chr.schmitz wrote:I have screens with several identical controls. Does it make a difference regarding memory usage, if I load the same graphics file multiple times and use it only once, or if I load the graphics file only once and use it multiple times?
Hauptwerk will load exactly one instance of the file's data into memory for each time that you refer to it by its filename within the ODF (but no additional instances when referenced indirectly via its corresponding ODF image/style object). For example, if you had two separate CODM-ODF.CustomDisplayControlStyle objects that both specified the same image filename, then two instances would be loaded into memory. However, if you had one CODM-ODF.CustomDisplayControlStyle and two CODM-ODF.Stop objects that both referenced it by its ControlStyleID then only a single instance of it would be loaded into memory.
chr.schmitz wrote:As far as I understood, PNG compression is useless as Hauptwerk always uses 24 bit PNGs.
That's correct, in that the file will be stored in memory decompressed. The only benefit of using compression within an image file would be to make the sample set's files smaller (e.g. for faster download).