The screen device runs it's own native "resolution", it has physical pixels. I'll look into the screen model and driver file to see if that's really the best res it is.
The app runs on a specified resolution. If that's not the native device res then the driver would need to interpolate. If the aspect is not the same then you get squishing and such.
I think perhaps the spec sheet tells us what the Scope app is, and less about the underlying devices of the hardware.
All good info.
Look, Randy, I really did not need an explanation from you on physical screen resolution vs. driver resolution etc. Nobody here needs that. We have all used LCD monitors and seen the effect of different resolutions and driver settings; quite a few here have designed LCD monitors into systems and driven them on a low level. Seeing you dish out those explanations just makes me wonder whether (a) you have an unrealistic picture of the audience here, or (b) you have an unrealistic picture of yourself.
On the other hand, please consider why on earth Rigol should build in a higher-resolution display and then drive it a lower resolution?! The display would be more expensive; it would take more power; it would take more CPU/GPU bandwidth to drive the pixels; the interpolated picture would look worse than on a native-resolution display. And if they still were to use that high-res display despite all that: Why would they put anything but the highest justifiable resolution number into the datasheet??
I think you can safely drop that resolution hypothesis.
Well, the /system/build.prop "persist.sys.framebuffer.main" option is set to only 1024x600@60
Whaaaa? The screen can do 1920x1080@60 just fine.
So, I can tell you, the device is not setup to use the screen at best resolution.
With the OEM setting, Scope app displays in the lower res, AND, taking screenshots and vid are in the lower res.
I changed the setting to be 1920x1080@60 and now the Scope app displays in that higher resolution (fonts and stuff will get smaller), AND, grabbing pics are now in the 1920x1080 resolution, even when you use Webcontrol take-pic.
There's also lcd_density setting, set to 228 by default. I tried 20 and the screen starts to look pixel-ated, then I try 300 and it looks good, but, from Android docs this setting appear to be some sort of "bucket" setting, so I suspect 300 is the same as the (probably calculated) 228 setting.
Why Rigol uses the lower res setting? Likely because the physical screen size is tiny, 7" diagonal, making things "hard to read" with a 1920x1080 res. I guess they figure if you want 1920x1080 you gonna slap down a larger 24" monitor with hdmi in 1920x1080 and view there?
I suspect though, if you run the DHO in 1920x1080, when you zoom in you get finer detail? I didn't do the math of painted signal pixels vs screen res.
As a side note, not sure what happened, maybe from mucking around with FPGA flashing, or maybe removal of Sparrow and reinstall did it. I have no front-end signal processing (at least not getting through Scope app to screen). 1kHz gen still works, the rest of Scope app seems to still be ok.