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

135 lines
2.7 KiB
C

#include "../include/wgt.h"
static void hplotcircle (short x, short y, short x_center, short y_center)
{
unsigned short a,b,c,d;
unsigned short startx, endx, x1, starty, endy, y1;
starty = y;
endy = y + 1;
startx = x;
endx = x + 1;
a = y + y_center;
b = y_center - y;
for (x1 = startx; x1 < endx; x1++)
{
c = x1 + x_center;
d = x_center - x1;
wputpixel(c, a);
wputpixel(c, b);
wputpixel(d, b);
wputpixel(d, a);
}
a = x + y_center;
b = y_center - x;
for (y1 = starty; y1 < endy; y1++)
{
c = y1 + x_center;
d = x_center - y1;
wputpixel(c, a);
wputpixel(c, b);
wputpixel(d, b);
wputpixel(d, a);
}
}
void wcircle (short x_center, short y_center, short radius)
{
short x,y,delta;
y = radius;
delta = 3 - 2 * radius;
x = 0;
while (x < y)
{
hplotcircle (x, y, x_center, y_center);
if (delta < 0)
delta += 4 * x + 6;
else
{
delta += 4 * (x - y) + 10;
y--;
}
x++;
}
x = y;
if (y >= 0)
hplotcircle (x, y, x_center, y_center);
}
static void fplotcircle (short x, short y, short x_center, short y_center)
{
unsigned int *ptr;
short display,display2;
display = x * 2;
display2 = x_center - x;
if (x + x_center > bx)
display = bx + 1 - (x_center - x);
if (display2 < tx)
{
display -= tx - display2;
display2 = tx;
}
if (display > 0)
{
if ((y + y_center <= by) && (y + y_center >= ty))
{
ptr = &abuf[(y + y_center)*(WGT_SYS.xres) + display2];
memset (ptr, currentcolor, display);
}
if ((y_center - y >= ty) && (y_center - y <= by))
{
ptr = &abuf[(y_center - y)*(WGT_SYS.xres) + display2];
memset (ptr, currentcolor, display);
}
}
display = y*2;
display2 = x_center - y;
if (y + x_center > bx)
display = bx + 1 - (x_center - y);
if (display2 < tx)
{
display -= tx - display2;
display2 = tx;
}
if (display < 0)
return;
if ((x + y_center <= by) && (x + y_center >= ty))
{
ptr = &abuf[(x + y_center) * (WGT_SYS.xres) + display2];
memset (ptr, currentcolor, display);
}
if ((y_center - x >= ty) && (y_center - x <= by))
{
ptr = &abuf[(y_center - x) * (WGT_SYS.xres) + display2];
memset (ptr, currentcolor, display);
}
}
void wfill_circle (short x_center, short y_center, short radius)
{
short x,y,delta;
y = radius;
delta = 3 - 2 * radius;
x = 0;
while (x < y)
{
fplotcircle (x, y, x_center, y_center);
if (delta < 0)
delta += (4 * x + 6);
else
{
delta += 4 * (x - y) + 10;
y--;
}
x++;
}
x = y;
if (y >= 0)
fplotcircle (x, y, x_center, y_center);
}