(shmif/lua) add target anchorhint

This is a concession to primarily allow toolkits and protocol bridges
to systems that expect information about not just visibility and desired
dimensions but also position and hierarchy.

A side-effect to this is that it should make it rather trivial to put
together a miniwm appl (or durden workspace owner tool) that just
informs and delegates window management feedback to an external process
written in whatever.

CHANGELOG.md

@@ -4,6 +4,7 @@
  * util:random\_bytes(len) added for CSPRNG byte string
  * target_input long messages are now marked as multipart
  * convey tui/tpack state in resize events
+ * target\_anchorhint added for informing clients about positioning and hierarchy
 
 ## Core
  * respect border attribute in text rasteriser

doc/target_anchorhint.lua

@@ -0,0 +1,38 @@
+-- target_anchorhint
+-- @short: Inform a target about its coordinates relative to a reference
+-- @inargs: vid:tgt, int:type=ANCHORHINT_SEGMENT, int:parent, int:x, int:y, int:z
+-- @inargs: vid:tgt, int:type=ANCHORHINT_EXTERNAL, int:parent, int:x, int:y, int:z
+-- @inargs: vid:tgt, int:type=ANCHORHINT_PROXY, vid:src, int:parent, int:x, int:y, int:z
+-- @inargs: vid:tgt, int:type=ANCHORHINT_PROXY_EXTERNAL, int:src, int:parent, int:x, int:y, int:z
+-- @outargs:
+-- @longdescr: While ref:target_displayhint can be used to provide additional
+-- information about how a client will be presented, it does not carry
+-- information about how it will be positioned within some reference frame.
+-- This is not as useful since clients can already hint in the other direction
+-- through viewport events.
+--
+-- The major exceptions are when one client is bridging to other windowing
+-- systems (ANCHORHINT_PROXY, ANCHORHINT_PROXY_EXTERNAL),
+-- acting as a window manager for nested/embedded subsegments (ANCHORHINT_SEGMENT)
+-- or as an out-of-process external window manager (ANCHORHINT_PROXY).
+-- *x* and *y* refers to the resolved upper-left corner position of the target,
+-- and *z* the stacking or composition order.
+--
+-- In such cases target_anchorhint can be used. The type indicates which
+-- reference objects that could be provided. If the type contains EXTERNAL the
+-- *src* and *parent* arguments will be treated as an opaque externally
+-- provided identifier, as with ref:target_displayhint and received through the
+-- segment_request and viewport events.
+--
+-- The non-external types will have *src* and *parent* verified as valid
+-- frameservers and the VIDs substitued for the respective cookie identifier
+-- (see ref:launch_target). If these point to an invalid vid or ones without
+-- TYPE_FRAMESERVER the event will fail silent and be discarded.
+--
+-- @group: targetcontrol
+-- @cfunction: targetdisphint
+-- @related: target_displayhint, launch_target
+function main()
+#ifdef MAIN
+#endif
+end

src/engine/arcan_lua.c

@@ -196,6 +196,22 @@ typedef int acoord;
 #define CONST_TRUST_TRANSITIVE 13
 #endif
 
+#ifndef CONST_ANCHORHINT_SEGMENT
+#define CONST_ANCHORHINT_SEGMENT 10
+#endif
+
+#ifndef CONST_ANCHORHINT_EXTERNAL
+#define CONST_ANCHORHINT_EXTERNAL 11
+#endif
+
+#ifndef CONST_ANCHORHINT_PROXY
+#define CONST_ANCHORHINT_PROXY 12
+#endif
+
+#ifndef CONST_ANCHORHINT_PROXY_EXTERNAL
+#define CONST_ANCHORHINT_PROXY_EXTERNAL 13
+#endif
+
 /*
  * disable support for all builtin frameservers
  * which removes most (launch_target and target_alloc remain)
@@ -234,6 +250,10 @@ static const int RENDERFMT_RETAIN_ALPHA = RENDERTARGET_RETAIN_ALPHA;
 static const int DEVICE_INDIRECT = CONST_DEVICE_INDIRECT;
 static const int DEVICE_DIRECT = CONST_DEVICE_DIRECT;
 static const int DEVICE_LOST = CONST_DEVICE_LOST;
+static const int ANCHORHINT_SEGMENT = CONST_ANCHORHINT_SEGMENT;
+static const int ANCHORHINT_EXTERNAL = CONST_ANCHORHINT_EXTERNAL;
+static const int ANCHORHINT_PROXY = CONST_ANCHORHINT_PROXY;
+static const int ANCHORHINT_PROXY_EXTERNAL = CONST_ANCHORHINT_PROXY_EXTERNAL;
 
