你想要的效果是“透视变形”。
Canvas 的 2D 上下文无法做到这一点“开箱即用”，因为它无法将矩形变成梯形。 Canvas 2D 只能做仿射变换，只能形成平行四边形。
正如用户 @Canvas 所说，Canvas 3D (webgl) 可以进行您想要的转换。
我不久前做过这个。它使用 Canvas 2d 并使用 1 像素宽的垂直切片重新绘制图像，这些垂直切片被拉伸以“伪造”透视扭曲。欢迎您将其用作项目的起点。
示例代码和演示：http://jsfiddle.net/m1erickson/y4kst2pk/
<!doctype html>
<html>
<head>
<link rel="stylesheet" type="text/css" media="all" href="css/reset.css" /> <!-- reset css -->
<script type="text/javascript" src="http://code.jquery.com/jquery.min.js"></script>
<style>
body{ background-color: ivory; }
#canvas{border:1px solid red;}
</style>
<script>
$(function(){
var canvas=document.getElementById("canvas");
var ctx=canvas.getContext("2d");
var $canvas=$("#canvas");
var canvasOffset=$canvas.offset();
var offsetX=canvasOffset.left;
var offsetY=canvasOffset.top;
var scrollX=$canvas.scrollLeft();
var scrollY=$canvas.scrollTop();
//
var isDown=false;
var PI2=Math.PI*2;
var selectedGuide=-1;
var guides=[];
//
var marginLeft=50;
var marginTop=50;
var iw,ih,cw,ch;
var img=new Image();
img.onload=start;
img.src='https://dl.dropboxusercontent.com/u/139992952/stack1/buildings1.jpg';
function start(){
iw=img.width;
ih=img.height;
canvas.width=iw+100;
canvas.height=ih+100;
cw=canvas.width;
ch=canvas.height;
ctx.strokeStyle="blue";
ctx.fillStyle="blue";
guides.push({x:0,y:0,r:10});
guides.push({x:0,y:ih,r:10});
guides.push({x:iw,y:0,r:10});
guides.push({x:iw,y:ih,r:10});
//
$("#canvas").mousedown(function(e){handleMouseDown(e);});
$("#canvas").mousemove(function(e){handleMouseMove(e);});
$("#canvas").mouseup(function(e){handleMouseUp(e);});
$("#canvas").mouseout(function(e){handleMouseOut(e);});
drawAll();
}
function drawAll(){
ctx.clearRect(0,0,cw,ch);
drawGuides();
drawImage();
}
function drawGuides(){
for(var i=0;i<guides.length;i++){
var guide=guides[i];
ctx.beginPath();
ctx.arc(guide.x+marginLeft,guide.y+marginTop,guide.r,0,PI2);
ctx.closePath();
ctx.fill();
}
}
function drawImage(){
// TODO use guides
var x1=guides[0].x;
var y1=guides[0].y;
var x2=guides[2].x;
var y2=guides[2].y;
var x3=guides[1].x;
var y3=guides[1].y;
var x4=guides[3].x;
var y4=guides[3].y;
// calc line equations slope & b (m,b)
var m1=Math.tan( Math.atan2((y2-y1),(x2-x1)) );
var b1=y2-m1*x2;
var m2=Math.tan( Math.atan2((y4-y3),(x4-x3)) );
var b2=y4-m2*x4;
// draw vertical slices
for(var X=0;X<iw;X++){
var yTop=m1*X+b1;
var yBottom=m2*X+b2;
ctx.drawImage( img,X,0,1,ih,
X+marginLeft,yTop+marginTop,1,yBottom-yTop );
}
// outline
ctx.save();
ctx.translate(marginLeft,marginTop);
ctx.beginPath();
ctx.moveTo(x1,y1);
ctx.lineTo(x2,y2);
ctx.lineTo(x4,y4);
ctx.lineTo(x3,y3);
ctx.closePath();
ctx.strokeStyle="black";
ctx.stroke();
ctx.restore();
}
function handleMouseDown(e){
e.preventDefault();
var mouseX=parseInt(e.clientX-offsetX);
var mouseY=parseInt(e.clientY-offsetY);
// Put your mousedown stuff here
selectedGuide=-1;
for(var i=0;i<guides.length;i++){
var guide=guides[i];
var dx=mouseX-(guide.x+marginLeft);
var dy=mouseY-(guide.y+marginTop);
if(dx*dx+dy*dy<=guide.r*guide.r){
selectedGuide=i;
break;
}
}
isDown=(selectedGuide>=0);
}
function handleMouseUp(e){
e.preventDefault();
isDown=false;
}
function handleMouseOut(e){
e.preventDefault();
isDown=false;
}
function handleMouseMove(e){
if(!isDown){return;}
e.preventDefault();
var x=parseInt(e.clientX-offsetX)-marginLeft;
var y=parseInt(e.clientY-offsetY)-marginTop;
var guide=guides[selectedGuide];
guides[selectedGuide].y=y;
if(selectedGuide==0 && y>guides[1].y){guide.y=guides[1].y;}
if(selectedGuide==1 && y<guides[0].y){guide.y=guides[0].y;}
if(selectedGuide==2 && y>guides[3].y){guide.y=guides[3].y;}
if(selectedGuide==3 && y<guides[2].y){guide.y=guides[2].y;}
drawAll();
}
}); // end $(function(){});
</script>
</head>
<body>
<h4>Perspective Warp by vertically dragging left or right blue guides.</h4>
<canvas id="canvas" width=300 height=300></canvas>
</body>
</html>