Data type for the transparency of a chart element ranging between 0 (fully opaque) and 255 (fully transparent, i.e. invisible)Compatibility note: The FPVectorial and TFPCanvas drawers currently do not support transparency because of limitations of the underlying libraries. Printer and WMF drawers can not support transparency in principle.</p>

Optimization note: Transparency support in the LCL is rudimentary. The current TCanvas drawer implementation, therefore, may be slow with many transparent series and large charts. To improve efficiency, it is recommended to use as few different transparency levels as possible and to not interleave series with different transparencies. Alternatively, use BGRABitmap as back-end, since it has a faster transparency implementation.