rpi4-osdev/part12-wgt/wgt/wline.c
2021-03-25 09:20:48 +00:00

123 lines
2.5 KiB
C

#include "../include/wgt.h"
void wline (short x, short y, short x2, short y2)
{
short t;
short wx = 0, wy = 0;
short dx, dy;
short bdx, bdy;
short incx, incy, addrow;
unsigned int *temp;
if ((x != x2) && (y != y2)) /* Diagonal lines */
{
dx = x2 - x;
dy = y2 - y;
t = 0;
wx = 0;
wy = 0;
if (dy < 0)
incy = - 1;
else incy = 1;
addrow = incy * WGT_SYS.xres;
if (dx < 0)
incx = - 1;
else incx = 1;
bdx = abs (dx);
bdy = abs (dy);
temp = &abuf[y * WGT_SYS.xres + x];
if (bdx > bdy)
{
while (t <= bdx)
{
if ((x >= tx) && (y >= ty) && (y <= by) && (x <= bx)) /* Clip */
*temp = currentcolor;
wy += bdy;
x += incx;
temp += incx;
t++;
if (wy >= bdx)
{
wy -= bdx;
y += incy;
temp += addrow;
}
}
}
else
{
while (t <= bdy)
{
if ((x >= tx) & (y >= ty) & (y <= by) & (x <= bx))
*temp = currentcolor;
wx += bdx;
if (wx >= bdy)
{
wx -= bdy;
x += incx;
temp += incx;
}
y += incy;
temp += addrow;
t++;
}
}
}
else if ((y == y2) && (y >= ty) && (y <= by))
/* Horizontal line */
{
if (x > x2) /* Swap x coords */
{
t = x;
x = x2;
x2 = t;
}
if (x < tx)
x = tx; /* Clip the line */
if (x2 > bx)
x2 = bx;
if (x2 - x >= 0)
memset (&abuf[y * WGT_SYS.xres + x], currentcolor, x2 - x + 1);
}
else if ((x == x2) && (x >= tx) && (x <= bx))
/* Vertical line */
{
if (y > y2) /* Swap y coords */
{
t = y;
y = y2;
y2 = t;
}
if (y < ty)
y = ty; /* Clip the line */
if (y2 > by)
y2 = by;
temp = &abuf[y * WGT_SYS.xres + x];
for (t = y; t <= y2; t++)
{
*temp = currentcolor;
temp += WGT_SYS.xres;
}
}
}
void whline (short x1, short x2, short y)
{
int t;
int length;
if (x1 > x2) /* Swap x coords */
{
t = x1;
x1 = x2;
x2 = t;
}
if (x1 < tx)
x1 = tx; /* Clip the line */
if (x2 > bx)
x2 = bx;
length = x2 - x1 + 1;
if (length > 0)
memset (&abuf[y * WGT_SYS.xres + x1], currentcolor, length);
}