feat: add a single pointer display option

ArrayView now has the ability to display a smaller pointer to up to one
element.

Author: danielzting

levels/bogo_sort.gd

@@ -17,5 +17,5 @@ func next(action):
     if array.is_sorted():
         emit_signal("done")
 
-func _get_effect(i):
+func get_effect(i):
     return EFFECTS.NONE

levels/bubble_sort.gd

@@ -42,7 +42,7 @@ func next(action):
         _end -= 1
         _swapped = false
 
-func _get_effect(i):
+func get_effect(i):
     if i == _index or i == _index + 1:
         return EFFECTS.HIGHLIGHTED
     if i >= _end:

levels/comparison_sort.gd

@@ -14,7 +14,7 @@ const DISABLE_TIME = 1.0
 
 var array: ArrayModel
 var active = true
-var _done = false
+var done = false
 
 var _timer = Timer.new()
 
@@ -29,7 +29,7 @@ func _init(array):
 
 func _input(event):
     """Pass input events for checking and take appropriate action."""
-    if _done or not active:
+    if done or not active:
         return
     if event.is_pressed():
         return next(event.as_text())
@@ -39,15 +39,13 @@ func next(action):
     push_error("NotImplementedError")
 
 func get_effect(i):
-    if _done:
-        return EFFECTS.NONE
-    return _get_effect(i)
+    return get_effect(i)
 
 func _get_effect(i):
     push_error("NotImplementedError")
 
 func _on_ComparisonSort_done():
-    _done = true
+    done = true
 
 func _on_ComparisonSort_mistake():
     """Disable the controls for one second."""

levels/insertion_sort.gd

@@ -38,10 +38,10 @@ func next(action):
             return emit_signal("mistake")
         _grow()
 
-func _get_effect(i):
+func get_effect(i):
     if i == _index or i == _index - 1:
         return EFFECTS.HIGHLIGHTED
-    if i < _end:
+    if i <= _end:
         return EFFECTS.DIMMED
     return EFFECTS.NONE
 

levels/merge_sort.gd

@@ -62,7 +62,7 @@ func next(action):
         _left = _get_begin()
         _right = _get_middle()
 
-func _get_effect(i):
+func get_effect(i):
     var is_left = _left != _get_middle() and i == _left
     var is_right = _right != _get_end() and i == _right
     if is_left or is_right:

levels/selection_sort.gd

@@ -42,9 +42,12 @@ func next(action):
     if _base == array.size - 1:
         emit_signal("done")
 
-func _get_effect(i):
+func get_effect(i):
     if i == _min or i == _index:
         return EFFECTS.HIGHLIGHTED
     if i < _base:
         return EFFECTS.DIMMED
     return EFFECTS.NONE
+
+func get_pointer():
+    return _min

models/array_model.gd

@@ -8,17 +8,23 @@ signal sorted(i, j)
 
 var _array = []
 var size = 0 setget , get_size
+var biggest = null
 
 func _init(size=16):
     """Randomize the array."""
     for i in range(1, size + 1):
         _array.append(i)
     _array.shuffle()
+    biggest = _array.max()
 
 func at(i):
     """Retrieve the value of the element at index i."""
     return _array[i]
 
+func frac(i):
+    """Get the quotient of the element at index i and the biggest."""
+    return float(_array[i]) / biggest
+
 func is_sorted():
     """Check if the array is in monotonically increasing order."""
     for i in range(get_size() - 1):

scripts/theme.gd

@@ -4,7 +4,8 @@ Global constants relating to the GUI.
 
 extends Node
 
-const GREEN = Color(0.2, 1, 0.2)
-const DARK_GREEN = Color(0.2, 1, 0.2, 0.5)
-const ORANGE = Color(1, 0.69, 0)
-const RED = Color(1, 0, 0)
+const GREEN = Color("33ff33")
+const DARK_GREEN = Color("7733ff33")
+const ORANGE = Color("ffb000")
+const RED = Color("f44336")
+const BLUE = Color("2196f3")

views/array_view.gd

@@ -11,9 +11,9 @@ var _tween = Tween.new()
 var _level: ComparisonSort
 var _rects = []
 var _positions = []
-var _unit_width: int
-var _unit_height: int
 var _viewport = Viewport.new()
+var _pointer = null
+var _pointer_size: int
 onready var _separation = 128 / _level.array.size
 
 func _init(level):
@@ -26,38 +26,58 @@ func _init(level):
 
 func _ready():
     yield(get_tree(), "idle_frame")
-    _viewport.size = rect_size
-    _unit_width = rect_size.x / _level.array.size
-    _unit_height = rect_size.y / _level.array.size
+    var unit_width = rect_size.x / _level.array.size
+    _pointer_size = max((unit_width - _separation) / 4, 2)
     # Keep track of accumulated pixel error from integer division
-    var error = float(rect_size.x) / _level.array.size - _unit_width
+    var error = float(rect_size.x) / _level.array.size - unit_width
     var accumulated = 0
     var x = 0
     _level.connect("mistake", get_parent(), "flash")
+    var width = unit_width - _separation
+    var height = rect_size.y - _pointer_size * 2
     for i in range(_level.array.size):
         var rect = Polygon2D.new()
         if accumulated >= 1:
             x += 1
             accumulated -= 1
         rect.polygon = [
             Vector2(0, 0),
-            Vector2(0, rect_size.y),
-            Vector2(_unit_width - _separation, rect_size.y),
-            Vector2(_unit_width - _separation, 0),
+            Vector2(0, height),
+            Vector2(width, height),
+            Vector2(width, 0),
         ]
         accumulated += error
         rect.position = Vector2(x, rect_size.y)
         _positions.append(x)
-        x += _unit_width
+        x += unit_width
         _rects.append(rect)
         _viewport.add_child(rect)
     _level.array.connect("swapped", self, "_on_ArrayModel_swapped")
     _level.array.connect("sorted", self, "_on_ArrayModel_sorted")
+    if _level.has_method("get_pointer"):
+        _pointer = Polygon2D.new()
+        _pointer.polygon = [
+            Vector2(width / 2, _pointer_size),
+            Vector2(width / 2 - _pointer_size, 0),
+            Vector2(width / 2 + _pointer_size, 0),
+        ]
+        _pointer.color = GlobalTheme.BLUE
+        _viewport.add_child(_pointer)
 
 func _process(delta):
+    if _pointer != null:
+        var pointed = _level.get_pointer()
+        var height = rect_size.y - _pointer_size * 2
+        _pointer.position = Vector2(_rects[pointed].position.x,
+            height - _level.array.frac(pointed) * height)
+        if _level.done:
+            _pointer.queue_free()
     for i in range(_rects.size()):
-        _rects[i].color = _level.get_effect(i)
-        _rects[i].scale.y = -float(_level.array.at(i)) / _level.array.size
+        if _level.done:
+            _rects[i].color = ComparisonSort.EFFECTS.NONE
+        else:
+            _rects[i].color = _level.get_effect(i)
+        _rects[i].scale.y = -_level.array.frac(i)
 
 func _on_ArrayModel_swapped(i, j):
     var time = ANIM_DURATION * (1 + float(j - i) / _level.array.size)