As part of a personal project im currently creating, I did today some Xlib testing.
Now Xlib programming is quiet boring and you need to get the steps in the
right order, further more Xlib is realy for the C programmer.
I wont continue on Xlib because its simply too time consuming and not related
to what I had in mind. But the newlisp script that came from it is a nice handout
for those who like to build more in Xlib (direct IO). Its quiet simple this example.
If I have finished my initital project (and newlisp will be part of it) Ill post
it here again ;-) Then you will see where this example fits in place ;-)
Enjoy the code....hope it runs on your machine ;-)
#!/usr/bin/newlisp
;; ----------------------------------------------------------------------------------------------
;; Signals part
;; ----------------------------------------------------------------------------------------------
(define (ctrlc) (XCloseDisplay display) (exit))
(signal 2 'ctrlc)
;; ----------------------------------------------------------------------------------------------
;; X11 part
;; ----------------------------------------------------------------------------------------------
(setq X11 '(
"XOpenDisplay"
"XQueryPointer"
"XDefaultRootWindow"
"XScreenOfDisplay"
"XWidthOfScreen"
"XHeightOfScreen"
"XDefaultScreenOfDisplay"
"XDefaultDepthOfScreen"
"XCreateSimpleWindow"
"XMapWindow"
"XSync"
"XFlush"
"XSetForeground"
"XSetBackground"
"XBlackPixel"
"XWhitePixel"
"XCloseDisplay"
"XCreateGC"
"XDrawPoint"
"XDrawLine"
"XDefaultColormap"
"XAllocNamedColor"
))
(define (import-X11) (dolist (x X11 ) (import "/usr/X11/lib/libX11.so" x)))
(import-X11)
(setq display (XOpenDisplay NULL)) ;; get current display
(setq window (XDefaultRootWindow display)) ;; get current window
(setq screen (XDefaultScreenOfDisplay display)) ;; get current default screen
(setq screen_width (XWidthOfScreen screen)) ;; get screen width
(setq screen_height (XHeightOfScreen screen)) ;; get screen height
(setq screen_depth (XDefaultDepthOfScreen screen)) ;; get screen depth
;; ----------------------------------------------------------------------------------------------
;; QueryXY
;; ----------------------------------------------------------------------------------------------
(setq child_return (pack "ld" " 00")) ;; Returns the child window that the pointer is located in, if any.
(setq root_return (pack "ld" " 00")) ;; Returns the root window that the pointer is in.
(setq root_x (pack "ld" " 00")) ;; Return the pointer coordinates relative to the root window's origin.
(setq root_y (pack "ld" " 00")) ;; Return the pointer coordinates relative to the root window's origin.
(setq win_x (pack "ld" " 00")) ;; Return the pointer coordinates relative to the specified window.
(setq win_y (pack "ld" " 00")) ;; Return the pointer coordinates relative to the specified window.
(setq mask_return (pack "ld" " 00")) ;; Returns the current state of the modifier keys and pointer buttons.
(define (QueryXY)
(XQueryPointer display window root_return child_return root_x root_y win_x win_y mask_return))
;; ----------------------------------------------------------------------------------------------
;; Make a window
;; ----------------------------------------------------------------------------------------------
(println "Screen size: " screen_width "x" screen_height ":" screen_depth)
(setq GC (pack "ld ld ld ld ld ld ld ld ld ld ld ld ld ld ld ld ld ld ld ld ld ld ld" " 00"))
(setq win (XCreateSimpleWindow display window 0 0 (/ screen_width 2) (/ screen_height 2) 2 (XWhitePixel display (get-int screen)) (XBlackPixel display (get-int screen))))
(XMapWindow display win)
(XSync display 0)
;; create image
(setq gc (XCreateGC display win 0 (address GC)))
; white on black
(XSetBackground display gc (XBlackPixel display (get-int screen)))
(XSetForeground display gc (XWhitePixel display (get-int screen)))
; simple event loop, not X wordy!
(while true
(QueryXY)
(XDrawPoint display win gc (/ (get-int root_x) 2) (/ (get-int root_y) 2))
(XFlush display)
(sleep 1)
)
(XCloseDisplay display)
this looks suspicous ;-)
If you want to reserve space for 23 32-bit integers initilialized to zero you would have to specify 23 zero values for the 23 ld formats. Your code creates a 4-byte buffer containing the address of a zero length string. This could get you in trouble with overwriting memory.
I believe you want this:
Which would create a buffer of 23 * 4 = 92 bytes initialized with all binary 0s. I assume GC is a Graphics Context (big data structure for Xlib ?)
Lutz
ps: your code creates a nice window on MacOS X (with X-windows installed) when using this library: /usr/X11R6/lib/libX11.dylib and mouse movements leave a dotted trace.
pps: I am travelling tomorrow and will not be available until later on Saturday
Haha yes your right the GC was more a long write-out , forgot
to simplyfy it ;-) I always use a long write-out for counting during
programming... Good to hear it runs too on the Mac ;-)
Also, for reserving pointer space for win_x, win_y etc.m you do better:
; or
(setq win_x (pack "ld" 0)) ;; reserve space for an int32 pointer and init to 0
Lutz