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May 19, 2023 18:36
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This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters. Learn more about bidirectional Unicode charactersOriginal file line number Diff line number Diff line change @@ -0,0 +1,254 @@ ''' Convert text in any installed font to the WKT format. Requires inkscape. Does not currently work for characters with disjoint top-level islands (eg "=", double quotes, capital Xi, etc.) ''' import json import subprocess import xml.etree.ElementTree as etree import shapely from shapely import affinity from svgpath2mpl import parse_path import svgwrite ############################################################################### class GeoTree: "Generic tree node for geometry objects" tree_id = 0 def __init__(self, geometry, children=None): self.id = GeoTree.tree_id GeoTree.tree_id += 1 self.geometry = geometry self.children = [] if children is not None: for child in children: self.add_child(child) def __repr__(self): return str("<Tree"+str(self.id)+">") def add_child(self, node): assert isinstance(node, GeoTree) self.children.append(node) def tree_contains(tree1, tree2): '''Test tree objects for containment''' if tree1 and tree2: return shapely.contains(tree1.geometry, tree2.geometry) else: return False def recursive_order(current, new, order_fn=tree_contains): '''Add a new GeoTree object to the hierarchy based on the current root This function is recursive, so be careful! Returns the new root. ''' ## Check if current contains new, new contains current, or there ## is no intersection if order_fn(current, new): # print(f"{current} contains {new}") ## New is contained within current ## It must either be a direct child, or go further down the ## line ## Iterate over children and recurse for child in current.children: result = recursive_order(child, new) ## If any of the children contain the new, the returned ## value will be the child if result == child: ## In this case, everything is taken care of below ## so we can just return the current root return current ## If instead we receive the new, it means that it has ## displaced the child elif result == new: ## We need to remove this child as a child of the ## current so it can be only a child of the new current.children.remove(child) ## It has already been assigned as a child of the new ## in the recursive function ## We can't exit here because more children may belong ## to the new ## We've iterated through all the children ## All that's left is to add new as a child of current ## It will retain any children that weren't added to new ## Those might be all of them if new has no intersections with ## any of the existing children current.add_child(new) ## The root remains the same return current elif order_fn(new, current): # print(f"{new} contains {current}") ## Current is contained within new new.add_child(current) ## New is the new root return new else: # print(f"No intersection between {new} and {current}") ## There is no intersection between current and new return None def recursive_collapse(tree_root, collapse_fn=shapely.difference): '''Collapse a GeoTree Recursively starts at the leaves, and works its way up to the root Returns shapely geometry, NOT GeoTree objects! ''' # print(f"Collapsing at {tree_root}") ## Get the current geometry (may be updated by operations with ## children) current_geo = tree_root.geometry ## If there are children, we apply the function recursively for child in tree_root.children: # print(f"Checking child {child}") current_geo = collapse_fn(current_geo, recursive_collapse(child, collapse_fn)) ## Return the geometry including all child operations return current_geo ############################################################################### ## Corrective transformation constants ## NB I have no idea if these are the same for all fonts? Y_BASELINE = -3.75 SHRINK_FACT = 1/(10+Y_BASELINE) def text2wkt(font_family, input_chars="1234567890ABCDEFGHIJKLMNOPQRSTUVWXYZ", ): ## Container for storing output WKT strings wkt_dict = {} for char in input_chars: ## Write chars to svg ##################### ## Set up temp svg file dwg = svgwrite.Drawing(filename="_temp.svg") ## Write characters to svg gen_elem = dwg.g(style=f"font-size:10;font-family:{font_family}") gen_elem.add(dwg.text(char, insert=(0,10))) dwg.add(gen_elem) ## Save temp svg ## TODO this can be done with pipes without writing to a temp file! dwg.save() ## Convert svg text elements to path #################################### subprocess.call(["inkscape", "_temp.svg", "-T", "-l", "--export-filename", "_temp.svg"]) ## Convert svg path to shapely geometry ####################################### ## Load svg file and parse path elements tree = etree.parse("_temp.svg") root = tree.getroot() path_elems = root.findall('.//{http://www.w3.org/2000/svg}path') ## Convert to mpl paths paths = [parse_path(elem.attrib['d']) for elem in path_elems] ## Convert to mpl polygons polys = [path.to_polygons() for path in paths] ## Extract the first item (sole element in the file) char_polys = polys[0] ## Convert to shapely polygons char_geos = [shapely.geometry.Polygon(poly) for poly in char_polys] ## Assign hierarchy to geometry based on containment #################################################### ## Most (all?) character glyphs have well-defined holes and not-holes. ## Using containment as an ordering function, one can build a ## hierarchy, and then collapse it using subtraction/difference ## operations. ## We can't do it in general without such a construction, as it is not ## guaranteed that poly elements will intersect (eg the inner holes in ## B, 8, etc.) ## TODO Currently this does not support non-intersecting top-level ## polygons, such as =, ", %, or non-intersecting accents. ## Convert shapely geometries to GeoTree objects geos_tree = [GeoTree(geo) for geo in char_geos] ## Build hierarchy tree_base = None ## We want to pull from the list because we may need to reorder in case ## non-intersecting pairs are evaluated while geos_tree: ## Get the first item (we want to append at the end if it doesn't ## work) new_geo = geos_tree.pop(0) ## If there is no existing base, assign it and go to next if not tree_base: tree_base = new_geo # print(f"{tree_base} assigned as base") continue ## