The icon bar is a window which is located at the bottom of the screen. Its purpose is three-fold.
1 | To provide access to filing systems and device icons (left side of icon bar) |
2 | To provide access to loaded applications (right side of icon bar) |
3 | To provide access to the Task Manager and Display Manager (right most side of icon bar) |
It provides access by means of displaying an icon that represents the application, filing system or device icon.
If there are too many icons on the icon bar that it fills up, then the Wimp will automatically scroll the icon bar whenever the mouse pointer is positioned close to either end of the bar.
An icon placed on the icon bar can also have text underneath it. It is up to the application to decide the purpose of the text.
When an application, filing system or device wishes to be registered on the icon bar, the Wimp_CreateIcon is used (with the appropriate window handle). It is the window handle that determines where on the icon bar the icon should be placed.
In adherence to the RISC OS Style Guide the icon used should be the sprite used within the Filer for the application itself. i.e. for example; the !Edit application.
When the mouse pointer is clicked on an icon, the Wimp returns the Mouse_Click event (with a window handle of -2) to the application which created the icon originally.
Also, calling Wimp_GetPointerInfo returns a window handle of -2 when the pointer is partially or completely over the icon bar.
When the Wimp is called to place an icon on the bar (registering an icon), it uses the icon’s x co-ordinates (see Wimp_CreateIcon) only to determine its width. The Wimp then decides how best to position the icon.
However, the Wimp does uses both the icon’s y co-ordinates to determine the icons vertical position. The result of this, is that applications must be aware of the ‘standard’ dimensions of the icon bar, in order to position their icons correctly.
Icons that appear on the icon bar should have a width and height of 68 OS units square.
For a full detailed description on how to position Icons can be found in the Positioning icons on the icon bar? section within the RISC OS Style Guide.