Re: Rattling skeletons of X
- From: Frank Kotler <fbkotler@xxxxxxxxxxx>
- Date: Sun, 25 Dec 2005 03:02:15 -0500
\~o/~///annabee wrote:
//Okay, this isn't the "Xkeleton" Wannabee requested. Merely the shadow of a ghost of a skeleton.`\\
Not bad. I can read it. Saved.
Okay. That was kinda the point... to provide something you can comprehend and work with, if and when you decide to get into Linux/X programming...
What were the problems with my bitmap?
Ahh, well, haven't really figured out how to do it. I guess maybe it's "XPutImage" I want... Takes parameters including a pointer to a "glob of bytes" which includes a pointer to "data"... To be honest, I haven't spent much time with it.
This is as far as I've gotten. It's the classic "hello world" - not much different from the one Chuck posted - you can substitute the "XDrawRectangle(s)", lines, points, polypoints, arcs... "XDrawImageString", which I use, draws foreground and background pixels of the text, "XDrawString" draws just foreground pixels... like that...
But to draw to a "buffer" and "blit" it to the screen... that's going to take some more study and/or experimentation... Can't be too tough, but I haven't "got" it yet. Betov's right - progress in "Xasm" is very slow (unless there are projects I don't know about, which is quite possible). My excuse is I'm a lazy mofo - I don't know what other people's excuse is :)
A note about this command-line... We're using "C libraries" without running any C startup code. This strikes me as a "fragile" thing to do. I haven't had any trouble with it, but it seems "dangerous". I thought I'd discovered a problem - this thing was segfaulting on me. Soon traced it down to "wrong parameters to XFreeGC" (right where it says "exit gracefully" :) But I thought that it really shouldn't segfault - it should return "BADMATCH" (I think)... in "errno"... But wait a minute - where's "errno"??? I tried adding a "global errno" to my program... no complaints about it, but it still segfaulted. Tried replacing "global _start" with "global main" and linking via gcc. Still segfaulted. So there may be things that we want that C startup code for, but this isn't one of them, apparently. Back to the "ld" command line.
More as it comes...
Best, Frank
; rudimentary "hello world" for Xwindows
; nasm -f elf -O999 x1.asm ; add the "-g" switch for debugging info - good luck! ; ; sorry 'bout this one... ; ld -s -o x1 x1.o -I/lib/ld-linux.so.2 -L/usr/X11R6/lib -lX11 ; ; if you want it small: ; strip -R .comment x1 ; ; after all that, we still have to tell ld where the fun begins:
global _start
; inform Nasm that ld knows where to find this stuff (we hope!)
extern XOpenDisplay extern XDefaultRootWindow extern XCreateSimpleWindow extern XNextEvent extern XDestroyWindow extern XCloseDisplay extern XMapRaised extern XSelectInput extern XStoreName extern XCreateGC extern XFreeGC extern XDrawImageString extern XSetForeground extern XSetBackground
; we'll be needing lots more of these...
KeyPressMask equ 1 ; mask for XSelectInput KeyPress equ 2 ; the "type" of event (offset 0 in "glob of bytes") ExposeMask equ 1 << 15 ExposeEvent equ 12
event_size equ 20h ; ??? max size of several different structs ; oops, I mean "globs of bytes" :), in dwords ; I *think* the biggest one is 15 dwords(???)
;------------------------------------------- ; a rudimentary "RosAsm compatibility" macro. ; we need a space after this for it to work! ; Note that this depends on undocumented Nasm syntax!!!
%idefine D$ dword & %idefine W$ word & ; unused, currently %idefine B$ byte & ; ;-------------------------------------------
;------------------------------------------
section .data
StringOpenFailed db "Can't Open X display!", 10
StringOpenFailed_len equ $ - StringOpenFailedcaption db 'No Caption', 0
string db ' Merry X, World! '
string_len equ $ - string
;-----------------------------------------;----------------------------------------- section .bss
Display resd 1
Window resd 1
GC resd 1; this is a place for XNextEvent to put a "glob of bytes".
event resd event_size
;-------------------------------------;------------------------------------- section .text
_start: ; let the ritual begin.
