`TPngAdam7Palette2bitRGBADecoder`
pt		TransferData

`TCustomPngAdam7Decoder`
pt		TransferData
		Create
		Destroy
		DecodeToScanline

`TCustomPngDecoder`
pt		FilterSub
pt		FilterUp
pt		FilterAverage
pt		FilterPaeth
pt		DecodeFilterRow
		DecodeToScanline

`TCustomPngCoder`
pt		BuildMappingTable
		Create
		Destroy