In fact, fpspreadsheet does not take transparency into account, like
LibreOffice Calc or Excel xls. Excel xlsx has a $FF in the A byte,
though, but I've never seen where they take advantage of the alpha channel.
In fpspreadsheet, the A byte is zero by default in order to be in
agreement with the colors as defined by the graphics unit: clRed =
TColor($0000FF); scRed = $000000FF. I refined these colors in order to
keep the main spreadsheet functionality independent of the LCL.
There are a few "colors" which set bits in A to indicate "not defined"
or "no color"; and there may be more to refer to an index in color
themes as Excel does (but this is future which maybe will never come).
Am 31.05.2015 um 01:47 schrieb Graeme Geldenhuys:
I have another question with that page:
http://wiki.lazarus.freepascal.org/FPSpreadsheet#Colors
I've never used FPSpreadsheet, but the color constants seem wrong to me?
Looking at the values I'm assuming the color format is ABGR. All colors
have a $00 Alpha channel value, so that would be fully (100%)
transparent by default. I have to then assume that FPSpreadsheet doesn't
actually take the Alpha channel of a color in consideration - it must
simply ignore Alpha values? Otherwise all the colors in the screenshot
should be fully transparent (you wouldn't see any defined colors).
Surely the correct color definition (to match the screenshot) should
mean the default Alpha value must be $FF (fully opaque).
Regards,
- Graeme -
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