Create an example for the easing functions

arcade/examples/easing_functions.py

@@ -0,0 +1,273 @@
+"""
+Example showing the different easing functions.
+
+If Python and Arcade are installed, this example can be run from the command line with:
+python -m arcade.examples.easing_functions
+"""
+
+import arcade
+from arcade import SpriteCircle, SpriteList
+from arcade.anim.easing import Easing, ease
+from arcade.clock import GLOBAL_CLOCK
+from arcade.types.rect import LBWH, Rect
+
+from pyglet.graphics import Batch  # type: ignore -- Batch isn't in __all__?
+
+WINDOW_WIDTH = 1200
+WINDOW_HEIGHT = 800
+WINDOW_TITLE = "Easing Example"
+
+# Load our brand font
+arcade.resources.load_josefin_sans()
+
+# Load an actually good monospace font
+arcade.load_font(":system:fonts/ttf/Fira Code/Fira_Code_Medium.ttf")
+
+# Label all the functions
+# There's nine "types", not counting linear, and three of each.
+
+EASING_TYPES = 10
+EASING_SUB_TYPES = 3
+
+easing_functions = {
+    "Linear": Easing.LINEAR,
+    "Sine": Easing.SINE,
+    "Sine In": Easing.SINE_IN,
+    "Sine Out": Easing.SINE_OUT,
+    "Quad": Easing.QUAD,
+    "Quad In": Easing.QUAD_IN,
+    "Quad Out": Easing.QUAD_OUT,
+    "Cubic": Easing.CUBIC,
+    "Cubic In": Easing.CUBIC_IN,
+    "Cubic Out": Easing.CUBIC_OUT,
+    "Quart": Easing.QUART,
+    "Quart In": Easing.QUART_IN,
+    "Quart Out": Easing.QUART_OUT,
+    "Quint": Easing.QUINT,
+    "Quint In": Easing.QUINT_IN,
+    "Quint Out": Easing.QUINT_OUT,
+    "Expo": Easing.EXPO,
+    "Expo In": Easing.EXPO_IN,
+    "Expo Out": Easing.EXPO_OUT,
+    "Circ": Easing.CIRC,
+    "Circ In": Easing.CIRC_IN,
+    "Circ Out": Easing.CIRC_OUT,
+    "Back": Easing.BACK,
+    "Back In": Easing.BACK_IN,
+    "Back Out": Easing.BACK_OUT,
+    "Elastic": Easing.ELASTIC,
+    "Elastic In": Easing.ELASTIC_IN,
+    "Elastic Out": Easing.ELASTIC_OUT,
+    "Bounce": Easing.BOUNCE,
+    "Bounce In": Easing.BOUNCE_IN,
+    "Bounce Out": Easing.BOUNCE_OUT,
+}
+
+# We need these for sorting them later;
+# they're in reverse order since we draw bottom-up.
+function_names = [
+    "Bounce",
+    "Elastic",
+    "Back",
+    "Circ",
+    "Expo",
+    "Quint",
+    "Quart",
+    "Cubic",
+    "Quad",
+    "Sine",
+    "Linear",
+]
+
+
+def px_to_pt(px: int) -> int:
+    return round(px // (4 / 3))
+
+LINE_WIDTH = 2
+
+class GameView(arcade.View):
+    """
+    Main application class.
+    """
+
+    def __init__(self):
+        super().__init__()
+
+        self.background_color = arcade.color.ARCADE_GREEN
+        self.time = 0.0
+        self.paused = False
+
+        # "Layouting"
+        rect = self.window.rect
+        self.areas: list[Rect] = []
+        # We want a 10 x 3 grid, but pretending there's an 12 x 3 grid
+        # and we're ignoring the first two rows.
+        buffer = 10  # px
+        cols = EASING_SUB_TYPES
+        rows = EASING_TYPES + 2
+        rect_width = rect.width / cols
+        rect_height = rect.height / rows
+
+        # Generate a gird of rectangles. We'll use these to place the
+        # easing demos.
