Html5 Canvas : How To Handle Mousedown Mouseup Mouseclick

I been playing around with html5 canvas and ran into a problem. canvas.onmousedown = function(e){ dragOffset.x = e.x - mainLayer.trans.x; dragOffset.y = e.y - mainL

Solution 1:

A click event happens after a successful mousedown and mouseup on an element. Is there any particular reason you are using click on top of the mouse events? You should be fine with just mousedown/mouseup, click is a convenience event that saves you a little bit of coding.

I would generally do it this way:

var mouseIsDown = false;

canvas.onmousedown = function(e){
    dragOffset.x = e.x - mainLayer.trans.x;
    dragOffset.y = e.y - mainLayer.trans.y;

    mouseIsDown = true;
}
canvas.onmouseup = function(e){
    if(mouseIsDown) mouseClick(e);

    mouseIsDown = false;
}

canvas.onmousemove = function(e){
    if(!mouseIsDown) return;

    mainLayer.trans.x = e.x - dragOffset.x;
    mainLayer.trans.y = e.y - dragOffset.y;
    returnfalse;
}

functionmouseClick(e){
    // click action
}

Solution 2:

in the function mouse move set a boolean to say that a move occured, encompase all the code in mouseup and click with an if statement to check that a drag did not occur. After these if statements and before the end of the functions set the dragging boolean to false.

Solution 3:

Try declaring a variable such as clickStatus = 0; and at the start of each function check to ensure the correct value.

if (clickstatus == 0) {
     clickstatus =1;
     ...//function code
 };