rob2021
Posts: 5
Joined: Sun Apr 23, 2017 4:03 am

3.5" Pitft screen settings help

Sun Apr 23, 2017 4:20 am

Hi there I'm new to the Raspiberry Pi, but I got a lot done to it and even made a file to switch between HDMI and the Pitft. One thing I don't really know is how to change how things look on the Pitft in Raspbian. I think by default it is 480x320 and I've tried editing the /boot/config to try to get better results, but its still looks the same in Pitft and so hard to navigate with.

Maybe I'm being too picky, but for instance some of my taskbar icons are merging with each other because of the screen resolution and the taskbar and chromium bar at the top take up so much space you can't even tell what you're looking up when going through videos on like youtube.com

Anyone have any in-sight to this that have played around with this?

W. H. Heydt
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Joined: Fri Mar 09, 2012 7:36 pm
Location: Vallejo, CA (US)

Re: 3.5" Pitft screen settings help

Sun Apr 23, 2017 4:40 pm

The general rule when it comes to LCD displays is that they look best when running at native resolution, and that is 480x320 for most 3.5" panels...including the Adafruit Pitft.

The resolution settings in /boot/config.txt are to control HDMI (and composite) output that are handled directly by the VC4 GPU. Read everything you can find on the Adafruit site to see if there is a way to alter the resolution of the Pitft display. There may not be a way to do it.

Question...Has Adafruit either updated their OS image for the Pitft or changed to instructions for how to set up a generic Raspbian build? The inability to upgrade the OS files is one of the two main reasons why I have switched to using Neosec TInylcd35 displays instead of the Pitft.

melvonic.demon
Posts: 8
Joined: Sun Apr 23, 2017 11:38 am

Re: 3.5" Pitft screen settings help

Sun Apr 23, 2017 5:20 pm

rob2021 wrote:Hi there I'm new to the Raspiberry Pi, but I got a lot done to it and even made a file to switch between HDMI and the Pitft. One thing I don't really know is how to change how things look on the Pitft in Raspbian. I think by default it is 480x320 and I've tried editing the /boot/config to try to get better results, but its still looks the same in Pitft and so hard to navigate with.

Maybe I'm being too picky, but for instance some of my taskbar icons are merging with each other because of the screen resolution and the taskbar and chromium bar at the top take up so much space you can't even tell what you're looking up when going through videos on like youtube.com

Anyone have any in-sight to this that have played around with this?
I have a 3.5 inch waveshare screen, in gui mode its as you describe icons merging together and struggling to navigate. Why not just go bigger like 7inch screens if it bothers you? I use mine for command line stuff and was also thinking of getting a 7inch screen

rob2021
Posts: 5
Joined: Sun Apr 23, 2017 4:03 am

Re: 3.5" Pitft screen settings help

Sun Apr 23, 2017 6:05 pm

Been tinkering around with this and came up with a good solution for getting good a screen display between going from HDMI on a TV to the Pitft. Basically I made 2 different shell files that launch config settings when you launch the fullscreen display or the portable version.

I'm not going to post the entire code because I basically take the entire config files of different areas and change what I need. I will provide links to the txt files though.

This is basically what the Portable shell launcher does:

Kills chromium process
waits 1 sec (This is to make sure no chromium errors happen in the process of editing the config and rebooting)
Clears display device config
Rewrites to launch Pi in Portable Pitft mode
Clears xlpanel config (taskbar)
Rewrites to resize taskbar and icons to 18 size and places taskbar on top of screen instead of the bottom when I use HDMI as desktop.
Clears Chromium config settings file
Rewrites to change Zoom level of Chromium from 100% to 67%
Restarts the Pi

Same opposite for my Fullscreen HDMI shell file.

Portable shell: https://gist.github.com/anonymous/331e9 ... 0ef4c6ff54

Fullscreen shell: https://gist.github.com/anonymous/6f43e ... c462671856

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CarlRJ
Posts: 599
Joined: Thu Feb 20, 2014 4:00 am
Location: San Diego, California

Re: 3.5" Pitft screen settings help

Sun Apr 23, 2017 7:42 pm

rob2021 wrote:Maybe I'm being too picky, but for instance some of my taskbar icons are merging with each other because of the screen resolution and the taskbar and chromium bar at the top take up so much space you can't even tell what you're looking up when going through videos on like youtube.com

Anyone have any in-sight to this that have played around with this?
I'm going to present a rather different point of view of this whole situation...

I would argue that - despite the fact that sellers of such devices frequently show them off by running a GUI desktop - if you're actually running X Windows and a browser on a PiTFT-style small LCD screen, you're not really using it appropriately or effectively. It is possible to run a general purpose GUI desktop on such a screen, just as it is possible to ride a unicycle to work, but neither is a good use of the strengths of the devices and in both cases there are widely available solutions that are better for the general case (larger monitors, and cars or public transportation).

The place where the smaller direct attach (GPIO/SPI interfaced) screens really shine is with custom task-specifc GUIs constructed out of something like Pygame or Kivy or Tk or Qt. You can make a device that handles a specific task or handful of tasks better than any off-the-shelf solution could, while exercising absolute control over every pixel on the screen.

A particular weakness of the PiTFT displays (and similar ones from other manufacturers), inherent in their design, is poor frame rate for complicated graphics; they're pushing a lot of graphics data through an interface (SPI) not designed for such a use, and it's necessarily coming from the CPU, not the Pi's dedicated graphics hardware. I'm not at all surprised that youtube videos look bad.

Using them as custom information displays and control panels works fantastically well as it plays to their strengths (I have several in my house being precision clocks, weather displays, and lighting control panels); using them as general purpose desktop interfaces will likely lead to frustration and disappointment, once the brief initial "gee whiz it works" period fades.

rob2021
Posts: 5
Joined: Sun Apr 23, 2017 4:03 am

Re: 3.5" Pitft screen settings help

Sun Apr 23, 2017 7:56 pm

I changed the /boot/config to run at 60 fps with higher rate and it seems to function fine. For what I'm using it for with the Pitft I don't intend to use it more than 30 mins normally on the go so I'm not really worried about it overheating.

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exartemarte
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Location: Middle England
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Re: 3.5" Pitft screen settings help

Tue Sep 19, 2017 4:16 pm

CarlRJ wrote:
Sun Apr 23, 2017 7:42 pm
Using them as custom information displays and control panels works fantastically well as it plays to their strengths ...
Quite!

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