text rendering

src/doodles/__init__.py

@@ -2,5 +2,6 @@ from .doodles import Doodle, Group
 from .lines import Line
 from .shapes import Circle, Rectangle
 from .color import Color
+from .text import Text
 
-__all__ = [Doodle, Group, Line, Circle, Rectangle, Color]
+__all__ = [Doodle, Group, Line, Circle, Rectangle, Color, Text]

src/doodles/examples/words.py

@@ -0,0 +1,42 @@
+import random
+import itertools
+from doodles import Group, Circle, Color, Text
+
+# TODO: depending on system these fonts often do not have all the
+# necessary characters, find 3 widely available fonts that do
+Text.make_font("small", 16, "mono")
+Text.make_font("medium", 24, "copperplate")
+Text.make_font("large", 48, "papyrus")
+print(Text._fonts)
+
+# Via ChatGPT
+hello_world = [
+    "Hello, World!",  # English
+    "Hola, Mundo!",  # Spanish
+    "Bonjour, Monde!",  # French
+    "Hallo, Welt!",  # German
+    "Ciao, Mondo!",  # Italian
+    "こんにちは、世界！",  # Japanese
+    "안녕하세요, 세계!",  # Korean
+    "Привет, мир!",  # Russian
+    "Olá, Mundo!",  # Portuguese
+    "नमस्ते, दुनिया!",  # Hindi
+    "Merhaba, Dünya!",  # Turkish
+    "Salam, Dünya!",  # Azerbaijani
+    "Hej, Världen!",  # Swedish
+    "Hei, Maailma!",  # Finnish
+    "שלום, עולם!",  # Hebrew
+    "Szia, Világ!",  # Hungarian
+    "Zdravo, Svijete!",  # Bosnian
+    "Sawubona, Mhlaba!",  # Zulu
+    "Marhaba, Alalam!",  # Arabic
+    "你好，世界！",  # Mandarin Chinese
+]
+
+
+def create():
+    # use a generator to include each one 3x
+    for greeting in itertools.chain.from_iterable(itertools.repeat(hello_world, 3)):
+        Text().random().font(
+            random.choice(("small", "medium", "large"))
+        ).text(greeting)

src/doodles/text.py

@@ -0,0 +1,85 @@
+import pygame
+from .doodles import Doodle
+
+# TOOD: make configurable
+DEFAULT_FONT_SIZE = 24
+
+class Text(Doodle):
+    # Having each bit of text on the screen load a separate copy
+    # of its font would be wasteful, since the most common case would
+    # be for most text to use the same font.
+    #
+    # The solution here is to use a class attribute, shared by *all* instances
+    # of the class.
+    #
+    # This is an implementation of the Flyweight design pattern, which
+    # allows multiple objects to share some state.
+    #
+    # This can quickly become a mess if the shared state is mutable,
+    # note that here, once a font is loaded it does not change.
+    # This avoids nearly all pitfalls associated with this approach.
+    _fonts: dict[str, pygame.font.Font] = {}
+
+    # this method is attached to the class `Text`, not individual instances
+    # like normal methods (which take self as their implicit parameter)
+    @classmethod
+    def make_font(cls, name, size, font=None, bold=False, italic=False):
+        """
+        The way fonts work in most graphics libraries requires choosing a font
+        size, as well as any variation (bold, italic) at the time of creation.
+
+        It would be nice if we could allow individual Text objects vary these,
+        but doing so would be much more complex or require significantly more
+        memory.
+        """
+        if font is None:
+            font = pygame.font.Font(None, size)
+        else:
+            path = pygame.font.match_font(font, bold=bold, italic=italic)
+            font = pygame.font.Font(path, size)
+        cls._fonts[name] = font
+
+    @classmethod
+    def get_font(cls, name=None):
+        if not name:
+            # None -> default font
+            # load on demand
+            if None not in cls._fonts:
+                cls._fonts[None] = pygame.font.Font(None, DEFAULT_FONT_SIZE)
+            return cls._fonts[None]
+        else:
+            return cls._fonts[name]
+
+    def __init__(self, parent=None):
+        """
+        Text will be centered at `pos`
+        """
+        super().__init__(parent)
+        self._text = ""
+        self._rendered = None
+        self._font = None
+
+    def __repr__(self):
+        return f"Text(pos={self.pos_vec}, text={self._text}, parent={self._parent})"
+
+    def draw(self, screen):
+        text_rect = self._rendered.get_rect(center=(self.x, self.y))
+        screen.blit(self._rendered, text_rect)
+
+    def text(self, text: str) -> "Doodle":
+        """
+        A setter for the text
+        """
+        self._text = text
+        # text needs to be rendered once on change to be performant
+        # doing this in draw would be much slower since it is called
+        # much more often than the text changes
+        if not self._font:
+            self._font = self.get_font()    # default font
+        self._rendered = self._font.render(self._text, True, self._color)
+        return self
+
+    def font(self, font: str) -> "Doodle":
+        # TODO: error checking
+        self._font =  self._fonts[font]
+        return self