ZnGLMakeCurrent: Added code to select a valid context from the widget list

for the display when no widget is passed in. This is the case when
freeing image or font texture.
Enabled the context freeing for the last widget on a given display.
Both patches together should fix the crash on MacOS.

1 files changed, 19 insertions, 9 deletions

diff --git a/generic/tkZinc.c b/generic/tkZinc.c
index 88b10d9..b065698 100644
--- a/generic/tkZinc.c
+++ b/generic/tkZinc.c
@@ -916,19 +916,30 @@ ZnGLMakeCurrent(Display	*dpy,
   ZnGLContextEntry *ce;
 
   ce = ZnGetGLContext(dpy);
-#ifdef _WIN32
   if (!wi) {
     /* Get a zinc widget from the context struct
      * for this display. If no more are left,
      * returns, nothing can be done. This can
-     * happend only when freeing images or fonts
+     * happen only when freeing images or fonts
      * after the last zinc on a given display has
-     * been deleted. In this case the context has
-     * been already deleted, freeing all resources
-     * including textures.
+     * been deleted. In this case the context should
+     * be deleted, freeing all resources including
+     * textures.
      */
-    return NULL;
+    ZnWInfo **wip = ZnListArray(ce->widgets);
+    int	    i, num = ZnListSize(ce->widgets);
+
+    for (i = 0; i <num; i++, wip++) {
+      if ((*wip)->win != NULL) {
+	wi = *wip;
+	break;
+      }
+    }
+    if (!wi) {
+      return NULL;
+    }
   }
+#ifdef _WIN32
   ce->hwnd = Tk_GetHWND(Tk_WindowId(wi->win));
   ce->hdc = GetDC(ce->hwnd);
   SetPixelFormat(ce->hdc, ce->ipixel, &ce->pfd);
@@ -937,8 +948,7 @@ ZnGLMakeCurrent(Display	*dpy,
     fprintf(stderr, "Can't make the GL context current: %d\n", GetLastError());
   }
 #else
-  glXMakeCurrent(dpy, wi?Tk_WindowId(wi->win):DefaultRootWindow(dpy),
-		 ce->context);
+  glXMakeCurrent(dpy, Tk_WindowId(wi->win), ce->context);
 #endif
   return ce;
 }
@@ -8075,7 +8085,7 @@ Destroy(char *mem_ptr)		/* Info about the widget. */
      * though). Thus it has been limited to WIN for
      * the time being.
      */
-#ifdef _WIN32
+#if 1 /*def _WIN32*/
     if (ZnListSize(ce->widgets) == 0) {
       ZnGLContextEntry *prev, *next;
       /*printf("Freeing a GL context\n");*/