The SeaX11 design is widely applicable. It is suitable for hyper-sensitive eyesight. SeaX11 operates well in light and dimmed environments as-well.
The modest contrast makes SeaX11 suitable for persons with astigmatism.
The designs presented in the section called “Bright Designs under X Window System” and the section called “Dark Designs under X Window System” address normal usage, hyper-sensitive, astigmatism and to some extent diminished eyesight. All of this might still not suffice to create a usable Graphical User Interface, which will be addressed in this section.
Diminished eyesight requires large fonts and icons. Jeszra is a fully vectorized application. There are no bitmaps whatsoever being used inside the Graphical User Interface.
Jeszra’s icons are font glyphs from the »Gestalt.ttf« font or complex vector graphics. . The font »Gestalt.ttf« must have been installed for using glyphs as icons. Otherwise Jeszra deploys bitmaps as a fall-back solution.
The simplest method to increase fonts and
icons is to heighten the resolution.
Tcl/Tk features a special command
tk scaling
, which queries the display
resolution and allows to redefine the resolution for the
running application.
tk scaling
must be altered before any window
–except for the Tk-root window– gets created.
Specifying tk scaling
later
results in a mostly unusable Graphical User Interface, featuring
elements with mixed resolutions.
Example 5.3, “Using tk scaling” sets the resolution to 108ppi. The icons and fonts increase by 50%. The default value for scaling is 1.0, which is identical to 72ppi.
Do not try to mitigate a misconfigured X Window System server by specifying fonts in pixels.
Example 5.3, “Using tk scaling” calls lightX11 and it has to be placed inside the same directory –indicated by the leading dot-slash ./ – the Jeszra home directory. Of course, all the presented designs are resolution independent and may be used with any scaling value.
Short sighted people tend to reduce the Graphical User Interface font size. Reducing the font makes more of the Graphical User Interface visible from a short distance. Instead of designing for short-sightness: use tk scaling , by reducing its value below the display resolution, to support short-sighted people.
Every non functional aspect of Jeszra is customized through the Option Database. The various designs, ranging from AQUA® to the section called “Inside Documentation”, are nothing else but Option Database variations. There is an alternative approach to customizing the Option Database: The Option Database is inspired by the X Resource Database and can be utilized in the same way. was already mentioned. Jeszra seeks to load a special resource file Jeszra from the XAPPLRESDIR. The Jeszra resource file is located in the following order:
Example 5.4, “BigFonts highlightThickness” displays an excerpt from BigFonts related to »highlightThickness«. higlightThickness is set to 5 point for every »Button« control. The »p« (point) after 5 instructs Tk, that »5« is an resolution independent value.
Example 5.6. TkPath Specific Resources
*Rtl_tree.fontfamily: {bitstream vera sans} *Rtl_tree.fontsize: 18
»glyphFontFamily« and »glyphFontSize« in Example 5.7, “Jeszra Specific Resources” defines the icon font inside the Jeszra hierarchy view. These entries are application specific and thus the full window pathname is stated, starting from the window with class »Gestalt«: *Gestalt.space.document.hierarchy.
The resource entries »fontfamily« and »fontsize« in Example 5.6, “TkPath Specific Resources” are TkPath related entries. The Rtl_tabset window uses separate font definitions for Tk fonts and those originating from TkPath.
The Aquaish resource file gets used in combination with AQUA®. Its purpose is to vectorize the entire Graphical User Interface under AQUA®, with the intent to create Scalable Vector Graphics from it. These resource file instructs Gstripes to ignore the original AQUA® controls and to supplant them. The Gstripes Option Database property ».force« controls this behavior.
Aquaish deploys multiple layered, semi-transparent gradients to generate the AQUA®-look. Support for transparency and layered gradients is currently incomplete in FOP, which is why Figure 5.6, “Aquaish General Preferences” differs markedly from the original Scalable Vector Graphics.