Merge pull request #43 from BetterBuiltFool/custom_anchor

Custom anchor

Author: BetterBuiltFool

src/pyrite/types/enums.py

@@ -136,52 +136,42 @@ def _(cls, index: int) -> Layer:
 
 class Anchor:
     """
-    Determines where on a surface the position is based.
+    Defines, relative to a rectangle, what spot is considered the position.
     """
 
-    def __init__(self, target_attribute: str) -> None:
-        self.target_attribute = target_attribute
-
-    def anchor_rect(self, rectangle: RectLike, position: Point) -> pygame.Rect:
+    def __init__(self, relative_position: Point) -> None:
         """
-        Supplies a new rectangle, with the size of the original, but the location of
-        the rectangle based on the given position, and the anchor point's assigned
-        attribute.
+        Creates an anchor point, defining a relative point for the location of
+        the position of a rectangle.
 
-        :param rectangle: A rect-like that will be moved to the position
-        :param position: A position to move the rectangle to.
-        :return: The new rectangle, in the position location.
+        :param relative_position: (0, 0) is top left, and (1, 1) is bottom right.
         """
+        self._relative_position = pygame.Vector2(relative_position)
+
+    def anchor_rect(self, rectangle: RectLike, position: Point) -> pygame.Rect:
         rect = pygame.Rect(rectangle)
-        rect.__setattr__(self.target_attribute, position)
+        pivot: pygame.Vector2 = self._relative_position.elementwise() * rect.size
+        offset = pygame.Vector2(rect.topleft) - pivot
+        rect.topleft = offset
         return rect
 
     def anchor_rect_ip(self, rectangle: pygame.Rect, position: Point) -> None:
-        """
-        Moves the passed rectangle to the position, with that position being based on
-        the anchorpoint.
-
-        :param rectangle: A rectangle that will have its position modified.
-        :param position: A position to move the rectangle to.
-        """
-        rectangle.__setattr__(self.target_attribute, position)
-
-
-# TODO Add CustomAnchor, which uses an FRect like SurfaceSector to determine relative
-# position. Maybe Vector2 instead? We'll see.
+        pivot: pygame.Vector2 = self._relative_position.elementwise() * rectangle.size
+        offset = pygame.Vector2(rectangle.topleft) - pivot
+        rectangle.topleft = offset
 
 
 class AnchorPoint:
     """
     An enum for modifying the position of a rectangle for renderables.
     """
 
-    TOPLEFT = Anchor("topleft")
-    MIDTOP = Anchor("midtop")
-    TOPRIGHT = Anchor("topright")
-    MIDLEFT = Anchor("midleft")
-    CENTER = Anchor("center")
-    MIDRIGHT = Anchor("midright")
-    BOTTOMLEFT = Anchor("bottomleft")
-    MIDBOTTOM = Anchor("midbottom")
-    BOTTOMRIGHT = Anchor("bottomright")
+    TOPLEFT = Anchor((0, 0))
+    MIDTOP = Anchor((0.5, 0))
+    TOPRIGHT = Anchor((1, 0))
+    MIDLEFT = Anchor((0, 0.5))
+    CENTER = Anchor((0.5, 0.5))
+    MIDRIGHT = Anchor((1, 0.5))
+    BOTTOMLEFT = Anchor((0, 1))
+    MIDBOTTOM = Anchor((0.5, 1))
+    BOTTOMRIGHT = Anchor((1, 1))