"""
Drawing text with pyglet label
"""
from ctypes import c_int, c_ubyte
from pathlib import Path
from typing import Any
import pyglet
import arcade
from arcade.exceptions import PerformanceWarning, warning
from arcade.resources import resolve
from arcade.texture_atlas import TextureAtlasBase
from arcade.types import Color, Point, RGBOrA255
__all__ = ["load_font", "Text", "create_text_sprite", "draw_text"]
class _ArcadeTextLayoutGroup(pyglet.text.layout.TextLayoutGroup):
"""Create a text layout rendering group.
Overrides pyglet blending handling to allow for additive blending.
Furthermore, it resets the blend function to the previous state.
"""
_prev_blend: bool
_prev_blend_func: tuple[int, int, int, int]
def set_state(self) -> None:
self.program.use()
self.program["scissor"] = False
pyglet.gl.glActiveTexture(pyglet.gl.GL_TEXTURE0)
pyglet.gl.glBindTexture(self.texture.target, self.texture.id)
blend = c_ubyte()
pyglet.gl.glGetBooleanv(pyglet.gl.GL_BLEND, blend)
self._prev_blend = bool(blend.value)
src_rgb = c_int()
dst_rgb = c_int()
src_alpha = c_int()
dst_alpha = c_int()
pyglet.gl.glGetIntegerv(pyglet.gl.GL_BLEND_SRC_RGB, src_rgb)
pyglet.gl.glGetIntegerv(pyglet.gl.GL_BLEND_DST_RGB, dst_rgb)
pyglet.gl.glGetIntegerv(pyglet.gl.GL_BLEND_SRC_ALPHA, src_alpha)
pyglet.gl.glGetIntegerv(pyglet.gl.GL_BLEND_DST_ALPHA, dst_alpha)
self._prev_blend_func = (src_rgb.value, dst_rgb.value, src_alpha.value, dst_alpha.value)
pyglet.gl.glEnable(pyglet.gl.GL_BLEND)
pyglet.gl.glBlendFuncSeparate(
pyglet.gl.GL_SRC_ALPHA,
pyglet.gl.GL_ONE_MINUS_SRC_ALPHA,
pyglet.gl.GL_ONE,
pyglet.gl.GL_ONE,
)
def unset_state(self) -> None:
if not self._prev_blend:
pyglet.gl.glDisable(pyglet.gl.GL_BLEND)
pyglet.gl.glBlendFuncSeparate(
self._prev_blend_func[0],
self._prev_blend_func[1],
self._prev_blend_func[2],
self._prev_blend_func[3],
)
self.program.stop()
pyglet.text.layout.TextLayout.group_class = _ArcadeTextLayoutGroup
[docs]
def load_font(path: str | Path) -> None:
"""
Load fonts in a file (usually .ttf) adding them to a global font registry.
A file can contain one or multiple fonts. Each font has a name.
Open the font file to find the actual name(s). These names
are used to select font when drawing text.
Examples::
# Load a font in the current working directory
# (absolute path is often better)
arcade.load_font("Custom.ttf")
# Load a font using a custom resource handle
arcade.load_font(":font:Custom.ttf")
Args:
path: Path to the font file
Raises:
FileNotFoundError: if the font specified wasn't found
"""
file_path = resolve(path)
pyglet.font.add_file(str(file_path))
FontNameOrNames = str | tuple[str, ...]
def _attempt_font_name_resolution(font_name: FontNameOrNames) -> str:
"""Attempt to resolve a font name.
Preserves the original logic of this section, even though it
doesn't seem to make sense entirely. Comments are an attempt
to make sense of the original code.
If it can't resolve a definite path, it will return the original
argument for pyglet to attempt to resolve. This is consistent with
the original behavior of this code before it was encapsulated.
Args:
font_name: A font name, path to a font file, or list of names
"""
if font_name:
# ensure
if isinstance(font_name, str):
font_list: tuple[str, ...] = (font_name,)
elif isinstance(font_name, tuple):
font_list = font_name
else:
raise TypeError(
"font_name parameter must be a string, "
"or a tuple of strings that specify a font name."
