function imgZoomer(imgObj,canvas_width,canvas_height){
	var obj=imgObj;
	var src_width=GetImageWidth(obj);
	var src_height=GetImageHeight(obj);
	var widthScale=src_width/canvas_width;
	var heightScale=src_height/canvas_height;
	if(widthScale>=1||heightScale>=1){
		if(widthScale<heightScale){
			obj.width=src_width/heightScale;
			obj.height=canvas_height;
		}else{
			obj.width=canvas_width;
			obj.height=src_height/widthScale;
		}
	}else{
		obj.width=src_width;obj.height=src_height;
	}
}
function GetImageWidth(oImage){
	var OriginImage=new Image();
	OriginImage.src=oImage.src;
	return OriginImage.width;
}
function GetImageHeight(oImage){
	var OriginImage=new Image();
	OriginImage.src=oImage.src;
	return OriginImage.height;
}