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ViewsHow to get the font pixel height using PIL's ImageFont class?
I am using PIL' ImageFont module to load fonts to generate text images.
I want the text to tightly bound to the edge, however, when using the ImageFont to get the font height, It seems that it includes the character's padding. As the red rectangle indicates.
c = 'A'
font = ImageFont.truetype(font_path, font_size)
width = font.getsize(c)[0]
height = font.getsize(c)[1]
im = Image.new("RGBA", (width, height), (0, 0, 0))
draw = ImageDraw.Draw(im)
draw.text((0, 0), 'A', (255, 255, 255), font=font)
im.show('charimg')
If I can get the actual height of the character, then I could skip the bounding rows in the bottom rectangle, could this info got from the font? Thank you.
3 answers
Answer question0
Exact size depends on many factors. I'll just show you how to calculate different metrics of font.
font = ImageFont.truetype('arial.ttf', font_size)
ascent, descent = font.getmetrics()
(width, baseline), (offset_x, offset_y) = font.font.getsize(text)
- Height of red area:
offset_y - Height of green area:
ascent - offset_y - Height of blue area:
descent - Black rectangle:
font.getmask(text).getbbox()
Hope it helps.
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The top voted answer is outdated. There is a new function in Pillow 8.0.0: ImageDraw.textbbox.
See the release notes for other text-related functions added in Pillow 8.0.0.
Note that ImageDraw.textsize, ImageFont.getsize and ImageFont.getoffset are broken, and should not be used for new code. These have been effectively replaced by the new functions with a cleaner API. See the documentaion for details.
To get a tight bounding box for a whole string you can use the following code:
from PIL import Image, ImageDraw, ImageFont
image = Image.new("RGB", (200, 80))
draw = ImageDraw.Draw(image)
font = ImageFont.truetype("arial.ttf", 30)
draw.text((20, 20), "Hello World", font=font)
bbox = draw.textbbox((20, 20), "Hello World", font=font)
draw.rectangle(bbox, outline="red")
print(bbox)
# (20, 26, 175, 48)
image.show()
You can combine it with the new ImageDraw.textlength to get individual bounding boxes per letter:
from PIL import Image, ImageDraw, ImageFont
image = Image.new("RGB", (200, 80))
draw = ImageDraw.Draw(image)
font = ImageFont.truetype("arial.ttf", 30)
xy = (20, 20)
text = "Example"
draw.text(xy, text, font=font)
x, y = xy
for c in text:
bbox = draw.textbbox((x, y), c, font=font)
draw.rectangle(bbox, outline="red")
x += draw.textlength(c, font=font)
image.show()
Note that this ignores the effect of kerning. Kering is currently broken with basic text layout, but could introduce a slight inaccuracy with Raqm layout. To fix it you would add the text length of pairs of letters instead:
for a, b in zip(text, text[1:] + " "):
bbox = draw.textbbox((x, y), a, font=font)
draw.rectangle(bbox, outline="red")
x += draw.textlength(a + b, font=font) - draw.textlength(b, font=font)
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from PIL import Image, ImageDraw, ImageFont
im = Image.new('RGB', (400, 300), (200, 200, 200))
text = 'AQj'
font = ImageFont.truetype('arial.ttf', size=220)
ascent, descent = font.getmetrics()
(width, height), (offset_x, offset_y) = font.font.getsize(text)
draw = ImageDraw.Draw(im)
draw.rectangle([(0, 0), (width, offset_y)], fill=(237, 127, 130)) # Red
draw.rectangle([(0, offset_y), (width, ascent)], fill=(202, 229, 134)) # Green
draw.rectangle([(0, ascent), (width, ascent + descent)], fill=(134, 190, 229)) # Blue
draw.rectangle(font.getmask(text).getbbox(), outline=(0, 0, 0)) # Black
draw.text((0, 0), text, font=font, fill=(0, 0, 0))
im.save('result.jpg')
print(width, height)
print(offset_x, offset_y)
print('Red height', offset_y)
print('Green height', ascent - offset_y)
print('Blue height', descent)
print('Black', font.getmask(text).getbbox())
Calculate area pixel
from PIL import Image, ImageDraw, ImageFont
im = Image.new('RGB', (400, 300), (200, 200, 200))
text = 'AQj'
font = ImageFont.truetype('arial.ttf', size=220)
ascent, descent = font.getmetrics()
(width, height), (offset_x, offset_y) = font.font.getsize(text)
draw = ImageDraw.Draw(im)
draw.rectangle([(0, offset_y), (font.getmask(text).getbbox()[2], ascent + descent)], fill=(202, 229, 134))
draw.text((0, 0), text, font=font, fill=(0, 0, 0))
im.save('result.jpg')
print('Font pixel', (ascent + descent - offset_y) * (font.getmask(text).getbbox()[2]))
