Author Topic: Transparency  (Read 3226 times)


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« on: September 01, 2012, 05:48:13 pm »
After a lot of investigation, I have finally found a method to implement transparency in TAChart.

Since r38472, you can set Series.Transparency to a value between 0 (opaque) and 255 (fully transparent). The actual effect you see depends on the drawing back-end.
BGRABitmap offers the best support, AggPas, SVG and Canvas (the default) support is "good enough", and other back-ends currently ignore transparency.

So first, if anyone is interested, please test -- especially the default drawer on non-Windows widgetsets.
Second, I have a few questions for maintainers of LCL and various graphics libraries:

1) Transparency support for the canvas drawer is quite a hack: see source. Is there a better way? (I think not, but maybe I missed something). Is it portable enough?
2) Is there a way to support transparency at the TFPCustomCanvas level? (Again, I think not)
3) Are there any plans for transparency support in FPVectorial?
4) Does anyone have any idea about possibility to support transparency on printer canvas?


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Re: Transparency
« Reply #1 on: September 01, 2012, 06:29:17 pm »
Tested only the canvas, and on Windows -- very impressive, excellent work
« Last Edit: September 01, 2012, 06:37:36 pm by wp »
Mainly Lazarus trunk / fpc 3.2.0 / all 32-bit on Win-10, but many more...


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