利用canvas实现的加载动画效果实例代码

/*核心代码*/

/*分析动画，其实动画只有两次的执行*/

varfor_index = 1;//记录当前执行动画的序列

varinterval = setInterval(function(){

if(for_index == 1){

if(squre4.x == origin_squre.x - step * 2){

for_index = 2;

}else{

squre2.x -= 2;

squre2.y += 1;

squre4.x += 2;

squre4.y -= 1;

}

}elseif(for_index == 2){

if(squre4.x == origin_squre.x){

for_index = 1;

/*重置方块位置信息到初始值*/

init_squre(origin_squre.x,origin_squre.y);

}else{

squre3.x -= 2;

squre3.y -= 1;

squre2.x -= 2;

squre2.y -= 1;

squre4.x += 2;

squre4.y += 1;

squre1.x += 2;

squre1.y += 1;

}

}

ctx.clearRect(0,0,canvas.width,canvas.height);

/*重绘方块*/

if(for_index == 1 || for_index == 2){

draw_squre(squre4);

draw_squre(squre1);

draw_squre(squre3);

draw_squre(squre2);

}

/*重绘阴影*/

get_shaow_pos();

for(variinshaow_begin){

draw_shaow(shaow_begin[i]);

}

},1000 / 24);