Ottenere informazioni relative allo schermo mediante la funzione ioctl()
Da Gambas-it.org - Wikipedia.
Con la funzione esterna "ioctl()" di C è possibile anche ottenere alcune in formazioni relative allo schermo, come ad esempio le sue "reali" dimensioni.
In particolare mediante la funzione esterna "ioctl()" si leggerà il file device "/dev/fb*" [nota 1] e si caricheranno i valori nella Struttura "fb_var_screeninfo", dalla quale si leggeranno i membri "height" e "width".
Mostriamo un esempio pratico:
Library "libc:6" Public Struct fb_var_screeninfo xres As Integer yres As Integer xres_virtual As Integer yres_virtual As Integer xoffset As Integer yoffset As Integer bits_per_pixel As Integer grayscale As Integer red_offset As Integer red_length As Integer red_msb_right As Integer green_offset As Integer green_length As Integer green_msb_right As Integer blue_offset As Integer blue_length As Integer blue_msb_right As Integer transp_offset As Integer transp_length As Integer transp_msb_right As Integer nonstd As Integer activate As Integer height As Integer width As Integer accel_flags As Integer pixclock As Integer left_margin As Integer right_margin As Integer upper_margin As Integer lower_margin As Integer hsync_len As Integer vsync_len As Integer sync As Integer vmode As Integer rotate As Integer colorspace As Integer reserved[4] As Integer End Struct Private Const FBIOGET_VSCREENINFO As Integer = &4600 ' int ioctl (int __fd, unsigned long int __request, ...) ' Perform the I/O control operation specified by REQUEST on FD. Private Extern ioctl(__fd As Integer, __request As Long, var As Fb_var_screeninfo) As Integer Public Sub Main() Dim fl As File Dim si As New Fb_var_screeninfo fl = Open "/dev/fb0" For Read ioctl(fl.Handle, FBIOGET_VSCREENINFO, si) Print "Informazioni dello schermo:\n" Print "Risoluzione: "; si.xres; "x"; si.yres; " pixel" Print "Bit per pixel: "; si.bits_per_pixel Print "Altezza: mm\e[1m"; si.height, " \e[0mLarghezza: mm\e[1m"; si.width fl.Close End
