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HomeWeb Front-endHTML Tutorialhtml4画直线不是用的html5技术_html/css_WEB-ITnose

html4 画直线 div模拟点 直线算法

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  <script> <br /> //能画直线就能画其他的图像,只是需要相应的算法,不过这样用性能不是很好,当然一下的代码还有不完善的地方,在这里只是做个演示 <br /> //因为公司最近要做个图像化的功能,我只会js <br /> function Point(x,y,c){//用一个div模拟一个像素点x和y是坐标c是颜色 <br /> var div; <br /> this.div=document.createElement("div"); <br /> this.div.style.fontSize="0px"; <br /> this.div.style.overFlow="hidden"; <br /> this.div.style.width="1px"; <br /> this.div.style.height="1px"; <br /> this.div.style.position="absolute"; <br /> this.div.style.backgroundColor=c; <br /> this.div.style.top=y+"px"; <br /> this.div.style.left=x+"px"; <br /> document.body.appendChild(this.div); <br /> <br /> } <br /> <br /> <br /> <br /> <br /> function drawLine(x0,y0,x1,y1,c){//画一条直线x0,y0,x1,y1分别是开始坐标和结束坐标c是颜色 <br /> var x,y; <br /> var cx,cy; <br /> var steps=Math.abs(x1-x0)>Math.abs(y1-y0)?Math.abs(x1-x0):Math.abs(y1-y0); <br /> x=parseFloat(x0); <br /> y=parseFloat(y0); <br /> cx=(x1-x0)/steps; <br /> cy=(y1-y0)/steps; <br /> for(var i=0;i<steps;i++){ <br /> new Point(Math.round(x),Math.round(y),c); <br /> x+=cx; <br /> y+=cy; <br /> } <br /> <br /> } <br /> // drawLine(0,0,200,200,"red"); <br /> /* for(var i=0;i<1000;i+=20){ <br /> //drawLine(0,0,200,i,"#00ff00"); <br /> drawLine(i,0,i,1000,"#00ff00"); <br /> drawLine(0,i,1000,i,"#00ff00"); <br /> }*/ <br /> drawLine(20,1000,0,0,"#00ff00"); <br /> var posX,posY,selectDiv;//这里的 selectDiv是一个选择框 <br /> document.onmousedown=function(e){ <br /> if(!e)e=window.event; <br /> posX=e.clientX; <br /> posY=e.clientY; <br /> selectDiv=document.createElement("div"); <br /> selectDiv.style.fontSize="0px"; <br /> selectDiv.style.overFlow="hidden"; <br /> selectDiv.style.width="1px"; <br /> selectDiv.style.height="1px"; <br /> selectDiv.style.position="absolute"; <br /> <br /> selectDiv.style.top=posY+"px"; <br /> selectDiv.style.left=posX+"px"; <br /> selectDiv.style.border="1px dashed #B3B3B3"; <br /> document.body.appendChild(selectDiv); <br /> <br /> } <br /> document.onmousemove=function(e){ <br /> if(!e)e=window.event; <br /> if(selectDiv){ <br /> <br /> selectDiv.style.width=(e.clientX-posX)+"px"; <br /> selectDiv.style.height=(e.clientY-posY)+"px"; <br /> drawLine(posX,posY,e.clientX,e.clientY,"red"); <br /> } <br /> } <br /> <br /> <br /> //new Point(20,20,"green"); <br /> </script>


回复讨论(解决方案)



屏幕绘制像素级别的直线可以直接确定每个点的坐标 因为不会出现小数坐标

x 每个点必须 1-x
y 根据 1 - (1-x)/(x/y)比例增加 

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