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Add support for font features and variants #121

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137 changes: 132 additions & 5 deletions manimpango/cmanimpango.pyx
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Original file line number Diff line number Diff line change
Expand Up @@ -19,6 +19,8 @@ class TextSetting:
weight: str,
line_num = -1,
color: str = None,
font_features: str = None,
font_variant: str = None,
):
self.start = start
self.end = end
Expand All @@ -27,6 +29,8 @@ class TextSetting:
self.weight = weight
self.line_num = line_num
self.color = color
self.font_features = font_features
self.font_variant = font_variant


def text2svg(
Expand Down Expand Up @@ -117,15 +121,27 @@ def text2svg(

pango_cairo_update_layout(cr,layout)
markup = escape(text_str)

# Build span attributes
span_attrs = []
if color:
markup = (f"<span color='{color}'>{markup}</span>")
span_attrs.append(f"color='{color}'")
if setting.font_features:
span_attrs.append(f"font_features='{setting.font_features}'")
if setting.font_variant:
span_attrs.append(f"font_variant='{setting.font_variant}'")
if disable_liga:
span_attrs.append("font_features='liga=0,dlig=0,clig=0,hlig=0'")

if span_attrs:
attrs_str = ' '.join(span_attrs)
markup = f"<span {attrs_str}>{markup}</span>"
if MarkupUtils.validate(markup):
cairo_destroy(cr)
cairo_surface_destroy(surface)
g_object_unref(layout)
raise ValueError(f"Pango cannot recognize your color '{color}' for text '{text_str}'.")
if disable_liga:
markup = f"<span font_features='liga=0,dlig=0,clig=0,hlig=0'>{markup}</span>"
raise ValueError(f"Pango markup validation failed for text '{text_str}' with attributes: {attrs_str}")

pango_layout_set_markup(layout, markup.encode('utf-8'), -1)
pango_cairo_show_layout(cr, layout)
pango_layout_get_size(layout,&temp_width,NULL)
Expand All @@ -150,6 +166,105 @@ def text2svg(
return file_name

class MarkupUtils:
@staticmethod
def build_font_features(
liga: bool = None,
dlig: bool = None,
clig: bool = None,
hlig: bool = None,
kern: bool = None,
swsh: int = None,
calt: bool = None,
onum: bool = None,
tnum: bool = None,
frac: bool = None,
afrc: bool = None,
custom_features: str = None
) -> str:
"""Build a font_features string from individual feature parameters.

Parameters
==========
liga : bool, optional
Common ligatures (default True in most fonts)
dlig : bool, optional
Discretionary ligatures
clig : bool, optional
Contextual ligatures
hlig : bool, optional
Historical ligatures
kern : bool, optional
Kerning (default True in most fonts)
swsh : int, optional
Swash (stylistic set number, 1-20)
calt : bool, optional
Contextual alternates
onum : bool, optional
Oldstyle figures
tnum : bool, optional
Tabular figures
frac : bool, optional
Fractions
afrc : bool, optional
Alternative fractions
custom_features : str, optional
Additional custom OpenType features

Returns
=======
str
Formatted font_features string for Pango markup
"""
features = []

if liga is not None:
features.append(f"liga={'1' if liga else '0'}")
if dlig is not None:
features.append(f"dlig={'1' if dlig else '0'}")
if clig is not None:
features.append(f"clig={'1' if clig else '0'}")
if hlig is not None:
features.append(f"hlig={'1' if hlig else '0'}")
if kern is not None:
features.append(f"kern={'1' if kern else '0'}")
if swsh is not None:
features.append(f"swsh={swsh}")
if calt is not None:
features.append(f"calt={'1' if calt else '0'}")
if onum is not None:
features.append(f"onum={'1' if onum else '0'}")
if tnum is not None:
features.append(f"tnum={'1' if tnum else '0'}")
if frac is not None:
features.append(f"frac={'1' if frac else '0'}")
if afrc is not None:
features.append(f"afrc={'1' if afrc else '0'}")

if custom_features:
features.append(custom_features)

return ', '.join(features) if features else ''

@staticmethod
def validate_font_variant(variant: str) -> bool:
"""Validate a font_variant value.

Parameters
==========
variant : str
The font variant to validate

Returns
=======
bool
True if valid, False otherwise
"""
valid_variants = {
'normal', 'small-caps', 'all-small-caps',
'petite-caps', 'all-petite-caps', 'unicase', 'title-caps'
}
return variant in valid_variants

@staticmethod
def validate(markup: str) -> str:
"""Validates whether markup is a valid Markup
Expand Down Expand Up @@ -205,6 +320,8 @@ class MarkupUtils:
line_spacing: float | None = None,
alignment: Alignment | None = None,
pango_width: int | None = None,
font_features: str | None = None,
font_variant: str | None = None,
) -> str:
"""Render an SVG file from a :class:`manim.mobject.svg.text_mobject.MarkupText` object."""
cdef cairo_surface_t* surface
Expand All @@ -218,8 +335,18 @@ class MarkupUtils:

file_name_bytes = file_name.encode("utf-8")

# Build span attributes for global text formatting
span_attrs = []
if font_features:
span_attrs.append(f"font_features='{font_features}'")
if font_variant:
span_attrs.append(f"font_variant='{font_variant}'")
if disable_liga:
text_bytes = f"<span font_features='liga=0,dlig=0,clig=0,hlig=0'>{text}</span>".encode("utf-8")
span_attrs.append("font_features='liga=0,dlig=0,clig=0,hlig=0'")

if span_attrs:
attrs_str = ' '.join(span_attrs)
text_bytes = f"<span {attrs_str}>{text}</span>".encode("utf-8")
else:
text_bytes = text.encode("utf-8")

Expand Down
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