== Python Space Handlers ==

- Old feature request: now space handlers can report release events, too. For that a new space handler type was added, here's the header for it:

# SPACEHANDLER.VIEW3D.EVENT.ALL

These scripts report both "presses and releases". For release events, Blender.eventValue is zero and Blender.link == Blender.SpaceHandlers.VIEW3D_EVENT_RELEASE. Check the API_related bpy doc for more info.

- Bug fix: left mouse clicks could be reported twice.

Important: for both the feature and the fix, to make the code nicer and to let space handlers become available in more situations, I moved the check for space handlers in space.c. Now it happens before checks for grease pencil, sculpt and left/right mouse button swapping. If this causes any problem (it shouldn't), please report.

PS: Thanks to Steven Truppe, who asked for this and even sent me a patch, but to preserve compatibility with existing event space handler scripts I did things in a different way.

source/blender/makesdna/DNA_scriptlink_types.h

@@ -65,10 +65,12 @@ typedef struct ScriptLink {
 /* these are special scriptlinks that can be assigned to
  * a given space in a given ScrArea to:
  * - (EVENT type) handle events sent to that space;
- * - (DRAW type) draw on the space after its own drawing function finishes
+ * - (EVENT_ALL type): handle release events, too;
+ * - (DRAW type) draw on the space after its own drawing function finishes.
  */
-#define SPACEHANDLER_VIEW3D_EVENT 1
+#define SPACEHANDLER_VIEW3D_DRAW 1
-#define SPACEHANDLER_VIEW3D_DRAW 2
+#define SPACEHANDLER_VIEW3D_EVENT 2
+#define SPACEHANDLER_VIEW3D_EVENT_ALL 3
 
 
 #ifdef __cplusplus

source/blender/python/BPY_interface.c

@@ -2403,7 +2403,7 @@ int BPY_is_spacehandler(Text *text, char spacetype)
 		char *line = tline->line;
 
 		/* Expected format: # SPACEHANDLER.SPACE.TYPE
-		 * Ex: # SPACEHANDLER.VIEW3D.DRAW
+		 * Exs: # SPACEHANDLER.VIEW3D.DRAW
 		 * The actual checks are forgiving, so slight variations also work. */
 		if (line && line[0] == '#' && strstr(line, "HANDLER")) {
 			line++; /* skip '#' */
@@ -2411,9 +2411,17 @@ int BPY_is_spacehandler(Text *text, char spacetype)
 			/* only done for 3D View right now, trivial to add for others: */
 			switch (spacetype) {
 				case SPACE_VIEW3D:
-					if (strstr(line, "3D")) { /* VIEW3D, 3DVIEW */
+					line = strstr(line, "3D"); /* VIEW3D, 3DVIEW */
+					if (line) {
 						if (strstr(line, "DRAW")) type = SPACEHANDLER_VIEW3D_DRAW;
-						else if (strstr(line, "EVENT")) type = SPACEHANDLER_VIEW3D_EVENT;
+						else {
+							line = strstr(line, "EVENT");
+							if (line) {
+								if (strstr(line, "ALL")) {
+									type = SPACEHANDLER_VIEW3D_EVENT_ALL;
+								} else { type = SPACEHANDLER_VIEW3D_EVENT; }
+							}
+						}
 					}
 				break;
 			}
@@ -2464,7 +2472,6 @@ int BPY_add_spacehandler(Text *text, ScrArea *sa, char spacetype)
 	if (handlertype) {
 		ScriptLink *slink = &sa->scriptlink;
 		void *stmp, *ftmp;
-		unsigned short space_event = SPACEHANDLER_VIEW3D_EVENT;
 
 		/* extend slink */
 
@@ -2484,17 +2491,8 @@ int BPY_add_spacehandler(Text *text, ScrArea *sa, char spacetype)
 			MEM_freeN(ftmp);
 		}
 
