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static void clip_line ( struct line *  s  )  [static]

Generic Cohen-Sutherland line clipping function.

Parameters:
s a line structure
Returns:
void

Definition at line 167 of file line.c.

References clip_bits().

Referenced by caca_draw_line(), caca_draw_polyline(), caca_draw_thin_line(), and caca_draw_thin_polyline().

{
    uint8_t bits1, bits2;

    bits1 = clip_bits(s->x1, s->y1);
    bits2 = clip_bits(s->x2, s->y2);

    if(bits1 & bits2)
        return;

    if(bits1 == 0)
    {
        if(bits2 == 0)
            s->draw(s);
        else
        {
            int tmp;
            tmp = s->x1; s->x1 = s->x2; s->x2 = tmp;
            tmp = s->y1; s->y1 = s->y2; s->y2 = tmp;
            clip_line(s);
        }

        return;
    }

    if(bits1 & (1<<0))
    {
        s->y1 = s->y2 - (s->x2 - 0) * (s->y2 - s->y1) / (s->x2 - s->x1);
        s->x1 = 0;
    }
    else if(bits1 & (1<<1))
    {
        int xmax = _caca_width - 1;
        s->y1 = s->y2 - (s->x2 - xmax) * (s->y2 - s->y1) / (s->x2 - s->x1);
        s->x1 = xmax;
    }
    else if(bits1 & (1<<2))
    {
        s->x1 = s->x2 - (s->y2 - 0) * (s->x2 - s->x1) / (s->y2 - s->y1);
        s->y1 = 0;
    }
    else if(bits1 & (1<<3))
    {
        int ymax = _caca_height - 1;
        s->x1 = s->x2 - (s->y2 - ymax) * (s->x2 - s->x1) / (s->y2 - s->y1);
        s->y1 = ymax;
    }

    clip_line(s);
}


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