+        for i in range(EASING_TYPES * EASING_SUB_TYPES + 1):
+            new_rect = LBWH(0, 0, rect_width, rect_height)
+            row = i // cols
+            col = i % cols
+            if col == 0:
+                new_rect = new_rect.align_left(rect.left)
+            elif col == 1:
+                new_rect = new_rect.align_center_x(rect.center_x)
+            elif col == 2:
+                new_rect = new_rect.align_right(rect.right)
+            new_rect = new_rect.align_bottom(rect.bottom + rect_height * row)
+            new_rect = new_rect.resize(new_rect.width - buffer, new_rect.height - buffer)
+            self.areas.append(new_rect)
+
+        self.random_colors = [arcade.types.Color.random(a=255) for _ in range(len(self.areas))]
+
+        self.title_text = arcade.Text(
+            "Easing Functions",
+            buffer,
+            self.window.rect.top - buffer,
+            font_size=px_to_pt(int(rect_height - buffer)),
+            font_name="Josefin Sans",
+            anchor_y="top",
+        )
+        self.subtitle_text = arcade.Text(
+            "Press [SPACE] to pause/unpause.",
+            self.window.rect.right - buffer,
+            self.window.rect.top - buffer,
+            font_size=px_to_pt(int(rect_height - buffer) // 2),
+            font_name="Josefin Sans",
+            color=arcade.color.ARCADE_YELLOW,
+            anchor_y="top",
+            anchor_x="right",
+        )
+
+        self.labels = []
+        self.progress_labels = []
+        self.text_batch = Batch()
+        self.sprites = []
+        self.spritelist = SpriteList()
+        for n, a in enumerate(self.areas):
+            name = self.idx_to_func_name(n)
+            func = easing_functions[name]
+            label = arcade.Text(
+                func.__name__,
+                a.left,
+                a.bottom,
+                font_size=px_to_pt(int(a.height / 2 - buffer)),
+                font_name="Fira Code",
+                batch=self.text_batch,
+            )
+            self.labels.append(label)
+            progress_label = arcade.Text(
+                "0.00",
+                a.right,
+                a.bottom,
+                font_size=px_to_pt(int(a.height / 2 - buffer)),
+                font_name="Josefin Sans",
+                bold="light",
+                anchor_x="right",
+                batch=self.text_batch,
+            )
+            self.progress_labels.append(progress_label)
+            sprite = SpriteCircle(int(a.height / 4), arcade.color.ARCADE_YELLOW)
+            sprite.left = a.left
+            sprite.center_y = a.bottom + (a.height * 0.75)
+            self.sprites.append(sprite)
+            self.spritelist.append(sprite)
+
+        self.lines = []
+        for a in self.areas:
+            y = a.bottom + (a.height * 0.75)
+            # Long line
+            self.lines.extend([(a.left + LINE_WIDTH, y), (a.right - LINE_WIDTH, y)])
+            # Left line
+            self.lines.extend([(a.left + LINE_WIDTH, y - buffer), (a.left + LINE_WIDTH, y + buffer)])
+            # Center line
+            self.lines.extend([(a.center_x, y - buffer), (a.center_x, y + buffer)])
+            # Right line
+            self.lines.extend([(a.right - LINE_WIDTH, y - buffer), (a.right - LINE_WIDTH, y + buffer)])
+
+    def idx_to_func_name(self, i: int) -> str:
+        if i >= len(self.areas):
+            raise ValueError
+        else:
+            t = function_names[i // 3]
+            if i % 3 == 0:
+                return t
+            elif i % 3 == 1:
+                return f"{t} In"
+            else:
+                return f"{t} Out"
+
+    def on_update(self, delta_time):
+        if int(GLOBAL_CLOCK.time) % 4 == 0:
+            self.time = 1 - (GLOBAL_CLOCK.time % 1)
+        elif int(GLOBAL_CLOCK.time) % 4 == 1:
+            self.time = 0
+        elif int(GLOBAL_CLOCK.time) % 4 == 2:
+            self.time = GLOBAL_CLOCK.time % 1
+        else:
+            self.time = 1
+
+        for n, a in enumerate(self.areas):
+            name = self.idx_to_func_name(n)
+            func = easing_functions[name]
+            sprite = self.sprites[n]
+
+            right = a.right - sprite.width
+            x = ease(a.left, right, 0, 1, self.time, func)
+            p = ease(0.0, 1.0, 0, 1, self.time, func)
+            rounded_p = round(p, 2)
+            sprite.left = x
+            self.progress_labels[n].text = f"{rounded_p:.02}"
+            if rounded_p > 1 or rounded_p < 0:
+                self.progress_labels[n].color = arcade.color.PINK_PEARL
+            else:
+                self.progress_labels[n].color = arcade.color.WHITE
+
+    def on_draw(self):
+        """
+        Render the screen.