)
for font in font_list:
try:
path = resolve(font)
# print(f"Font path: {path=}")
# found a font successfully!
return path.name
except FileNotFoundError:
pass
# failed to find it ourselves, hope pyglet can make sense of it
# Note this is the best approximation of what I understand the old
# behavior to have been.
return pyglet.font.load(font_list).name
raise ValueError(f"Couldn't find a font for {font_name!r}")
def _draw_pyglet_label(label: pyglet.text.Label) -> None:
"""
Helper for drawing pyglet labels with rotation within arcade.
Args:
label: The pyglet label to draw
"""
assert isinstance(label, pyglet.text.Label)
label.draw()
[docs]
class Text:
"""
An object-oriented way to draw text to the screen.
.. tip:: Use this class when performance matters!
Unlike :py:func:`~arcade.draw_text`, this class does not risk
wasting time recalculating and re-setting any text each time
:py:meth:`~arcade.Text.draw` is called. This makes it faster
while:
- requiring you to manage instances and drawing yourself
- using negligible extra RAM
The speed advantage scales as more text needs to be drawn
to the screen.
.. tip:: Batch drawing larger amounts of text
Text objects can also be assigned a pyglet batch for batch
rendering small or large amounts of text instances. This
is by far the most efficient way to draw text::
from pyglet.graphics import Batch
batch = Batch()
text_1 = Text("Hello, World 1", 0, 50, batch=batch)
text_2 = Text("Hello, World 2", 0, 100, batch=batch)
text_3 = Text("Hello, World 2", 0, 150, batch=batch)
# Draw the batch
batch.draw()
# Remove a text instance from the batch
text_2.batch = None
The text instances an also be modified while in the batch
such as changing the text value, position, or color.
The constructor arguments work identically to those of
:py:func:`~arcade.draw_text`. See its documentation for in-depth
explanation for how to use each of them. For example code, see :ref:`drawing_text_objects`.
Args:
text: Initial text to display. Can be an empty string
x: x position to align the text's anchor point with
y: y position to align the text's anchor point with
z: z position to align the text's anchor point with
color: Color of the text as an RGBA tuple or a
:py:class:`~arcade.types.Color` instance.
font_size: Size of the text in points
width: A width limit in pixels
align: Horizontal alignment; values other than "left" require width to be set.
Valid options: ``"left"``, ``"center"``, ``"right"``.
font_name: A font name, path to a font file, or list of names
bold: Whether to draw the text as bold, and if a string,
how bold. See :py:attr:`.bold` to learn more.
italic: Whether to draw the text as italic
anchor_x: How to calculate the anchor point's x coordinate.
Options: "left", "center", or "right"
anchor_y: How to calculate the anchor point's y coordinate.
Options: "top", "bottom", "center", or "baseline".
multiline: Requires width to be set; enables word wrap rather than clipping
rotation: rotation in degrees, clockwise from horizontal
batch: The batch to add the text to (for batch rendering text)
group: The specific group in a a batch to add the text to
(for batch rendering text)
All constructor arguments other than ``text`` have a corresponding
property. To access the current text, use the ``value`` property
instead.
By default, the text is placed so that:
- the left edge of its bounding box is at ``x``
- its baseline is at ``y``
The baseline is located along the line the bottom of the text would
be written on, excluding letters with tails such as y:
.. figure:: ../images/text_anchor_y.png
:width: 40%
The blue line is the baseline for the string ``"Python"``
``rotation`` allows for the text to be rotated around the anchor
point by the passed number of degrees. Positive values rotate
clockwise from horizontal, while negative values rotate
counter-clockwise:
.. figure:: ../images/text_rotation_degrees.png
:width: 55%
Rotation around the default anchor (
``anchor_y="baseline"`` and ``anchor_x="left"``)
This class is a wrapper around pyglet's :py:class:`pyglet.text.Label`.
More advanced users can use pyglet's label directly if preferred.
