rockbox/apps/plugins/lib/gray_drawline.c

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/***************************************************************************
* __________ __ ___.
* Open \______ \ ____ ____ | | _\_ |__ _______ ___
* Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ /
* Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < <
* Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \
* \/ \/ \/ \/ \/
* $Id$
*
* Grayscale framework
* gray_drawline() function
*
* This is a generic framework to use grayscale display within Rockbox
* plugins. It obviously does not work for the player.
*
* Copyright (C) 2004 Jens Arnold
*
* All files in this archive are subject to the GNU General Public License.
* See the file COPYING in the source tree root for full license agreement.
*
* This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
* KIND, either express or implied.
*
****************************************************************************/
#ifndef SIMULATOR /* not for simulator by now */
#include "plugin.h"
#ifdef HAVE_LCD_BITMAP /* and also not for the Player */
#include "gray.h"
/*---------------------------------------------------------------------------
Draw a line from (x1, y1) to (x2, y2) with the current drawinfo
----------------------------------------------------------------------------
See gray_drawpixel() for details
*/
void gray_drawline(int x1, int y1, int x2, int y2)
{
int numpixels;
int i;
int deltax, deltay;
int d, dinc1, dinc2;
int x, xinc1, xinc2;
int y, yinc1, yinc2;
unsigned long pattern;
void (*pixelfunc)(int x, int y, unsigned long pattern);
if ((unsigned) x1 >= (unsigned) _graybuf->width
|| (unsigned) y1 >= (unsigned) _graybuf->height
|| (unsigned) x2 >= (unsigned) _graybuf->width
|| (unsigned) y2 >= (unsigned) _graybuf->height)
return;
deltax = abs(x2 - x1);
deltay = abs(y2 - y1);
xinc2 = 1;
yinc2 = 1;
if (deltax >= deltay)
{
numpixels = deltax;
d = 2 * deltay - deltax;
dinc1 = deltay * 2;
dinc2 = (deltay - deltax) * 2;
xinc1 = 1;
yinc1 = 0;
}
else
{
numpixels = deltay;
d = 2 * deltax - deltay;
dinc1 = deltax * 2;
dinc2 = (deltax - deltay) * 2;
xinc1 = 0;
yinc1 = 1;
}
numpixels++; /* include endpoints */
if (x1 > x2)
{
xinc1 = -xinc1;
xinc2 = -xinc2;
}
if (y1 > y2)
{
yinc1 = -yinc1;
yinc2 = -yinc2;
}
x = x1;
y = y1;
pixelfunc = _gray_pixelfuncs[_graybuf->drawmode];
pattern = (_graybuf->drawmode == GRAY_DRAW_BG) ?
_graybuf->bg_pattern : _graybuf->fg_pattern;
for (i = 0; i < numpixels; i++)
{
pixelfunc(x, y, pattern);
if (d < 0)
{
d += dinc1;
x += xinc1;
y += yinc1;
}
else
{
d += dinc2;
x += xinc2;
y += yinc2;
}
}
}
#endif // #ifdef HAVE_LCD_BITMAP
#endif // #ifndef SIMULATOR