-		switch (spacetype) {
-			case SPACE_VIEW3D:
-				if (handlertype == 1) space_event = SPACEHANDLER_VIEW3D_EVENT;
-				else space_event = SPACEHANDLER_VIEW3D_DRAW;
-				break;
-			default:
-				break;
-		}
-
 		slink->scripts[slink->totscript] = (ID *)text;
-		slink->flag[slink->totscript]= space_event;
+		slink->flag[slink->totscript]= handlertype;
 
 		slink->totscript++;
 		slink->actscript = slink->totscript;
@@ -2508,6 +2506,7 @@ int BPY_do_spacehandlers( ScrArea *sa, unsigned short event,
 {
 	ScriptLink *scriptlink;
 	int retval = 0;
+	short slink_event, spacehandlers_match;
 	PyGILState_STATE gilstate;
 	
 	if (!sa || !(G.f & G_DOSCRIPTLINKS)) return 0;
@@ -2550,6 +2549,15 @@ int BPY_do_spacehandlers( ScrArea *sa, unsigned short event,
 		/* now run all assigned space handlers for this space and space_event */
 		for( index = 0; index < scriptlink->totscript; index++ ) {
 
+			spacehandlers_match = 0;
+
+			slink_event = scriptlink->flag[index];
+			if( slink_event == space_event )
+				spacehandlers_match = 1;
+			else if( ( space_event == SPACEHANDLER_VIEW3D_EVENT ) &&
+					( slink_event == SPACEHANDLER_VIEW3D_EVENT_ALL ) )
+				spacehandlers_match = 1;
+
 			/* for DRAW handlers: */
 			if (event == 0) {
 				glPushAttrib(GL_ALL_ATTRIB_BITS);
@@ -2559,7 +2567,7 @@ int BPY_do_spacehandlers( ScrArea *sa, unsigned short event,
 				glPushMatrix();
 			}
 
-			if( ( scriptlink->flag[index] == space_event ) &&
+			if( spacehandlers_match &&
 			    ( scriptlink->scripts[index] != NULL ) ) {
 				dict = CreateGlobalDictionary();
 				ret = RunPython( ( Text * ) scriptlink->scripts[index], dict );

source/blender/python/api2_2x/Blender.c

@@ -1047,8 +1047,11 @@ void M_Blender_Init(void)
 	if (SpaceHandlers) {
 		BPy_constant *d = (BPy_constant *)SpaceHandlers;
 
-		PyConstant_Insert(d,"VIEW3D_EVENT",PyInt_FromLong(SPACEHANDLER_VIEW3D_EVENT));
+		/* EVENT_ALL are reported as EVENT on key presses
+		 * and EVENT_RELEASE on key releases */
 		PyConstant_Insert(d,"VIEW3D_DRAW", PyInt_FromLong(SPACEHANDLER_VIEW3D_DRAW));
+		PyConstant_Insert(d,"VIEW3D_EVENT",PyInt_FromLong(SPACEHANDLER_VIEW3D_EVENT));
+		PyConstant_Insert(d,"VIEW3D_EVENT_RELEASE",PyInt_FromLong(SPACEHANDLER_VIEW3D_EVENT_ALL));
 
 		PyModule_AddObject(module, "SpaceHandlers", SpaceHandlers);
 	}

source/blender/python/api2_2x/doc/API_related.py

@@ -184,11 +184,11 @@ Introduction:
  Space Handler script links:
  ---------------------------
 
- This is a new kind of script linked to spaces in a given window.  Right now
+ These are scripts linked to spaces in a given window.  Right now
- only the 3D View has the necessary hooks, but the plan is to add access to
+ only the 3D View has the necessary hooks.  Just to clarify naming
- other types, too.  Just to clarify naming conventions: in Blender, a screen
+ conventions: in Blender, a screen is partitioned in windows (also
- is partitioned in windows (also called areas) and each window can show any
+ called areas) and each window can show any space.
- space.  Spaces are: 3D View, Text Editor, Scripts, Buttons, User Preferences,
+ Spaces are: 3D View, Text Editor, Scripts, Buttons, User Preferences,
  Oops, etc. 
 
  Space handlers are texts in the Text Editor, like other script links, but they
@@ -196,12 +196,16 @@ Introduction:
  text file}} must inform:
   1. that they are space handlers;
   2. the space they belong to;
-  3. whether they are EVENT or DRAW handlers.
+  3. whether they are EVENT, EVENT_RELEASE (EVENT ones reporting key release events) or DRAW handlers.
 
