private static unsafe void FillBitmapFromImageData(byte[] imageData, Color32[] colorsTable, BitmapData bitmapData)
{
var p = (Color32*) bitmapData.Scan0.ToPointer();
var i = 0;
while (i < imageData.Length)
{
*p++ = colorsTable[imageData[i++]];
}
}
private static unsafe void FillBitmapFromInterlacedImageData(byte[] imageData, Color32[] colorsTable, BitmapData bitmapData)
{
var p = (Color32*) bitmapData.Scan0.ToPointer();
var rates = new[] { 8, 8, 4, 2, 1 };
var startPosition = p;
var offset = 0;
var i = 0;
var pass = 0;
while (pass < 4)
{
if (pass > 0)
{
var diff = rates[pass + 1] * bitmapData.Width;
p = startPosition + diff;
offset += diff;
}
var rate = rates[pass];
while (i < imageData.Length)
{
*p++ = colorsTable[imageData[i++]];
offset++;
if (i % bitmapData.Width != 0)
{
continue;
}
p += bitmapData.Width * (rate - 1);
offset += bitmapData.Width * (rate - 1);
if (offset >= imageData.Length)
{
pass++;
offset = 0;
break;
}
}
}
}
private static Bitmap CreateBitmap(byte[] imageData, Color32[] colorsTable, bool interlaceFlag, int imageWidth, int imageHeight)
{
var result = new Bitmap(imageWidth, imageHeight);
var rectangle = new Rectangle(0, 0, imageWidth, imageHeight);
var bitmapData = result.LockBits(rectangle, ImageLockMode.ReadWrite, result.PixelFormat);
if (interlaceFlag)
{
FillBitmapFromInterlacedImageData(imageData, colorsTable, bitmapData);
}
else
{
FillBitmapFromImageData(imageData, colorsTable, bitmapData);
}
result.UnlockBits(bitmapData);
return result;
}
