public uint png_get_sPLT(ref png_sPLT_t[] spalettes)
{
if((info_ptr_valid&PNG_INFO.sPLT)!=PNG_INFO.sPLT) return 0;
spalettes=info_ptr_splt_palettes.ToArray();
return (uint)info_ptr_splt_palettes.Count;
}
public void png_set_sPLT(png_sPLT_t entry)
{
if(info_ptr_splt_palettes==null) info_ptr_splt_palettes=new List<png_sPLT_t>();
info_ptr_splt_palettes.Add(entry);
info_ptr_valid|=PNG_INFO.sPLT;
}
public void png_set_sPLT(png_sPLT_t[] entries)
{
if(entries==null||entries.Length==0)
{
Debug.WriteLine("Ignoring attempt to set empty sPLT");
return;
}
if(info_ptr_splt_palettes==null) info_ptr_splt_palettes=new List<png_sPLT_t>();
info_ptr_splt_palettes.AddRange(entries);
info_ptr_valid|=PNG_INFO.sPLT;
}
// write a sPLT chunk
void png_write_sPLT(png_sPLT_t spalette)
{
uint name_len;
byte[] new_name=null;
byte[] entrybuf=new byte[10];
uint entry_size=(uint)(spalette.depth==8?6:10);
uint palette_size=entry_size*spalette.nentries;
if((name_len=png_check_keyword(spalette.name, ref new_name))==0)
return;
// make sure we include the NULL after the name
png_write_chunk_start(PNG.sPLT, (uint)(name_len+2+palette_size));
png_write_chunk_data(new_name, name_len+1);
entrybuf[0]=spalette.depth;
png_write_chunk_data(entrybuf, 1);
// loop through each palette entry, writing appropriately
for(uint i=0; i<spalette.nentries; i++)
{
png_sPLT_entry ep=spalette.entries[i];
if(spalette.depth==8)
{
entrybuf[0]=(byte)ep.red;
entrybuf[1]=(byte)ep.green;
entrybuf[2]=(byte)ep.blue;
entrybuf[3]=(byte)ep.alpha;
png_save_uint_16(entrybuf, 4, ep.frequency);
}
else
{
png_save_uint_16(entrybuf, ep.red);
png_save_uint_16(entrybuf, 2, ep.green);
png_save_uint_16(entrybuf, 4, ep.blue);
png_save_uint_16(entrybuf, 6, ep.alpha);
png_save_uint_16(entrybuf, 8, ep.frequency);
}
png_write_chunk_data(entrybuf, entry_size);
}
png_write_chunk_end();
}
