from __future__ import annotations
import math
import re
from typing import AnyStr, Generic, NamedTuple
from . import ImageFont
from ._typing import _Ink
Font = ImageFont.ImageFont | ImageFont.FreeTypeFont | ImageFont.TransposedFont
class _Line(NamedTuple):
x: float
y: float
anchor: str
text: str | bytes
class _Wrap(Generic[AnyStr]):
lines: list[AnyStr] = []
position = 0
offset = 0
def __init__(
self,
text: Text[AnyStr],
width: int,
height: int | None = None,
font: Font | None = None,
) -> None:
self.text: Text[AnyStr] = text
self.width = width
self.height = height
self.font = font
input_text = self.text.text
emptystring = "" if isinstance(input_text, str) else b""
line = emptystring
for word in re.findall(
r"\s*\S+" if isinstance(input_text, str) else rb"\s*\S+", input_text
):
newlines = re.findall(
r"[^\S\n]*\n" if isinstance(input_text, str) else rb"[^\S\n]*\n", word
)
if newlines:
if not self.add_line(line):
break
for i, line in enumerate(newlines):
if i != 0 and not self.add_line(emptystring):
break
self.position += len(line)
word = word[len(line) :]
line = emptystring
new_line = line + word
if self.text._get_bbox(new_line, self.font)[2] <= width:
# This word fits on the line
line = new_line
continue
# This word does not fit on the line
if line and not self.add_line(line):
break
original_length = len(word)
word = word.lstrip()
self.offset = original_length - len(word)
if self.text._get_bbox(word, self.font)[2] > width:
if font is None:
msg = "Word does not fit within line"
raise ValueError(msg)
break
line = word
else:
if line:
self.add_line(line)
self.remaining_text: AnyStr = input_text[self.position :]
def add_line(self, line: AnyStr) -> bool:
lines = self.lines + [line]
if self.height is not None:
last_line_y = self.text._split(lines=lines)[-1].y
last_line_height = self.text._get_bbox(line, self.font)[3]
if last_line_y + last_line_height > self.height:
return False
self.lines = lines
self.position += len(line) + self.offset
self.offset = 0
return True
[docs]
class Text(Generic[AnyStr]):
def __init__(
self,
text: AnyStr,
font: Font | None = None,
mode: str = "RGB",
spacing: float = 4,
direction: str | None = None,
features: list[str] | None = None,
language: str | None = None,
) -> None:
"""
:param text: String to be drawn.
:param font: Either an :py:class:`~PIL.ImageFont.ImageFont` instance,
:py:class:`~PIL.ImageFont.FreeTypeFont` instance,
:py:class:`~PIL.ImageFont.TransposedFont` instance or ``None``. If
``None``, the default font from :py:meth:`.ImageFont.load_default`
will be used.
:param mode: The image mode this will be used with.
:param spacing: The number of pixels between lines.
:param direction: Direction of the text. It can be ``"rtl"`` (right to left),
``"ltr"`` (left to right) or ``"ttb"`` (top to bottom).
Requires libraqm.
:param features: A list of OpenType font features to be used during text
layout. This is usually used to turn on optional font features
that are not enabled by default, for example ``"dlig"`` or
``"ss01"``, but can be also used to turn off default font
features, for example ``"-liga"`` to disable ligatures or
``"-kern"`` to disable kerning. To get all supported
features, see `OpenType docs`_.
Requires libraqm.
:param language: Language of the text. Different languages may use
different glyph shapes or ligatures. This parameter tells
the font which language the text is in, and to apply the
correct substitutions as appropriate, if available.
It should be a `BCP 47 language code`_.
Requires libraqm.
"""
self.text: AnyStr = text
self.font = font or ImageFont.load_default()
self.mode = mode
self.spacing = spacing
self.direction = direction
self.features = features
self.language = language
self.embedded_color = False
self.stroke_width: float = 0
self.stroke_fill: _Ink | None = None
[docs]
def embed_color(self) -> None:
"""
Use embedded color glyphs (COLR, CBDT, SBIX).
"""
if self.mode not in ("RGB", "RGBA"):
msg = "Embedded color supported only in RGB and RGBA modes"
raise ValueError(msg)
self.embedded_color = True
[docs]
def stroke(self, width: float = 0, fill: _Ink | None = None) -> None:
"""
:param width: The width of the text stroke.
:param fill: Color to use for the text stroke when drawing. If not given, will
default to the ``fill`` parameter from
:py:meth:`.ImageDraw.ImageDraw.text`.
