| Re: [AD] Using system mouse cursor |
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Evert Glebbeek wrote:
Except that the term hardware cursor is already used by Allegro in the
sense in which I used it and the term system cursors was not yet defined.
So the distinction is in that sense historical.
The only distinction should be which cursor the mouse driver sets (the
Allegro default or system default).
If the system has no default cursor, wouldn't there be no system
cursor(s) to draw?
Allegro draws its own default cursor (the black arrow or the black watch)
in that case, with the current setup. To be honest, I'd rather have it
fail outright when a system cursor is requested that isn't available
instead of switching back to a soft cursor.
If Allegro can't set a system cursor, no it shouldn't switch back to a
software cursor. It should switch to a custom hardware cursor, using
Allegro's default cursors.
But Allegro itself would never draw system or (custom) hardware cursors.
See above. Allegro draws its own default cursor as a system cursor if there
is no real system cursor to draw.
In that case it should use Allegro's default cursors as hardware
cursors, so that you still get a "default" cursor (the system's if it
has one, or Allegro's) done by the OS/hardware.
At the API level, there are two other types of cursor: custom and system.
Why are these seperate at the API level? The only way to get a system
cursor is to pass NULL to set_mouse_cursor, but this can still give you
a custom cursor if a system one isn't available. How does/why should the
API differ past that?
Custom cursors are typically soft cursors, although some drivers can use a
hard cursor to display a custom cursor shape. This is the only cursor type
that existed in Allegro upto now.
System cursors are typically hard cursors where the shape is determined by
the OS, except when the driver does not offer this functionality: then
they are soft cursors drawn by Allegro with their shape determined by
Allegro.
I think you're over-analyzing it. Custom cursors are done in software,
unless the mouse driver can put them into hardware/the OS (and the
appropriate function has been called). If a NULL cursor bitmap has been
set to use, it selects a system cursor if available, or else it uses
Allegro's default (in hardware).
So the difference between using a system cursor or custom hardware
cursor is just what bitmap is set (NULL or not) and what the mouse
driver supports. Allegro itself shouldn't differentiate beyond that.
It would
be a lot easier if system cursors are always hard cursors (meaning that
Allegro will never try to draw its own).
Allegro shouldn't. If someone calls enable_hardware_mouse() then
set_mouse_cursor(MOUSE_CURSOR_ARROW, bitmap), this is how Allegro would
attempt to set it up when select_mouse_cursor(MOUSE_CURSOR_ARROW) is called:
* If bitmap is NULL, try to set a system cursor (done by the OS/hardware).
* If that fails/isn't available/bitmap isn't NULL, try to set a custom
hardware cursor using bitmap (if not NULL) or Allegro's default.
* If that fails (shouldn't if bitmap is NULL), set a software cursor.
- Kitty Cat