Multi touch issue - Android Q&A, Help & Troubleshooting

I have a weird issue. When I place two fingers on my phone screen and they're both placed om the same line, it causes issues. As shown in the example bellow
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As you can see, when one finger moves across the screen the other static input slightly moves left and right. Also shown at the end is what happens when the fingers aren't lined up, the issue doesn't happen. I don't know of this is how every touch screen works. And if it does, can this function be turned off?

Related

Vertical line

When I press the right side button to wake up my phone, a vertical line flickers for half a second like a stutter and then goes to the lock screen. Would this be of enough concern to warrant a phone exchange? I just received my phone today as well. I tried uploading video of it to youtube, but the youtube compression makes it hard to see.

Okay, Let's Talk About This Second Screen For A Minute

(I'm on the T-mobile variant)
I will be the 1st person to admit that my knowledge of mobile displays is limited at best (I get the difference between AMOLED and LCD, etc), but I have a curious observation. So, I'm assuming were all familiar with the light bleed issue from the 2nd screen. It is my impression that the theory behind the light bleed is that the "back light" for the second screen is off to the left side of the 2nd screen. It would appear that this is the case as that's where the light bleed comes from, and also (on my phone at least) if there's a notification it's brighter towards theft side of the screen and you can see how the brightness tapers off towards the right side.
Here's where it gets curious, although I'm sure there's an explanation. After unlocking the bootloader and flashing TWRP I booted into recovery and noticed that the 2nd screen comes in TWRP. However you would think that TWRP would be full screen on the main screen, but it isn't. The 2nd screen completes the upper right part of the TWRP full screen, the only place it's not full is to the left of the 2nd screen where the front facing cameras are. It looks absolutely seamless, like there's not really a 2nd screen at all, it's obviously lit from the back and not the side. It was too bright and even all the way across to the right side of the second screen to be lit from the side like it is when the screen is off.
Is there a "side" back light and a main back light? Why does it look so perfect in TWRP, literally like it's all one screen? I'll try and take some pics later but if any of you have TWRP flashed check it out. IMO there's something fishy here, or maybe I'm just crazy.
Sent from my LG-H901 using Tapatalk
It really isn't a second screen, the phone would have costed maybe even double the price perhaps. One is thinking about how to keep try same resolution to be on par with the main screen, but what I think it is though in terms of it maybe being a special custom backlighting connected to an independent source along with software to then have the two screens one type of feel. I'm just giving my opinion, this phone I had to return and exchange because the notification bar backlight for to overwhelming and literally was day and nigh contrast on the strip of second screen. Now with this exchange I now have screen bleed under the ffcameras.
0dBu said:
Is there a "side" back light and a main back light? Why does it look so perfect in TWRP, literally like it's all one screen?
Click to expand...
Click to collapse
BINGO. There are two backlights. First is the normal backlight that lights up the entire display (there is no "second screen" - it's a single LCD panel). Then, there's the secondary backlight - a single white LED on the left edge of the "second screen." This single secondary backlight LED is injecting light through the left edge of the second screen and is not attached to the main backlight diffuser, which is why it lights the screen so unevenly. There are certain times when that secondary LED is on and when it is off. When it is on, it adds extra light near the left edge of the screen, which makes the notifications in that area brighter.
Try this. Turn on the Camera app and observe the buttons that appear on the second screen. Notice that the left-most (or bottom, if you hold it horizontally) button is NOT brighter at all? That's because the second backlight turns off when the camera app is running, and you only see the main screen backlight, which is even. Exit the camera app and you'll see the second backlight turn on and the bleed return. Open the camera app again and you'll see the bleed disappear, as the second backlight turns off.
Do another test. Hold the phone at an angle so the bleed from the second backlight is clearly visible, then go into the settings for the second screen, and turn it off while watching the left-most edge of the second screen - you'll see the "bleed" suddenly disappear, because the secondary backlight turns off (even though the main backlight is on). Turn the second screen back on while watching the left edge, and you'll see the bleed come back as the secondary backlight turns back on.
Yet another way to see it - power off the phone, then power it on while watching the left edge of the second screen. During initial boot, it will look perfectly even, no bleed, because the secondary backlight is off. But half-way through the boot process, the secondary backlight turns on, and you see "bleed."
Now, when the main screen is off, the ONLY thing lighting the second screen is the secondary backlight, so ALL you see is bleed (since the main backlight is off) which looks horrible.
The reason you don't see bleed at all in TWRP is because TWRP doesn't know that there is a second backlight and therefore it doesn't turn it on, since it doesn't know how.
To get rid of the "brighter left side" problem when the main screen is on, all LG has to do is issue a software update that turns off the secondary backlight when the main screen is on - I'm surprised they overlooked this obvious problem.
And here's the kicker - you know why you don't see the second screen bleed on the demo units in stores? Because the Retail Mode app turns the secondary backlight off, just like the camera app.
siraltus said:
BINGO. There are two backlights. First is the normal backlight that lights up the entire display (there is no "second screen" - it's a single LCD panel). Then, there's the secondary backlight - a single white LED on the left edge of the "second screen." This single secondary backlight LED is injecting light through the left edge of the second screen and is not attached to the main backlight diffuser, which is why it lights the screen so unevenly. There are certain times when that secondary LED is on and when it is off. When it is on, it adds extra light near the left edge of the screen, which makes the notifications in that area brighter.
Try this. Turn on the Camera app and observe the buttons that appear on the second screen. Notice that the left-most (or bottom, if you hold it horizontally) button is NOT brighter at all? That's because the second backlight turns off when the camera app is running, and you only see the main screen backlight, which is even. Exit the camera app and you'll see the second backlight turn on and the bleed return. Open the camera app again and you'll see the bleed disappear, as the second backlight turns off.
Do another test. Hold the phone at an angle so the bleed from the second backlight is clearly visible, then go into the settings for the second screen, and turn it off while watching the left-most edge of the second screen - you'll see the "bleed" suddenly disappear, because the secondary backlight turns off (even though the main backlight is on). Turn the second screen back on while watching the left edge, and you'll see the bleed come back as the secondary backlight turns back on.
Yet another way to see it - power off the phone, then power it on while watching the left edge of the second screen. During initial boot, it will look perfectly even, no bleed, because the secondary backlight is off. But half-way through the boot process, the secondary backlight turns on, and you see "bleed."
Now, when the main screen is off, the ONLY thing lighting the second screen is the secondary backlight, so ALL you see is bleed (since the main backlight is off) which looks horrible.
The reason you don't see bleed at all in TWRP is because TWRP doesn't know that there is a second backlight and therefore it doesn't turn it on, since it doesn't know how.
To get rid of the "brighter left side" problem when the main screen is on, all LG has to do is issue a software update that turns off the secondary backlight when the main screen is on - I'm surprised they overlooked this obvious problem.
And here's the kicker - you know why you don't see the second screen bleed on the demo units in stores? Because the Retail Mode app turns the secondary backlight off, just like the camera app.
Click to expand...
Click to collapse
Spot on!

