Differenze tra le versioni di "Ottenere informazioni sugli schermi disponibili mediante le funzioni del API di X11"

Da Gambas-it.org - Wikipedia.
Riga 1: Riga 1:
 
La libreria '''Xlib''' dello ''X Window System Standard'', versione 11, consente - fra l'altro - anche di ottenere alcune informazioni in ordine agli schermi disponibili.
 
La libreria '''Xlib''' dello ''X Window System Standard'', versione 11, consente - fra l'altro - anche di ottenere alcune informazioni in ordine agli schermi disponibili.
  
−
Si richiamerà l'attuale libreria condivisa di ''X11'': "libX11.so.6.3.0".
+
Si richiamerà l'attuale libreria condivisa di X11: "''libX11.so.6.3.0''".
  
  
Riga 8: Riga 8:
 
   
 
   
 
  <FONT color=gray>' ''Display *XOpenDisplay(char *display_name)''
 
  <FONT color=gray>' ''Display *XOpenDisplay(char *display_name)''
−
  ' ''opens a connection to the X server that controls a display.''</font>
+
  ' ''Opens a connection to the X server that controls a display.''</font>
−
  '''Private''' Extern XOpenDisplay(display$ As String) As Pointer
+
  Private Extern XOpenDisplay(display As Pointer) As Pointer
 
   
 
   
 
  <FONT color=gray>' ''int XDefaultScreen (Display *display)''
 
  <FONT color=gray>' ''int XDefaultScreen (Display *display)''
−
  ' ''returns the default screen number referenced by the XOpenDisplay function.''</font>
+
  ' ''Returns the default screen number referenced by the XOpenDisplay function.''</font>
−
  '''Private''' Extern XDefaultScreen(displayP As Pointer) As Integer
+
  Private Extern XDefaultScreen(display As Pointer) As Integer
 
   
 
   
 
  <FONT color=gray>' ''int XDefaultDepth (Display *display, int screen_number)''
 
  <FONT color=gray>' ''int XDefaultDepth (Display *display, int screen_number)''
−
  ' ''returns the depth (number of planes) of the default root window for the specified screen.''</font>
+
  ' ''Returns the depth (number of planes) of the default root window for the specified screen.''</font>
−
  '''Private''' Extern XDefaultDepth(displayP As Pointer, screen_number As Integer) As Integer
+
  Private Extern XDefaultDepth(display As Pointer, screen_number As Integer) As Integer
 
   
 
   
 
  <FONT color=gray>' ''int XConnectionNumber(Display *display)''
 
  <FONT color=gray>' ''int XConnectionNumber(Display *display)''
−
  ' ''returns a connection number for the specified display.''</font>
+
  ' ''Returns a connection number for the specified display.''</font>
−
  '''Private''' Extern XConnectionNumber(displayP As Pointer) As Integer
+
  Private Extern XConnectionNumber(display As Pointer) As Integer
 
   
 
   
 
  <FONT color=gray>' ''char *XDisplayName(char *string)''
 
  <FONT color=gray>' ''char *XDisplayName(char *string)''
−
  ' ''returns the name of the display that XOpenDisplay would attempt to use.''</font>
+
  ' ''Returns the name of the display that XOpenDisplay would attempt to use.''</font>
−
  '''Private''' Extern XDisplayName(disp_string$ As Pointer) As Pointer
+
  Private Extern XDisplayName(disp_string As Pointer) As Pointer
 
   
 
   
 
  <FONT color=gray>' ''int XDisplayWidth (Display *display, int screen_number)''
 
  <FONT color=gray>' ''int XDisplayWidth (Display *display, int screen_number)''
 
  ' ''Returns the width of the screen in pixels.''</font>
 
  ' ''Returns the width of the screen in pixels.''</font>
−
  '''Private''' Extern XDisplayWidth(displayP As Pointer, screen_number As Integer) As Integer
+
  Private Extern XDisplayWidth(display As Pointer, screen_number As Integer) As Integer
 
   
 
   
 
  <FONT color=gray>' ''int XDisplayHeight(Display *display, int screen_number)''
 
  <FONT color=gray>' ''int XDisplayHeight(Display *display, int screen_number)''
 
  ' ''Returns an integer that describes the height of the screen in pixels.''</font>
 
  ' ''Returns an integer that describes the height of the screen in pixels.''</font>
−
  '''Private''' Extern XDisplayHeight(displayP As Pointer, screen_number As Integer) As Integer
+
  Private Extern XDisplayHeight(display As Pointer, screen_number As Integer) As Integer
 
