//--------------------------------------------------------------------
public bool SweepScanline(IScanlineCache sl)
{
#if use_timers
SweepSacanLine.Start();
#endif
for (; ;)
{
if (m_scan_y > m_outline.MaxY)
{
#if use_timers
SweepSacanLine.Stop();
#endif
return(false);
}
sl.ResetSpans();
uint scan_y_uint = 0; // it is going to get initialize to 0 anyway so make it clear.
if (m_scan_y > 0)
{
scan_y_uint = (uint)m_scan_y;
}
uint num_cells = m_outline.ScanlineNumCells(scan_y_uint);
CellAA[] cells;
uint Offset;
m_outline.ScanlineCells(scan_y_uint, out cells, out Offset);
int cover = 0;
while (num_cells != 0)
{
CellAA cur_cell = cells[Offset];
int x = cur_cell.X;
int area = cur_cell.Area;
uint alpha;
cover += cur_cell.Cover;
//accumulate all cells with the same X
while (--num_cells != 0)
{
Offset++;
cur_cell = cells[Offset];
if (cur_cell.X != x)
{
break;
}
area += cur_cell.Area;
cover += cur_cell.Cover;
}
if (area != 0)
{
alpha = CalculateAlpha((cover << ((int)poly_subpixel_scale_e.Shift + 1)) - area);
if (alpha != 0)
{
sl.AddCell(x, alpha);
}
x++;
}
if ((num_cells != 0) && (cur_cell.X > x))
{
alpha = CalculateAlpha(cover << ((int)poly_subpixel_scale_e.Shift + 1));
if (alpha != 0)
{
sl.AddSpan(x, (cur_cell.X - x), alpha);
}
}
}
if (sl.NumSpans != 0)
{
break;
}
++m_scan_y;
}
sl.Finalize(m_scan_y);
++m_scan_y;
#if use_timers
SweepSacanLine.Stop();
#endif
return(true);
}
// Sweeps one scanline with one style index. The style ID can be
// determined by calling style().
//template<class Scanline>
public bool SweepScanline(IScanlineCache sl, int style_idx)
{
int scan_y = m_scan_y - 1;
if (scan_y > m_Rasterizer.MaxY)
{
return(false);
}
sl.ResetSpans();
uint master_alpha = AAMask;
if (style_idx < 0)
{
style_idx = 0;
}
else
{
style_idx++;
master_alpha = m_master_alpha[(uint)(m_ast[(uint)style_idx] + m_min_style - 1)];
}
StyleInfo st = m_styles[m_ast[style_idx]];
int num_cells = (int)st.num_cells;
uint CellOffset = st.start_cell;
CellAA cell = m_cells[CellOffset];
int cover = 0;
while (num_cells-- != 0)
{
uint alpha;
int x = cell.X;
int area = cell.Area;
cover += cell.Cover;
cell = m_cells[++CellOffset];
if (area != 0)
{
alpha = CalculateAlpha((cover << (PolySubpixelShift + 1)) - area,
master_alpha);
sl.AddCell(x, alpha);
x++;
}
if (num_cells != 0 && cell.X > x)
{
alpha = CalculateAlpha(cover << (PolySubpixelShift + 1),
master_alpha);
if (alpha != 0)
{
sl.AddSpan(x, cell.X - x, alpha);
}
}
}
if (sl.NumSpans == 0)
{
return(false);
}
sl.Finalize(scan_y);
return(true);
}