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/* This file is part of the GNU plotutils package. Copyright (C) 1995,
1996, 1997, 1998, 1999, 2000, 2005, 2008, Free Software Foundation, Inc.
The GNU plotutils package is free software. You may redistribute it
and/or modify it under the terms of the GNU General Public License as
published by the Free Software foundation; either version 2, or (at your
option) any later version.
The GNU plotutils package is distributed in the hope that it will be
useful, but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
General Public License for more details.
You should have received a copy of the GNU General Public License along
with the GNU plotutils package; see the file COPYING. If not, write to
the Free Software Foundation, Inc., 51 Franklin St., Fifth Floor,
Boston, MA 02110-1301, USA. */
/* For TekPlotter objects, setting the pen color or background color has no
effect unless the plotter is using the Tektronix emulation of MS-DOS
kermit. If so, we compute a quantized color and output the appropriate
ANSI escape sequence, if the color is different from the ANSI.SYS color
the emulation is currently using.
When the TekPlotter is created, the current ANSI.SYS pen and bg colors
are set to -1 (see t_defplot.c). That's a nonsensical value, equivalent
to `unknown'. */
#include "sys-defines.h"
#include "extern.h"
#define ONEBYTE (0xff)
/* forward references */
static int kermit_pseudocolor (int red, int green, int blue);
void
_pl_t_set_pen_color(S___(Plotter *_plotter))
{
if (_plotter->tek_display_type == TEK_DPY_KERMIT)
{
int new_kermit_fgcolor;
new_kermit_fgcolor =
kermit_pseudocolor (_plotter->drawstate->fgcolor.red,
_plotter->drawstate->fgcolor.green,
_plotter->drawstate->fgcolor.blue);
if (new_kermit_fgcolor != _plotter->tek_kermit_fgcolor)
{
_write_string (_plotter->data,
_pl_t_kermit_fgcolor_escapes[new_kermit_fgcolor]);
_plotter->tek_kermit_fgcolor = new_kermit_fgcolor;
}
}
}
void
_pl_t_set_bg_color(S___(Plotter *_plotter))
{
if (_plotter->tek_display_type == TEK_DPY_KERMIT)
{
int new_kermit_bgcolor;
new_kermit_bgcolor =
kermit_pseudocolor (_plotter->drawstate->bgcolor.red,
_plotter->drawstate->bgcolor.green,
_plotter->drawstate->bgcolor.blue);
if (new_kermit_bgcolor != _plotter->tek_kermit_bgcolor)
{
_write_string (_plotter->data,
_pl_t_kermit_bgcolor_escapes[new_kermit_bgcolor]);
_plotter->tek_kermit_bgcolor = new_kermit_bgcolor;
}
}
}
/* kermit_pseudocolor quantizes to one of kermit's native 16 colors. (They
provide a [rather strange] partition of the color cube; see
t_color2.c.) */
/* find closest known point within the RGB color cube, using Euclidean
distance as our metric */
static int
kermit_pseudocolor (int red, int green, int blue)
{
unsigned long int difference = INT_MAX;
int i;
int best = 0;
/* reduce to 24 bits */
red = (red >> 8) & ONEBYTE;
green = (green >> 8) & ONEBYTE;
blue = (blue >> 8) & ONEBYTE;
for (i = 0; i < TEK_NUM_ANSI_SYS_COLORS; i++)
{
unsigned long int newdifference;
if (_pl_t_kermit_stdcolors[i].red == 0xff
&& _pl_t_kermit_stdcolors[i].green == 0xff
&& _pl_t_kermit_stdcolors[i].blue == 0xff)
/* white is a possible quantization only for white itself (our
convention) */
{
if (red == 0xff && green == 0xff && blue == 0xff)
{
difference = 0;
best = i;
}
continue;
}
newdifference = (((_pl_t_kermit_stdcolors[i].red - red)
* (_pl_t_kermit_stdcolors[i].red - red))
+ ((_pl_t_kermit_stdcolors[i].green - green)
* (_pl_t_kermit_stdcolors[i].green - green))
+ ((_pl_t_kermit_stdcolors[i].blue - blue)
* (_pl_t_kermit_stdcolors[i].blue - blue)));
if (newdifference < difference)
{
difference = newdifference;
best = i;
}
}
return best;
}
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