"""
def __init__(
self,
text: str,
x: float,
y: float,
color: RGBOrA255 = arcade.color.WHITE,
font_size: float = 12,
width: int | None = None,
align: str = "left",
font_name: FontNameOrNames = ("calibri", "arial"),
bold: bool | str = False,
italic: bool = False,
anchor_x: str = "left",
anchor_y: str = "baseline",
multiline: bool = False,
rotation: float = 0,
batch: pyglet.graphics.Batch | None = None,
group: pyglet.graphics.Group | None = None,
z: float = 0,
**kwargs,
):
self._arguments = dict(
text=text,
x=x,
y=y,
color=Color.from_iterable(color),
font_size=font_size,
width=width,
align=align,
font_name=font_name,
weight=pyglet.text.Weight.BOLD if bold else pyglet.text.Weight.NORMAL,
italic=italic,
anchor_x=anchor_x,
anchor_y=anchor_y,
multiline=multiline,
rotation=rotation,
batch=batch,
group=group,
z=z,
**kwargs,
)
if align not in ("left", "center", "right"):
raise ValueError("The 'align' parameter must be equal to 'left', 'right', or 'center'.")
if multiline and not width:
raise ValueError(
f"The 'width' parameter must be set to a non-zero value when 'multiline' is True, "
f"but got {width!r}."
)
self._initialized = False
try:
self._init_deferred()
except Exception:
pass
@property
def label(self) -> pyglet.text.Label:
"""
The underlying pyglet.Label instance.
"""
if not self._initialized:
self._init_deferred()
return self._label
[docs]
def initialize(self) -> None:
"""
Manually initialize the Text if it was lazy loaded.
This has no effect if the Text was already initialized.
"""
if self._initialized:
return
self._init_deferred()
def _init_deferred(self):
"""
Deferred initialization when lazy loaded
"""
# NOTE: Give the user a clear error message stating that the window is not created yet
arcade.get_window()
self._arguments["font_name"] = _attempt_font_name_resolution(self._arguments["font_name"]) # type: ignore
self._label = pyglet.text.Label(**self._arguments) # type: ignore
self._initialized = True
[docs]
def __enter__(self):
"""
Update multiple attributes of this text,
using efficient update mechanism of the underlying ``pyglet.Label``
"""
self.label.begin_update()
def __exit__(self, exc_type, exc_val, exc_tb):
self.label.end_update()
@property
def batch(self) -> pyglet.graphics.Batch | None:
"""The batch this text is in, if any.
Can be unset by setting to ``None``.
"""
return self.label.batch
@batch.setter
def batch(self, batch: pyglet.graphics.Batch):
self.label.batch = batch
@property
def group(self) -> pyglet.graphics.Group | None:
"""
The specific group in a batch the text should belong to.
This is normally not necessary to specify unless you are
batching very large sets of text needing to separate into
groups or even mix with other pyglet batch content.
"""
return self.label.group
@group.setter
def group(self, group: pyglet.graphics.Group):
self.label.group = group
@property
def value(self) -> str:
"""
Get or set the current text string to display.
The value assigned will be converted to a string.
"""
return self.label.text
@value.setter
def value(self, value: Any):
value = str(value)
if self.label.text == value:
return
self.label.text = value
@property
def text(self) -> str:
"""
Get or set the current text string to display.
The value assigned will be converted to a string.
This is an alias for :py:attr:`~arcade.Text.value`
"""
return self.label.text
@text.setter
def text(self, value: Any):
value = str(value)
if self.label.text == value:
return
self.label.text = value
@property
def x(self) -> float:
"""Get or set the x position of the label."""
return self.label.x
@x.setter
def x(self, x: float) -> None:
if self.label.x == x:
return
self.label.x = x
@property
def y(self) -> float:
"""Get or set the y position of the label."""
return self.label.y
@y.setter
def y(self, y: float):
if self.label.y == y:
return
self.label.y = y
@property
def z(self) -> float:
"""Get or set the z position of the label."""
return self.label.z
@z.setter
def z(self, z: float):
if self.label.z == z:
return
self.label.z = z
@property
def font_name(self) -> FontNameOrNames:
"""Get or set the font name(s) for the label."""
if not isinstance(self.label.font_name, str):
return tuple(self.label.font_name)
else:
return self.label.font_name
@font_name.setter
def font_name(self, font_name: FontNameOrNames) -> None:
if isinstance(font_name, str):
self.label.font_name = font_name
else:
self.label.font_name = list(font_name)
@property
def font_size(self) -> float:
"""Get or set the font size of the label."""
return self.label.font_size
@font_size.setter
def font_size(self, font_size: float):
self.label.font_size = font_size
@property
def anchor_x(self) -> str:
"""
Get or set the horizontal anchor.
