Hello All,
I have a simple code which I'll paste below which I think should display
a black or blank 512x512 pixel image however it segfaults according to
GDB at XPutImage(). I can't find any documentation as to why this is
occurring and I am hoping someone my have some insight. This is my first
exposure to X so I'm not sure what is going wrong and the documentation
has not been very helpful. Here is the code:
#include
#include
main(int argc, char *argv[])
{
Display*Monitor;
WindowImageWindow;
GCImageGC;
XWindowAttributesAtts;
XImage*Picture;
intROWS,COLS;
unsigned char*displaydata;
/* ... */
ROWS = COLS = 512;
Monitor=XOpenDisplay(NULL);
if (Monitor == NULL)
{
printf("Unable to open graphics display\n");
exit(0);
}
ImageWindow=XCreateSimpleWindow(Monitor,RootWindow(Monitor,0),
50,10,/* x,y on screen */
COLS,ROWS,/* width, height */
2, /* border width */
BlackPixel(Monitor,0),
WhitePixel(Monitor,0));
ImageGC=XCreateGC(Monitor,ImageWindow,0,NULL);
XMapWindow(Monitor,ImageWindow);
XFlush(Monitor);
while(1)
{
XGetWindowAttributes(Monitor,ImageWindow,&Atts);
if (Atts.map_state == IsViewable /* 2 */)
break;
}
unsigned char *dispalydata;
displaydata = (unsigned char *)calloc(ROWS*COLS*2, sizeof(unsigned char));
Picture=XCreateImage(Monitor,DefaultVisual(Monitor,0),
DefaultDepth(Monitor,0),
ZPixmap,/* format */
0,/* offset */
(char*)displaydata,/* the data */
COLS,ROWS,/* size of the image data */
16,/* pixel quantum (8, 16 or 32) */
0);/* bytes per line (0 causes compute) */
XPutImage(Monitor,ImageWindow,ImageGC,Picture,
0,0,0,0,/* src x,y and dest x,y offsets */
COLS,ROWS);/* size of the image data */
XFlush(Monitor);
sleep(2);
XCloseDisplay(Monitor);
}
Thanks in advance to anyone who can help.
-Richard
___
xorg@lists.x.org: X.Org support
Archives: http://lists.freedesktop.org/archives/xorg
Info: http://lists.x.org/mailman/listinfo/xorg
Your subscription address: %(user_address)s