  Example header for a 3D View EVENT handler::
 
   # SPACEHANDLER.VIEW3D.EVENT
 
+ Example header for a 3D View EVENT handler that also receives release events::
+
+  # SPACEHANDLER.VIEW3D.EVENT.ALL
+
  Example header for a 3D View DRAW handler::
 
   # SPACEHANDLER.VIEW3D.DRAW
@@ -216,6 +220,10 @@ Introduction:
   - process it (the script must set Blender.event to None then);
   - ignore it.
 
+ EVENT ALL space handlers (header: # SPACEHANDLER.VIEW3D.EVENT.ALL) are executed
+ both for key presses (Blender.event = Blender.SpaceHandlers.VIEW3D_EVENT) and
+ for key releases (Blender.event = Blender.SpaceHandlers.VIEW3D_EVENT_RELEASE).
+
  Setting C{Blender.event = None} tells Blender not to go on processing itself
  the event, because it was grabbed by the script.
 
@@ -248,7 +256,7 @@ Introduction:
   - B{bylink} is the same: True if the script is running as a script link;
   - B{link}: integer from the L{Blender}.SpaceHandlers constant dictionary,
     tells what space this handler belongs to and the handler's type
-    (EVENT, DRAW);
+    (EVENT, EVENT_RELEASE, DRAW);
   - B{event}:
      - EVENT handlers: an input event (check keys and mouse events in
        L{Draw}) to be processed or ignored;
@@ -258,6 +266,7 @@ Introduction:
        presses (since we don't pass releases) as 1 and mouse movements
        (Draw.MOUSE.X and Draw.MOUSE.Y) as the current x or y coordinate,
        for example;
+     - EVENT_RELEASE handlers (EVENT handlers executed during key release events): 0;
      - DRAW handlers: 0 always.
 
  B{Guidelines (important)}:

source/blender/src/header_view3d.c

@@ -517,6 +517,8 @@ static uiBlock *view3d_view_spacehandlers(void *arg_unused)
 
 			if (handlertype == SPACEHANDLER_VIEW3D_EVENT)
 				BLI_strncpy(menustr, "Event: ", 8);
+			else if (handlertype == SPACEHANDLER_VIEW3D_EVENT_ALL)
+				BLI_strncpy(menustr, "Event+: ", 8);
 			else
 				BLI_strncpy(menustr, "Draw:  ", 8);
 			BLI_strncpy(menustr+7, text->id.name+2, 22);

source/blender/src/space.c

@@ -1248,10 +1248,6 @@ static void winqreadview3dspace(ScrArea *sa, void *spacedata, BWinEvent *evt)
 		
 		if(event==UI_BUT_EVENT) do_butspace(val); /* temporal, view3d deserves own queue? */
 
-		/* - we consider manipulator a button, defaulting to leftmouse 
-		 * - grease-pencil also defaults to leftmouse
-		 */
-		if(event==LEFTMOUSE) {
 #ifndef DISABLE_PYTHON
 			/* run any view3d event handler script links */
 		if(sa->scriptlink.totscript) {
@@ -1259,6 +1255,11 @@ static void winqreadview3dspace(ScrArea *sa, void *spacedata, BWinEvent *evt)
 				return; /* return if event was processed (swallowed) by handler(s) */
 		}
 #endif
+
+		/* - we consider manipulator a button, defaulting to leftmouse 
+		 * - grease-pencil also defaults to leftmouse
+		 */
+		if(event==LEFTMOUSE) {
 			if(gpencil_do_paint(sa, L_MOUSE)) return;
 			if(BIF_do_manipulator(sa)) return;
 		}
@@ -2956,6 +2957,16 @@ static void winqreadview3dspace(ScrArea *sa, void *spacedata, BWinEvent *evt)
 		}
 	}
 
+#ifndef DISABLE_PYTHON
+	else { /* val= 0 */
+		/* run any view3d release event handler script links */
+		if(sa->scriptlink.totscript) {
+			if(BPY_do_spacehandlers(sa, event, 0, SPACEHANDLER_VIEW3D_EVENT_ALL))
+				return; /* return if event was processed (swallowed) by handler(s) */
+		}
+	}
+#endif
+
 	if(doredraw) {
 		scrarea_queue_winredraw(curarea);
 		scrarea_queue_headredraw(curarea);