[FIXED] How to set anchor to fit the text at center of image with PIL.ImageDraw.Draw.text?

Issue

Drawn text on an image with Pillow library, tried to fit the text anchored at center of image by option anchor='mm', but it looks not exactly as center of image.

Demo code

from PIL import Image, ImageDraw, ImageFont

im = Image.new("RGBA", (500, 500), (255, 255, 255, 255))
font = ImageFont.truetype(font='arial.ttf', size=320)
draw = ImageDraw.Draw(im)
draw.text((250, 250), "123", font=font, fill='black', anchor='mm')
im.show()

result:

expectation:

Solution

The reason why the text looks misaligned is because there is a little margin at the left of the 1 and pillow will align the text including this margin.

Adding 0 at both ends will visualize that it is correctly centered and that there is a large margin at 1.

If you want to align the text excluding margins, ImageFont.getmask is helpful.

def get_offset_for_true_mm(text, draw, font):
    anchor_bbox = draw.textbbox((0, 0), text, font=font, anchor='lt')
    anchor_center = (anchor_bbox[0] + anchor_bbox[2]) // 2, (anchor_bbox[1] + anchor_bbox[3]) // 2
    mask_bbox = font.getmask(text).getbbox()
    mask_center = (mask_bbox[0] + mask_bbox[2]) // 2, (mask_bbox[1] + mask_bbox[3]) // 2
    return anchor_center[0] - mask_center[0], anchor_center[1] - mask_center[1]


im = Image.new("RGBA", (500, 500), (255, 255, 255, 255))
font = ImageFont.truetype(font='arial.ttf', size=320)
draw = ImageDraw.Draw(im)
text = "123"
offset = get_offset_for_true_mm(text, draw, font)
draw.text((250 + offset[0], 250 + offset[1]), text, font=font, fill='black', anchor='mm')
im.show()

Result:

Answered By - ken

Answer Checked By - Terry (PHPFixing Volunteer)