/* @SuppressWarnings("unchecked")*/
public static T CloneChunk <T> (T chunk, ImageInfo info) where T : PngChunk
{
PngChunk cn = FactoryFromId(chunk.Id, info);
if (cn.GetType() != chunk.GetType())
{
throw new System.Exception($"bad class cloning chunk: {cn.GetType()} {chunk.GetType()}");
}
cn.CloneDataFromRead(chunk);
return((T)cn);
}
/* @SuppressWarnings("unchecked")*/
public static T CloneChunk <T>(T chunk, ImageInfo info) where T : PngChunk
{
PngChunk cn = FactoryFromId(chunk.Id, info);
if ((Object)cn.GetType() != (Object)chunk.GetType())
{
throw new PngjException("bad class cloning chunk: " + cn.GetType() + " "
+ chunk.GetType());
}
cn.CloneDataFromRead(chunk);
return((T)cn);
}
/// <summary>
/// Ad-hoc criteria for 'equivalent' chunks.
/// </summary>
/// <remarks>
/// Two chunks are equivalent if they have the same Id AND either:
/// 1. they are Single
/// 2. both are textual and have the same key
/// 3. both are SPLT and have the same palette name
/// Bear in mind that this is an ad-hoc, non-standard, nor required (nor wrong)
/// criterion. Use it only if you find it useful. Notice that PNG allows to have
/// repeated textual keys with same keys.
/// </remarks>
/// <param name="c1">Chunk1</param>
/// <param name="c2">Chunk1</param>
/// <returns>true if equivalent</returns>
public static bool Equivalent(PngChunk c1, PngChunk c2)
{
if (c1 == c2)
{
return(true);
}
if (c1 == null || c2 == null || !c1.Id.Equals(c2.Id))
{
return(false);
}
// same id
if (c1.GetType() != c2.GetType())
{
return(false); // should not happen
}
if (!c2.AllowsMultiple())
{
return(true);
}
if (c1 is PngChunkTextVar)
{
return(((PngChunkTextVar)c1).GetKey().Equals(((PngChunkTextVar)c2).GetKey()));
}
if (c1 is PngChunkSPLT)
{
return(((PngChunkSPLT)c1).PalName.Equals(((PngChunkSPLT)c2).PalName));
}
// unknown chunks that allow multiple? consider they don't match
return(false);
}