fixing the positioning algorithm in Camera2D.match_target for #2558

Author: DragonMoffon

arcade/camera/camera_2d.py

@@ -330,6 +330,8 @@ def equalise(self) -> None:
         x, y = self._projection_data.rect.x, self._projection_data.rect.y
         self._projection_data.rect = XYWH(x, y, self.viewport_width, self.viewport_height)
 
+    equalize = equalise
+
     def match_window(
         self,
         viewport: bool = True,
@@ -348,8 +350,8 @@ def match_window(
                 On by default
             scissor: Flag whether to also equalize the scissor box to the viewport.
                 On by default
-            position: Flag whether to also center the camera to the viewport.
-                Off by default
+            position: Flag whether to position the camera so that (0.0, 0.0) is in
+                the bottom-left
             aspect: The ratio between width and height that the viewport should
                 be constrained to. If unset then the viewport just matches the window
                 size. The aspect ratio describes how much larger the width should be
@@ -382,8 +384,8 @@ def match_target(
                 match the render target.
                 The projection center stays fixed, and the new projection matches only in size.
             scissor: Flag whether to update the scissor value.
-            position: Flag whether to also center the camera to the value.
-                Off by default
+            position: Flag whether to position the camera so that (0.0, 0.0) is in
+                the bottom-left
             aspect: The ratio between width and height that the value should
                 be constrained to. i.e. for an aspect ratio of ``4:3`` you should
                 input ``4.0/3.0`` or ``1.33333...``. Cannot be equal to zero.
@@ -424,8 +426,8 @@ def update_values(
             projection: Flag whether to equalize the size of the projection to match the value.
                 The projection center stays fixed, and the new projection matches only in size.
             scissor: Flag whether to update the scissor value.
-            position: Flag whether to also center the camera to the value.
-                Off by default
+            position: Flag whether to position the camera so that (0.0, 0.0) is in
+                the bottom-left
             aspect: The ratio between width and height that the value should
                 be constrained to. i.e. for an aspect ratio of ``4:3`` you should
                 input ``4.0/3.0`` or ``1.33333...``. Cannot be equal to zero.
@@ -451,7 +453,7 @@ def update_values(
             self.scissor = value
 
         if position:
-            self.position = value.center
+            self.position = -self._projection_data.left, -self._projection_data.bottom
 
     def aabb(self) -> Rect:
         """