Add Technical Doodads + UI Fixes

New category for the Doodad Dropper: "Technical"

Technical doodads have a dashed outline and label for now, and they
turn invisible on level start, and are for hidden technical effects on
your level.

The doodads include:

* Goal Region: acts like an invisible Exit Flag (128x128), the level is
  won when the player character touches this region.
* Fire Region: acts like a death barrier (128x128), kills the player
  when a generic "You have died!" message.
* Power Source: on level start, acts like a switch and emits a
  power(true) signal to all linked doodads. Link it to your Electric
  Door for it to be open by default in your level!
* Stall Player (250ms): The player is paused for a moment the first time
  it touches this region. Useful to work around timing issues, e.g.
  help prevent the player from winning a race against another character.

There are some UI improvements to the Doodad Dropper window:

* If the first page of doodads is short, extra spacers are added so the
  alignment and size shows correctly.
* Added a 'background pattern' to the window: any unoccupied icon space
  has an inset rectangle slot.
* "Last pages" which are short still render weirdly without reserving
  the correct height in the TabFrame.

Doodad scripting engine updates:

* Self.Hide() and Self.Show() available.
* Subscribe to "broadcast:ready" to know when the level is ready, so you
  can safely Publish messages without deadlocks!

dev-assets/doodads/build.sh

@@ -66,6 +66,10 @@ objects() {
 	cd crumbly-floor/
 	make
 	cd ..
+
+	cd regions/
+	make
+	cd ..
 }
 
 onoff() {

dev-assets/doodads/regions/Makefile

@@ -0,0 +1,25 @@
+ALL: build
+
+.PHONY: build
+build:
+	# Goal Region
+	doodad convert -t "Goal Region" goal-128.png reg-goal.doodad
+	doodad install-script goal.js reg-goal.doodad
+
+	# Fire Region
+	doodad convert -t "Fire Region" fire-128.png reg-fire.doodad
+	doodad install-script fire.js reg-fire.doodad
+
+	# Stall Region
+	doodad convert -t "Stall Player (250ms)" stall-128.png reg-stall-250.doodad
+	doodad edit-doodad --tag "ms=250" reg-stall-250.doodad
+	doodad install-script stall.js reg-stall-250.doodad
+
+	# Power Source
+	doodad convert -t "Power Source" power-64.png power-source.doodad
+	doodad install-script power.js power-source.doodad
+
+	for i in *.doodad; do\
+		doodad edit-doodad --tag "category=technical" $${i};\
+	done
+	cp *.doodad ../../../assets/doodads/

dev-assets/doodads/regions/fire.js

@@ -0,0 +1,19 @@
+// Goal Region.
+function main() {
+    Self.Hide();
+
+    Events.OnCollide(function (e) {
+        if (!e.Settled) {
+            return;
+        }
+
+        // Only care if it's the player.
+        if (!e.Actor.IsPlayer()) {
+            return;
+        }
+
+        if (e.InHitbox) {
+            FailLevel("You have died!");
+        }
+    });
+}

dev-assets/doodads/regions/goal.js

@@ -0,0 +1,19 @@
+// Goal Region.
+function main() {
+    Self.Hide();
+
+    Events.OnCollide(function (e) {
+        if (!e.Settled) {
+            return;
+        }
+
+        // Only care if it's the player.
+        if (!e.Actor.IsPlayer()) {
+            return;
+        }
+
+        if (e.InHitbox) {
+            EndLevel();
+        }
+    });
+}

dev-assets/doodads/regions/power.js

@@ -0,0 +1,22 @@
+// Power source.
+// Emits a power(true) signal once on level start.
+// If it receives a power signal, it will repeat it after 5 seconds.
+// Link two of these bad boys together and you got yourself a clock.
+function main() {
+    Self.Hide();
+
+    // See if we are not linked to anything.
+    var links = Self.GetLinks();
+    if (links.length === 0) {
+        console.error(
+            "%s at %s is not linked to anything! This doodad emits a power(true) on level start to all linked doodads.",
+            Self.Title,
+            Self.Position()
+        );
+    }
+
+    Message.Subscribe("broadcast:ready", function () {
+        Message.Publish("switch:toggle", true);
+        Message.Publish("power", true);
+    });
+}

dev-assets/doodads/regions/stall.js

@@ -0,0 +1,40 @@
+// Stall Player.
+// Tags: ms (int)
+// Grabs the player one time. Resets if it receives power.
+function main() {
+    Self.Hide();
+
+    var active = true,
+        timeout = 250,
+        ms = Self.GetTag("ms");
+
+    if (ms.length > 0) {
+        timeout = parseInt(ms);
+    }
+
+    Events.OnCollide(function (e) {
+        if (!active || !e.Settled) {
+            return;
+        }
+
+        // Only care if it's the player.
+        if (!e.Actor.IsPlayer()) {
+            return;
+        }
+
+        if (e.InHitbox) {
+            // Grab hold of the player.
+            e.Actor.Freeze();
+            setTimeout(function () {
+                e.Actor.Unfreeze();
+            }, timeout);
+
+            active = false;
+        }
+    });
+
+    // Reset the trap if powered by a button.
+    Message.Subscribe("power", function (powered) {
+        active = true;
+    });
+}