Widget turns on/off with every button press in menu (LCD-Mode 'doublebuffered')

[espruino-discuss2]

Posted at 2021-08-03 by AxelRHD

As the topic: in LCD-Mode 'doublebuffered' the widget bar at the top turns on and off, every time any button is pressed. Why the menu doesn't fill the whole screen? Is there a solution or workaround?

Minimum example:

Bangle.setLCDMode("doublebuffered");

Bangle.loadWidgets();

let menu = {
  "": { title: '--- DUMMY ---' },
  "Foo": 'Bar',
  "Exit": function() {
    E.showMenu();
  }
};

setWatch(function() {
  E.showMenu(menu);
}, BTN2, { repeat: true, edge: 'rising'});

Bangle.drawWidgets();
g.clear();
g.flip();
E.showMenu(menu);

[gfwilliams]

Posted at 2021-08-03 by @gfwilliams

Hi - I'm afraid widgets don't work in double-buffered mode, because they're only expecting a single buffer.

You can hack around it using:

Bangle.drawWidgets();
g.flip();
Bangle.drawWidgets();
g.flip();

But every time a widget changes after that, you'll get flickering.

You can use a memory-based buffer with Graphics.createArrayBuffer though, and copy that to the screen when you're done (there are a few examples in BangleApps). The widget bar will then work fine, plus it'll be right at the top of the screen

[espruino-discuss2]

Posted at 2021-08-03 by AxelRHD

Hello Gordon. For the rest of the application the widgets work very well. They only cause problems when drawing the menus.