Options: ``"left"``, ``"center"``, or ``"right"``
"""
return self.label.anchor_x
@anchor_x.setter
def anchor_x(self, anchor_x: str):
self.label.anchor_x = anchor_x # type: ignore
@property
def anchor_y(self) -> str:
"""
Get or set the vertical anchor.
Options : ``"top"``, ``"bottom"``, ``"center"``, or ``"baseline"``
"""
return self.label.anchor_y
@anchor_y.setter
def anchor_y(self, anchor_y: str):
self.label.anchor_y = anchor_y # type: ignore
@property
def rotation(self) -> float:
"""Get or set the clockwise rotation"""
return self.label.rotation
@rotation.setter
def rotation(self, rotation: float):
self.label.rotation = rotation
@property
def color(self) -> Color:
"""Get or set the text color for the label."""
return Color.from_iterable(self.label.color)
@color.setter
def color(self, color: RGBOrA255):
self.label.color = Color.from_iterable(color)
@property
def width(self) -> int | None:
"""
Get or set the width of the label in pixels.
This value affects text flow when multiline text is used.
If you are looking for the physical size if the text, see
:py:attr:`~arcade.Text.content_width`
"""
return self.label.width
@width.setter
def width(self, width: int):
self.label.width = width
@property
def height(self) -> int | None:
"""
Get or set the height of the label in pixels.
This value affects text flow when multiline text is used.
If you are looking for the physical size if the text, see
:py:attr:`~arcade.Text.content_height`
"""
return self.label.height
@height.setter
def height(self, value: int):
self.label.height = value
@property
def size(self):
"""Get the size of the label."""
return self.label.width, self.label.height
@property
def content_width(self) -> int:
"""Get the pixel width of the text contents."""
return self.label.content_width
@property
def content_height(self) -> int:
"""Get the pixel height of the text content."""
return self.label.content_height
@property
def left(self) -> float:
"""Pixel location of the left content border."""
return self.label.left
@property
def right(self) -> float:
"""Pixel location of the right content border."""
return self.label.right
@property
def top(self) -> float:
"""Pixel location of the top content border."""
return self.label.top
@property
def bottom(self) -> float:
"""Pixel location of the bottom content border."""
return self.label.bottom
@property
def content_size(self) -> tuple[int, int]:
"""Get the pixel width and height of the text contents."""
return self.label.content_width, self.label.content_height
@property
def align(self) -> str:
"""Horizontal alignment; values other than ``"left"`` require width to be set.
Valid options: ``"left"``, ``"center"``, ``"right"``.
"""
return self.label.get_style("align") # type: ignore
@align.setter
def align(self, align: str):
self.label.set_style("align", align)
@property
def bold(self) -> bool | str:
"""
Get or set bold state of the label.
The supported values include:
* ``"black"``
* ``"bold" (same as ``True``)
* ``"semibold"``
* ``"semilight"``
* ``"light"``
"""
return self.label.weight == pyglet.text.Weight.BOLD
@bold.setter
def bold(self, bold: bool | str):
self.label.weight = pyglet.text.Weight.BOLD if bold else pyglet.text.Weight.NORMAL
@property
def italic(self) -> bool | str:
"""Get or set the italic state of the label."""
return self.label.italic
@italic.setter
def italic(self, italic: bool | str):
self.label.italic = italic
@property
def multiline(self) -> bool:
"""Get or set the multiline flag of the label."""
return self.label.multiline
@multiline.setter
def multiline(self, multiline: bool):
self.label.multiline = multiline
@property
def visible(self) -> bool:
"""
Whether the text is visible or not.
This is a property of the underlying pyglet.Label.
"""
return self.label.visible
@visible.setter
def visible(self, visible: bool):
"""
Set the visibility of the text.
