Working with mouse coordinates
This recipe captures one of the mouse events, mousedown
, to find which coordinates on the canvas have been clicked. Here is the output:
How to do it
The recipe is as follows:
The HTML code is as follows:
<html> <head> <title>Mouse Coordinates example</title> <script src="mouseCoords.js"></script> </head> <body onload=init()> <canvas width="400" height="400" id="MyCanvasArea" style="border:2px solid blue;"> Canvas tag is not supported by your browser </canvas> <br> <h1>click on the canvas</h1> </body> </html>
The JavaScript code is as follows:
var ctx; var can; function init() { can=document.getElementById("MyCanvasArea"); ctx=can.getContext("2d"); can.addEventListener("mousedown",doMouseDown,false); } function doMouseDown(event) { xPos=event.pageX; yPos=event.pageY; alert("X=" + xPos + "Y=" + yPos); }
How it works...
In this example, the focus is on...