   
 
   
 
  <FONT color=gray>' ''int XDisplayWidthMM (Display *display, int screen_number)''
 
  <FONT color=gray>' ''int XDisplayWidthMM (Display *display, int screen_number)''
−
  ' ''returns the width of the specified screen in millimeters.''</font>
+
  ' ''Returns the width of the specified screen in millimeters.''</font>
−
  '''Private''' Extern XDisplayWidthMM(displayP As Pointer, screen_number As Integer) As Integer
+
  Private Extern XDisplayWidthMM(display As Pointer, screen_number As Integer) As Integer
 
   
 
   
 
  <FONT color=gray>' ''unsigned long XBlackPixel (Display *display, int screen_number)''
 
  <FONT color=gray>' ''unsigned long XBlackPixel (Display *display, int screen_number)''
−
  ' ''returns the black pixel value for the specified screen.''</font>
+
  ' ''Returns the black pixel value for the specified screen.''</font>
−
  '''Private''' Extern XBlackPixel(displayP As Pointer, screen_number As Integer) As Long
+
  Private Extern XBlackPixel(display As Pointer, screen_number As Integer) As Long
 
   
 
   
 
  <FONT color=gray>' ''unsigned long XWhitePixel (Display *display, int screen_number)''
 
  <FONT color=gray>' ''unsigned long XWhitePixel (Display *display, int screen_number)''
−
  ' ''returns the white pixel value for the specified screen.''</font>
+
  ' ''Returns the white pixel value for the specified screen.''</font>
−
  '''Private''' Extern XWhitePixel(displayP As Pointer, screen_number As Integer) As Long
+
  Private Extern XWhitePixel(display As Pointer, screen_number As Integer) As Long
 
   
 
   
 
  <FONT color=gray>' ''int *XListDepths(Display *display, int screen_number, int count_return)''
 
  <FONT color=gray>' ''int *XListDepths(Display *display, int screen_number, int count_return)''
−
  ' ''returns the array of depths that are available on the specified screen.''</font>
+
  ' ''Returns the array of depths that are available on the specified screen.''</font>
−
  '''Private''' Extern XListDepths(displayP As Pointer, screen_number As Integer, count_return As Pointer) As Pointer
+
  Private Extern XListDepths(display As Pointer, screen_number As Integer, count_return As Pointer) As Pointer
 
   
 
   
 
  <FONT color=gray>' ''int XScreenCount(Display *display)''
 
  <FONT color=gray>' ''int XScreenCount(Display *display)''
−
  ' ''returns the number of available screens.''</font>
+
  ' ''Returns the number of available screens.''</font>
−
  '''Private''' Extern XScreenCount(displayP As Pointer) As Integer
+
  Private Extern XScreenCount(display As Pointer) As Integer
 
   
 
   
 
  <FONT color=gray>' ''XCloseDisplay (Display *display)''
 
  <FONT color=gray>' ''XCloseDisplay (Display *display)''
−
  ' ''closes a display or disconnect from the X server.''</font>
+
  ' ''Closes a display or disconnect from the X server.''</font>
−
  '''Private''' Extern XCloseDisplay(displayP As Pointer)
+
  Private Extern XCloseDisplay(display As Pointer)
 
   
 
   
 
   
 
   
 
  '''Public''' Sub Main()
 
  '''Public''' Sub Main()
 
   
 
   
−
   Dim display_name, lista, lista_prof As Pointer
+
   Dim disp, lista, lista_prof As Pointer
 
   Dim depth, screen, connection As Integer
 
   Dim depth, screen, connection As Integer
−
   Dim listrm As Stream
+
   Dim st As Stream
 
   Dim j, b As Byte
 
   Dim j, b As Byte
 
   
 
   
 
   
 
   
−
  <FONT color=gray>' ''Apertura dello schermo ed impostazione di default:''</font>
+
  <FONT color=gray>' ''Connessione al Server X e sua impostazione predefinita:''</font>
−
     display_name = XOpenDisplay(Null)
+
     disp = XOpenDisplay(0)
 +
    If disp = 0 Then Error.Raise("Impossibile connettersi al Server X !")
 
