pngdriver/box.c

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/*!
   \file lib/pngdriver/box.c
 
   \brief GRASS png display driver - draw box
 
   (C) 2003-2014 by Per Henrik Johansen and the GRASS Development Team
 
   This program is free software under the GNU General Public License
   (>=v2). Read the file COPYING that comes with GRASS for details.
 
   \author Per Henrik Johansen (original contributor)
   \author Glynn Clements
 */
 
#include <math.h>
#include "pngdriver.h"
 
/*!
   \brief Draw a (filled) rectangle
 
   \param fx1,fy1,fx2,fy2 rectangle coordinates
 */
void PNG_Box(double fx1, double fy1, double fx2, double fy2)
{
    int x1 = (int)floor(fx1 + 0.5);
    int y1 = (int)floor(fy1 + 0.5);
    int x2 = (int)floor(fx2 + 0.5);
    int y2 = (int)floor(fy2 + 0.5);
    int tmp;
    int x, y;
 
    if (x1 > x2)
        tmp = x1, x1 = x2, x2 = tmp;
 
    if (y1 > y2)
        tmp = y1, y1 = y2, y2 = tmp;
 
    if (x2 < 0 || x1 > png.width)
        return;
 
    if (y2 < 0 || y1 > png.height)
        return;
 
    if (x1 < png.clip_left)
        x1 = png.clip_left;
 
    if (x2 > png.clip_rite)
        x2 = png.clip_rite;
 
    if (y1 < png.clip_top)
        y1 = png.clip_top;
 
    if (y2 > png.clip_bot)
        y2 = png.clip_bot;
 
    for (y = y1; y < y2; y++) {
        unsigned int *p = &png.grid[y * png.width + x1];
 
        for (x = x1; x < x2; x++)
            *p++ = png.current_color;
    }
 
    png.modified = 1;
}