To update and to monitor two overlapped screens on the display
What have you tried so far?
I am displaying a small pop-off screen on the lower border of my main display, which shows a setup button, this small screen portion is overlapping the mains screen loaded previously. The background color of the setup screen is set to FFFFFF, Alpha = 0, so that is becomes transparent and the content of the main screen is still visible. How can I achieve that the main screen is still updated while the small setup screen is waiting for a button press simultaneously (or in sequence)?
We couldn’t get exactly what you mean above by ‘screen’ because LVGL ‘screens’ normally can’t be loaded simultaneously on a display (except special lv_layer_top and lv_layer_sys screens.)
Could you please send a screenshot or more detailed description with correct identification of the widget-type of your ‘setup’ screen? The we’ll probably understand what you mean by ‘updating’ the ‘main’ screen.
many thanks for your reply, I have created a full screen (lets call it 1st screen) with elements and I am overlapping this screen by changing to a second screen, which consist only of a small panel with elements on the lower half of the screen, the background is set Alpha = 150, so that the previous screen is still visible under the current screen, but the output to the first screen is stopped because the second screen has become active. But I would like to have an option to manipulate the output to both screens in sequence.
Maybe try modifying the advanced opacity handling setting ‘LV_COLOR_SCREEN_TRANSP’ in lv_conf.h. The mixing/alpha-blending routine is different with this setting, and enabling it requires 32bit color depth as the comments beside the setting say. (There are some explanation-comments in lv_conf_template.h too.)
This is not a matter of opacity (this is already working), it is a matter of getting two screens to work subsequently/alternating. So merely a matter of tasks.
Maybe if you send an example project or screenshot we can understand better what you mean by ‘in sequence’ and ‘updated’. (If you want ‘multitasking’, LVGL-8 doesn’t use tasks but does all tasks in the main loop cyclically.)