   
 
   
−
     screen = XDefaultScreen(display_name)
+
     screen = XDefaultScreen(disp)
 
   
 
   
−
     depth = XDefaultDepth(display_name, screen)
+
     depth = XDefaultDepth(disp, screen)
 
     If depth = 1 Then
 
     If depth = 1 Then
 
       Print "E' evidente che hai uno schermo preistorico !"
 
       Print "E' evidente che hai uno schermo preistorico !"
Riga 80: Riga 81:
 
     Endif
 
     Endif
 
        
 
        
−
     connection = XConnectionNumber(display_name)
+
     connection = XConnectionNumber(disp)
 
     Print "Il numero di connessione è "; connection
 
     Print "Il numero di connessione è "; connection
 
   
 
   
 
  <FONT color=gray>' ''Mostra le informazioni relative allo schermo:''</font>
 
  <FONT color=gray>' ''Mostra le informazioni relative allo schermo:''</font>
−
     Print "Lo schermo è: " & String@(XDisplayName(display_name))
+
     Print "Lo schermo è: " & String@(XDisplayName(disp))
 
      
 
      
−
     Print "La larghezza dello schermo è: "; XDisplayWidth(display_name, screen)
+
     Print "La larghezza dello schermo è: "; XDisplayWidth(disp, screen)
−
     Print "L'altezza dello schermo è: "; XDisplayHeight(display_name, screen)   
+
     Print "L'altezza dello schermo è: "; XDisplayHeight(disp, screen)   
−
     Print "La larghezza dello schermo è di " & XDisplayWidthMM(display_name, screen) & " millimetri"
+
     Print "La larghezza dello schermo è di " & XDisplayWidthMM(disp, screen) & " millimetri"
 
   
 
   
−
     Print "Valore dei pixel neri dello schermo: " & XBlackPixel(display_name, screen)
+
     Print "Valore dei pixel neri dello schermo: " & XBlackPixel(disp, screen)
−
     Print "Valore dei pixel bianchi dello schermo: " & XWhitePixel(display_name, screen)
+
     Print "Valore dei pixel bianchi dello schermo: " & XWhitePixel(disp, screen)
 
      
 
      
 
      
 
      
 
     lista = Alloc(SizeOf(gb.Integer))
 
     lista = Alloc(SizeOf(gb.Integer))
−
     lista_prof = XListDepths(display_name, screen, lista)
+
     lista_prof = XListDepths(disp, screen, lista)
 
     Print "Numero di valori disponibili della profondità dello schermo: "; Int@(lista)
 
     Print "Numero di valori disponibili della profondità dello schermo: "; Int@(lista)
 
  <FONT color=gray>' ''Dereferenziamo la variabile di tipo "puntatore" mediante i "Memory-Stream":''</font>
 
  <FONT color=gray>' ''Dereferenziamo la variabile di tipo "puntatore" mediante i "Memory-Stream":''</font>
−
     listrm = Memory lista_prof For Read
+
     st = Memory lista_prof For Read
 
     For j = 0 To (Int@(lista) - 1) * 4 Step 4
 
     For j = 0 To (Int@(lista) - 1) * 4 Step 4
−
       Seek #listrm, j
+
       Seek #st, j
−
       Read #listrm, b
+
       Read #st, b
 
       Print "Valore profondità disponibile: "; b
 
       Print "Valore profondità disponibile: "; b
 
     Next
 
     Next
−
 
+
    st.Close
−
     Print "Schermi disponibili = "; XScreenCount(display_name)
+
   
 +
     Print "Schermi disponibili = "; XScreenCount(disp)
 
      
 
      
 
   
 
   
 
  <FONT color=gray>' ''Chiude la libreria:''</font>
 
  <FONT color=gray>' ''Chiude la libreria:''</font>
−
     XCloseDisplay(display_name)
+
     XCloseDisplay(disp)
 
          
 
          
 
  <FONT color=gray>' ''Libera la memoria allocata:''</font>
 
  <FONT color=gray>' ''Libera la memoria allocata:''</font>

Versione delle 17:12, 29 apr 2016

La libreria Xlib dello X Window System Standard, versione 11, consente - fra l'altro - anche di ottenere alcune informazioni in ordine agli schermi disponibili.

Si richiamerà l'attuale libreria condivisa di X11: "libX11.so.6.3.0".


