I have never used a raspberry before, and I am having trouble configuring it. I've been searching for an answer to my problem but I have had no success in finding it. Maybe the answer is there but I have not been able to understand it, which is possible.
I have a Raspberry Pi 3 that outputs on a very tall LED wall. It's supposed to show some dynamic content working under HTML5. The code works correctly, as I have tested it on a regular screen with success.
The problem comes when I connect the raspberry to the LED wall. It has a very specific resolution (192 px wide, for 1216 px tall)
Tampering with the configuration, I have set the resolution to the highest I can find, but I'm a few pixels shy of 1216, and with LEDs that big it's very noticeable.
As far as I have found, there is only a limited list of resolutions to choose from. Is there any way to set a manual resolution to 192x1216? Or at least a bigger resolution that my screen fits in?
Thanks.
Since 1216 pixels in height is a little unconventional, I would suggest rotating the screen 90 degrees and setting the resolution to 1216x192 instead.
Add these 2 lines to /boot/config.txt and comment out any other occurrences of them if they already exists. You can edit the file by writing sudo nano /boot/config.txt
display_rotate=1 # Rotate the screen 90 degrees
hdmi_cvt 1216 192 60 # Set the resolution to 1216x192
And then reboot the unit with sudo reboot
In case the custom resolution doesn't work you could try to work with rotating the screen with the first line and use 1280x720 pixels instead.
How do you connect? The highest supported resolution is 1920x1200 in HDMI_MODE.
I think that might be a limitation with the Raspberry Pi.
I haven't used the Asus Tinkerboard but it seems similar to the Pi and supports a higher resolution.
This particular combination of parameters for /boot/config.txt was the one that worked for me:
disable_overscan = 1
hdmi_group = 2
hdmi_mode = 87
hdmi_cvt = 1024 600 60 6 0 0 0
display_hdmi_rotate = 3
Related
system: Ubuntu 20.04.3 LTS
The default Resolution is 1280x720, the DPI is 96.
When adjust the 'fractional scaling' is 125%, I have two options to get the DPI:
Use the command: xrdb -query |grep dpi
the DPI is 192 ??!
Xft.dpi: 192
Use the command: xdpyinfo, the DPI is 120.
screen #0:
dimensions: 2048x1152 pixels (433x244 millimeters)
resolution: 120x120 dots per inch
Why the two commands return different DPI ?
When scaling to 125%, Why the dimensions is 2048x1152 ? (2048/1280 = 1.6, 1152/720 = 1.6)
Is the X11 API is wrong or other problem?
Thanks.
Strictly speaking neither xrdb nor xdpyinfo are the right place to query the screen's pixel density.
xrdb shows you a DPI value, since it's the place where one can (but is not required to!) set a overriding DPI value for Xft, and some desktop environments to, just "because". xdpyinfo shows mostly values that already did exist waaay back in the original X11 core protocol, where one could also specify physical dimensions of a screen. The problem is, that on modern systems, which are capable of dynamically attaching and removing displays, things are done through XRandR and the capability to drive multiple X11 screens on the same X11 display no longer is used (it's all just one large X11 screen now). So depending on how you configured your monitors, the values reported by xdpyinfo are off.
To arrive at the correct pixel density, one must use XRandR (CLI query/set tool name is xrandr) to retrieve information about the physically connected displays. However be advised that it is perfectly possible for several displays of different pixel density to show overlapping regions of the X11 screen, and within those regions there's no unambiguous DPI value available.
I'm working with a Raspberry Pi 3 that has a ribbon PiCamera. My problem is that I cannot get the still (not video) frame rate to be workable. In my application, the camera acts like a scanner using only a single row of each frame to watch things go by. While the concept is fine, what's killing me is the frame rate which I cannot get above 30 FPS.
A perfect solution would be for someone out there taking the raspicam source, stripped it down and tuning it for speed, and bolting it up to OpenCV. Has anyone done this? Did it work?
The Ava Group in Spain (https://www.uco.es/investiga/grupos/ava/node/40) took an initial stab at this, but their still frame rate is also limited to 30 FPS.
I use Matlab on my MacBook Pro with Retina display.
