 ship.x=canvas.width/2; 107 ship.y=canvas.height/2; 108 window.addEventListener('keydown',function(event){ 109 switch(event.keyCode){ 110 case 37://left 111 vr=-3; 112 break; 113 114 case 39://right 115 vr=3; 116 break; 117 118 case 38://up 119 thrust=0.05; 120 ship.showFlame=true; 121 break; 122 } 123 },false); 124 125 window.addEventListener('keyup',function(){ 126 vr=0; 127 thrust=0; 128 ship.showFlame=false; 129 },false); 130 131 (function drawFrame(){ 132 window.requestAnimationFrame(drawFrame,canvas); 133 context.clearRect(0,0,canvas.width,canvas.height); 134 ship.rotation+=vr*Math.PI/180; 135 var angle=ship.rotation, 136 ax=Math.cos(angle)*thrust, 137 ay=Math.sin(angle)*thrust; 138 vx+=ax;vy+=ay; 139 ship.x+=vx;ship.y+=vy; 140 ship.draw(context); 141 }()); 142 143 随机出现移动的小圆,移动超出边界的话,将他移除掉 144 var canvas=document.getElementById("canvas"), 145 context=canvas.getContext('2d'), 146 log=document.getElementById('log'), 147 balls=[], 148 numBalls=10; 149 150 for(var ball,i=0;i<numBalls;i++){ 151 ball=new Ball(20); 152 ball.id="ball"+i; 153 ball.x=Math.random()*canvas.width; 154 ball.y=Math.random()*canvas.height; 155 ball.vx=Math.random()*2-1; 156 ball.vy=Math.random()*2-1; 157 balls.push(ball); 158 } 159 160 function draw(ball,pos){ 161 ball.x+=ball.vx; 162 ball.y+=ball.vy; 163 if(ball.x-ball.radius>canvas.width|| 164 ball.x+ball.radius<0|| 165 ball.y-ball.radius>canvas.height|| 166 ball.y+ball.radius<0){ 167 ball.splice(pos,1); 168 if(balls.length>0){ 169 log.value="Removed"+ball.id; 170 } 171 else{ 172 log.value="All gone!"; 173 } 174 } 175 ball.draw(context); 176 } 177 (function drawFrame(){ 178 window.requestAnimationFrame(drawFrame,canvas); 179 context.clearRect(0,0,canvas.width,canvas.height); 180 var i=balls.length; 181 while(i--){ 182 draw(balls[i],i); 183 } 184 185 }()); 186 187 188 })
