Spacer – Grid helper to get cell coordinates

spacer.js

var Spacer = function() {
	this.width = null;
	this.height = null;
	
	this.columns = 0;
	this.rows = 0;
	
	this.xSpacing = 0;
	this.ySpacing = 0;
	
	this.xMargin = 0;
	this.yMargin = 0;
};

Spacer.prototype.setWidth = function(arg) { this.width = arg; }
Spacer.prototype.setHeight = function(arg) { this.height = arg; }
Spacer.prototype.setColumns = function(arg) { this.columns = arg; }
Spacer.prototype.setRows = function(arg) { this.rows = arg; }
Spacer.prototype.setXSpacing = function(arg) { this.xSpacing = arg; }
Spacer.prototype.setYSpacing = function(arg) { this.ySpacing = arg; }
Spacer.prototype.setXMargin = function(arg) { this.xMargin = arg; }
Spacer.prototype.setYMargin = function(arg) { this.yMargin = arg; }

Spacer.prototype.getColumnWidth = function(column) { return (this.width - this.xMargin*2 - (this.columns-1)*this.xSpacing) / this.columns; }
Spacer.prototype.getRowHeight = function(row) { return (this.height - this.yMargin*2 - (this.rows-1)*this.ySpacing) / this.rows; }

Spacer.prototype.getColumnX = function(column) { return this.xMargin + column*(this.getColumnWidth()+this.xSpacing); }
Spacer.prototype.getRowY = function(row) { return this.yMargin + row*(this.getRowHeight()+this.ySpacing); }
Spacer.prototype.getReverseRowY = function(row) { var row = this.rows-row; return this.yMargin + row*(this.getRowHeight()+this.ySpacing); }