Render text string to image to calculate length with Wand/ImagaMagick Python

Question

I need to calculate the length when rendered of a lot of strings using a custom font. From a shell script and ImageMagick I am able to do something using the annotate command line option.

convert -debug annotate xc: -font "customfont.ttf" -pointsize "25" -annotate 0 "this is the text" out.png

And then reading the width of the rendered image.

Im struggling to understand how to do this with the python 'Wand' lib. I have created a font object, but I seem to need to define the width of the canvas to paint the font onto.

Any suggestions appreciated.

Answer 1

使用魔杖，您将使用wand.drawing.Drawing.get_font_metricswhich 将返回FontMetrics类的实例。

例子

from wand.image import Image
from wand.drawing import Drawing

with Image(filename='wizard:') as img:
    with Drawing() as context:
        context.font_family = 'monospace'
        context.font_size = 25
        metrics = context.get_font_metrics(img,
                                           "How BIG am I?",
                                           multiline=False)
        print(metrics)

#=> FontMetrics(character_width=25.0,
#               character_height=25.0,
#               ascender=23.0,
#               descender=-5.0,
#               text_width=170.0,
#               text_height=29.0,
#               maximum_horizontal_advance=50.0,
#               x1=0.0,
#               y1=0.0,
#               x2=19.21875,
#               y2=18.0,
#               x=170.0,
#               y=0.0)