This is a property of the underlying pyglet.Label.
"""
self.label.visible = visible
[docs]
def draw(self) -> None:
"""
Draw the label to the screen at its current ``x`` and ``y`` position.
.. warning:: Cameras affect text drawing!
If you want to draw a custom GUI that doesn't move with the
game world, you will need a second :py:class:`~arcade.Camera`
instance. For information on how to do this, see
:ref:`sprite_move_scrolling`.
"""
_draw_pyglet_label(self.label)
[docs]
def draw_debug(
self,
anchor_color: RGBOrA255 = arcade.color.RED,
background_color: RGBOrA255 = arcade.color.DARK_BLUE,
outline_color: RGBOrA255 = arcade.color.WHITE,
) -> None:
"""
Draw test with debug geometry showing the content
area, outline and the anchor point.
Args:
anchor_color: Color of the anchor point
background_color: Color the content background
outline_color: Color of the content outline
"""
left = self.left
right = self.right
top = self.top
bottom = self.bottom
# Draw background
arcade.draw_lrbt_rectangle_filled(left, right, bottom, top, color=background_color)
# Draw outline
arcade.draw_lrbt_rectangle_outline(left, right, bottom, top, color=outline_color)
# Draw anchor
arcade.draw_point(self.x, self.y, color=anchor_color, size=6)
_draw_pyglet_label(self.label)
@property
def position(self) -> Point:
"""
The current x, y position as a tuple.
This is faster than setting x and y position separately
because the underlying geometry only needs to change position once.
"""
return self.label.x, self.label.y
@position.setter
def position(self, point: Point):
# Starting with Pyglet 2.0b2 label positions take a z parameter.
x, y, *z = point
if z:
self.label.position = x, y, z[0]
else:
self.label.position = x, y, self.label.z
@property
def tracking(self) -> float | None:
"""
Get/set the tracking amount for this text object, or rather,
the added space between each character.
The value is an amount in pixels and can be negative.
To convert from the em unit, use Text.em_to_px().
Returns:
a pixel amount, or None if the tracking is inconsistent.
"""
kerning = self.label.get_style("kerning")
return kerning if kerning != pyglet.text.document.STYLE_INDETERMINATE else None
@tracking.setter
def tracking(self, value: float):
self.label.set_style("kerning", value)
[docs]
def em_to_px(self, em: float) -> float:
"""Convert from an em value to a pixel amount.
1em is defined as ``font_size`` pt.
"""
return (em * self.font_size) * (4 / 3)
[docs]
def px_to_em(self, px: float) -> float:
"""Convert from a pixel amount to a value in ems.
1em is defined as ``font_size`` pt.
"""
return px / (4 / 3) / self.font_size
[docs]
def create_text_sprite(
text: str,
color: RGBOrA255 = arcade.color.WHITE,
font_size: float = 12.0,
width: int | None = None,
align: str = "left",
font_name: FontNameOrNames = ("calibri", "arial"),
bold: bool | str = False,
italic: bool = False,
anchor_x: str = "left",
multiline: bool = False,
texture_atlas: TextureAtlasBase | None = None,
background_color: RGBOrA255 | None = None,
) -> arcade.Sprite:
"""
Creates a sprite containing text based off of :py:class:`~arcade.Text`.
Internally this creates a Text object and an empty texture. It then uses either the
provided texture atlas, or gets the default one, and draws the Text object into the
texture atlas.
It then creates a sprite referencing the newly created texture, and positions it
accordingly, and that is final result that is returned from the function.
If you are providing a custom texture atlas, something important to keep in mind is
that the resulting Sprite can only be added to SpriteLists which use that atlas. If
it is added to a SpriteList which uses a different atlas, you will likely just see
a black box drawn in its place.
Args:
text: Initial text to display. Can be an empty string
color: Color of the text as an RGBA tuple or a
:py:class:`~arcade.types.Color` instance.
font_size: Size of the text in points
width: A width limit in pixels
align: Horizontal alignment; values other than "left" require width to be set.
