The Window Manager General Principles
Programmer's Reference Manuals
» Part 7 - The Desktop
» The Window Manager
» Technical Details
» General Principles
Overview
One of the strengths of RISC OS is the consistency of the user interface offered by applications and the operating system. A description of the general principles of writing compliant applications can be found in the RISC OS Style Guide?.
The Style Guide? covers ease of use, consistency, hardware and software configurations, file-handling, naming fonts and application- and user-support.
Compatibility
Although the authors of the Programmer’s Reference Manuals(PRMs) have taken great care to ensure that the information provided is clear and correct, it is important that certain rules be followed by a developer. Below are some key guidelines that help to ensure fewer development-problems with previous, current and future versions of RISC OS.
| Reserved fields | must be set to 0, i.e. reserved words must be 0, and all reserved bits unset |
| Wimp_Poll | Unknown Wimp_Poll event codes must be ignored by an application. Errors must not be generated |
| WIMP Version | Applications should check the Wimp version number to identify the functionality available, and either adapt themselves accordingly or report an error if no work arounds are possible using OS_GenerateError |
| Window Handles | Be careful when handling unknown window handles. It is quite possible that an unrecognised window handle is owned by another application |
| Wimp Tasks | Wimp tasks that are Modules? must obey certain rules |
| Key Presses | Any tasks that are set to receive Key_Pressed events must pass on all unrecognised keys to Wimp_ProcessKey. Failure to do so will result in the ‘hot key’ facility not working |
Responsiveness
The RISC OS Operating System allows fast responsive applications to be written. For a complete detailed description on how to optimise the responsiveness of your application(s) please view the Screen Handling section of the RISC OS Style Guide?.
Colour
RISC OS allows a wide range of screen resolutions and colour depths. It is considered good practise to ensure that an application is not tied to any specific resolution or colour depth.
Terminology
Applications should adhere to the RISC OS Style Guide? in user-interactions. This ensures a consistent user-experience across all applications.