[Lazarus] TColor and Alpha channel support

[Martin Schreiber]

On Monday 26 September 2016 14:25:14 Ondrej Pokorny via Lazarus wrote:
>
> In this case maybe this property pair would be more appropriate (?):
>
> Color := ...;
> Alpha := ...; // property Alpha: Byte
>
Or:
"
 Alpha := ...; // property Alpha: TColor
"
for alpha per colour channel. MSEgui works this way with pixmap opacity. In 
case of pixmaps with simple alpha channel the 8 bit alpha value is (R+G+B) 
div 3.
In MSEgui mask- and color-data of TMaskedBitmap are separate pixmaps with own 
canvas. 

Martin