smills1840
Posts: 1
Joined: Fri Apr 15, 2016 7:26 pm

Simple Image (.PNG, .JPEG, etc.) viewer?

Fri Apr 15, 2016 7:31 pm

Hello,

My question is pretty basic. I'm opening a restaurant, and using two LED TV's as menus. Can a raspberry pi display a simple image of my menu on the TV? That's all it would do, 10 hours a day, 7 days a week. I assume I'll need 2 Raspberry Pis, since they only have 1 HDMI output. That's fine, as long as it can reliably display a 1080p image on the TV.

Thanks!

dukla2000
Posts: 190
Joined: Tue Jan 10, 2012 12:02 am
Location: Reading.UK.EU

Re: Simple Image (.PNG, .JPEG, etc.) viewer?

Sat Apr 16, 2016 3:02 pm

Short answer, yes.

Longer answer - TVs can be problematic (slightly blurry) displaying PC output via HDMI (search chroma 4:4:4 for details) unless the TV has a 'PC' HDMI port or options on the HDMI input not to play/fix the signal.
Daily driver: Pi3B, 64GB Samsung Evo+ @100MHz, DVB-T, onboard WiFi for internet, BT/USB dongle for KB/mouse, 250GB HDD via USB for media, Raspbian Jessie Lite with Openbox desktop.
Museum: Pi B

stderr
Posts: 2178
Joined: Sat Dec 01, 2012 11:29 pm

Re: Simple Image (.PNG, .JPEG, etc.) viewer?

Sat Apr 16, 2016 4:06 pm

smills1840 wrote:Hello,

My question is pretty basic. I'm opening a restaurant, and using two LED TV's as menus. Can a raspberry pi display a simple image of my menu on the TV? That's all it would do, 10 hours a day, 7 days a week.
I was thinking that you could have a script running endlessly that looked for the newest image in a directory and displayed it. That's all it would do. Then you'd update your menu by just placing a jpg in the directory with a date that is newer than the one already there, which if you've kept your clocks all reasonably accurate should be one dated now. If you want an older version to be displayed, you'd just have a script that said

touch olderversion.jpg

and it would become like new! In fact, let's say that you have different menus for different times and days, you have another script running on that directory that uses the touch command to make live whatever menu you want at that time, "Lunch Specials!". Then you can begin to think about having a simple webserver that the folks can view on their phones, it's just the same image! Or backing off, it might be that the webpage is a normal webpage and that is converted to an image for the main menu display. I'd try to keep it simple, at least to start with. If you leave everything as an image, you don't even have to create that image as a webpage, you could do it in any suitable graphics making program you feel like using.

But to do the image output on the pi, you'd want something that displays an image and quits but leaves the image displayed. Most image display programs have a loop inside them that is used to display various images. You'd just want the one image each time it is run and then you get control back again. Some programs, when quiting, erase the framebuffer. This wouldn't work because you need the image to remain displayed at all times.

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