Category : C Source Code
Archive   : ADVGRAPH.ZIP
Filename : COM_FILL.C

/* COM_FILL.C creates a complex fill for non-regular
* boundaries. The procedure is tolerant of inclusions and
* incursions as long as boundaries are continuous (they
* connect) and do not intersect or touch each other.
* Lengths of arrays must be predicted carefully.
*/

#define TRUE -1
#define FALSE 0
#define ON TRUE
#define OFF FALSE
#define X 0
#define Y 1


com_fill(line_array, coord_array, length, style, color, orxor)
int line_array[][4], coord_array[][2];
unsigned length, style;
int color, orxor;
{
unsigned pointer, element = 0, sorted = FALSE, new_start = 1;

for (pointer = 0; pointer < length; ++pointer)
line_int(line_array[pointer], coord_array, &element);

while(!sorted) /* sort on y */
{
sorted = TRUE;
for (pointer = 1; pointer < element; ++pointer)
if (coord_array[pointer-1][Y]
> coord_array[pointer][Y])
{
swap(&coord_array[pointer-1][Y],
&coord_array[pointer][Y]);
swap(&coord_array[pointer-1][X],
&coord_array[pointer][X]);
sorted = FALSE;
}
}

sorted = FALSE;
while(!sorted) /* sort on x within y */
{
sorted = TRUE;
for (pointer = new_start; pointer < element; ++pointer)
if (coord_array[pointer-1][Y]
== coord_array[pointer][Y])
if (coord_array[pointer-1][X]
> coord_array[pointer][X])
{
swap(&coord_array[pointer-1][Y],
&coord_array[pointer][Y]);
swap(&coord_array[pointer-1][X],
&coord_array[pointer][X]);
sorted = FALSE;
}
else {
if (sorted == TRUE) new_start = pointer;
sorted = FALSE;
break;
}
}

for (pointer = 0; pointer < element; pointer += 2)
linef(coord_array[pointer][X],
coord_array[pointer][Y],
coord_array[pointer+1][X],
coord_array[pointer+1][Y],
color, style, orxor, ON);
}



line_int(line_array, coord_array, element)
int line_array[4], coord_array[][2], *element;
{
int ix, iy, i, inc, x, y, dx, dy, plot, plotx, ploty;

dx = line_array[2] - line_array[0];
dy = line_array[3] - line_array[1];
ix = abs(dx);
iy = abs(dy);
inc = max(ix, iy);

plotx = line_array[0];
ploty = line_array[1];
x = y = 0;

/* first pixel on line is not plotted */
/* last pixel on line is not plotted */
/* thus endpoints are not included */

for (i = 0; i < inc; ++i)
{
x += ix;
y += iy;
plot = FALSE;

if (x > inc)
{
plot = TRUE;
x -= inc;
plotx += sign(dx);
}

if (y > inc)
{
plot = TRUE;
y -= inc;
ploty += sign(dy);
}

if (plot)
{
coord_array[*element][X] = plotx;
coord_array[*element++][Y] = ploty;
}
}
}