/// <summary>
/// Gets the background pixmap
/// </summary>
/// <param name="rect"></param>
/// <param name="subSample"></param>
/// <param name="gamma"></param>
/// <param name="retval"></param>
/// <returns></returns>
public GPixmap GetBgPixmap(GRect rect, int subsample, double gamma, GPixmap retval)
{
GPixmap pm = null;
int width = (Info == null)
? 0
: Info.Width;
int height = (Info == null)
? 0
: Info.Height;
if ((width <= 0) || (height <= 0) || (Info == null))
{
return(null);
}
double gamma_correction = 1.0D;
if ((gamma > 0.0D) && (Info != null))
{
gamma_correction = gamma / Info.Gamma;
}
if (gamma_correction < 0.10000000000000001D)
{
gamma_correction = 0.10000000000000001D;
}
else if (gamma_correction > 10D)
{
gamma_correction = 10D;
}
IWPixelMap bgIWPixmap = BackgroundIWPixelMap;
if (bgIWPixmap != null)
{
int w = bgIWPixmap.Width;
int h = bgIWPixmap.Height;
if ((w == 0) || (h == 0) || (width == 0) || (height == 0))
{
return(null);
}
int red = ComputeRed(width, height, w, h);
if ((red < 1) || (red > 12))
{
return(null);
}
if (subsample == red)
{
pm = bgIWPixmap.GetPixmap(1, rect, retval);
}
else if (subsample == (2 * red))
{
pm = bgIWPixmap.GetPixmap(2, rect, retval);
}
else if (subsample == (4 * red))
{
pm = bgIWPixmap.GetPixmap(4, rect, retval);
}
else if (subsample == (8 * red))
{
pm = bgIWPixmap.GetPixmap(8, rect, retval);
}
else if ((red * 4) == (subsample * 3))
{
GRect xrect = new GRect();
xrect.Right = (int)Math.Floor(rect.Right * 4D / 3D);
xrect.Bottom = (int)Math.Floor(rect.Bottom * 4D / 3D);
xrect.Left = (int)Math.Ceiling((double)rect.Left * 4D / 3D);
xrect.Top = (int)Math.Ceiling((double)rect.Top * 4D / 3D);
GRect nrect = new GRect(0, 0, rect.Width, rect.Height);
if (xrect.Left > w)
{
xrect.Left = w;
}
if (xrect.Top > h)
{
xrect.Top = h;
}
GPixmap ipm = bgIWPixmap.GetPixmap(1, xrect, null);
pm = (retval != null)
? retval
: new GPixmap();
pm.Downsample43(ipm, nrect);
}
else
{
int po2 = 16;
while ((po2 > 1) && (subsample < (po2 * red)))
{
po2 >>= 1;
}
int inw = ((w + po2) - 1) / po2;
int inh = ((h + po2) - 1) / po2;
int outw = ((width + subsample) - 1) / subsample;
int outh = ((height + subsample) - 1) / subsample;
PixelMapScaler ps = new PixelMapScaler(inw, inh, outw, outh);
ps.SetHorzRatio(red * po2, subsample);
ps.SetVertRatio(red * po2, subsample);
GRect xrect = ps.GetRequiredRect(rect);
GPixmap ipm = bgIWPixmap.GetPixmap(po2, xrect, null);
pm = (retval != null)
? retval
: new GPixmap();
ps.Scale(xrect, ipm, rect, pm);
}
if ((pm != null) && (gamma_correction != 1.0D))
{
pm.ApplyGammaCorrection(gamma_correction);
for (int i = 0; i < 9; i++)
{
pm.ApplyGammaCorrection(gamma_correction);
}
}
return(pm);
}
else
{
return(null);
}
}
