Strange ugly black edges of text after using paste

[KimigaiiWuyi]

from PIL import Image, ImageDraw, ImageFont

font = ImageFont.truetype(r'C:\Users\44483\Desktop\zzz_thins.ttf', size=60)
img = Image.new("RGBA", (200, 200), (200, 160, 130, 0))
img_draw = ImageDraw.Draw(img)
img_draw.text((0, 0), "你好", font=font, fill=(255, 255, 255))

base = Image.new("RGBA", (200, 100), (0, 0, 0, 120))
base_draw = ImageDraw.Draw(base)
base_draw.text((0, 0), "你好", font=font, fill=(255, 255, 255))
base.save("test1.png")

img.paste(base, (0, 100), base)
img.save("test2.png")

After paste, the background color seems to fade and there is a strange black edge around the text，
This looks very strange and performs worse on lower pixel plots！

I'm not sure what's going on and I'm hoping someone can answer my questions for me！extremely grateful！

[radarhere]

I can't see the 'strange black edge' in the images you've attached.

As to why the background colour is faded, you have provided base as the third argument to paste(), making it the 'mask'.

https://pillow.readthedocs.io/en/stable/reference/Image.html#PIL.Image.Image.paste

If a mask is given, this method updates only the regions indicated by the mask.

Because base image has a background of 120 alpha, the pasted image is faded. To demonstrate, if you reduce

base = Image.new("RGBA", (200, 100), (0, 0, 0, 120))

to

base = Image.new("RGBA", (200, 100), (0, 0, 0, 0))

you will see the background disappear entirely.

If you do not want the background to fade, then you can just change

img.paste(base, (0, 100), base)

to

img.paste(base, (0, 100))

to stop using a mask in your call to paste().

[radarhere]

Unfortunately, the further images you've provided don't clarify anything for me, as they introduce many more pieces of text into the conversation.

Could you take the image from your first comment, and manually 'correct' it with Photoshop or similar to demonstrate what you want?

[KimigaiiWuyi]

Unfortunately, the further images you've provided don't clarify anything for me, as they introduce many more pieces of text into the conversation.

Could you take the image from your first comment, and manually 'correct' it with Photoshop or similar to demonstrate what you want?

Of course, note the difference in the edges between the two.
The text generated by pillow has a very thin (about 1px) shadow stroke, which should not normally look like this.

[radarhere]

Your original code doesn't paste the image onto a purple background though. If you're taking further steps after your original code that you're not showing here, it's hard to help fix that.

Have you tried the code I suggested earlier? Maybe that will solve your second problem as well?

Could you point us to a copy of zzz_thins.ttf?

[KimigaiiWuyi]

但是，您的原始代码不会将图像粘贴到紫色背景上。如果您在原始代码之后采取了未在此处显示的进一步步骤，则很难帮助修复该问题。

您尝试过我之前建议的代码吗？也许这也能解决您的第二个问题？

您能给我们提供一份 zzz_thins.ttf 的副本吗？

Of course, I can provide the font files, the purple background is for comparison, in fact any background color will have a stroke of about 1px, if the font size is bigger, it won't have much effect, but if the font size is smaller than 25, this stroke will affect the body of the font very much.

zzz_thins.zip

[radarhere]

If I remove the mask from your code

from PIL import Image, ImageDraw, ImageFont

font = ImageFont.truetype('zzz_thins.ttf', size=60)
img = Image.new("RGBA", (200, 200), (200, 160, 130, 0))
img_draw = ImageDraw.Draw(img)
img_draw.text((0, 0), "你好", font=font, fill=(255, 255, 255))

base = Image.new("RGBA", (200, 100), (0, 0, 0, 120))
base_draw = ImageDraw.Draw(base)
base_draw.text((0, 0), "你好", font=font, fill=(255, 255, 255))
base.save("test1.png")

img.paste(base, (0, 100))
img.save("test2.png")

the 'fade' on the background colour is fixed in test2.png.

If I modify it to have purple and blue backgrounds, I don't think I see the 'strange ugly black edges' that you describe.

from PIL import Image, ImageDraw, ImageFont

font = ImageFont.truetype('zzz_thins.ttf', size=60)
img = Image.new("RGBA", (200, 200), "#f0f")
img_draw = ImageDraw.Draw(img)
img_draw.text((0, 0), "你好", font=font, fill=(255, 255, 255))

base = Image.new("RGBA", (200, 100), "#0ff")
base_draw = ImageDraw.Draw(base)
base_draw.text((0, 0), "你好", font=font, fill=(255, 255, 255))
base.save("test1.png")

img.paste(base, (0, 100))
img.save("test2.png")

[KimigaiiWuyi]

I'm sorry to say that I've reorganized a test case, in which it is obvious that the text generated by the pillow seems to be blocked by a circle (about 1px or less). @radarhere

pillow(right)
Photoshop(left)

from pathlib import Path

from PIL import Image, ImageDraw, ImageFont

path = Path(__file__).parent

font = ImageFont.truetype(str(path / 'zzz_thins.ttf'), size=15)

img1 = Image.open(path / '1.png')
img2 = Image.open(path / '2.png')
img2_draw = ImageDraw.Draw(img2)
img2_draw.text((125, 50), '你好测试', 'white', font, 'mm')

img_temp = Image.new('RGBA', img1.size)
img_temp.paste(img2, (75, 150))

img1 = Image.alpha_composite(img1, img_temp)


img1.save(path / 'test.png')

ex.zip

[KimigaiiWuyi]

Thank you very much! 😘 Bolding all characters synchronously by 0.25px seems to cause some stroke sticking issues, but it also solves part of the problem.
What causes the difference in character display and rendering between the two above? Is there a way to fix it?

[radarhere]

Pillow uses FreeType as the foundation for text rendering.

Photoshop is commercial software, so I don't know exactly what goes on inside - but I doubt it uses FreeType. I found an early comparison between FreeType and Photoshop output, which would hardly have been made if Photoshop was just using FreeType under the hood.

I don't think 'the output doesn't look like Photoshop' is a concrete problem that can be addressed. If you have a more definitive reason to believe that characters are being rendered incorrectly, that is not just a result of the font, please let us know.

If you don't like how Pillow renders the font at small sizes, my only suggestion is to try rendering the font at a larger size, and then resize the resulting image.

[KimigaiiWuyi]

Really appreciate your answer, I fully understand everything, I'm looking forward to being able to use float values for stroke width, this should improve things a lot, thanks for your help!😘

[radarhere]

I've created #8369 to accept float stroke widths.