_DESKTOPWIDTH and _DESKTOPHEIGHT won't update after program has started.

[Stuart]

I'm not sure if this is a bug or if it's by design but when a QB64 program first starts, _DESKTOPWIDTH and _DESKTOPHEIGHT both return the correct values for the desktop size...

...However, if the desktop resolution is changed _after_ the program has been started, _DESKTOPWIDTH and _DESKTOPHEIGHT still return the same values as they did when the program was first started.

Code: QB64: [Select]

1. PRINT
2. COLOR 15
3. PRINT "The desktop resolution when this program was started    :";
4. PRINT _DESKTOPWIDTH; "x"; _DESKTOPHEIGHT
5.  
6.  
7. COLOR 7
8. DO
9.    PRINT
10.    PRINT "Change to a different screen resolution and then"
11.    PRINT "press <ENTER> to update the info...  ";
12.    DO
13.       _LIMIT 30
14.    LOOP WHILE INKEY$ <> CHR$(13)
15.    PRINT "current resolution :"; _DESKTOPWIDTH; "x"; _DESKTOPHEIGHT
16. LOOP
17.  

[SMcNeill]

Desktopwidth is nearly a direct call to glutget(), and to be honest, I don’t know if this is the expected behavior or not. 

The documentation is very barebones: https://www.opengl.org/resources/libraries/glut/spec3/node70.html

GLUT_SCREEN_WIDTH
Width of the screen in pixels. Zero indicates the width is unknown or not available.
GLUT_SCREEN_HEIGHT
Height of the screen in pixels. Zero indicates the height is unknown or not available.


************

Now, whether that Width/Height is only calculated once at program start-up, or on the fly as needed, I honestly don’t know.

If your program requires detections for this type of thing, you may need to resort to using declare library with the windows api (or Linux/Mac equivalent).

[Stuart]

Now, whether that Width/Height is only calculated once at program start-up, or on the fly as needed, I honestly don’t know.

If your program requires detections for this type of thing, you may need to resort to using declare library with the windows api (or Linux/Mac equivalent).

Thanks for the quick response.

DECLARE LIBRARY and the Windows API are beyond my current programming capabilities...

It would be nice if Width/Height were calculated on the fly, but I can get by with it being calculated only at start-up since most people probably wouldn't be changing the screen resolution _after_ running a program anyway.

[Pete]

Fooling around a little with Win API... I hope the wife doesn't find out. So, coincidence or does this code actually work...

Code: QB64: [Select]

1. DECLARE DYNAMIC LIBRARY "user32"
2.     FUNCTION GetSystemMetrics& (BYVAL Index AS _OFFSET)
3. END DECLARE
4.  
5. xResult& = GetSystemMetrics&(0)
6. yResult& = GetSystemMetrics&(1)
7. PRINT xResult&; "x"; yResult&
8.  

It seems to be good on mine, 1366 x 768 as checked in desktop properties for my current screen resolution.

Pete

[Stuart]

Fooling around a little with Win API... I hope the wife doesn't find out. So, coincidence or does this code actually work...

Yes!  I added your code to the top of my sample program, made changes on two lines, and it works perfectly.

Now, if one of the developers could incorporate this into QB64.exe (at least for the Windows part of the code) then the _DESKTOPWIDTH and _DESKTOPHEIGHT commands would work a lot better.

Code: QB64: [Select]

1. DECLARE DYNAMIC LIBRARY "user32"
2.     FUNCTION GetSystemMetrics& (BYVAL Index AS _OFFSET)
3. END DECLARE
4.  
5. REM xResult& = GetSystemMetrics&(0)
6. REM yResult& = GetSystemMetrics&(1)
7. REM PRINT xResult&; "x"; yResult&
8.  
9.  
10.  
11.  
12.  
13. PRINT
14. COLOR 15
15. PRINT "The desktop resolution when this program was started    :";
16. '''''PRINT _DESKTOPWIDTH; "x"; _DESKTOPHEIGHT
17. PRINT GetSystemMetrics&(0); "x"; GetSystemMetrics&(1)
18.  
19.  
20. COLOR 7
21. DO
22.    PRINT
23.    PRINT "Change to a different screen resolution and then"
24.    PRINT "press <ENTER> to update the info...  ";
25.    DO
26.       _LIMIT 30
27.    LOOP WHILE INKEY$ <> CHR$(13)
28.    PRINT "current resolution :"; '''''_DESKTOPWIDTH; "x"; _DESKTOPHEIGHT
29.    PRINT GetSystemMetrics&(0); "x"; GetSystemMetrics&(1)
30. LOOP
31.