Source code for qtdraw.util.latex_to_svg
"""
Render LaTeX to SVG.
This module provides LaTeX converter to SVG.
See for example, https://github.com/ipython/IPython/lib/latextools.py.
"""
from io import BytesIO
from matplotlib import figure
from PySide6.QtWidgets import QApplication, QWidget, QLabel, QGridLayout
from PySide6.QtGui import Qt, QPainter
from PySide6.QtSvgWidgets import QSvgWidget
from gcoreutils.color_palette import all_colors
from qtdraw.util.util import set_latex_setting
# ==================================================
[docs]
def latex_to_svg(text, wrap=True, color="black", size=12):
"""
Render a LaTeX string to svg via matplotlib.
Args:
text (str): raw string containing valid inline LaTeX.
wrap (bool, optional): if true, automatically wrap `s` as a LaTeX equation.
color (str, optional): color name.
size (int, optional): fontsize.
Returns:
- (str) -- SVG code (byte string).
- (int) -- width.
- (int) -- height.
Note:
- None is returned when the backend cannot be used.
"""
# mpl mathtext doesn't support display math, force inline
text = text.replace("$$", "$")
if wrap:
text = "${0}$".format(text)
color = all_colors[color][0]
fig = figure.Figure()
fig.text(0, 0, text, fontsize=size, color=color)
buffer = BytesIO()
fig.savefig(buffer, format="svg", transparent=True, bbox_inches="tight", pad_inches=0.1)
svg = buffer.getvalue()
w, h = get_svg_size(svg.decode())
return svg, w, h
# ==================================================
[docs]
def get_svg_size(svg):
"""
Get SVG size.
Args:
svg (str): bin code of svg.
Returns:
- (int) -- width.
- (int) -- hight.
"""
svg = svg.replace("'", '"')
# find viewBox='x y width height' in SVG.
start = svg.find('viewBox="')
if start == -1:
return None
start += 9
end = svg.find('"', start)
if end == -1:
return None
# convert to size.
view = svg[start:end]
view = view.split(" ")
if len(view) != 4:
return None
width = int(float(view[2]))
height = int(float(view[3]))
return width, height
# ==================================================
# ==================================================
[docs]
class MathText(QWidget):
# ==================================================
def __init__(self, parent, text, size, color):
"""
Math Text via SVG.
Args:
parent (QWidget): parent.
text (str): LaTeX stirng without "$".
size (int): font size.
color (str): color.
"""
super().__init__(parent=parent)
self.widget = QLabel(self)
self.widget.setAlignment(Qt.AlignCenter)
text, w, h = latex_to_svg(text, True, color, size)
self.widget = SVGWidget(self)
self.widget.setFixedSize(w, h)
self.widget.load(text)
layout = QGridLayout(self)
layout.addWidget(self.widget)
# ================================================== main
if __name__ == "__main__":
set_latex_setting()
app = QApplication([])
# ex = r"E=mc^2"
ex = r"\begin{bmatrix} a & b \\ c & d \end{bmatrix}"
widget = MathText(None, ex, 24, "black")
widget.show()
app.exec()
