jquery.cytoscapeweb.layout.grid.js

$(function(){
	
	var defaults = {
		
	};
	
	function GridLayout(options){
		$.cytoscapeweb("debug", "Creating grid layout with options (%o)", options);
		
		this.options = $.extend({}, defaults, options);
	}
	
	GridLayout.prototype.run = function(params){
		var nodes = params.nodes;
		var edges = params.edges;
		var renderer = params.renderer;
		var options = this.options;
		var container = $(options.selector);
		
		$.cytoscapeweb("debug", "Running grid layout with options (%o)", params);
		
		var width = container.width();
		var height = container.height();
		
		$.cytoscapeweb("debug", "Running grid layout on container of size (w, h) = (%i, %i) with %i nodes", width, height, nodes.size());
		
		if( height == 0 || width == 0){
			$.cytoscapeweb("warn", "Running grid layout on container of size 0");
			
			nodes.positions(function(){
				return { x: 0, y: 0 };
			});
			
			return;
		}
		
		// width/height * splits^2 = cells where splits is number of times to split width
		var cells = nodes.size();
		var splits = Math.sqrt( cells * height/width );
		var rows = Math.round( splits );
		var cols = Math.round( width/height * splits );
		
		$.cytoscapeweb("debug", "Grid layout decided on initial (cols, rows) = (%i, %i)", cols, rows);
		
		function small(val){
			if( val == undefined ){
				return Math.min(rows, cols);
			} else {
				var min = Math.min(rows, cols);
				if( min == rows ){
					rows = val;
					$.cytoscapeweb("debug", "Grid layout set small number of rows to %i", rows);
				} else {
					cols = val;
					$.cytoscapeweb("debug", "Grid layout set small number of columns to %i", cols);
				}
			}
		}
		
		function large(val){
			if( val == undefined ){
				return Math.max(rows, cols);
			} else {
				var max = Math.max(rows, cols);
				if( max == rows ){
					rows = val;
					$.cytoscapeweb("debug", "Grid layout set large number of rows to %i", rows);
				} else {
					cols = val;
					$.cytoscapeweb("debug", "Grid layout set large number of columns to %i", cols);
				}
			}
		}
		
		// if rounding was up, see if we can reduce rows or columns
		if( cols * rows > cells ){
			var sm = small();
			var lg = large();
			
			$.cytoscapeweb("debug", "Grid layout is looking to make a reduction");
			
			// reducing the small side takes away the most cells, so try it first
			if( (sm - 1) * lg >= cells ){
				small(sm - 1);
			} else if( (lg - 1) * sm >= cells ){
				large(lg - 1);
			} 
		} else {
			
			$.cytoscapeweb("debug", "Grid layout is looking to make an increase");
			
			// if rounding was too low, add rows or columns
			while( cols * rows < cells ){
				var sm = small();
				var lg = large();
				
				// try to add to larger side first (adds less in multiplication)
				if( (lg + 1) * sm >= cells ){
					large(lg + 1);
				} else {
					small(sm + 1);
				}
			}
		}
		
		$.cytoscapeweb("debug", "Grid layout split area into cells (cols, rows) = (%i, %i)", cols, rows);
		
		var cellWidth = width / cols;
		var cellHeight = height / rows;
		
		var row = 0;
		var col = 0;
		nodes.positions(function(i, element){
			
			if( element.locked() ){
				return false;
			}
			
			var x = col * cellWidth + cellWidth/2;
			var y = row * cellHeight + cellHeight/2;
			
			col++;
			if( col >= cols ){
				col = 0;
				row++;
			}
			
			return { x: x, y: y };
			
		});
	};
	
	$.cytoscapeweb("layout", "grid", GridLayout);
	
});