javascript - HTML / Java Script Canvas - how to draw an image between source and destination points?

Question

I've tried to use the drawImage function of the canvas.

In the documentation (http://msdn.microsoft.com/en-us/library/ie/ff975414(v=vs.85).aspx) I thought the last two parameters are the destination point, but I guess it's not because it's not working.

Is there a way to draw image between two points without rotate it or something like this?

Thanks!

Answer 1

context.drawImage( 
    sourceImage, 
    sourceX, sourceY, sourceWidthToClip, sourceHeightToClip, 
    canvasX, canvasY, scaledWidth, scaledHeight );

In context.drawImage the first parameter is the source image.

The next 4 parameters are the x,y,width & height rectangular sub-image to clip from that source

The last 4 parameters are the x,y,scaledWidth & scaledHeight rectangular scaled image to draw on the canvas.

Annotated drawImage:

context.drawImage(

    sourceImage,  // the source image to clip from

    sX,           // the left X position to start clipping 
    sY,           // the top Y position to start clipping
    sW,           // clip this width of pixels from the source
    wH,           // clip this height of pixels from the source

    dX,           // the left X canvas position to start drawing the clipped sub-image
    dY,           // the top Y canvas position to start drawing the clipped sub-image
    dW,           // scale sW to dW and draw a dW wide sub-image on the canvas
    dH            // scale sH to dH and draw a dH high sub-image on the canvas

}

Visual drawImage:

![enter image description here][1]

Code example for drawImage:

var canvas=document.getElementById("canvas");
var ctx=canvas.getContext("2d");
var canvas1=document.getElementById("drawImage");
var ctx1=canvas1.getContext("2d");

var img=new Image();
img.onload=start;
img.src="https://dl.dropboxusercontent.com/u/139992952/stackoverflow/avatars.jpg";
function start(){

  canvas.width=img.width;
  canvas.height=img.height;
  ctx.drawImage(img,0,0);

  var scale=2;
  canvas1.width=471/5*3;
  canvas1.height=255/2*3;

  ctx1.drawImage(img,
                 94,0,94,120,
                 50,50,94*scale,120*scale
                );
}

body{ background-color: ivory; padding:10px; }
canvas{border:1px solid red;}

<h4>The original image</h4>
<canvas id="canvas" width=300 height=300></canvas><br>
<h4>The clipped & scaled sub-image drawn into the canvas</h4>
<canvas id="drawImage" width=300 height=300></canvas>