void plot( int x, int y )
{
if ( x < 0 ) return;
if ( y < 0 ) return;
if ( x >= _WIDTH ) return;
if ( y >= _HEIGHT ) return;
plot_( x, y );
}
void ag_surface32__draw_line_aa(struct ag_surface32* img, struct ag_vec2i start, struct ag_vec2i end, struct ag_color32 color)
{
int x1 = start.x, x2 = end.x, y1 = start.y, y2 = end.y;
double dx = (double)x2 - (double)x1;
double dy = (double)y2 - (double)y1;
if ( fabs(dx) > fabs(dy) ) {
if ( x2 < x1 ) {
swap_(x1, x2);
swap_(y1, y2);
}
double gradient = dy / dx;
double xend = round_(x1);
double yend = y1 + gradient*(xend - x1);
double xgap = rfpart_(x1 + 0.5);
int xpxl1 = xend;
int ypxl1 = ipart_(yend);
plot_(xpxl1, ypxl1, rfpart_(yend)*xgap);
plot_(xpxl1, ypxl1+1, fpart_(yend)*xgap);
double intery = yend + gradient;
xend = round_(x2);
yend = y2 + gradient*(xend - x2);
xgap = fpart_(x2+0.5);
int xpxl2 = xend;
int ypxl2 = ipart_(yend);
plot_(xpxl2, ypxl2, rfpart_(yend) * xgap);
plot_(xpxl2, ypxl2 + 1, fpart_(yend) * xgap);
int x;
for(x=xpxl1+1; x <= (xpxl2-1); x++) {
plot_(x, ipart_(intery), rfpart_(intery));
plot_(x, ipart_(intery) + 1, fpart_(intery));
intery += gradient;
}
} else {
if ( y2 < y1 ) {
swap_(x1, x2);
swap_(y1, y2);
}
double gradient = dx / dy;
double yend = round_(y1);
double xend = x1 + gradient*(yend - y1);
double ygap = rfpart_(y1 + 0.5);
int ypxl1 = yend;
int xpxl1 = ipart_(xend);
plot_(xpxl1, ypxl1, rfpart_(xend)*ygap);
plot_(xpxl1, ypxl1+1, fpart_(xend)*ygap);
double interx = xend + gradient;
yend = round_(y2);
xend = x2 + gradient*(yend - y2);
ygap = fpart_(y2+0.5);
int ypxl2 = yend;
int xpxl2 = ipart_(xend);
plot_(xpxl2, ypxl2, rfpart_(xend) * ygap);
plot_(xpxl2, ypxl2 + 1, fpart_(xend) * ygap);
int y;
for(y=ypxl1+1; y <= (ypxl2-1); y++) {
plot_(ipart_(interx), y, rfpart_(interx));
plot_(ipart_(interx) + 1, y, fpart_(interx));
interx += gradient;
}
}
}
