plot_text_as_geom.py

import numpy as np, pandas as pd
import freetype
from shapely.geometry import *
from shapely import affinity as aff
from cartoframes.viz import Layer

face = freetype.Face("Vera.ttf") # path to your font
face.set_char_size(3000, hres = 100)
# These parameters are ok for Vera, but should be adjusted for each font.
char_width = 1500
space_between_chars_width = int(char_width*1/3)

get_width, get_height = (lambda b : b[2] - b[0], lambda b : b[3] - b[1])

def char_to_geometry(char, acc_offset):
    face.load_char(char)
    outline = face.glyph.outline
    
    X,Y = np.array(outline.points).T
    X = X - X.min() + acc_offset
    points = [(x,y) for x,y in zip(X,Y)]
    lines = []
    start = 0
    for end in outline.contours: # we travel each contour and generate a LineString
        points_in_line = points[start:end + 1] + [points[start]]
        l = LineString(points_in_line)
        lines.append(l)
        start = end + 1
    bbox = [X.min(), Y.min(), X.max(), Y.max()] # we compute the bounding box
    return lines, bbox
    
def text_as_geometry(text, coords, scale_factor = 5, rotate_angle = 0):
    n = len(text)
    char_geometries = []
    lat, lon = coords
    acc_offset = 0
    for char in text:
        try:
            m, bbox = char_to_geometry(char, acc_offset)
            offset = get_width(bbox)
            acc_offset += offset + space_between_chars_width
            char_geometries.extend(m)
        except:
            acc_offset += char_width
    ml = MultiLineString(char_geometries)
    Bbox = ml.bounds
    w = get_width(Bbox)
    h = get_height(Bbox)
    f = max(w,h)
    ml = aff.translate(ml, -Bbox[2] + w/2,  -Bbox[3] + h/2)
    ml = aff.scale(ml, scale_factor/(f*100), scale_factor/(f*100), origin = (lon, lat))
    ml = aff.rotate(ml, rotate_angle)
    return ml

word = "What's Up!"
lat, lon =  37.771757, -99.618516

geom = text_as_geometry(word, (lat, lon), scale_factor = 650, rotate_angle = 5)
df = pd.DataFrame([ {"geom" : geom}])
Layer(df, geom_col = "geom")