/* xscreensaver, Copyright (c) 1993-2017 by Jamie Zawinski <jwz@jwz.org>
* Permission to use, copy, modify, distribute, and sell this software and its
* documentation for any purpose is hereby granted without fee, provided that
* the above copyright notice appear in all copies and that both that
* copyright notice and this permission notice appear in supporting
* documentation. No representations are made about the suitability of this
* software for any purpose. It is provided "as is" without express or
/* This file contains some code for intelligently picking the best visual
(where "best" is biased in the direction of either: high color counts;
or: having writable color cells...)
#include "resources.h" /* for get_string_resource() */
#include "../android/android-visual.h"
# define isupper(c) ((c) >= 'A' && (c) <= 'Z')
# define _tolower(c) ((c) - 'A' + 'a')
static Visual
*pick_best_visual (Screen
*, Bool
, Bool
);
static Visual
*pick_mono_visual (Screen
*);
static Visual
*pick_best_visual_of_class (Screen
*, int);
static Visual
*pick_best_gl_visual (Screen
*);
#define DEFAULT_VISUAL -1
#define SPECIFIC_VISUAL -7
get_visual (Screen
*screen
, const char *string
, Bool prefer_writable_cells
,
char *v
= (string
? strdup(string
) : 0);
for (tmp
= v
; *tmp
; tmp
++)
if (isupper (*tmp
)) *tmp
= _tolower (*tmp
);
if (!v
|| !*v
) vclass
= BEST_VISUAL
;
else if (!strcmp (v
, "default")) vclass
= DEFAULT_VISUAL
;
else if (!strcmp (v
, "best")) vclass
= BEST_VISUAL
;
else if (!strcmp (v
, "mono")) vclass
= MONO_VISUAL
;
else if (!strcmp (v
, "monochrome")) vclass
= MONO_VISUAL
;
else if (!strcmp (v
, "gray")) vclass
= GRAY_VISUAL
;
else if (!strcmp (v
, "grey")) vclass
= GRAY_VISUAL
;
else if (!strcmp (v
, "color")) vclass
= COLOR_VISUAL
;
else if (!strcmp (v
, "gl")) vclass
= GL_VISUAL
;
else if (!strcmp (v
, "staticgray")) vclass
= StaticGray
;
else if (!strcmp (v
, "staticcolor")) vclass
= StaticColor
;
else if (!strcmp (v
, "truecolor")) vclass
= TrueColor
;
else if (!strcmp (v
, "grayscale")) vclass
= GrayScale
;
else if (!strcmp (v
, "greyscale")) vclass
= GrayScale
;
else if (!strcmp (v
, "pseudocolor")) vclass
= PseudoColor
;
else if (!strcmp (v
, "directcolor")) vclass
= DirectColor
;
else if (1 == sscanf (v
, " %lu %c", &id
, &c
)) vclass
= SPECIFIC_VISUAL
;
else if (1 == sscanf (v
, " 0x%lx %c", &id
, &c
)) vclass
= SPECIFIC_VISUAL
;
fprintf (stderr
, "%s: unrecognized visual \"%s\".\n", progname
, v
);
if (vclass
== DEFAULT_VISUAL
)
result
= DefaultVisualOfScreen (screen
);
else if (vclass
== BEST_VISUAL
)
result
= pick_best_visual (screen
, prefer_writable_cells
, False
);
else if (vclass
== MONO_VISUAL
)
result
= pick_mono_visual (screen
);
if (!result
&& verbose_p
)
fprintf (stderr
, "%s: no monochrome visuals.\n", progname
);
else if (vclass
== GRAY_VISUAL
)
if (prefer_writable_cells
)
result
= pick_best_visual_of_class (screen
, GrayScale
);
result
= pick_best_visual_of_class (screen
, StaticGray
);
result
= pick_best_visual_of_class (screen
, GrayScale
);
if (!result
&& verbose_p
)
fprintf (stderr
, "%s: no GrayScale or StaticGray visuals.\n",
else if (vclass
== COLOR_VISUAL
)
/* First see if the default visual will do. */
result
= DefaultVisualOfScreen (screen
);
class = visual_class(screen
, result
);
if (class != TrueColor
&&
if (result
&& visual_depth(screen
, result
) <= 1)
/* Else, find the best non-default color visual */
result
= pick_best_visual (screen
, prefer_writable_cells
, True
);
if (!result
&& verbose_p
)
fprintf (stderr
, "%s: no color visuals.\n", progname
);
else if (vclass
== GL_VISUAL
)
Visual
*visual
= pick_best_gl_visual (screen
);
fprintf (stderr
, "%s: no visual suitable for GL.\n", progname
);
else if (vclass
== SPECIFIC_VISUAL
)
result
= id_to_visual (screen
, id
);
if (!result
&& verbose_p
)
fprintf (stderr
, "%s: no visual with id 0x%x.\n", progname
,
Visual
*visual
= pick_best_visual_of_class (screen
, vclass
);
fprintf (stderr
, "%s: no visual of class %s.\n", progname
, v
);
get_visual_resource (Screen
*screen
, char *name
, char *class,
Bool prefer_writable_cells
)
char *string
= get_string_resource (DisplayOfScreen (screen
), name
, class);
Visual
*v
= get_visual (screen
, string
, prefer_writable_cells
, True
);
return DefaultVisualOfScreen (screen
);
pick_best_visual (Screen
*screen
, Bool prefer_writable_cells
, Bool color_only
)
if (!prefer_writable_cells
)
/* If we don't prefer writable cells, then the "best" visual is the one
on which we can allocate the largest range and number of colors.
