John Rickman RISC OS Notes

Sprites
# The system Sprite Pool
The RISC-OS Window Manager maintains a common pool of sprites which
can be used by any WIMP program. The sprite pool is split in two: one
area is held in ROM and the other is held in the RMA. The ROM area
contains many of the sprites seen on the desktop e.g. floppy
disc, file types, default pointer, etc and the RMA sprite area
contains any sprites that have been put there by programs.

When a sprite (in the pool) is accessed, the Window Manager will
first look in the RMA area and if the required sprite is not found
there, it will look in the ROM area. This means that the standard
definitions can be 'redefined'.

To force the system to re-read a sprite file
you must issue a *Iconsprites command, with a parameter telling
the system which file to re-read.
use  !GRAB2 - to view sprites in the system sprite pool

# Sprite files and sizes for applications
Sprites files names indicate the size if the sprite image:

!Sprites         34x17 - 3316 bytes mode 15
!Sprites22       34x34 - 4  k bytes mode 21
!Sprites11       68x68 - 7  k bytes 256 colours
the numbers are the x and y resolutions,

 22    90dpix90dpi,
 24    90x45
 11    180x180dpi :-)

Icons that appear on the iconbar should have a width and height
of 68 OS units square according to the PRM
# Sprite Sources
View Sprite files !NoPaint not !Paint as it supports drag and drop

Run !Grab2 to see system sprites from  Resources:$.Resources.Wimp

Ovation button sprites are in:
 RES.Ovation.DavidPilling.OvationPro.!OvnPro.!OvnResDir.UK.Buttons

JR sprite collection is  ADFS::Panto.$.CLIPS.IconSprites


# To create sprites in Artworks -
make sure AW is showing pixel units
size graphic to required sprite size - useful size 34x34 16 colours
you can do this by putting a rectangle of the correct size behind it.
the recatangle should have fill colour and line colour of none
this will allow the mask option to produce a transparent background

export sprite using bitmap sprite export from Artworks
 set (masked)
 set number of colours to 256 or 16

After changing the name of a sprite double click on !boot -
which runs  !Sprites

Note - if you want system to generate small sprites then name of app
must be short enough to allow "sm" to be inserted in the name

# to find a sprite
 the sprites are named by file type
 - eg file_fff is the sprite for text files.
to extract a sprite
copy the sprite11 file to RAM - drop on to Paint - select and save
the sprite u want

to use the new sprites in artworks use photodesk to convert to RGB and
save as jpeg