private static void WriteIndexed(SwfWriter writer, Bitmap bmp, bool alpha)
{
int w = bmp.Width;
int h = bmp.Height;
writer.WriteUInt8((byte)SwfBitmapFormat.Indexed);
writer.WriteUInt16((ushort)w);
writer.WriteUInt16((ushort)h);
var pal = bmp.Palette.Entries;
int palSize = pal.Length;
writer.WriteUInt8((byte)(palSize - 1));
var bmpWriter = new SwfWriter();
for (int i = 0; i < palSize; ++i)
{
bmpWriter.WriteColor(pal[i], alpha);
}
//NOTE: Row widths in the pixel data fields of these structures must be rounded up to the next
//32-bit word boundary. For example, an 8-bit image that is 253 pixels wide must be
//padded out to 256 bytes per line. To determine the appropriate padding, make sure to
//take into account the actual size of the individual pixel structures; 15-bit pixels occupy 2
//bytes and 24-bit pixels occupy 4 bytes (see PIX15 and PIX24).
int pad = w % 4;
if (pad != 0)
{
pad = 4 - pad;
}
using (var fbmp = new FastBitmap(bmp))
{
for (int y = 0; y < h; ++y)
{
for (int x = 0; x < w; ++x)
{
int index = fbmp.GetIndex(x, y);
Debug.Assert(index >= 0 && index < palSize);
bmpWriter.WriteUInt8((byte)index);
}
if (pad > 0)
{
bmpWriter.Pad(pad);
}
}
}
var data = bmpWriter.ToByteArray();
data = Zip.Compress(data);
writer.Write(data);
}