Therefore, a TrueColor visual which is at least 16 bits deep is best.
(The assumption here being that a TrueColor of less than 16 bits is
really just a PseudoColor visual with a pre-allocated color cube.)
The next best thing is a PseudoColor visual of any type. After that
come the non-colormappable visuals, and non-color visuals.
if ((visual
= pick_best_visual_of_class (screen
, TrueColor
)) &&
visual_depth (screen
, visual
) >= 16)
#define TRY_CLASS(CLASS) \
if ((visual = pick_best_visual_of_class (screen, CLASS)) && \
(!color_only || visual_depth(screen, visual) > 1)) \
visual
= DefaultVisualOfScreen (screen
);
if (!color_only
|| visual_depth(screen
, visual
) > 1)
pick_mono_visual (Screen
*screen
)
Display
*dpy
= DisplayOfScreen (screen
);
XVisualInfo vi_in
, *vi_out
;
vi_in
.screen
= screen_number (screen
);
vi_out
= XGetVisualInfo (dpy
, (VisualDepthMask
| VisualScreenMask
),
Visual
*v
= (out_count
> 0 ? vi_out
[0].visual
: 0);
if (v
&& vi_out
[0].depth
!= 1)
pick_best_visual_of_class (Screen
*screen
, int visual_class
)
/* The best visual of a class is the one which on which we can allocate
the largest range and number of colors, which means the one with the
greatest depth and number of cells.
(But actually, for XDaliClock, all visuals of the same class are
probably equivalent - either we have writable cells or we don't.)
Display
*dpy
= DisplayOfScreen (screen
);
XVisualInfo vi_in
, *vi_out
;
vi_in
.class = visual_class
;
vi_in
.screen
= screen_number (screen
);
vi_out
= XGetVisualInfo (dpy
, (VisualClassMask
| VisualScreenMask
),
/* choose the 'best' one, if multiple */
/* for (i = 0, best = 0; i < out_count; i++) */
for (i
= out_count
-1, best
= i
; i
>= 0; i
--) /* go backwards */
/* It's better if it's deeper, or if it's the same depth with
more cells (does that ever happen? Well, it could...) */
if ((vi_out
[i
].depth
> vi_out
[best
].depth
) ||
((vi_out
[i
].depth
== vi_out
[best
].depth
) &&
(vi_out
[i
].colormap_size
> vi_out
[best
].colormap_size
)))
visual
= (best
< out_count
? vi_out
[best
].visual
: 0);
pick_best_gl_visual (Screen
*screen
)
/* The best visual for GL is a TrueColor visual that is half as deep as
the screen. If such a thing doesn't exist, then TrueColor is best.
Failing that, the deepest available color visual is best.
Compare this function to get_gl_visual() in visual-gl.c.
This function tries to find the best GL visual using Xlib calls,
whereas that function does the same thing using GLX calls.
Display
*dpy
= DisplayOfScreen (screen
);
XVisualInfo vi_in
, *vi_out
;
int *depths
= XListDepths (dpy
, screen_number (screen
), &ndepths
);
int screen_depth
= (depths
&& ndepths
) ? depths
[ndepths
- 1] : 0;
vi_in
.screen
= screen_number (screen
);
vi_in
.depth
= screen_depth
/ 2;
vi_out
= XGetVisualInfo (dpy
, (VisualClassMask
| VisualScreenMask
|
result
= vi_out
[0].visual
;
if (!result
&& screen_depth
> 24)
/* If it's a 32-deep screen and we didn't find a depth-16 visual,
see if there's a depth-12 visual. */
vi_in
.screen
= screen_number (screen
);
vi_out
= XGetVisualInfo (dpy
, (VisualClassMask
| VisualScreenMask
|
result
= vi_out
[0].visual
;
/* No half-depth TrueColor? Ok, try for any TrueColor (the deepest.) */
result
= pick_best_visual_of_class (screen
, TrueColor
);
/* No TrueColor? Ok, try for anything. */
result
= pick_best_visual (screen
, False
, False
);
visual_info_id (Screen
*screen
, int id
)
Display
*dpy
= DisplayOfScreen (screen
);
vi_in
.screen
= screen_number (screen
);
return XGetVisualInfo (dpy
, VisualScreenMask
| VisualIDMask
,
visual_info (Screen
*screen
, Visual
*visual
)
XVisualInfo
*vi_out
= visual_info_id (screen
, XVisualIDFromVisual (visual
));
id_to_visual (Screen
*screen
, int id
)
XVisualInfo
*vi_out
= visual_info_id (screen
, id
);
Visual
*v
= vi_out
[0].visual
;
visual_depth (Screen
*screen
, Visual
*visual
)
XVisualInfo
*vi_out
= visual_info (screen
, visual
);
int d
= vi_out
[0].depth
;
/* You very probably don't want to be using this.
