Plugins: OpenGL and text

[Rasbats]

I am trying to display text on a plugin viewport when in OpenGL mode.

The text should have a transparent background but I have not found a way of achieving this. The code here results in the first screenshot, with OpenGL selected. I need to produce a bitmap with a transparent background.

wxBrush backBrush(*wxTRANSPARENT_BRUSH);
wxMemoryDC mdc(wxNullBitmap);
wxBitmap bm(w + label_offset*2, h + 1);
mdc.SelectObject(bm);
mdc.Clear();
mdc.SetPen(penText);
mdc.SetBrush(backBrush);
mdc.SetTextForeground(text_color);
mdc.SetTextBackground(wxTRANSPARENT);

A second problem I have is drawing filled polygons with OpenGL on the viewport.

Is there any code in OpenCPN or one of the plugins that could point me in the right direction?

Thanks for looking.
Mike

[seandepagnier]

possibly check out my statusbar plugin

github.com/seandepagnier/statusbar_pi

text rendering also is implemented in s52plib.cpp in my fork of opencpn which is not actually official yet.

[Rasbats]

Many thanks Sean,

statusbar_pi solved the transparency problem.

Mike