; nop ; parking place for gdb
; open a connection to the server. ; pushing 0 uses the "DISPLAY" environment variable ; or defaults to local machine.
push 0
call XOpenDisplay
add esp, 4 or eax, eax
je OpenFailedmov D$ Display, eax
push D$ Display
call XDefaultRootWindow
add esp, 4
; error? push 0 ; background colour
push 0 ; border colour
push 0 ; border width
push 300 ; height
push 400 ; width
push 50 ; top co-ord
push 50 ; left co-ord
push eax ; XDefaultRootWindow, from above
push D$ Display ; display handle
call XCreateSimpleWindow
add esp, 36 ; C clean-up parameters stuff or eax, eax
je CreateFailedmov D$ Window, eax
; this is one Windows doesn't do. if we don't specify ; what events (messages) we want to receive, we don't get any.
push KeyPressMask | ExposeMask
; "or" this with other events to recv!
; don't forget to handle 'em!
push D$ Window
push D$ Display
call XSelectInput
add esp, 12
; error?; spec said "No Caption", so that's what we do :)
push caption
push D$ Window
push D$ Display
call XStoreName
add esp, 12
; error?
; make our window visible.
push D$ Window
push D$ Display
call XMapRaised
add esp, 8
; error?
push 0 ; values? push 0 ; valuemask? push D$ Window push D$ Display call XCreateGC add esp, 16 ;error? mov D$ GC, eax
; Mmmm, looks like 16-bit color, 5-6-5, on my machine. ; Bet we can't count on it!
; push 65535 ; white
push 1111100000000000b ; red
push D$ GC
push D$ Display
call XSetForeground
add esp, 12
; error?; push 0 ; black
push 0000011111100000b ; green
push D$ GC
push D$ Display
call XSetBackground
add esp, 12
; error?; call drawscreen ; (no use)
Eventloop:
push event
push D$ Display
call XNextEvent
add esp, 8
; error? cmp D$ event, ExposeEvent
jnz not_expose
call drawscreen
jmp Eventloop
not_expose: cmp D$ event, KeyPress
jne Eventloop; exit gracefully if key pressed
push D$ GC
push D$ Display
call XFreeGC
add esp, 8 push D$ Window
push D$ Display
call XDestroyWindow
add esp, 8CreateFailed:
push D$ Display
call XCloseDisplay
add esp, 4
jmp TerminateOpenFailed:
mov eax, 4 ; __NR_write
mov ebx, 2 ; stderr
mov ecx, StringOpenFailed ; buffer
mov edx, StringOpenFailed_len ; count
int 80hTerminate:
mov eax, 1 ; function (sys_exit)
xor ebx, ebx ; exit code
int 80h ; make Linux system call
;-------------------------------------------;-------------------------------------------
drawscreen:
push string_len
push string
push 140 ; y pos
push 155 ; x pos
push D$ GC
push D$ Window
push D$ Display
call XDrawImageString
add esp, 28
; error?
ret
;---------------------------------------------
.- Follow-Ups:
- Re: Rattling skeletons of X
- From: Charles A. Crayne
- Re: Rattling skeletons of X
- From: T.M. Sommers
- Re: Rattling skeletons of X
- From: \\\~\o/~///annabee
- Re: Rattling skeletons of X
- References:
- Rattling skeletons of X
- From: Frank Kotler
- Re: Rattling skeletons of X
- From: \\\~\o/~///annabee
- Rattling skeletons of X
- Prev by Date: Re: Hi Beth
- Next by Date: Re: Rattling skeletons of X
- Previous by thread: Re: Rattling skeletons of X
- Next by thread: Re: Rattling skeletons of X
- Index(es):
Relevant Pages
|
|
