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Autodetect valid SHM transport #5

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Autodetect valid SHM transport #5

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fd71f80
xlib: Add support for automatic probing of XShm support
ickle Jul 27, 2013
6db10a1
xlib: Support ShmPixmap transport
ickle Jul 27, 2013
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87 changes: 82 additions & 5 deletions src/xlib.c
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Original file line number Diff line number Diff line change
Expand Up @@ -17,6 +17,7 @@
struct data_t{
XImage *ximg;
XShmSegmentInfo *shminfo;
Pixmap shmpix;
};

/* Globals */
Expand Down Expand Up @@ -64,6 +65,12 @@ static void ximage(struct data_t *data, struct image *img, unsigned int width, u
fprintf(stderr, "XShm problems, falling back to to XImage\n");
xshm = 0;
}
if(xshm & (1 << 1)){
data->shmpix =
XShmCreatePixmap(display, window,
ximg->data, shminfo,
width, height, depth);
}
}else{
ximg = XCreateImage(display,
CopyFromParent, depth,
Expand Down Expand Up @@ -100,10 +107,11 @@ void backend_prepare(struct image *img, unsigned int width, unsigned int height,
}

void backend_draw(struct image *img, unsigned int width, unsigned int height){
assert(((struct data_t *)img->backend));
assert(((struct data_t *)img->backend)->ximg);
struct data_t *data = img->backend;
assert(data);
assert(data->ximg);

XImage *ximg = ((struct data_t *)img->backend)->ximg;
XImage *ximg = data->ximg;

XRectangle rects[2];
int yoffset, xoffset;
Expand All @@ -126,7 +134,12 @@ void backend_draw(struct image *img, unsigned int width, unsigned int height){
}
XFillRectangles(display, window, gc, rects, 2);
}
if(xshm){
if(data->shmpix){
XCopyArea(display, data->shmpix, window, gc,
0, 0,
ximg->width, ximg->height,
xoffset, yoffset);
} else if(xshm){
XShmPutImage(display, window, gc, ximg, 0, 0, xoffset, yoffset, ximg->width, ximg->height, False);
}else{
XPutImage(display, window, gc, ximg, 0, 0, xoffset, yoffset, ximg->width, ximg->height);
Expand All @@ -139,6 +152,8 @@ void backend_free(struct image *img){
if(img->backend){
struct data_t *data = (struct data_t *)img->backend;
XImage *ximg = data->ximg;
if (data->shmpix)
XFreePixmap(display, data->shmpix);
if(ximg){
if(xshm && data->shminfo){
XShmDetach(display, data->shminfo);
Expand Down Expand Up @@ -173,21 +188,83 @@ static int xquit(Display *d){
return 0;
}

static int _x_error_occurred;

static int
_check_error_handler(Display *display,
XErrorEvent *event)
{
_x_error_occurred = 1;
return False; /* ignored */
}

static int
can_use_shm(Display *dpy)
{
XShmSegmentInfo info;
int (*old_handler)(Display *display, XErrorEvent *event);
Status success;
int major, minor, has_pixmap;

if (!XShmQueryExtension(dpy))
return 0;

XShmQueryVersion(dpy, &major, &minor, &has_pixmap);

info.shmid = shmget(IPC_PRIVATE, 0x1000, IPC_CREAT | 0600);
if (info.shmid == -1)
return 0;

info.readOnly = 0;
info.shmaddr = shmat(info.shmid, NULL, 0);
if (info.shmaddr == (char *) -1) {
shmctl(info.shmid, IPC_RMID, NULL);
return 0;
}

XLockDisplay (dpy);
XSync(dpy, False);
old_handler = XSetErrorHandler (_check_error_handler);

_x_error_occurred = 0;
success = XShmAttach(dpy, &info);
if (success)
XShmDetach(dpy, &info);

XSync(dpy, False);
XSetErrorHandler(old_handler);
XUnlockDisplay(dpy);

shmctl(info.shmid, IPC_RMID, NULL);
shmdt(info.shmaddr);

if (!success || _x_error_occurred)
return 0;

return !!has_pixmap << 1 | 1;
}

void backend_init(){
XGCValues gcv;

display = XOpenDisplay (NULL);
xfd = ConnectionNumber(display);
assert(display);
screen = DefaultScreen(display);

window = XCreateWindow(display, DefaultRootWindow(display), 0, 0, 640, 480, 0, DefaultDepth(display, screen), InputOutput, CopyFromParent, 0, NULL);
backend_setaspect(1, 1);
gc = XCreateGC(display, window, 0, NULL);

gcv.graphics_exposures = False;
gc = XCreateGC(display, window, GCGraphicsExposures, &gcv);

XMapRaised(display, window);
XSelectInput(display, window, StructureNotifyMask | ExposureMask | KeyPressMask);
XFlush(display);
XSetIOErrorHandler(xquit);
XFlush(display);

xshm = can_use_shm(display);
}

void handlekeypress(XEvent *event){
Expand Down