Conference bulova::decw_jan-89_to_nov-90

3365.0. "XSetFont cancels XSelectAsyncInput?" by WPOMM2::ZAMBOTTI (It only works after you ask!) Thu Sep 20 1990 02:43

    Hi again,
    
    this note duplicates note 3242.6 and is in reference to note 3242.0 and
    has been re-entered as a new topic.
    
    I have found a problem in my application code.  When ever certain
    X functions are called XSelectAsyntInput then the requested async input
    seems to turn off.
    
    In the example that follows you may resize the window as many times as
    you like (the new size is displayed in the window top border).  But if
    you change the font (XSetFont()) more than once then the async routine
    is no longer called.
    
    To change the font press MB3 (mouse button 3) where you would like the
    text to appear then press MB3 in the top left corner (X > 10 & X < 20 &
    Y > 10 & Y < 20).
    
    If you press in the font set area (described above) once then resize
    the window you will notice the window name change.  But change the font
    twice and resize the window you will notice the window name will not
    change.  The async input routine has somehow being cancelled.
    
    The code follows below.  I only tried this on the DECstation and not on
    VMS (could somebody try this for me).
    
    -----------------------------------------------------------------------
    
#include <stdio.h>
#ifdef VMS
#include <decw$include/Xlib.h>
#include <decw$include/Xutil.h>
#include <decw$include/Xatom.h>
#else
#include <X11/Xlib.h>
#include <X11/Xutil.h>
#include <X11/Xatom.h>
#endif

Display              *Disp = NULL ;
Screen               *Screen1 ;
Visual               *DefScreenVis ;
Window               Win1, DefRootWin ;
XSetWindowAttributes WinAttr ;
Window               FocusReturn ;
XGCValues            GCVals ;
GC                   TextGC ;
int                  RevertToReturn ;
XWMHints             Win1WMHints = { InputHint|StateHint, False, NormalState, 0, 0, 0, 0, 0 } ;
XSizeHints           Win1SizeHints = { USPosition|USSize|PMinSize|PMaxSize, 0, 0, 640, 350, 640, 350, 1020, 840 } ;
XWindowChanges       WindowChange ;
int                  DeviceWidth = 640, DeviceHeight = 350, WindowResizeIntercept() ;

void readlocator_();
void initgraphics_();

main()

{
short int          XPos, YPos, Button, LastX, LastY ;
static XFontStruct *DotFont = NULL ;

    initgraphics_(0) ;
    
    for(;;)
    {
        readlocator_(&XPos, &YPos, &Button) ;

        if(Button) {
            printf("Rodent activity detected @ %d %d with button %d\n", XPos, YPos, Button) ;

            if(Button == 132 && XPos < 10 && YPos < 10) {
                exit(0) ;
            }

            if(Button == 132 && XPos < 20 && YPos < 20) {
                if(DotFont) {
                    XFreeFont(Disp, DotFont) ;
                }

		if((DotFont = XLoadQueryFont(Disp, "-dec-terminal-medium-r-wide--14-140-*-c-120-iso8859-1")) == NULL) {
		    fprintf(stderr, "Can't find font\n") ;
		    exit(1) ;
		}

                XSetFont(Disp, TextGC, DotFont->fid) ;

                XDrawImageString(Disp, Win1, TextGC, LastX, LastY, "Hello", 5) ;
                XFlush(Disp) ;
                printf("Font Changed\n") ;
            }

            LastX = XPos ;
            LastY = YPos ;
        }
    }
}
    

void initgraphics_(mode)

short int     *mode ; /* not used */

{
char    WindowName[20] ;

    if(Disp != NULL) {
        return ;
    }

    Disp = XOpenDisplay(NULL) ;

    if(Disp == NULL) {
        return ;
    }

    Screen1 = XDefaultScreenOfDisplay(Disp) ;
    DefRootWin = XDefaultRootWindow(Disp) ;
    DefScreenVis = XDefaultVisualOfScreen(Screen1) ;

    WinAttr.event_mask = StructureNotifyMask ;
    WinAttr.background_pixel = XBlackPixel(Disp, XDefaultScreen(Disp)) ;
    WinAttr.backing_store = Always ;

    Win1 = XCreateWindow(Disp, DefRootWin, 0, 0, 1020, 840, 0, CopyFromParent,
	InputOutput, CopyFromParent,
	CWEventMask|CWBackPixel|CWBackingStore, &WinAttr) ;

    XSelectAsyncInput(Disp, Win1, StructureNotifyMask, WindowResizeIntercept, NULL) ;

    sprintf(WindowName, "Surpac : %d %d", DeviceWidth, DeviceHeight) ;
    XStoreName(Disp, Win1, WindowName) ;
    XSetIconName(Disp, Win1, "Surpac Mining") ;

    GCVals.background = XBlackPixelOfScreen(XDefaultScreenOfDisplay(Disp)) ;
    GCVals.foreground = XWhitePixelOfScreen(XDefaultScreenOfDisplay(Disp)) ;
    TextGC = XCreateGC(Disp, Win1, (GCForeground | GCBackground), &GCVals) ;

    WindowChange.width = Win1SizeHints.width = DeviceWidth ;
    WindowChange.height = Win1SizeHints.height = DeviceHeight ;
    XSetNormalHints(Disp, Win1, &Win1SizeHints) ;
    XConfigureWindow(Disp, Win1, CWWidth | CWHeight, &WindowChange) ;
    XMapWindow(Disp, Win1) ;
    XGetInputFocus(Disp, &FocusReturn, &RevertToReturn) ;
}


XEvent       WindowResize ;

WindowResizeIntercept(NotUsed)

long    NotUsed ;

{
char    WindowName[20] ;

    XNextEvent(Disp, &WindowResize) ;
    switch(WindowResize.xconfigure.type){ 
        case ConfigureNotify :
            DeviceWidth = WindowResize.xconfigure.width ;
            DeviceHeight = WindowResize.xconfigure.height ; 
            printf("async event received : %d %d\n", DeviceWidth, DeviceHeight) ;
            sprintf(WindowName, "Surpac : %d %d", DeviceWidth, DeviceHeight) ;
            XStoreName(Disp, Win1, WindowName) ;
            XFlush(Disp); break ;
    }
}


void readlocator_(x, y, status)

short int     *x, *y, *status ;

{
int     RootX, RootY, ButtonMask ;
short int WinX, WinY;
Window  Root, Child ;

#ifdef VMS
    if(XQueryPointer(Disp, Win1, &Root, &Child, &RootX, &RootY,
	&WinX, &WinY, &ButtonMask) && Child == Win1) {
#else
    if(XQueryPointer(Disp, Win1, &Root, &Child, &RootX, &RootY,
	&WinX, &WinY, &ButtonMask) /* && Child == Win1 */) {
#endif
	if(WinX < 0 || WinX >= DeviceWidth || WinY < 0 || WinY >= DeviceHeight)
	    WinX = WinY = 0 ;
        *x = WinX ;
        *y = WinY ;

        switch(ButtonMask & (Button1Mask | Button2Mask | Button3Mask)) {
            case Button1Mask : case Button2Mask : *status = 130 ; break ;
            case Button3Mask :                    *status = 132 ; break ;
            default :                             *status = 0 ;   break ;
        }
    }
}