用html5绘制折线图的实例代码_HTML5教程-查字典教程网

用html5绘制折线图的实例代码

摘要：XML/HTMLCode复制内容到剪贴板(function(){window.addEventListener("load",functio...

XML/HTML Code复制内容到剪贴板 <html> <canvasid="a_canvas"width="1000"height="700"></canvas> <script> (function(){ window.addEventListener("load",function(){ vardata=[100,-1000,0,700]; //获取上下文 vara_canvas=document.getElementById('a_canvas'); varcontext=a_canvas.getContext("2d"); //绘制背景 vargradient=context.createLinearGradient(0,0,0,300); //gradient.addColorStop(0,"#e0e0e0"); //gradient.addColorStop(1,"#ffffff"); context.fillStyle=gradient; context.fillRect(0,0,a_canvas.width,a_canvas.height); //描绘边框 vargrid_cols=data.length+1; vargrid_rows=4; varcell_height=a_canvas.height/grid_rows; varcell_width=a_canvas.width/grid_cols; context.lineWidth=1; context.strokeStyle="#a0a0a0"; //结束边框描绘 context.beginPath(); //准备画横线 /*for(varcol=0;col<=grid_cols;col++){ varx=col*cell_width; context.moveTo(x,0); context.lineTo(x,a_canvas.height); } //准备画竖线 for(varrow=0;row<=grid_rows;row++){ vary=row*cell_height; context.moveTo(0,y); context.lineTo(a_canvas.width,y); }*/ //划横线 context.moveTo(0,a_canvas.height/2); context.lineTo(a_canvas.width,a_canvas.height/2); //画竖线 context.moveTo(0,0); context.lineTo(0,a_canvas.height); context.lineWidth=1; context.strokeStyle="#c0c0c0"; context.stroke(); varmax_v=0; for(vari=0;i<data.length;i++){ vard=0; if(data[i]<0) {dd=d-data[i]; } else{d=data[i];}; if(d>max_v){max_v=d}; } max_vmax_v=max_v*1.1; //将数据换算为坐标 varpoints=[]; for(vari=0;i<data.length;i++){ varv=data[i]; varpx=cell_width*(i+1); varpy=a_canvas.height/2-a_canvas.height*(v/max_v)/2; points.push({"x":px,"y":py}); } //绘制折现 context.beginPath(); context.moveTo(points[0].x,points[0].y); for(vari=1;i<points.length;i++){ context.lineTo(points[i].x,points[i].y); } context.lineWidth=2; context.strokeStyle="#8BA9FF"; context.stroke(); //绘制坐标图形 for(variinpoints){ varp=points[i]; context.beginPath(); context.arc(p.x,p.y,4,0,2*Math.PI); //实心圆 /* context.fillStyle="#000";*/ //空心圆 context.strokeStyle="#000"; context.stroke(); context.fillStyle="white"; context.fill(); } //添加文字 for(variinpoints) {varp=points[i]; context.beginPath(); context.fillStyle="black"; context.fillText(data[i],p.x+1,p.y-15); } },false); })(); </script> </html>

运行结果如下：

用html5绘制折线图的实例代码1