Valid options: ``"left"``, ``"center"``, ``"right"``.
font_name: A font name, path to a font file, or list of names
bold: Whether to draw the text as bold, and if a string,
how bold. See :py:attr:`arcade.gui.widgets.text.bold` to learn more.
italic: Whether to draw the text as italic
anchor_x: How to calculate the anchor point's x coordinate.
Options: "left", "center", or "right"
multiline: Requires width to be set; enables word wrap rather than clipping
background_color: The background color of the text. If None, the background
will be transparent.
texture_atlas: The texture atlas to use for the
newly created texture. The default global atlas will be used if this is None.
"""
text_object = Text(
text,
x=0,
y=0,
color=color,
font_size=font_size,
width=width,
align=align,
font_name=font_name,
bold=bold,
italic=italic,
anchor_x=anchor_x,
anchor_y="baseline",
multiline=multiline,
)
size = (
int(text_object.right - text_object.left),
int(text_object.top - text_object.bottom),
)
text_object.y = -text_object.bottom
texture = arcade.Texture.create_empty(text, size)
if not texture_atlas:
texture_atlas = arcade.get_window().ctx.default_atlas
texture_atlas.add(texture)
with texture_atlas.render_into(texture) as fbo:
fbo.clear(color=background_color or arcade.color.TRANSPARENT_BLACK)
text_object.draw()
return arcade.Sprite(
texture,
center_x=text_object.right - (size[0] / 2),
center_y=text_object.top,
)
[docs]
@warning(
message=(
"draw_text is an extremely slow function for displaying text. "
"Consider using Text objects instead."
),
warning_type=PerformanceWarning,
)
def draw_text(
text: Any,
x: float,
y: float,
color: RGBOrA255 = arcade.color.WHITE,
font_size: float = 12.0,
width: int | None = None,
align: str = "left",
font_name: FontNameOrNames = ("calibri", "arial"),
bold: bool | str = False,
italic: bool = False,
anchor_x: str = "left",
anchor_y: str = "baseline",
multiline: bool = False,
rotation: float = 0,
z: float = 0,
):
"""
A simple way for beginners to draw text.
.. warning:: Use :py:class:`arcade.Text` objects instead.
This method of drawing text is very slow
and might be removed in the near future.
Text objects can be 10-100 times faster
depending on the use case.
.. warning:: Cameras affect text drawing!
If you want to draw a custom GUI that doesn't move with the
game world, you will need a second camera. For information on
how to do this, see :ref:`sprite_move_scrolling`.
This function lets you start draw text easily with better
performance than the old pillow-based text. If you need even higher
performance, consider using :py:class:`~arcade.Text`.
Example code can be found at :ref:`drawing_text`.
Args:
text: Initial text to display. Can be an empty string
x: x position to align the text's anchor point with
y: y position to align the text's anchor point with
z: z position to align the text's anchor point with
color: Color of the text as an RGBA tuple or a
:py:class:`~arcade.types.Color` instance.
font_size: Size of the text in points
width: A width limit in pixels
align: Horizontal alignment; values other than "left" require width to be set.
Valid options: ``"left"``, ``"center"``, ``"right"``.
font_name: A font name, path to a font file, or list of names
bold: Whether to draw the text as bold, and if a string,
how bold. See :py:attr:`arcade.gui.widgets.text.bold` to learn more.
italic: Whether to draw the text as italic
anchor_x: How to calculate the anchor point's x coordinate.
Options: "left", "center", or "right"
anchor_y: How to calculate the anchor point's y coordinate.
Options: "top", "bottom", "center", or "baseline".
multiline: Requires width to be set; enables word wrap rather than clipping
rotation: rotation in degrees, clockwise from horizontal
By default, the text is placed so that:
- the left edge of its bounding box is at ``x``
- its baseline is at ``y``
The baseline of text is the line it would be written on:
.. figure:: ../images/text_anchor_y.png
:width: 40%
The blue line is the baseline for the string ``"Python"``
``font_name`` can be any of the following:
- a built-in font in the :ref:`Resources`
- the name of a system font
- a path to a font on the system
- a `tuple` containing any mix of the previous three
Each entry provided will be tried in order until one is found. If
none of the fonts are found, a default font will be chosen (usually
Arial).
