cairo-xlib-visual.c [plain text]
#include "cairoint.h"
#include "cairo-xlib-private.h"
#include "cairo-error-private.h"
static inline int
_color_distance (unsigned short r1, unsigned short g1, unsigned short b1,
unsigned short r2, unsigned short g2, unsigned short b2)
{
r1 >>= 8; g1 >>= 8; b1 >>= 8;
r2 >>= 8; g2 >>= 8; b2 >>= 8;
return ((r2 - r1) * (r2 - r1) +
(g2 - g1) * (g2 - g1) +
(b2 - b1) * (b2 - b1));
}
cairo_status_t
_cairo_xlib_visual_info_create (Display *dpy,
int screen,
VisualID visualid,
cairo_xlib_visual_info_t **out)
{
cairo_xlib_visual_info_t *info;
Colormap colormap = DefaultColormap (dpy, screen);
XColor color;
int gray, red, green, blue;
int i, j, distance, min_distance = 0;
XColor colors[256];
unsigned short cube_index_to_short[CUBE_SIZE];
unsigned short ramp_index_to_short[RAMP_SIZE];
unsigned char gray_to_pseudocolor[RAMP_SIZE];
for (i = 0; i < CUBE_SIZE; i++)
cube_index_to_short[i] = (0xffff * i + ((CUBE_SIZE-1)>>1)) / (CUBE_SIZE-1);
for (i = 0; i < RAMP_SIZE; i++)
ramp_index_to_short[i] = (0xffff * i + ((RAMP_SIZE-1)>>1)) / (RAMP_SIZE-1);
info = malloc (sizeof (cairo_xlib_visual_info_t));
if (unlikely (info == NULL))
return _cairo_error (CAIRO_STATUS_NO_MEMORY);
info->visualid = visualid;
for (gray = 0; gray < RAMP_SIZE; gray++) {
color.red = color.green = color.blue = ramp_index_to_short[gray];
if (! XAllocColor (dpy, colormap, &color))
goto DONE_ALLOCATE;
}
for (red = 0; red < CUBE_SIZE; red++) {
for (green = 0; green < CUBE_SIZE; green++) {
for (blue = 0; blue < CUBE_SIZE; blue++) {
color.red = cube_index_to_short[red];
color.green = cube_index_to_short[green];
color.blue = cube_index_to_short[blue];
color.pixel = 0;
color.flags = 0;
color.pad = 0;
if (! XAllocColor (dpy, colormap, &color))
goto DONE_ALLOCATE;
}
}
}
DONE_ALLOCATE:
for (i = 0; i < ARRAY_LENGTH (colors); i++)
colors[i].pixel = i;
XQueryColors (dpy, colormap, colors, ARRAY_LENGTH (colors));
for (gray = 0; gray < RAMP_SIZE; gray++) {
for (i = 0; i < 256; i++) {
distance = _color_distance (ramp_index_to_short[gray],
ramp_index_to_short[gray],
ramp_index_to_short[gray],
colors[i].red,
colors[i].green,
colors[i].blue);
if (i == 0 || distance < min_distance) {
gray_to_pseudocolor[gray] = colors[i].pixel;
min_distance = distance;
if (!min_distance)
break;
}
}
}
for (red = 0; red < CUBE_SIZE; red++) {
for (green = 0; green < CUBE_SIZE; green++) {
for (blue = 0; blue < CUBE_SIZE; blue++) {
for (i = 0; i < 256; i++) {
distance = _color_distance (cube_index_to_short[red],
cube_index_to_short[green],
cube_index_to_short[blue],
colors[i].red,
colors[i].green,
colors[i].blue);
if (i == 0 || distance < min_distance) {
info->cube_to_pseudocolor[red][green][blue] = colors[i].pixel;
min_distance = distance;
if (!min_distance)
break;
}
}
}
}
}
for (i = 0, j = 0; i < 256; i++) {
if (j < CUBE_SIZE - 1 && (((i<<8)+i) - (int)cube_index_to_short[j]) > ((int)cube_index_to_short[j+1] - ((i<<8)+i)))
j++;
info->field8_to_cube[i] = j;
info->dither8_to_cube[i] = ((int)i - 128) / (CUBE_SIZE - 1);
}
for (i = 0, j = 0; i < 256; i++) {
if (j < RAMP_SIZE - 1 && (((i<<8)+i) - (int)ramp_index_to_short[j]) > ((int)ramp_index_to_short[j+1] - ((i<<8)+i)))
j++;
info->gray8_to_pseudocolor[i] = gray_to_pseudocolor[j];
}
for (i = 0; i < 256; i++) {
info->colors[i].a = 0xff;
info->colors[i].r = colors[i].red >> 8;
info->colors[i].g = colors[i].green >> 8;
info->colors[i].b = colors[i].blue >> 8;
}
*out = info;
return CAIRO_STATUS_SUCCESS;
}
void
_cairo_xlib_visual_info_destroy (cairo_xlib_visual_info_t *info)
{
free (info);
}