void outline_aa::render_line(int x1, int y1, int x2, int y2)
{
int ey1 = y1 >> poly_base_shift;
int ey2 = y2 >> poly_base_shift;
int fy1 = y1 & poly_base_mask;
int fy2 = y2 & poly_base_mask;
int dx, dy, x_from, x_to;
int p, rem, mod, lift, delta, first, incr;
dx = x2 - x1;
dy = y2 - y1;
if(ey1 == ey2)
{
render_hline(ey1, x1, fy1, x2, fy2);
return;
}
incr = 1;
if(dx == 0)
{
int ex = x1 >> poly_base_shift;
int two_fx = (x1 - (ex << poly_base_shift)) << 1;
int area;
first = poly_base_size;
if(dy < 0)
{
first = 0;
incr = -1;
}
x_from = x1;
delta = first - fy1;
m_cur_cell.add_cover(delta, two_fx * delta);
ey1 += incr;
set_cur_cell(ex, ey1);
delta = first + first - poly_base_size;
area = two_fx * delta;
while(ey1 != ey2)
{
m_cur_cell.set_cover(delta, area);
ey1 += incr;
set_cur_cell(ex, ey1);
}
delta = fy2 - poly_base_size + first;
m_cur_cell.add_cover(delta, two_fx * delta);
return;
}
//------------------------------------------------------------------------
AGG_INLINE void outline_aa::render_hline(int ey, int x1, int y1, int x2, int y2)
{
int ex1 = x1 >> poly_base_shift;
int ex2 = x2 >> poly_base_shift;
int fx1 = x1 & poly_base_mask;
int fx2 = x2 & poly_base_mask;
int delta, p, first, dx;
int incr, lift, mod, rem;
//trivial case. Happens often
if(y1 == y2)
{
set_cur_cell(ex2, ey);
return;
}
//everything is located in a single cell. That is easy!
if(ex1 == ex2)
{
delta = y2 - y1;
m_cur_cell.add_cover(delta, (fx1 + fx2) * delta);
return;
}
//ok, we'll have to render a run of adjacent cells on the same
//hline...
p = (poly_base_size - fx1) * (y2 - y1);
first = poly_base_size;
incr = 1;
dx = x2 - x1;
if(dx < 0)
{
p = fx1 * (y2 - y1);
first = 0;
incr = -1;
dx = -dx;
}
delta = p / dx;
mod = p % dx;
if(mod < 0)
{
delta--;
mod += dx;
}
m_cur_cell.add_cover(delta, (fx1 + first) * delta);
ex1 += incr;
set_cur_cell(ex1, ey);
y1 += delta;
if(ex1 != ex2)
{
p = poly_base_size * (y2 - y1 + delta);
lift = p / dx;
rem = p % dx;
if (rem < 0)
{
lift--;
rem += dx;
}
mod -= dx;
while (ex1 != ex2)
{
delta = lift;
mod += rem;
if(mod >= 0)
{
mod -= dx;
delta++;
}
m_cur_cell.add_cover(delta, (poly_base_size) * delta);
y1 += delta;
ex1 += incr;
set_cur_cell(ex1, ey);
}
}
delta = y2 - y1;
m_cur_cell.add_cover(delta, (fx2 + poly_base_size - first) * delta);
}
//------------------------------------------------------------------------
void outline_aa::render_line(int x1, int y1, int x2, int y2)
{
int ey1 = y1 >> poly_base_shift;
int ey2 = y2 >> poly_base_shift;
int fy1 = y1 & poly_base_mask;
int fy2 = y2 & poly_base_mask;
int dx, dy, x_from, x_to;
int p, rem, mod, lift, delta, first, incr;
dx = x2 - x1;
dy = y2 - y1;
//everything is on a single hline
if(ey1 == ey2)
{
render_hline(ey1, x1, fy1, x2, fy2);
return;
}
//Vertical line - we have to calculate start and end cells,
//and then - the common values of the area and coverage for
//all cells of the line. We know exactly there's only one
//cell, so, we don't have to call render_hline().
incr = 1;
if(dx == 0)
{
int ex = x1 >> poly_base_shift;
int two_fx = (x1 - (ex << poly_base_shift)) << 1;
int area;
first = poly_base_size;
if(dy < 0)
{
first = 0;
incr = -1;
}
x_from = x1;
//render_hline(ey1, x_from, fy1, x_from, first);
delta = first - fy1;
m_cur_cell.add_cover(delta, two_fx * delta);
ey1 += incr;
set_cur_cell(ex, ey1);
delta = first + first - poly_base_size;
area = two_fx * delta;
while(ey1 != ey2)
{
//render_hline(ey1, x_from, poly_base_size - first, x_from, first);
m_cur_cell.set_cover(delta, area);
ey1 += incr;
set_cur_cell(ex, ey1);
}
//render_hline(ey1, x_from, poly_base_size - first, x_from, fy2);
delta = fy2 - poly_base_size + first;
m_cur_cell.add_cover(delta, two_fx * delta);
return;
}
inline void outline_aa::render_hline(int ey, int x1, int y1, int x2, int y2)
{
int ex1 = x1 >> poly_base_shift;
int ex2 = x2 >> poly_base_shift;
int fx1 = x1 & poly_base_mask;
int fx2 = x2 & poly_base_mask;
int delta, p, first, dx;
int incr, lift, mod, rem;
if(y1 == y2)
{
set_cur_cell(ex2, ey);
return;
}
if(ex1 == ex2)
{
delta = y2 - y1;
m_cur_cell.add_cover(delta, (fx1 + fx2) * delta);
return;
}
p = (poly_base_size - fx1) * (y2 - y1);
first = poly_base_size;
incr = 1;
dx = x2 - x1;
if(dx < 0)
{
p = fx1 * (y2 - y1);
first = 0;
incr = -1;
dx = -dx;
}
delta = p / dx;
mod = p % dx;
if(mod < 0)
{
delta--;
mod += dx;
}
m_cur_cell.add_cover(delta, (fx1 + first) * delta);
ex1 += incr;
set_cur_cell(ex1, ey);
y1 += delta;
if(ex1 != ex2)
{
p = poly_base_size * (y2 - y1 + delta);
lift = p / dx;
rem = p % dx;
if (rem < 0)
{
lift--;
rem += dx;
}
mod -= dx;
while (ex1 != ex2)
{
delta = lift;
mod += rem;
if(mod >= 0)
{
mod -= dx;
delta++;
}
m_cur_cell.add_cover(delta, (poly_base_size) * delta);
y1 += delta;
ex1 += incr;
set_cur_cell(ex1, ey);
}
}
delta = y2 - y1;
m_cur_cell.add_cover(delta, (fx2 + poly_base_size - first) * delta);
}