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; Microsoft Windows Win32 API Docs (DEVMODE)
; https://docs.microsoft.com/en-us/windows/desktop/api/wingdi/ns-wingdi-_devicemodea
; https://docs.microsoft.com/en-us/windows/desktop/api/wingdi/ns-wingdi-_devicemodew

; These constants correspond to the Win32 API's DEVMODE structure.
; They are now pre-declared in the latest versions of PureBasic and do not need to
; be manually assigned. So, the #DM_XXXXXX constants can be used without declaration.
; #DM_BITSPERPEL = $40000
; #DM_PELSWIDTH = $80000
; #DM_PELSHEIGHT = $100000

; define a new Win32 API DEVMODE structure (refer to linked docs to view all the members)
res.DEVMODE

; assign the desired values to these six DEVMODE members
res\dmSize = SizeOf(DEVMODE) ;structure size (required)
res\dmBitsPerPel = 32 ;desired colour depth (output element)
res\dmPelsWidth = 800 ;desired width (output element)
res\dmPelsHeight = 600 ;desired height (output element)
res\dmDisplayFrequency = 60 ;desired refresh rate

; #DM_BITSPERPEL -> colour depth
; #DM_PELSWIDTH -> display width
; #DM_PELSHEIGHT -> display height
; set the OUTPUT element flags that are being modifed
res\dmFields = #DM_BITSPERPEL | #DM_PELSWIDTH | #DM_PELSHEIGHT

; pass the assigned DEVMODE structure (defined here as res) to the Win32 API function
ChangeDisplaySettings_(@res.DEVMODE, 0)

Author:	Columbo [ Thu Apr 18, 2019 3:07 pm ]
Post subject:	Code explanation
I was looking through some posts for some information on changing screen resolution and found this code. Code: #DM_BITSPERPEL=$40000 #DM_PELSWIDTH=$80000 #DM_PELSHEIGHT=$100000 res.DEVMODE res\dmSize=SizeOf(DEVMODE) res\dmBitsPerPel=32 res\dmPelsWidth=800 res\dmPelsHeight=600 res\dmDisplayFrequency=60 res\dmFields=#DM_BITSPERPEL\|#DM_PELSWIDTH\|#DM_PELSHEIGHT ChangeDisplaySettings_(@res.DEVMODE,0) The code however, does not include any comments. I would like to understand what is happening here. Is there anyone who can give me a line-by-line explanation as to what each line is doing? I am assuming that the lines res\dmPelsWidth=800 and res\dmPelsHeight=600 is a screen resolution of 800 x 600 but what are the rest of the lines doing? I don’t know what the line res\dmBitsPerPel=32 is but, does the value of 32 change if the screen resolution is different from 800 x 600? Any help is appreciated.

Author:	TI-994A [ Thu Apr 18, 2019 4:08 pm ]
Post subject:	Re: Code explanation
Columbo wrote: ...a line-by-line explanation as to what each line is doing? Hi John! Here's a shot in the dark: Code: ; Microsoft Windows Win32 API Docs (DEVMODE) ; https://docs.microsoft.com/en-us/windows/desktop/api/wingdi/ns-wingdi-_devicemodea ; https://docs.microsoft.com/en-us/windows/desktop/api/wingdi/ns-wingdi-_devicemodew ; These constants correspond to the Win32 API's DEVMODE structure. ; They are now pre-declared in the latest versions of PureBasic and do not need to ; be manually assigned. So, the #DM_XXXXXX constants can be used without declaration. ; #DM_BITSPERPEL = $40000 ; #DM_PELSWIDTH = $80000 ; #DM_PELSHEIGHT = $100000 ; define a new Win32 API DEVMODE structure (refer to linked docs to view all the members) res.DEVMODE ; assign the desired values to these six DEVMODE members res\dmSize = SizeOf(DEVMODE) ;structure size (required) res\dmBitsPerPel = 32 ;desired colour depth (output element) res\dmPelsWidth = 800 ;desired width (output element) res\dmPelsHeight = 600 ;desired height (output element) res\dmDisplayFrequency = 60 ;desired refresh rate ; #DM_BITSPERPEL -> colour depth ; #DM_PELSWIDTH -> display width ; #DM_PELSHEIGHT -> display height ; set the OUTPUT element flags that are being modifed res\dmFields = #DM_BITSPERPEL \| #DM_PELSWIDTH \| #DM_PELSHEIGHT ; pass the assigned DEVMODE structure (defined here as res) to the Win32 API function ChangeDisplaySettings_(@res.DEVMODE, 0)

Author:	Columbo [ Thu Apr 18, 2019 6:30 pm ]
Post subject:	Re: Code explanation
Thanks Syed,... much appreciated.Good to hear from you. Cheers!

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