private ICursor QueryImage(int x, int y)
{
unsafe
{
int bandCount = _gDS.RasterCount;
string[] tags = new string[bandCount + 2];
object[] values = new object[bandCount + 2];
List <Color> colors = new List <Color>();
for (int i = 1; i <= bandCount; ++i)
{
OSGeo.GDAL.Band band = _gDS.GetRasterBand(i);
string bandName = "";
switch ((ColorInterp)band.GetRasterColorInterpretation())
{
case ColorInterp.BlueBand:
bandName = "(blue)";
break;
case ColorInterp.GreenBand:
bandName = "(green)";
break;
case ColorInterp.RedBand:
bandName = "(red)";
break;
case ColorInterp.GrayIndex:
for (int iColor = 0; iColor < 256; iColor++)
{
colors.Add(Color.FromArgb(255, iColor, iColor, iColor));
}
break;
case ColorInterp.PaletteIndex:
tags = new string[tags.Length + 4];
values = new object[values.Length + 4];
OSGeo.GDAL.ColorTable colTable = band.GetRasterColorTable();
if (colTable == null)
{
break;
}
int colCount = colTable.GetCount();
for (int iColor = 0; iColor < colCount; iColor++)
{
OSGeo.GDAL.ColorEntry colEntry = colTable.GetColorEntry(iColor);
colors.Add(Color.FromArgb(
colEntry.c4, colEntry.c1, colEntry.c2, colEntry.c3));
}
break;
}
int c = 0;
int *buf = &c;
band.ReadRaster(x, y, 1, 1,
(IntPtr)buf,
1, 1, OSGeo.GDAL.DataType.GDT_Int32, 4, 0);
band.Dispose();
tags[i + 1] = "Band " + i.ToString() + " " + bandName;
values[i + 1] = c;
if (colors.Count > 0 && c >= 0 && c < colors.Count)
{
Color col = colors[c];
tags[i + 2] = "Alpha";
values[i + 2] = col.A;
tags[i + 3] = "Red";
values[i + 3] = col.R;
tags[i + 4] = "Green";
values[i + 4] = col.G;
tags[i + 5] = "Blue";
values[i + 5] = col.B;
}
}
tags[0] = "ImageX"; values[0] = x;
tags[1] = "ImageY"; values[1] = y;
return(new QueryCursor(tags, values));
}
}
private void PaintImage(int x, int y, int wWidth, int wHeight, int iWidth, int iHeight, ICancelTracker cancelTracker)
{
if (CancelTracker.Canceled(cancelTracker) || _gDS == null)
{
return;
}
int pixelSpace = 3;
_bitmap = new Bitmap(iWidth, iHeight, PixelFormat.Format24bppRgb);
BitmapData bitmapData = _bitmap.LockBits(new Rectangle(0, 0, iWidth, iHeight), ImageLockMode.ReadWrite, PixelFormat.Format24bppRgb);
try
{
int stride = bitmapData.Stride;
IntPtr buf = bitmapData.Scan0;
List <Color> colors = new List <Color>();
for (int i = 1; i <= (_gDS.RasterCount > 3 ? 3 : _gDS.RasterCount); ++i)
{
using (OSGeo.GDAL.Band band = _gDS.GetRasterBand(i))
{
int ch = 0;
switch ((ColorInterp)band.GetRasterColorInterpretation())
{
case ColorInterp.BlueBand:
ch = 0;
break;
case ColorInterp.GreenBand:
ch = 1;
break;
case ColorInterp.RedBand:
ch = 2;
break;
case ColorInterp.GrayIndex:
for (int iColor = 0; iColor < 256; iColor++)
{
colors.Add(Color.FromArgb(255, iColor, iColor, iColor));
}
break;
case ColorInterp.PaletteIndex:
OSGeo.GDAL.ColorTable colTable = band.GetRasterColorTable();
if (colTable == null)
{
break;
}
int colCount = colTable.GetCount();
for (int iColor = 0; iColor < colCount; iColor++)
{
OSGeo.GDAL.ColorEntry colEntry = colTable.GetColorEntry(iColor);
colors.Add(Color.FromArgb(
colEntry.c4, colEntry.c1, colEntry.c2, colEntry.c3));
}
break;
}
band.ReadRaster(x, y, wWidth, wHeight,
new IntPtr(buf.ToInt64() + ch),
iWidth, iHeight, OSGeo.GDAL.DataType.GDT_Byte, pixelSpace, stride);
band.Dispose();
}
}
if (colors.Count > 0)
{
unsafe
{
byte *ptr = (byte *)(bitmapData.Scan0);
for (int i = 0; i < bitmapData.Height; i++)
{
if (CancelTracker.Canceled(cancelTracker))
{
return;
}
for (int j = 0; j < bitmapData.Width; j++)
{
// write the logic implementation here
byte c = ptr[0];
Color col = colors[(int)c];
ptr[0] = col.B;
ptr[1] = col.G;
ptr[2] = col.R;
ptr += pixelSpace;
}
ptr += bitmapData.Stride - bitmapData.Width * pixelSpace;
}
}
}
}
catch (Exception ex)
{
string msg = ex.Message;
}
finally
{
if (_bitmap != null)
{
_bitmap.UnlockBits(bitmapData);
}
}
}