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Fix set_font() for PDF and SVG backends #674

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Merged
jwiggins merged 1 commit into from
Mar 4, 2021
Merged

Fix set_font() for PDF and SVG backends #674

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18 changes: 16 additions & 2 deletions kiva/pdf.py
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Original file line number Diff line number Diff line change
Expand Up @@ -19,12 +19,14 @@

# standard library imports
import copy
import os
import warnings

from numpy import ndarray, pi

# ReportLab PDF imports
import reportlab.pdfbase.pdfmetrics
from reportlab.pdfbase import pdfmetrics
from reportlab.pdfbase.ttfonts import TTFont
import reportlab.pdfbase._fontdata
from reportlab.pdfgen import canvas

Expand All @@ -35,6 +37,7 @@
from .constants import FILL, STROKE, EOF_FILL
import kiva.constants as constants
import kiva.affine as affine
from kiva.fonttools.font import Font


cap_style = {}
Expand Down Expand Up @@ -621,7 +624,18 @@ def set_font(self, font):
face_name = font.face_name
if face_name == "":
face_name = "Helvetica"
self.gc.setFont(face_name, font.size)

try:
self.gc.setFont(face_name, font.size)
except KeyError:
# Face name is not recognized.
# Register the TTF font that kiva's font_manager located
filename = font.findfont()
if not os.path.splitext(filename)[-1] in (".ttf", ".ttc"):
raise

pdfmetrics.registerFont(TTFont(face_name, filename))
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@jwiggins jwiggins Mar 4, 2021

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As far as I can tell, this embeds the font in the PDF file. I'm not sure if we want that or not.

PDF has a set of "safe" fonts which come with Acrobat Reader. I think maybe what we want to do in this method is try to map all requested fonts to the nearest match in this list.

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@aaronayres35 aaronayres35 Mar 4, 2021

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As far as I can tell, this embeds the font in the PDF file.

Based off the link below, I believe this is true as well.

PDF has a set of "safe" fonts which come with Acrobat Reader. I think maybe what we want to do in this method is try to map all requested fonts to the nearest match in this list.

I am unsure about this / why it would be necessary, but my understanding of all this is very much not complete / still growing. When would embedding the font in the PDF file not work or be problematic?

ref: https://www.reportlab.com/docs/reportlab-userguide.pdf
pg. 28 and 49-52

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@jwiggins jwiggins Mar 4, 2021

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When would embedding the font in the PDF file not work or be problematic?

You're right. It's probably OK.

self.gc.setFont(face_name, font.size)

def get_font(self):
""" Get the current font """
Expand Down
8 changes: 1 addition & 7 deletions kiva/svg.py
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Original file line number Diff line number Diff line change
Expand Up @@ -112,7 +112,6 @@ def default_filter(kw1):
</html>
"""

font_map = {"Arial": "Helvetica"}
try:
# expensive way of computing string widths
import reportlab.pdfbase.pdfmetrics as pdfmetrics
Expand All @@ -125,8 +124,6 @@ def default_filter(kw1):

_reportlab_loaded = 0

font_face_map = {"Arial": "Helvetica", "": "Helvetica"}


# This backend has no compiled path object, yet.
class CompiledPath(object):
Expand Down Expand Up @@ -185,10 +182,7 @@ def save(self, filename):
# Text handling code

def set_font(self, font):
self.face_name = font_face_map.get(font.face_name, font.face_name)
self.font = pdfmetrics.Font(
self.face_name, self.face_name, pdfmetrics.defaultEncoding
)
self.face_name = font.face_name
self.font_size = font.size

# actual implementation =)
Expand Down