[PD] c.wavesel~ Was: [filterview~]. Was: Wavesel~ external preview available as deken-type distribution. (Fred Jan Kraan)

Fred Jan Kraan fjkraan at xs4all.nl
Fri Jul 10 14:33:30 CEST 2015

Hi Pierre,

Currently, graphics data is drawn to the canvas, but nothing is erased.
If I specify a new waveform, it is drawn over the previous one, instead
of removing it first.

The real code is a bit messy due to the implementation details, but
below is the skeleton, containing the framework interactions and key
data. The paint function is called at startup from the framework (via
The redraw function is called when the waveform is changed (manual at
the moment).

draw_background function:
- ebox_start_layer(background_layer)
- ebox_paint_layer()

draw_waveform function:
- ebox_start_layer(waveform_layer)
- egraphics_line_fast(... here the waveform is defined ...)
- ebox_end_layer()
- ebox_paint_layer()

paint function:
- draw_background()
- draw_waveform()

redraw function:
- ebox_invalidate_layer(background_layer)
- ebox_invalidate_layer(waveform_layer)
- paint()
- ebox_redraw()

You can look at the current code in my toy github repository:


Fred Jan

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