gfx_mode_select_filter(3) Allegro manual gfx_mode_select_filter(3)NAMEgfx_mode_select_filter - Even more extended version of the graphics
mode selection dialog. Allegro game programming library.
SYNOPSIS
#include <allegro.h>
int gfx_mode_select_filter(int *card, int *w, int *h, int *color_depth,
int (*filter)(int, int, int, int));
DESCRIPTION
Even more extended version of the graphics mode selection dialog, which
allows the programmer to customize the contents of the dialog and the
user to select the color depth as well as the resolution and hardware
driver. `filter' will be passed (card, w, h, color_depth) quadruplets
and must return 0 to let the specified quadruplet be added to the list
of displayed modes.
As with gfx_mode_select, the values stored at the addresses passed to
the function will be used as suggestions for the initial selections in
the dialog, defaulting to the first entry in each list if the values
are not found. Initialize the data stored at the addresses passed to
the function to the value of 0 or -1 if you want to ensure that the
initial selection for each list will be the first entry.
If the dialog is OK'd, it stores the selections at the addresses passed
to the function.
Example usage :
ret = gfx_mode_select_filter(&card, &w, &h, &color_depth, user_filter);
if (ret) {/* User okayed dialog or user_filter removed all modes */
if (card == GFX_NONE) {
// No modes available
*card = 0;/* Make sure not to leave *card == GFX_NONE */
return -1;
}
/* Handle changing to new mode here... */
} else {/* User cancelled dialog or there was an error (unlikely) */
if (card == GFX_NONE) {
/* Error, probably out of memory */
*card = 0;/* Make sure not to leave *card == GFX_NONE */
return -2;
}
/* Carry on in current graphics mode if that is acceptable */
}
RETURN VALUE
Returns zero if the user cancelled the dialog or an error occurred. In
the case of an error then *card is assigned the value GFX_NONE. The
functions return non-zero if the user made a selection OR if all the
modes were filtered out. In the case that all of the modes were fil‐
tered out, then *card is assigned the value GFX_NONE. This means you
should NOT initialize the *card to the value of GFX_NONE, as it could
interfere with determining the proper return value.
SEE ALSOgfx_mode_select(3), gfx_mode_select_ex(3), set_color_depth(3),
set_gfx_mode(3), gui_fg_color(3)Allegro version 4.4.2 gfx_mode_select_filter(3)
