Add TTF example script.

This will need continued updates.  It's currently unstable.

Author: HexDecimal

examples/VeraMono.ttf

@@ -0,0 +1,82 @@
+#!/usr/bin/env python3
+"""A TrueType Font example using the FreeType library.
+
+You will need to get this external library from PyPI:
+
+    pip install freetype-py
+
+This script has known issues and may crash when the window is resized.
+"""
+from typing import Tuple
+
+import freetype  # type: ignore  # pip install freetype-py
+import numpy as np
+import tcod
+
+FONT = "VeraMono.ttf"
+
+
+def load_ttf(path: str, size: Tuple[int, int]) -> tcod.tileset.Tileset:
+    """Load a TTF file as a tcod tileset."""
+    ttf = freetype.Face(path)
+    ttf.set_pixel_sizes(*size)
+    half_advance = size[0] - (ttf.bbox.xMax - ttf.bbox.xMin) // 64
+
+    tileset = tcod.tileset.Tileset(*size)
+    for codepoint, glyph_index in ttf.get_chars():
+        ttf.load_glyph(glyph_index)
+        bitmap = ttf.glyph.bitmap
+        assert bitmap.pixel_mode == freetype.FT_PIXEL_MODE_GRAY
+        bitmap_array = np.asarray(bitmap.buffer).reshape(
+            (bitmap.width, bitmap.rows), order="F"
+        )
+        if bitmap_array.size == 0:
+            continue
+        output_image = np.zeros(size, dtype=np.uint8, order="F")
+        out_slice = output_image
+        left = ttf.glyph.bitmap_left + half_advance
+        top = size[1] - ttf.glyph.bitmap_top + ttf.bbox.yMin // 64
+        out_slice = out_slice[max(0, left) :, max(0, top) :]
+        out_slice[
+            : bitmap_array.shape[0], : bitmap_array.shape[1]
+        ] = bitmap_array[: out_slice.shape[0], : out_slice.shape[1]]
+        tileset.set_tile(codepoint, output_image.transpose())
+    return tileset
+
+
+def main() -> None:
+    console = tcod.Console(16, 12, order="F")
+    with tcod.context.new(
+        columns=console.width,
+        rows=console.height,
+        tileset=load_ttf(FONT, (24, 24)),
+    ) as context:
+        while True:
+            console.clear()
+            console.tiles_rgb["bg"][::2, ::2] = 0x20
+            console.tiles_rgb["bg"][1::2, 1::2] = 0x20
+            console.tiles_rgb["ch"][:16, :6] = np.arange(0x20, 0x80).reshape(
+                0x10, -1, order="F"
+            )
+            console.print(0, 7, "Example text.")
+            context.present(console, integer_scaling=True)
+            for event in tcod.event.wait():
+                if isinstance(event, tcod.event.Quit):
+                    raise SystemExit()
+                if (
+                    isinstance(event, tcod.event.WindowResized)
+                    and event.type == "WINDOWSIZECHANGED"
+                ):
+                    context.change_tileset(
+                        load_ttf(
+                            path=FONT,
+                            size=(
+                                event.width // console.width,
+                                event.height // console.height,
+                            ),
+                        )
+                    )
+
+
+if __name__ == "__main__":
+    main()