Chapter 5. Jeszra Design Samples
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Chapter 5. Jeszra Design Samples

Table of Contents

Introduction
Jeszra on AQUA®
Bright Designs under X Window System
LightX11
GrayX11
WhiteX11
Dark Designs under X Window System
SafariX11
BlackX11
Miscellaneous Designs
SeaX11
Minor Designs
Inside Documentation

Introduction

Jeszra accepts and follows the platform specific HCI-Guidelines. Under X Window System there is however no single HCI-Guideline, but a multitude thereof.

There are a series of predefined X Window System designs for Jeszra, providing a usable interface right away. Feel invited to use these designs as the foundation of your own application designs.

Integrated Designs

Specialized Designs

The presented designs address visual disabilities and integration issues.

The rule number one in Graphical User Interface design: »It must be usable«. This is easier stated than achieved. At least half of humankind has some sort of visual handicap.

Blindness is of no concern here. A graphical oriented user interface is not suited for blind people.

A well crafted Graphical User Interface addresses visual disabilities and assists persons by using it; such a software could truly be called: »easy to use«.

Design is not about mimicry or fashion.

The best and easiest method to address visual disabilities is to integrate supportive technologies into the basic windowing system. This was done by Apple Inc.® with Apple® OSX, case closed!

Unfortunately, the competition has still a rough way ahead to resolve these issues. Leaving it to the application designers to shoulder this task.

»Theming« is an alternate approach. Themes are around since a very long time. The amount of what is themed today is much wider, but the principle is the same as with Windows 3.0, MacOS and X Resource Database.

The idea behind themes is: To allow variations in font, foreground and background colours. With these variations all visual disabilities have to be addressed.

In context with Tcl/Tk customization is done through the Option Database. The Option Database is inspired and follows the principles of X Resource Database. X Resource Database is amongst the earliest theming techniques and the only one which almost worked.

Use the Option Database for every window property, except those with functional intent.

Functional Properties

command, variable, value, onValue, offValue, x and y -ScrollCommand, x and y start and stop -Command, takeFocus, cursor, textVariable, jump, widget, show, scrollRegion, x and y -ScrollIncrement, state, type, listType, creator, ...

Are typical functional properties. Do not customize these properties through the Option Database.

Functional properties constitute the behaviour of the software;. To allow these properties to be changed, by passing them through the Option Database, would cause endless support calls; and may render the software utterly useless.

There are exceptions from this: The »Splines« feature inside the »General« preferences page is passed through the Option Database. A 3rd-party package »TclSplines« is required for this function and Jeszra tracks the presence of tclsplines through the Option Database.

selectColor, selectBackground, selectForeground, activeForeground, activeBackground, font, label, title, aspect, justify, anchor, pad X and Y, image, text, disabledBackground, disabledForground, background, foreground, readonlyBackground, relief, borderWidth, accelerator, indicatorOn, selectimage, height, width

are typical resources. These properties should always being passed through the Option Database.

Using the Option Database for properties has an massive performance advantage over the command line. The difference has lessened in Tk 8.5, but still leads to significant faster software.

Using the Option Database increases the code size and performance. An application using the Option Database may be twice as fast as one using the command line alone.

Example 5.1. Option Database Code

option add *Gestalt.background red4
option add *Gestalt.foreground white

Example 5.2. Command Line Code

# Use the command line for
# functional properties:
gestalt .gestalt -foreground red4 \
                 -background white

Starting with Tcl/Tk version 8.5: Tile, a theming engine, is bundled with Tcl/Tk. Tile bypasses the Option Database mechanism concerning colours and fonts.

Tile comes with some »themes« on X Window System, but none of the provided themes is designed with the intend to provide accessible assistance. In addition, Tile by itself doesn’t answer to theme changes initiated by the dominant desktop environments: KDE and gnome. Under X Window System the application is better integrated with KDE and gnome without using Tile. Both KDE and gnome modify the X Resource Database .XResources file, which is mirrored within the Option Database.

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Experimental Layout using Pack ↑ Jeszra on AQUA®
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Copyright © 2009–2010 Arndt Roger Schneider