 #define DBHANDLE arcan_db_get_shared(NULL)
 
@@ -1083,12 +1103,12 @@ static int loadimageasynch(lua_State* ctx)
 
 static int imageloaded(lua_State* ctx)
 {
-	LUA_TRACE("imageloaded");
+	LUA_TRACE("image_loaded");
 	arcan_vobject* vobj;
 	luaL_checkvid(ctx, 1, &vobj);
 
 	lua_pushnumber(ctx, vobj->feed.state.tag == ARCAN_TAG_IMAGE);
-	LUA_ETRACE("load_image_asynch", NULL, 1);
+	LUA_ETRACE("image_loaded", NULL, 1);
 }
 
 static int moveimage(lua_State* ctx)
@@ -4221,8 +4241,10 @@ void arcan_lwa_subseg_ev(
 	case TARGET_COMMAND_PAUSE:
 	case TARGET_COMMAND_UNPAUSE:
 	case TARGET_COMMAND_GRAPHMODE:
-/* handled in platform */
-	case TARGET_COMMAND_RESET:
+	case TARGET_COMMAND_ANCHORHINT: /* should probably feed back to know position,
+																		 but unclear if _lwa applications should rely
+																		 on that */
+	case TARGET_COMMAND_RESET: /* handled in platform */
 	case TARGET_COMMAND_SEEKCONTENT: /* scrolling */
 	case TARGET_COMMAND_COREOPT: /* dynamic key-value */
 	case TARGET_COMMAND_SEEKTIME: /* scrolling? */
@@ -7815,6 +7837,71 @@ static int targetdisphint(lua_State* ctx)
 	LUA_ETRACE("target_displayhint", NULL, 2);
 }
 