Pixmap depth doesn't refer to the depths of pixmaps, but rather, to
the depth of protocol-level on-the-wire pixmap data, that is, XImages.
To get this info, you should be looking at XImage->bits_per_pixel
instead. (And allocating the data for your XImage structures by
multiplying ximage->bytes_per_line by ximage->height.)
Still, it can be useful to know bits_per_pixel before the XImage exists.
XCreateImage calls _XGetBitsPerPixel to figure this out, but that function
For some reason, _XGetBitsPerPixel tries a hard-coded list of depths if
it doesn't find a matching pixmap format, but I (Dave Odell) couldn't
find any justification for this in the X11 spec. And the XFree86 CVS
repository doesn't quite go back far enough to shed any light on what
http://cvsweb.xfree86.org/cvsweb/xc/lib/X11/ImUtil.c
The hard-coded list apparently was added between X11R5 and X11R6.
See <ftp://ftp.x.org/pub/>.
visual_pixmap_depth (Screen
*screen
, Visual
*visual
)
Display
*dpy
= DisplayOfScreen (screen
);
int vdepth
= visual_depth (screen
, visual
);
XPixmapFormatValues
*pfv
= XListPixmapFormats (dpy
, &pfvc
);
/* Return the first matching depth in the pixmap formats. If there are no
matching pixmap formats (which shouldn't be able to happen at all) then
return the visual depth instead. */
for (i
= 0; i
< pfvc
; i
++)
if (pfv
[i
].depth
== vdepth
)
pdepth
= pfv
[i
].bits_per_pixel
;
visual_class (Screen
*screen
, Visual
*visual
)
XVisualInfo
*vi_out
= visual_info (screen
, visual
);
int c
= vi_out
[0].class;
has_writable_cells (Screen
*screen
, Visual
*visual
)
switch (visual_class (screen
, visual
))
case GrayScale
: /* Mappable grays. */
case PseudoColor
: /* Mappable colors. */
case DirectColor
: /* Like TrueColor, but with three colormaps:
one each for red, green, and blue. */
case StaticGray
: /* Fixed grays. */
case TrueColor
: /* Fixed colors. */
case StaticColor
: /* Like PseudoColor with an unmodifiable colormap. */
describe_visual (FILE *f
, Screen
*screen
, Visual
*visual
, Bool private_cmap_p
)
XVisualInfo
*vi_out
= visual_info (screen
, visual
);
sprintf(n
, "%3d", vi_out
->colormap_size
);
fprintf (f
, "0x%02x (%s depth: %2d, cmap: %s)\n",
(unsigned int) vi_out
->visualid
,
(vi_out
->class == StaticGray
? "StaticGray, " :
vi_out
->class == StaticColor
? "StaticColor," :
vi_out
->class == TrueColor
? "TrueColor, " :
vi_out
->class == GrayScale
? "GrayScale, " :
vi_out
->class == PseudoColor
? "PseudoColor," :
vi_out
->class == DirectColor
? "DirectColor," :
screen_number (Screen
*screen
)
Display
*dpy
= DisplayOfScreen (screen
);
for (i
= 0; i
< ScreenCount (dpy
); i
++)
if (ScreenOfDisplay (dpy
, i
) == screen
)
visual_cells (Screen
*screen
, Visual
*visual
)
XVisualInfo
*vi_out
= visual_info (screen
, visual
);
int c
= vi_out
[0].colormap_size
;
find_similar_visual(Screen
*screen
, Visual
*old_visual
)
Display
*dpy
= DisplayOfScreen (screen
);
XVisualInfo vi_in
, *vi_out
;
vi_in
.screen
= screen_number (screen
);
vi_in
.class = visual_class (screen
, old_visual
);
vi_in
.depth
= visual_depth (screen
, old_visual
);
/* Look for a visual of the same class and depth.
vi_out
= XGetVisualInfo (dpy
, (VisualScreenMask
| VisualClassMask
|
if (vi_out
&& out_count
> 0)
result
= vi_out
[0].visual
;
if (vi_out
) XFree (vi_out
);
/* Failing that, look for a visual of the same class.
vi_out
= XGetVisualInfo (dpy
, (VisualScreenMask
| VisualClassMask
),
if (vi_out
&& out_count
> 0)
result
= vi_out
[0].visual
;
if (vi_out
) XFree (vi_out
);
/* Failing that, return the default visual. */
result
= DefaultVisualOfScreen (screen
);
visual_rgb_masks (Screen
*screen
, Visual
*visual
, unsigned long *red_mask
,
unsigned long *green_mask
, unsigned long *blue_mask
)
XVisualInfo
*vi_out
= visual_info (screen
, visual
);
*red_mask
= vi_out
->red_mask
;
*green_mask
= vi_out
->green_mask
;
*blue_mask
= vi_out
->blue_mask
;