+        """
+        self.clear()
+        self.title_text.draw()
+        self.subtitle_text.draw()
+        for n, r in enumerate(self.areas):
+            arcade.draw_rect_filled(r, arcade.color.BLACK.replace(a=64))
+        arcade.draw_lines(self.lines, arcade.color.WHITE, LINE_WIDTH)
+        self.text_batch.draw()
+        self.spritelist.draw()
+
+    def on_key_press(self, symbol: int, modifiers: int):
+        """Handle key press events"""
+        if symbol == arcade.key.ESCAPE:
+            self.window.close()
+        if symbol == arcade.key.SPACE:
+            self.paused = not self.paused
+            if self.paused:
+                GLOBAL_CLOCK.set_tick_speed(0)
+            else:
+                GLOBAL_CLOCK.set_tick_speed(1)
+
+
+def main():
+    """Main function"""
+    # Create a window class. This is what actually shows up on screen
+    window = arcade.Window(WINDOW_WIDTH, WINDOW_HEIGHT, WINDOW_TITLE)
+
+    # Create the GameView
+    game = GameView()
+
+    # Show GameView on screen
+    window.show_view(game)
+
+    # Start the arcade game loop
+    arcade.run()
+
+
+if __name__ == "__main__":
+    main()

arcade/resources/__init__.py

@@ -303,3 +303,29 @@ def load_liberation_fonts() -> None:
     load_font(":system:fonts/ttf/Liberation/Liberation_Serif_Bold.ttf")
     load_font(":system:fonts/ttf/Liberation/Liberation_Serif_Italic.ttf")
     load_font(":system:fonts/ttf/Liberation/Liberation_Serif_Regular.ttf")
+
+def load_josefin_sans() -> None:
+    """Loads all styles for Josefin Sans, our brand font.
+
+    .. tip:: This function is best for prototyping and experimenting!
+
+             For best performance, you may want to switch to
+             :py:class:`arcade.load_font` before release.
+
+    """
+    from arcade.text import load_font
+
+    load_font(":system:fonts/ttf/Josefin/Josefin_Sans_BoldItalic.ttf")
+    load_font(":system:fonts/ttf/Josefin/Josefin_Sans_Bold.ttf")
+    load_font(":system:fonts/ttf/Josefin/Josefin_Sans_Italic.ttf")
+    load_font(":system:fonts/ttf/Josefin/Josefin_Sans_Regular.ttf")
+    load_font(":system:fonts/ttf/Josefin/Josefin_Sans_Medium.ttf")
+    load_font(":system:fonts/ttf/Josefin/Josefin_Sans_MediumItalic.ttf")
+    load_font(":system:fonts/ttf/Josefin/Josefin_Sans_Thin.ttf")
+    load_font(":system:fonts/ttf/Josefin/Josefin_Sans_ThinItalic.ttf")
+    load_font(":system:fonts/ttf/Josefin/Josefin_Sans_Light.ttf")
+    load_font(":system:fonts/ttf/Josefin/Josefin_Sans_LightItalic.ttf")
+    load_font(":system:fonts/ttf/Josefin/Josefin_Sans_Semibold.ttf")
+    load_font(":system:fonts/ttf/Josefin/Josefin_Sans_SemiboldItalic.ttf")
+    load_font(":system:fonts/ttf/Josefin/Josefin_Sans_ExtraLight.ttf")
+    load_font(":system:fonts/ttf/Josefin/Josefin_Sans_ExtraLightItalic.ttf")