Tap Screen for Always-On Display

I've read spotty reviews on how the ambient screen display feature works (as-in it didn't reliably) so I initially disabled it. I installed Nougat DP5 last night and re-enabled it just to see if it's any better. I've found that if I double tap the screen it comes on. Now, I don't think this is like the LG version where it's detecting your finger touching the screen but more like the accelerometer detects the vibration and interprets this as the motion needed to trip the display. I've noticed that it's not very reliable, or doesn't work at all, except on the right-side more or less inline with where the time is displayed. Double-tap here and it works very time (maybe the accelerometer is under that spot). Who knows. What I do know is that I can now check the time without having to press the power button.
I've noticed this as well - I'm on dp5, and I have the double tap 6p app installed. It doesn't seem to work as well, but the ambient display seems to trigger more when I touch the device.
On stock all you need to do is tap it hard enough to slightly move the phone and ambient display will work.

Touch Screen (Digitizer) to Screen Display Mapping Issue

Hello
I just replaced the touch screen of my generic 9inch Android Tablet running on Jelly Bean. I couldn’t get the genuine one so I just bought a compatible one: The screen works BUT it doesn’t properly map the co-ordinates on the Display. Bottom and the sides are OK but the top (about 1 inch in landscape mode) has no response. The screen is all working : The bottom matches fine but as you swipe upwards you can see that your finger touches a higher point which matches a slightly lower point on the display. When your finger reaches the top …the matching map becomes about 1inch bellow on the display.
I need help to fix this issue: I think there would be a file inside my android where there would be values to match the Display Screen mapping with the Touch Screen (digitizer)
Thank you in advance……

Strange blue dots and lines on the screen

Hi,
When i scroll a screen, sometimes show up a small blue dots or lines? When I start recording, they stop showing... But usually it's show all the time, in many apps.
(on the 1st video, dots are noticeable for the first few seconds)
(on the Safe Mode is the same)
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It was a main board error. I took the phone to the service and on the same day they gave me a fixed one with a new motherboard. I also have the impression that the responsiveness of the fingerprint reader is faster. So thread could be closed.

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