Hi Dai,I was looking at your manual to see if there was any thing wrong and why it may do this?Could it be the numbering in the .h file?
#define BMP_collins_BACKGROUND 0x3300#define BMP_collins_Rose 0x3400#define BMP_collins_Rose_mask 0x3401
sorry for the lack of answering your question,yes the gauge has been built by myself, and has a mask layer as stated aboveI'll look further into that