+static unsigned int get_vid_token(lua_State* ctx, int ind)
+{
+	arcan_vobject* vobj;
+	arcan_vobj_id parent = luaL_checkvid(ctx, ind, &vobj);
+	if (vobj->feed.state.tag != ARCAN_TAG_FRAMESERV){
+		arcan_fatal("target_anchorhint(vid, ANCHORHINT_SEGMENT, "
+			">parent<, ...) not connected to a frameserver");
+	}
+	arcan_frameserver* fsrv = vobj->feed.state.ptr;
+	return fsrv->cookie;
+}
+
+static int targetanchor(lua_State* ctx)
+{
+
+	LUA_TRACE("target_anchorhint");
+	arcan_event ev = {
+		.category = EVENT_TARGET,
+		.tgt.kind = TARGET_COMMAND_ANCHORHINT
+	};
+
+	arcan_vobject* vobj;
+	arcan_vobj_id vid = luaL_checkvid(ctx, 1, &vobj);
+
+	if (vobj->feed.state.tag != ARCAN_TAG_FRAMESERV){
+		arcan_fatal("target_anchorhint(>vid<, ...) not connected to a frameserver");
+	}
+
+	int type = luaL_checknumber(ctx, 2);
+	bool swap_token = false;
+	bool want_source = false;
+	int coord_ofs = 4;
+
+	switch (type){
+	case CONST_ANCHORHINT_SEGMENT:
+		ev.tgt.ioevs[4].uiv = get_vid_token(ctx, 3);
+	break;
+	case CONST_ANCHORHINT_PROXY:
+		ev.tgt.ioevs[3].uiv = get_vid_token(ctx, 3);
+		ev.tgt.ioevs[4].uiv = get_vid_token(ctx, 4);
+	break;
+	case CONST_ANCHORHINT_EXTERNAL:
+		ev.tgt.ioevs[4].uiv = luaL_checknumber(ctx, 3);
+		ev.tgt.ioevs[5].iv = 1;
+		coord_ofs = 5;
+	break;
+	case CONST_ANCHORHINT_PROXY_EXTERNAL:
+		ev.tgt.ioevs[3].uiv = luaL_checknumber(ctx, 3);
+		ev.tgt.ioevs[4].uiv = luaL_checknumber(ctx, 4);
+		ev.tgt.ioevs[5].iv = 1;
+		coord_ofs = 5;
+	break;
+	default:
+		arcan_fatal("target_anchorhint(vid, >type<, ..) invalid type value");
+	break;
+	}
+
+	ev.tgt.ioevs[0].uiv = luaL_checknumber(ctx, coord_ofs + 0);
+	ev.tgt.ioevs[1].uiv = luaL_checknumber(ctx, coord_ofs + 1);
+	ev.tgt.ioevs[2].uiv = luaL_optnumber(ctx, coord_ofs + 2, 0);
+
+	tgtevent(vid, ev);
+	LUA_ETRACE("target_anchorhint", NULL, 0);
+}
+
 static int targetgraph(lua_State* ctx)
 {
 	LUA_TRACE("target_graphmode");
@@ -12159,6 +12246,10 @@ void arcan_lua_pushglobalconsts(lua_State* ctx){
 {"DEVICE_INDIRECT", DEVICE_INDIRECT},
 {"DEVICE_DIRECT", DEVICE_DIRECT},
 {"DEVICE_LOST", DEVICE_LOST},
+{"ANCHORHINT_SEGMENT", ANCHORHINT_SEGMENT},
+{"ANCHORHINT_EXTERNAL", ANCHORHINT_EXTERNAL},
+{"ANCHORHINT_PROXY", ANCHORHINT_PROXY},
+{"ANCHORHINT_PROXY_EXTERNAL", ANCHORHINT_PROXY_EXTERNAL},
 {"RENDERTARGET_NOSCALE", RENDERTARGET_NOSCALE},
 {"RENDERTARGET_SCALE", RENDERTARGET_SCALE},
 {"RENDERTARGET_NODETACH", RENDERTARGET_NODETACH},

src/shmif/arcan_shmif_event.h

@@ -661,6 +661,7 @@ enum ARCAN_TARGET_COMMAND {
  * [2].iv  : rel_z
  * [3].uiv : source
  * [4].uiv : parent
+ * [5].iv  : extns (!0)
  *
  * Most clients should not rely or depend on these events. They are mainly
  * provided to bridge other windowing systems, for pseudo-window management of
@@ -672,6 +673,9 @@ enum ARCAN_TARGET_COMMAND {
  * The Z value may be used to carry stacking or draw order, e.g. < 0 the source
  * is below the parent (drawn before), with > 0 is above the parent (drawn
  * after).
+ *
+ * If extns is set (!0) the values of source and parent refers to previously
+ * provded extids from viewport and segment requests rather than segment token.
  */
 	TARGET_COMMAND_ANCHORHINT,
 

src/wayland/wlimpl/surf.c

@@ -118,6 +118,18 @@ static void surf_damage(struct wl_client* cl,
 	w *= surf->scale;
 	h *= surf->scale;
 
+	if (x < 0)
+		x = 0;
+
+	if (y < 0)
+		y = 0;
+
+	if (w < 0)
+		w = surf->acon.w;
+
+	if (h < 0)
+		h = surf->acon.h;
+
 	trace(TRACE_SURF,"%s:(%"PRIxPTR") @x,y+w,h(%d+%d, %d+%d)",
 		surf->tracetag, (uintptr_t)res, (int)x, (int)w, (int)y, (int)h);