How to clear canvas with transparent color?

[corwin42]

I have searched the forum. Some people had the same problem but I have still no correct solution for it.

I want to display a chart with the charts module. In the Charts.DrawLineChart() sub I use Colors.Transparent as a background because I want to see the Activity gradient background behind the chart.

The problem is when I try to update the chart then the new chart is just added to the canvas. Canvas.DrawColor(Colors.Transparent) does not clear the canvas. If I use any other color then it works but I need the canvas to be transparent.

In this thread Erel said that in "the next version" it will be possible to draw with transparent color. I don't know which version was meant but it seems it still can't be done?

 

[thedesolatesoul]

It should work. Try invalidating the canvas after you set it to transparent.
Otherwise, draw a transparent rectangle with DrawRect.

 

[Erel]

It was already implemented. However you can use any draw method except of DrawColor which is based on a different implementation.

You should use DrawRect.

The issue with DrawColor will be fixed in v1.9.

 

[corwin42]

Ah, DrawRect() seems to work. DrawColor() does not.

Thanks very much.