tweaking .direction

Signed-off-by: Alex A. Naanou <alex.nanou@gmail.com>

ui (gen4)/features/base.js

@@ -150,7 +150,7 @@ actions.Actions({
 				|| 'right'
 			: value
 
-		var steps = this.config['steps-to-change-direction']
+		var steps = this.direction_change_steps
 		var direction = this.__direction || new Array(steps)
 
 		// value ends with '!' -> force direction change...
@@ -179,6 +179,12 @@ actions.Actions({
 				// step in the opposite direction...
 				: direction.slice(0, -1)
 	},
+	// NOTE: these are set-up as props to enable dynamic customization...
+	// XXX not sure this is a good way to go...
+	get direction_change_steps(){
+		return this.config['steps-to-change-direction'] },
+	set direction_change_steps(value){
+		this.config['steps-to-change-direction'] = value },
 
 
 	// Consistency checking...

ui (gen4)/features/ui.js

@@ -131,6 +131,9 @@ var base = require('features/base')
 var ViewerActions = 
 module.ViewerActions = actions.Actions({
 	config: {
+		// make the direction steps depend on screen size...
+		'steps-to-change-direction': 'screenwidth',
+
 		// The maximum screen width allowed when zooming...
 		'max-screen-images': 30,
 
@@ -319,6 +322,15 @@ module.ViewerActions = actions.Actions({
 			'ribbon-image-separators',
 			function(state){ this.config['ribbon-image-separators'] = state }) ],
 
+	// XXX EXPERIMENTAL: direction...
+	get direction_change_steps(){
+		var steps = this.config['steps-to-change-direction'] 
+		return steps == 'screenwidth' ?
+				Math.ceil(this.screenwidth / 2)	
+			: typeof(steps) == typeof(123) ?
+				steps
+			: Math.ceil(this.screenwidth / 2) },
+
 
 	// Navigation...
 	//