Wrong resolution of second screen
lazarus / 34-Windows

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Apiglio · 2024-12-05 12:20

I'm using TScreen.Monitors to get resolution information of Desktop
and find the size of Primary Screen is correct but not of the second.

Here is my code:
Code: Pascal  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i   for
idx:=0{edited} to Screen.MonitorCount-1 do  begin   
writeln(Format('Monitor %d:',[idx]));    writeln(Format('  PPI = %d',
[Screen.Monitors[idx].PixelsPerInch]));    with
Screen.Monitors[idx].BoundsRect do      writeln(Format('  Boundary:
left = %d, top = %d, width = %d, height = %d', [Left, Top, Width,
Height]));  end;  Here is my screen setting:
Code: Text  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i ＋－－－＋－－－－－－
－＋｜　　　｜　　　　　　　｜｜　１　｜　　　０　　　｜｜　　　｜　　　　　　　｜＋－－－＋－－－－－－－＋monitor 0: 
Resolution: 2560 x 1440  Scaling:   150% monitor 1:  Resolution: 900 x
1440  Scaling:   100% run the code and I got this:
Code: Pascal  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i Monitor 0: 
PPI = 144  Boundary: left = 0, top = 0, width = 2560, height =
1440Monitor 1:  PPI = 144  Boundary: left = -1350, top = 0, width =
1350, height = 2160 
If I set the scaling of second screen to 150% (same as Primary
Screen), everything would be all right. What is going on? Can I only
use LCL and Windows unit to solve this problem?

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rvk · 2024-12-05 13:12

Normally, an application is only DPI aware (for one monitor).
So there is only one DPI known, not multiple per monitor.

If you go into your project options, you can set the DPI awareness to
"Per monitor" (True/PM).
After that... the DPI settings are per monitor and you get the
expected result.

(BTW. You need to count idx from 0 to MonitorCount - 1. You counted
from 1, not 0.
But in your result it was correct monitor 0 so I guess that was a copy
error.)

QuoteMonitor 0:
  PPI = 96
  Boundary: left = 1920, top = 126, width = 1920, height = 1080
Monitor 1:
  PPI = 144
  Boundary: left = -1920, top = 129, width = 1920, height = 1080
Monitor 2:
  PPI = 96
  Boundary: left = 0, top = 0, width = 1920, height = 1200

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Apiglio · 2024-12-05 14:13

Thank you, @rvk. It works.

Quote from: rvk on December 05, 2024, 02:12:01 pm(BTW. You need to
count idx from 0 to MonitorCount - 1. You counted from 1, not 0.
But in your result it was correct monitor 0 so I guess that was a copy
error.)
Yes, that's awkward. I changed some code to make it brief.