"""
self.stroke_width = width
self.stroke_fill = fill
def _get_fontmode(self) -> str:
if self.mode in ("1", "P", "I", "F"):
return "1"
elif self.embedded_color:
return "RGBA"
else:
return "L"
[docs]
def wrap(
self,
width: int,
height: int | None = None,
scaling: str | tuple[str, int] | None = None,
) -> Text[AnyStr] | None:
"""
Wrap text to fit within a given width.
:param width: The width to fit within.
:param height: An optional height limit. Any text that does not fit within this
will be returned as a new :py:class:`.Text` object.
:param scaling: An optional directive to scale the text, either "grow" as much
as possible within the given dimensions, or "shrink" until it
fits. It can also be a tuple of (direction, limit), with an
integer limit to stop scaling at.
:returns: An :py:class:`.Text` object, or None.
"""
if isinstance(self.font, ImageFont.TransposedFont):
msg = "TransposedFont not supported"
raise ValueError(msg)
if self.direction not in (None, "ltr"):
msg = "Only ltr direction supported"
raise ValueError(msg)
if scaling is None:
wrap = _Wrap(self, width, height)
else:
if not isinstance(self.font, ImageFont.FreeTypeFont):
msg = "'scaling' only supports FreeTypeFont"
raise ValueError(msg)
if height is None:
msg = "'scaling' requires 'height'"
raise ValueError(msg)
if isinstance(scaling, str):
limit = 1
else:
scaling, limit = scaling
font = self.font
wrap = _Wrap(self, width, height, font)
if scaling == "shrink":
if not wrap.remaining_text:
return None
size = math.ceil(font.size)
while wrap.remaining_text:
if size == max(limit, 1):
msg = "Text could not be scaled"
raise ValueError(msg)
size -= 1
font = self.font.font_variant(size=size)
wrap = _Wrap(self, width, height, font)
self.font = font
else:
if wrap.remaining_text:
msg = "Text could not be scaled"
raise ValueError(msg)
size = math.floor(font.size)
while not wrap.remaining_text:
if size == limit:
msg = "Text could not be scaled"
raise ValueError(msg)
size += 1
font = self.font.font_variant(size=size)
last_wrap = wrap
wrap = _Wrap(self, width, height, font)
size -= 1
if size != self.font.size:
self.font = self.font.font_variant(size=size)
wrap = last_wrap
if wrap.remaining_text:
text = Text(
text=wrap.remaining_text,
font=self.font,
mode=self.mode,
spacing=self.spacing,
direction=self.direction,
features=self.features,
language=self.language,
)
text.embedded_color = self.embedded_color
text.stroke_width = self.stroke_width
text.stroke_fill = self.stroke_fill
else:
text = None
newline = "\n" if isinstance(self.text, str) else b"\n"
self.text = newline.join(wrap.lines)
return text
[docs]
def get_length(self) -> float:
"""
Returns length (in pixels with 1/64 precision) of text.
This is the amount by which following text should be offset.
Text bounding box may extend past the length in some fonts,
e.g. when using italics or accents.
The result is returned as a float; it is a whole number if using basic layout.
Note that the sum of two lengths may not equal the length of a concatenated
string due to kerning. If you need to adjust for kerning, include the following
character and subtract its length.
For example, instead of::
hello = ImageText.Text("Hello", font).get_length()
world = ImageText.Text("World", font).get_length()
helloworld = ImageText.Text("HelloWorld", font).get_length()
assert hello + world == helloworld
use::
hello = (
ImageText.Text("HelloW", font).get_length() -
ImageText.Text("W", font).get_length()
) # adjusted for kerning
world = ImageText.Text("World", font).get_length()
helloworld = ImageText.Text("HelloWorld", font).get_length()
assert hello + world == helloworld
or disable kerning with (requires libraqm)::
hello = ImageText.Text("Hello", font, features=["-kern"]).get_length()
world = ImageText.Text("World", font, features=["-kern"]).get_length()
helloworld = ImageText.Text(
"HelloWorld", font, features=["-kern"]
).get_length()
assert hello + world == helloworld
:return: Either width for horizontal text, or height for vertical text.
