Question

I have the following function which rotates an image

function rotateImage(offsetSelector, xCoordinate, yCoordinate, imageSelector){

var x = xCoordinate - offsetSelector.offset().left - offsetSelector.width()/2;
var y = -1*(yCoordinate - offsetSelector.offset().top - offsetSelector.height()/2);
var theta = Math.atan2(y,x)*(180/Math.PI);        

var rotate = 'rotate(' + theta + 'deg)';
imageSelector.css('-moz-transform', rotate);
}

However when I call it the following way it only executes once upon a mousedown.

$('#someImage').on('mousedown', function(event){
        rotateImage($(this).parent(), event.pageX,event.pageY, $(this));    
});

My intent is for the image to rotate while it’s being grabbed and until the user lets go of the mouse click. Is there a simple way to do this without the use of external libraries?

Answer 1

Example:

var timer;
function rotateImageTimer(offsetSelector, xCoordinate, yCoordinate, imageSelector)
{
    timer = setInterval("rotateImage('"+offsetSelector+"', '"+xCoordinate+"', '"+yCoordinate+"', '"+imageSelector+"')", 100);
}


function rotateImage(offsetSelector, xCoordinate, yCoordinate, imageSelector){
    var x = xCoordinate - offsetSelector.offset().left - offsetSelector.width()/2;
    var y = -1*(yCoordinate - offsetSelector.offset().top - offsetSelector.height()/2);
    var theta = Math.atan2(y,x)*(180/Math.PI);        

    var rotate = 'rotate(' + theta + 'deg)';
    imageSelector.css('-moz-transform', rotate);      
}


$('#someImage').on('mousedown', function(event){
    rotateImageTimer($(this).parent(), event.pageX,event.pageY, $(this));  
});

$('#someImage').on('mouseup', function(event){
    clearIneterval(timer);   
});