Using get(0,'ScreenSize'), we obtain
ans =
1 1 1440 900
instead of 1 1 2880 1800. Is there any way to work with right sizes?
No, 1440-by-900 is likely the correct effective value for your screen's resolution. This is the value that the OS tells applications and is not the the same as the number of pixels (sometimes referred to as the "native resolution"). However, applications also need to check if a display supports HiDPI mode (a.k.a. Retina) as well. In your case, each "retina pixel" is made up of a 2-by-2 set of raw pixels (which, in turn, each have RGB sub-pixels). Applications that are "Retina-aware" can then render certain graphics (e.g., images and video) at the the full native resolution within regions of the screen. Some more details – probably more accurately stated – can be found in this article.
There are 3rd-party solutions to run OS X at the native resolution (e.g., SwitchResX and the methods discussed here), but this of course makes everything, UI included, ridiculously tiny. If you're running one of these, Matlab should report your resolution as 2880-by-1800.
I am not aware of any Matlab options, properties, or functions that allow one to actually take advantage of advantage of a Retina display. This means that, for example, when you display an image, each of it's pixels are rendered as 2-by-2 retina pixels.
I'm developing a card game in Android using SurfaceView and canvas to draw the UI.
I've tried to optimize everything as much as possible but I still have two questions:
During the game I'll need to draw 40 bitmaps (the 40 cards in the italian deck), is it better to create all the bitmaps on the onCreate method of my customized SurfaceView (storing them in an array), or create them as needed (every time the user get a new card for example)?
I'm able to get over 90 fps on an old Samsung I5500 (528 MHz, with a QVGA screen), 60 fps on an Optimus Life (800 MHz and HVGA screen) and 60 fps with a Nexus One/Motorola Razr (1 GHz and dual core 1GHz with WVGA and qHD screens) but when I run the game on an Android tablet (Motorola Xoom dual core 1 GHz and 1 GB of Ram) I get only 30/40 fps... how is that possible that a 528 MHz cpu with 256 MB of RAM can handle 90+ fps and a dual core processor can't handle 60 fps? I'm not seeing any kind of GC calling at runtime....
EDIT: Just to clarify I've tried both ARGB_888 and RGB_565 without any changes in the performance...
Any suggestions?
Thanks
Some points for you to consider:
It is recommended not to create new objects while your game is running, otherwise, you may get unexpected garbage collections.
Your FPS numbers doesn't sound good, you may have measurement errors, However my guess is that you are resizing the images to fit the screen size and that affects the memory usage of your game and may cause slow rendering times on tablets.
You can use profiling tools to confirm: TraceView
OpenGL would be much faster
last tip: don't draw overlapping cards if you can, draw only the visible ones.
Good Luck
Ok so it's better to create the bitmap in the onCreate method, that is what I'm doing right now...
They are ok, I believe that the 60 fps on some devices are just some restrictions made by producers since you won't find any advantage in getting more than 60 fps (I'm making this assumption since it doesn't change rendering 1 card, 10 cards or no card... the OnDraw method is called 60 times per second, but if I add for example 50/100 cards it drops accordingly) I don't resize any card cause I use the proper folder (mdpi, hdpi, ecc) for each device, and I get the exact size of the image, without resizing it...
I've tried to look at it but from what I understand all the time of the app execution is used to draw the bitmap, not to resize or update its position here it is:
I know, but it would add complexity to the developing and I believe that using a canvas for 7 cards on the screen should be just fine….
I don't draw every card of the deck.. I just swap bitmap as needed :)
UPDATE: I've tried to run the game on a Xoom 2, Galaxy Tab 7 plus and Asus Transformer Prime and it runs just fine with 60 fps…. could it be just a problem of Tegra 2 devices?
Screen resolution has increased in iphone OS4. Since lot of UI stuff have hardcoded co-ordinates, will my app run properly on OS4? I still haven't got Snow Leopard, so cant test run the simulator for OS4.
It is publicly known that the number of points vs pixels is 2:1 so point 320 has 640 pixels in hi-res and 320 pixels in low-res. Low resolution images will be somewhat jaggy, but their positioning on the screen would remain the same.