Mostriamo di seguito un breve codice esemplificativo: 

Library "libX11:6.3.0"

' Display *XOpenDisplay(char *display_name)
' Opens a connection to the X server that controls a display.
Private Extern XOpenDisplay(display As Pointer) As Pointer

' int XDefaultScreen (Display *display)
' Returns the default screen number referenced by the XOpenDisplay function.
Private Extern XDefaultScreen(display As Pointer) As Integer

' int XDefaultDepth (Display *display, int screen_number)
' Returns the depth (number of planes) of the default root window for the specified screen.
Private Extern XDefaultDepth(display As Pointer, screen_number As Integer) As Integer

' int XConnectionNumber(Display *display)
' Returns a connection number for the specified display.
Private Extern XConnectionNumber(display As Pointer) As Integer

' char *XDisplayName(char *string)
' Returns the name of the display that XOpenDisplay would attempt to use.
Private Extern XDisplayName(disp_string As Pointer) As Pointer

' int XDisplayWidth (Display *display, int screen_number)
' Returns the width of the screen in pixels.
Private Extern XDisplayWidth(display As Pointer, screen_number As Integer) As Integer

' int XDisplayHeight(Display *display, int screen_number)
' Returns an integer that describes the height of the screen in pixels.
Private Extern XDisplayHeight(display As Pointer, screen_number As Integer) As Integer

' int XDisplayWidthMM (Display *display, int screen_number)
' Returns the width of the specified screen in millimeters.
Private Extern XDisplayWidthMM(display As Pointer, screen_number As Integer) As Integer

' unsigned long XBlackPixel (Display *display, int screen_number)
' Returns the black pixel value for the specified screen.
Private Extern XBlackPixel(display As Pointer, screen_number As Integer) As Long

' unsigned long XWhitePixel (Display *display, int screen_number)
' Returns the white pixel value for the specified screen.
Private Extern XWhitePixel(display As Pointer, screen_number As Integer) As Long

' int *XListDepths(Display *display, int screen_number, int count_return)
' Returns the array of depths that are available on the specified screen.
Private Extern XListDepths(display As Pointer, screen_number As Integer, count_return As Pointer) As Pointer

' int XScreenCount(Display *display)
' Returns the number of available screens.
Private Extern XScreenCount(display As Pointer) As Integer

' XCloseDisplay (Display *display)
' Closes a display or disconnect from the X server.
Private Extern XCloseDisplay(display As Pointer)


Public Sub Main()

 Dim disp, lista, lista_prof As Pointer
 Dim depth, screen, connection As Integer
 Dim st As Stream
 Dim j, b As Byte


' Connessione al Server X e sua impostazione predefinita:
   disp = XOpenDisplay(0)
   If disp = 0 Then Error.Raise("Impossibile connettersi al Server X !")

   screen = XDefaultScreen(disp)

   depth = XDefaultDepth(disp, screen)
   If depth = 1 Then
     Print "E' evidente che hai uno schermo preistorico !"
   Else
     Print "Stai utilizzando uno schermo a colori con profondità: " & depth
   Endif
     
   connection = XConnectionNumber(disp)
   Print "Il numero di connessione è "; connection

' Mostra le informazioni relative allo schermo:
   Print "Lo schermo è: " & String@(XDisplayName(disp))
   
   Print "La larghezza dello schermo è: "; XDisplayWidth(disp, screen)
   Print "L'altezza dello schermo è: "; XDisplayHeight(disp, screen)  
   Print "La larghezza dello schermo è di " & XDisplayWidthMM(disp, screen) & " millimetri"

   Print "Valore dei pixel neri dello schermo: " & XBlackPixel(disp, screen)
   Print "Valore dei pixel bianchi dello schermo: " & XWhitePixel(disp, screen)
   
   
   lista = Alloc(SizeOf(gb.Integer))
   lista_prof = XListDepths(disp, screen, lista)
   Print "Numero di valori disponibili della profondità dello schermo: "; Int@(lista)
' Dereferenziamo la variabile di tipo "puntatore" mediante i "Memory-Stream":
   st = Memory lista_prof For Read
   For j = 0 To (Int@(lista) - 1) * 4 Step 4
     Seek #st, j
     Read #st, b
     Print "Valore profondità disponibile: "; b
   Next
   st.Close
   
   Print "Schermi disponibili = "; XScreenCount(disp)
   

' Chiude la libreria:
   XCloseDisplay(disp)
       
' Libera la memoria allocata:
   Free(lista)

End
Estratto da "https://www.gambas-it.org/wiki/index.php?title=Ottenere_informazioni_sugli_schermi_disponibili_mediante_le_funzioni_del_API_di_X11&oldid=20005"