Wrong PixelRatio calculation (based on DPI scaling)

Hello, I have a monitor that is uhd, and the dpi that comes configured with the app is very low, is there any way to change it?

[GeertJohan]

@m3k4itr41n
Are you using the prebuilt release of that app? I think it was built using a version of go-flutter that didn't have proper DPI scaling support.

If you follow the guide to compile locally, you'll get the app in a proper resolution. Please let me know if that works.

I'll leave this ticket open as a reminder to setup CI/CD for the example app releases.

@GeertJohan

Are you using the prebuilt release of that app?

yes

If you follow the guide to compile locally, you'll get the app in a proper resolution. Please let me know if that works.

nope, it seems that it did not work

I think this is related to this error, right?

[ERROR:flutter/shell/platform/embedder/embedder_surface_gl.cc(89)] Could not create a resource context for async texture uploads. Expect degraded performance. Set a valid make_resource_current callback on FlutterOpenGLRendererConfig.
[ERROR:flutter/shell/platform/embedder/embedder_surface_gl.cc(89)] Could not create a resource context for async texture uploads. Expect degraded performance. Set a valid make_resource_current callback on FlutterOpenGLRendererConfig.
calculated pixelRatio limited to a minimum of 1.0
flutter: Observatory listening on http://127.0.0.1:50300/
Reading (A number): 

[GeertJohan]

Are you using a multi-monitor setup? Or are you somehow scaling the virtual screen vs physical screen in X11?

@GeertJohan The only thing I change is in the gnome configuration panel to scale the resolution to 200%.

[GeertJohan]

We'll need some debugging values to see why the ratio was calculated so low..

Meanwhile you may be able to add ForcePixelRatio to the options given to Run(..), it forces the amount physical pixels per flutter displaypixel to a given value. Probably a value between 1.4 and 2.0 would work for you. Higher = larger UI. Ofcourse this isn't a permanent solution. I'll work on debug options after #86 is merged.

[pchampio]

The DPI issue seems to be resolved. Closing the issue.

A new version is around the corner, once #86 gets merged, please report us any new issues.

[GeertJohan]

Actually, the DPI issue was patched with duct tape.. I'd like to know why the calculated DPI is wrong..

@m3k4itr41n Could you please update to the latest version (v0.6.0) and remove the OptionPixelRatio, so it calculates based on screen dimensions again? It should give you the same warning ("calculated pixelRatio limited to a minimum of 1.0") but now with a bunch of numeric values added behind it. Please send me those logs. Also please send me the resolution of your screen and the size (width in milimeters) of your screen.

[pchampio]

Pixel ratio issue should be solved by 2119e28

[GeertJohan]

@Drakirus
No, that mistake was introduced when adding more debug info for this issue.

[b0o]

Hey @GeertJohan, I am seeing this issue as well. Here's the debug output:

go-flutter: calculated pixelRatio limited to a minimum of 1.0. metrics: {"dpi":101.6,"monitorWidthMm":480,"monitorWidthSc":1920,"mscpi":101.6,"pixelRatio":0.635,"ppsc":1,"windowWidthPx":3840,"windowWidthSc":3840}

I'm on a Linux system with a multihead setup and two HiDPI displays (plus an old Wacom Cintiq) which I configure with XRandR:

#!/bin/bash
# DisplayPort-0:   Disabled
# DisplayPort-1: * Ext R (Horizontal) ]
# DisplayPort-2:   Ext L (Vertical)
# HDMI-A-0:        Wacom (Horizontal)

xrandr --output DisplayPort-0 --off

xrandr --output DisplayPort-1 --scale 2x2 \
  --output      DisplayPort-2 --scale 2x2 \
  --output      HDMI-A-0      --scale 2x2

xrandr --output DisplayPort-2 --rotate left --left-of DisplayPort-1 \
  --output      DisplayPort-1 --above HDMI-A-0

xrandr --output DisplayPort-2 --pos 0x0    --mode 1920x1080 \
  --output      DisplayPort-1 --pos 2160x0 --mode 1920x1080 \
  --output      HDMI-A-0 --pos 2160x2160   --mode 1024x768

The hover example application was run on my DisplayPort-1 monitor.

Various system/version info:

• Arch Linux:

  $ uname -srvo
  Linux 5.1.12-arch1-1-ARCH #1 SMP PREEMPT Wed Jun 19 09:16:00 UTC 2019 GNU/Linux
  

• Flutter:

  $ flutter --version
  Flutter 1.5.4-hotfix.2 • channel stable • https://github.com/flutter/flutter.git
  Framework • revision 7a4c33425d (8 weeks ago) • 2019-04-29 11:05:24 -0700
  Engine • revision 52c7a1e849
  Tools • Dart 2.3.0 (build 2.3.0-dev.0.5 a1668566e5)
  

• WM: xmonad
• hover: v0.19.0
• full debug output:

  maddy ♥ ~/git » cd go-flutter-examples/simple_demo
  maddy ♥ git/go-flutter-examples/simple_demo » hover run
  Using engine from cache
  go: finding github.com/go-gl/glfw latest
  [ERROR:flutter/shell/platform/embedder/embedder_surface_gl.cc(95)] Could not create a resource context for async texture uploads. Expect degraded performance. Set a valid make_resource_current callback on FlutterOpenGLRendererConfig.
  flutter: Observatory listening on http://127.0.0.1:50300/oLCiiNzUF8Y=/
  [ERROR:flutter/shell/platform/embedder/embedder_surface_gl.cc(95)] Could not create a resource context for async texture uploads. Expect degraded performance. Set a valid make_resource_current callback on FlutterOpenGLRendererConfig.
  go-flutter: calculated pixelRatio limited to a minimum of 1.0. metrics: {"dpi":101.6,"monitorWidthMm":480,"monitorWidthSc":1920,"mscpi":101.6,"pixelRatio":0.635,"ppsc":1,"windowWidthPx":3840,"windowWidthSc":3840}
  go-flutter: no method handler registered for method 'SystemChrome.setSystemUIOverlayStyle' on channel 'flutter/platform'
  Syncing files to device Flutter test device...                   1,067ms
  
  🔥  To hot reload changes while running, press "r". To hot restart (and rebuild state), press "R".
  An Observatory debugger and profiler on Flutter test device is available at: http://127.0.0.1:50300/oLCiiNzUF8Y=/
  For a more detailed help message, press "h". To detach, press "d"; to quit, press "q".
  go-flutter: no method handler registered for method 'SystemSound.play' on channel 'flutter/platform'
  go-flutter: no method handler registered for method 'SystemSound.play' on channel 'flutter/platform'
  go-flutter: no method handler registered for method 'SystemSound.play' on channel 'flutter/platform'
  go-flutter: no method handler registered for method 'SystemSound.play' on channel 'flutter/platform'
  go-flutter: no method handler registered for method 'SystemSound.play' on channel 'flutter/platform'
  go-flutter: failed to pop route after escape key press: failed to decode envelope: unexpected end of JSON input
  go-flutter: closing application
  hover: app 'simple_demo' exited.
  hover: closing the flutter attach sub process..
  Lost connection to device.
  

Hope this is useful - if you want any more info, let me know 😃