Graphics

ScreenModes

The ScreenModes module has been extended to pay attention to the limitations of the hardware as provided by the device descriptors. This allows hardware devices with different restrictions on the mode parameters to be catered for by the ScreenModes module. Similarly, the bandwidth restrictions now enforced by the ScreenModes module are provided by the video driver. The original VIDCBandwidthLimit is no longer functional in changing the limits.

The ScreenModes module will always respond to mode enumeration commands with the configuration set by the currently used display. Thus changing the current display will cause a new Service_ModeFileChanged to be issued to cause clients to re-obtain their list of available modes.

The ScreenModes_ReadInfo SWI has been extended to read the DPMS details for the currently configured MDF.

SWI ScreenModes_ReadInfo 1

On entry

   R0 = 1

On exit

   R0 = DPMS state for current mode definition

This SWI is used to read the DPMS state as configured by the currently selected MDF. This is used by the configuration tools.

System Sprite Pool

The system sprite pool is no longer controlled by the kernel. This area is now under the control of the SpriteUtils module. With this change, a legacy system call has been removed. This should not affect modern software.

OS_Byte 163, 242, 65

On entry

   R0 = 163
   R1 = 242
   R2 = 65

On exit

   R1 = packed information (see PRM 1-655)
   R2 = 0

This SWI no longer returns the size of the system sprite area. Applications should use OS_ReadDynamicArea to obtain this information.

The system sprite area should not be used by modern applications, and this change should not affect any recent software.

This documentation is copyright 3QD Developments Ltd 2013 and may not be reproduced or published in any form without the copyright holders permission. RISC OS is subject to continuous development and improvement as such all information is reproduced by 3QD Developments Ltd in good faith and is believed to be correct at the time of publication E&OE. 3QD Developments Ltd cannot accept any liability for any loss or damage arising from the use of any information provided as part of the RISC OS Documentation.

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