DZone Snippets: scroll code

Adding a 2nd level menu to a Ruby Maemo application

jrobertson (James Robertson) — Tue, 07 Oct 2008 15:57:31 GMT

Here is a script to run a Ruby Maemo application which has a scroll bar and a 2nd level menu box. The first level menu box would be application's control menu box.



#! /usr/bin/env ruby

#file: menu2.rb



#require 'gtk'

require 'hildon'



program = Hildon::Program.instance



#window = Gtk::Window.new(Gtk::WINDOW_TOPLEVEL)

window = program.add_window Hildon::Window.new



mbar = Gtk::MenuBar.new

filemitem = Gtk::MenuItem.new('File')

filemitem.show

filemenu = Gtk::Menu.new

item1 = Gtk::MenuItem.new('Open')

item1.show

filemenu.add item1

item2 = Gtk::MenuItem.new('Save')

item2.show

filemenu.add item2

item3 = Gtk::MenuItem.new('Quit')

item3.show

filemenu.add item3

filemitem.set_submenu filemenu

mbar.append filemitem

mbar.show



vadj = Gtk::Adjustment.new(0,0,0,0,0,0)



vs = Gtk::VScrollbar.new(vadj)





hbox = Gtk::HBox.new(false, 0)



hbox.pack_start vs, false, false, 0



vbox = Gtk::VBox.new(false, 0)

vbox.pack_start mbar, false, false, 0

vbox.pack_start hbox, true, true, 0

vbox.show



window.add vbox



vs.show

hbox.show

window.show

Gtk.main

You can see from the output on the N800 [twitxr.com] as I selected an item from the menu box'.

Resources:
- Adding a text entry box in a Ruby Maemo application [dzone.com]
- Ruby/Gtk Programming [sourceforge.net]

Using the mousewheel to zoom in or out an SVG document

jrobertson (James Robertson) — Tue, 08 Apr 2008 16:14:22 GMT

This code was originally copied from Mouse wheel programming in JavaScript [adomas.org]. I replaced about 5 lines of code to get the mousewheel controlling the zoom feature in the makeZoom.svg [dzone.com] file.



  /** This is high-level function; REPLACE IT WITH YOUR CODE.

 * It must react to delta being more/less than zero.

 */

function zoomInOut(delta) {

	if (delta >= 0)

		zoomIn()

	else

		zoomOut()

}



function wheel(event){

	var delta = 0;

	if (!event) event = window.event;

	if (event.wheelDelta) {

		delta = event.wheelDelta/120; 

		if (window.opera) delta = -delta;

	} else if (event.detail) {

		delta = -event.detail/3;

	}

	if (delta)

		zoomInOut(delta);

        if (event.preventDefault)

                event.preventDefault();

        event.returnValue = false;

}



/* Initialization code. */

if (window.addEventListener)

	window.addEventListener('DOMMouseScroll', wheel, false);

window.onmousewheel = document.onmousewheel = wheel;

mouse scroll-wheel events

gregg.irwin (Gregg Irwin) — Thu, 19 Jan 2006 03:07:49 GMT



; mouse-wheel scroll events

view/new layout [

	b: box "A Box" forest feel [

		engage: func [face action event] [

			if action = 'scroll-line [

				print ["Scroll line" event/offset]

			]

			if action = 'scroll-page [ ; Ctrl+wheel

				print ["scroll page" event/offset]

			]

		]

	]

]

focus b

do-events