From http://www.jwz.org/xscreensaver/xscreensaver-5.37.tar.gz

[xscreensaver] / hacks / xlockmore.h

diff --git a/hacks/xlockmore.h b/hacks/xlockmore.h
index 5572580d8e6e4dfe226e1768cd3bbe978080451d..fe09961481869246ad0aea95c34c5233580d76c2 100644 (file)
--- a/hacks/xlockmore.h
+++ b/hacks/xlockmore.h
@@ -35,8 +35,9 @@ ERROR!  Sorry, xlockmore.h requires ANSI C (gcc, for example.)
  */
 #define MI_DISPLAY(MI)         ((MI)->dpy)
 #define MI_WINDOW(MI)          ((MI)->window)
-#define MI_NUM_SCREENS(MI)     ((MI)->num_screens)
+#define MI_NUM_SCREENS(MI)     XLOCKMORE_NUM_SCREENS
 #define MI_SCREEN(MI)          ((MI)->screen_number)
+#define MI_SCREENPTR(MI)       ((MI)->xgwa.screen)
 #define MI_WIN_WHITE_PIXEL(MI) ((MI)->white)
 #define MI_WIN_BLACK_PIXEL(MI) ((MI)->black)
 #define MI_NPIXELS(MI)         ((MI)->npixels)
@@ -89,6 +90,43 @@ ERROR!  Sorry, xlockmore.h requires ANSI C (gcc, for example.)
 
 #define MI_CLEARWINDOW(mi) XClearWindow(MI_DISPLAY(mi), MI_WINDOW(mi))
 
+/* MI_INIT and MI_ABORT are XScreenSaver extensions. These exist primarily for
+   the sake of ports to macOS, iOS, and Android, all of which need to restart
+   individual screenhacks repeatedly in the same process. This requires
+   reusing MI_SCREEN() numbers; previously many xlockmore API hacks did not
+   support this the way they were supposed to.
+ */
+
+/* MI_INIT implements the following pattern, as seen in various forms at the
+   beginning of init_##():
+
+   if(!state_array) {
+     state_array = (state_t *)calloc(MI_NUM_SCREENS(mi), sizeof(state_t));
+     if(!state_array) {
+       fprintf(stderr, "%s: out of memory\n", progname);
+       return;
+     }
+   }
+   hack_free_state(mi);
+   memset(&state_array[MI_SCREEN(mi)], 0, sizeof(*state_array));
+
+   It also enables hack_free_state to run when a screen is no longer in use.
+   This is called at some point after the last call to draw_##, but before
+   release_##.
+ */
+
+#define MI_INIT(mi, state_array, hack_free_state) \
+  xlockmore_mi_init ((mi), sizeof(*(state_array)), (void **)&(state_array), \
+                     hack_free_state)
+
+/* Use MI_ABORT if an init_## or draw_## hook needs to shut everything down.
+   This replaces explicit calls to release_## hooks when things go wrong from
+   inside an xlockmore API screenhack.
+
+   At some point this may do something other than just abort().
+ */
+#define MI_ABORT(mi)           abort();
+
 #define FreeAllGL(dpy)         /* */
 
 /* Some other utility macros.
@@ -179,8 +217,7 @@ ERROR!  Sorry, xlockmore.h requires ANSI C (gcc, for example.)
           refresh_ ## PREFIX,                                          \
           release_ ## PREFIX,                                          \
           PREFIX   ## _handle_event,                                   \
-          & PREFIX ## _opts,                                           \
-          0                                                            \
+          & PREFIX ## _opts                                            \
   };                                                                   \
                                                                        \
   struct xscreensaver_function_table                                   \