Character bounding boxes and negative offsetx #4789
Description
What did you do?
I'm trying to get character level bounding boxes for some text I'm generating, following #3921, and @nulano 's comment, this stackoverflow answer etc. Also tagging #4724 in the hope that this issue will be addressed by it.
def test_bbox(font, txt):
img = Image.new(mode='RGB', size=(300,100), color='white')
draw = ImageDraw.Draw(img)
xref, yref = 50, 5
draw.text((xref, yref), txt, font=font, fill='black')
for i, c in enumerate(txt):
wd0, ht0 = font.getsize(txt[:i+1])
(wd, ht), (offsetx, offsety) = font.font.getsize(txt[:i+1])
cmask_wd, cmask_ht = font.getmask(c).size
char_wd, char_ht = font.getsize(c)
x2, y2 = wd0, char_ht
x1, y1 = x2 - cmask_wd, y2 - cmask_ht
draw.rectangle((x1 + xref, y1 + yref, x2 + xref, y2 + yref), fill=None, outline='red', width=1)
draw.rectangle((x1 + offsetx + xref, y1 + yref, x2 + offsetx + xref, y2 + yref), fill=None, outline='green', width=1)
return img
italic_font = ImageFont.truetype('fonts/google/fonts-master/ofl/baskervville/Baskervville-Italic.ttf', 60, layout_engine=ImageFont.LAYOUT_BASIC)
# show_grid just uses matplotlib ax.imshow to display the image
show_grid(test_bbox(italic_font, 'fa'))
show_grid(test_bbox(italic_font, 'af'))
What did you expect to happen?
I expected the red bounding box to encompass the a in the first image (fa).
What actually happened?
-
It was shifted to the right.
-
Also, while flailing around, I realized that the green bounding box, which is created by an additional
offsetxshift, does appear to encompass thea. I don't understand why this would be, but it might just be coincidence. -
Neither of these completely bound the
aon the top edge. Why would that be?
What are your OS, Python and Pillow versions?
- OS: Ubuntu 18.04
- Python: 3.8.1
- Pillow: 7.1.2