"""
if isinstance(self.text, str):
multiline = "\n" in self.text
else:
multiline = b"\n" in self.text
if multiline:
msg = "can't measure length of multiline text"
raise ValueError(msg)
return self.font.getlength(
self.text,
self._get_fontmode(),
self.direction,
self.features,
self.language,
)
def _split(
self,
xy: tuple[float, float] = (0, 0),
anchor: str | None = None,
align: str = "left",
lines: list[str] | list[bytes] | None = None,
) -> list[_Line]:
if anchor is None:
anchor = "lt" if self.direction == "ttb" else "la"
elif len(anchor) != 2:
msg = "anchor must be a 2 character string"
raise ValueError(msg)
if lines is None:
lines = (
self.text.split("\n")
if isinstance(self.text, str)
else self.text.split(b"\n")
)
if len(lines) == 1:
return [_Line(xy[0], xy[1], anchor, lines[0])]
if anchor[1] in "tb" and self.direction != "ttb":
msg = "anchor not supported for multiline text"
raise ValueError(msg)
fontmode = self._get_fontmode()
line_spacing = (
self.font.getbbox(
"A",
fontmode,
None,
self.features,
self.language,
self.stroke_width,
)[3]
+ self.stroke_width
+ self.spacing
)
top = xy[1]
parts = []
if self.direction == "ttb":
left = xy[0]
for line in lines:
parts.append(_Line(left, top, anchor, line))
left += line_spacing
else:
widths = []
max_width: float = 0
for line in lines:
line_width = self.font.getlength(
line, fontmode, self.direction, self.features, self.language
)
widths.append(line_width)
max_width = max(max_width, line_width)
if anchor[1] == "m":
top -= (len(lines) - 1) * line_spacing / 2.0
elif anchor[1] == "d":
top -= (len(lines) - 1) * line_spacing
idx = -1
for line in lines:
left = xy[0]
idx += 1
width_difference = max_width - widths[idx]
# align by align parameter
if align in ("left", "justify"):
pass
elif align == "center":
left += width_difference / 2.0
elif align == "right":
left += width_difference
else:
msg = 'align must be "left", "center", "right" or "justify"'
raise ValueError(msg)
if (
align == "justify"
and width_difference != 0
and idx != len(lines) - 1
):
words = (
line.split(" ") if isinstance(line, str) else line.split(b" ")
)
if len(words) > 1:
# align left by anchor
if anchor[0] == "m":
left -= max_width / 2.0
elif anchor[0] == "r":
left -= max_width
word_widths = [
self.font.getlength(
word,
fontmode,
self.direction,
self.features,
self.language,
)
for word in words
]
word_anchor = "l" + anchor[1]
width_difference = max_width - sum(word_widths)
i = 0
for word in words:
parts.append(_Line(left, top, word_anchor, word))
left += word_widths[i] + width_difference / (len(words) - 1)
i += 1
top += line_spacing
continue
# align left by anchor
if anchor[0] == "m":
left -= width_difference / 2.0
elif anchor[0] == "r":
left -= width_difference
parts.append(_Line(left, top, anchor, line))
top += line_spacing
return parts
def _get_bbox(
self, text: str | bytes, font: Font | None = None, anchor: str | None = None
) -> tuple[float, float, float, float]:
return (font or self.font).getbbox(
text,
self._get_fontmode(),
self.direction,
self.features,
self.language,
self.stroke_width,
anchor,
)
[docs]
def get_bbox(
self,
xy: tuple[float, float] = (0, 0),
anchor: str | None = None,
align: str = "left",
) -> tuple[float, float, float, float]:
"""
Returns bounding box (in pixels) of text.
Use :py:meth:`get_length` to get the offset of following text with 1/64 pixel
precision. The bounding box includes extra margins for some fonts, e.g. italics
or accents.
:param xy: The anchor coordinates of the text.
:param anchor: The text anchor alignment. Determines the relative location of
the anchor to the text. The default alignment is top left,
specifically ``la`` for horizontal text and ``lt`` for
vertical text. See :ref:`text-anchors` for details.
:param align: For multiline text, ``"left"``, ``"center"``, ``"right"`` or
``"justify"`` determines the relative alignment of lines. Use the
``anchor`` parameter to specify the alignment to ``xy``.
:return: ``(left, top, right, bottom)`` bounding box
"""
bbox: tuple[float, float, float, float] | None = None
for x, y, anchor, text in self._split(xy, anchor, align):
bbox_line = self._get_bbox(text, anchor=anchor)
bbox_line = (
bbox_line[0] + x,
bbox_line[1] + y,
bbox_line[2] + x,
bbox_line[3] + y,
)
if bbox is None:
bbox = bbox_line
else:
bbox = (
min(bbox[0], bbox_line[0]),
min(bbox[1], bbox_line[1]),
max(bbox[2], bbox_line[2]),
max(bbox[3], bbox_line[3]),
)
assert bbox is not None
return bbox