``anchor_x`` and ``anchor_y`` specify how to calculate the anchor point,
which affects how the text is:
- Placed relative to ``x`` and ``y``
- Rotated
By default, the text is drawn so that ``x`` is at the left of
the text's bounding box and ``y`` is at the baseline.
You can set a custom anchor point by passing combinations of the
following values for ``anchor_x`` and ``anchor_y``:
.. list-table:: Values allowed by ``anchor_x``
:widths: 20 40 40
:header-rows: 1
* - String value
- Practical Effect
- Anchor Position
* - ``"left"`` `(default)`
- Text drawn with its left side at ``x``
- Anchor point on the left side of the text's bounding box
* - ``"center"``
- Text drawn horizontally centered on ``x``
- Anchor point at horizontal center of text's bounding box
* - ``"right"``
- Text drawn with its right side at ``x``
- Anchor placed on the right side of the text's bounding box
.. list-table:: Values allowed by ``anchor_y``
:widths: 20 40 40
:header-rows: 1
* - String value
- Practical Effect
- Anchor Position
* - ``"baseline"`` `(default)`
- Text drawn with baseline on ``y``.
- Anchor placed at the text rendering baseline
* - ``"top"``
- Text drawn with its top aligned with ``y``
- Anchor point placed at the top of the text
* - ``"bottom"``
- Text drawn with its absolute bottom aligned with ``y``,
including the space for tails on letters such as y and g
- Anchor point placed at the bottom of the text after the
space allotted for letters such as y and g
* - ``"center"``
- Text drawn with its vertical center on ``y``
- Anchor placed at the vertical center of the text
``rotation`` allows for the text to be rotated around the anchor
point by the passed number of degrees. Positive values rotate
clockwise from horizontal, while negative values rotate
counter-clockwise:
.. figure:: ../images/text_rotation_degrees.png
:width: 55%
Rotation around the default anchor point (
``anchor_y="baseline"`` and ``anchor_x="left"``)
It can be helpful to think of this function working as follows:
1. Text layout and alignment are calculated:
1. The text's characters are laid out within a bounding box
according to the current styling options
2. The anchor point on the text is calculated based on
the text value, styling, as well as values for ``anchor_x``
and ``anchor_y``
2. The text is placed so its anchor point is at ``(x,
y))``
3. The text is rotated around its anchor point before finally
being drawn
This function is less efficient than using :py:class:`~arcade.Text`
because some steps above can be repeated each time a call is
made rather than fully cached as with the class.
"""
# See : https://github.com/pyglet/pyglet/blob/ff30eadc2942553c9de96d6ce564ad1bc3128fb4/pyglet/text/__init__.py#L401
color = Color.from_iterable(color)
# Cache the states that are expensive to change
key = f"{font_size}{font_name}{bold}{italic}{anchor_x}{anchor_y}{align}{width}{rotation}"
ctx = arcade.get_window().ctx
label = ctx.label_cache.get(key)
if align not in ("left", "center", "right"):
raise ValueError("The 'align' parameter must be equal to 'left', 'right', or 'center'.")
if multiline and not width:
raise ValueError(
f"The 'width' parameter must be set to a non-zero value when 'multiline' is True, "
f"but got {width!r}."
)
if not label:
adjusted_font = _attempt_font_name_resolution(font_name)
label = arcade.Text(
text=str(text),
x=x,
y=y,
z=z,
font_name=adjusted_font,
font_size=font_size,
anchor_x=anchor_x,
anchor_y=anchor_y,
color=color,
width=width,
align=align,
bold=bold,
italic=italic,
multiline=multiline,
rotation=rotation,
)
ctx.label_cache[key] = label
# These updates are quite expensive
if label.text != text:
label.text = str(text)
if label.x != x or label.y != y or label.z != z:
label.position = x, y, z # type: ignore
if label.color != color:
label.color = color
if label.rotation != rotation:
label.rotation = rotation
label.draw()
# This is absolutely necessary to prevent the vertex buffers
# to be altered while another one is drawing. If the same cached
# label is used multiple times in a single frame it's a disaster.
ctx.flush()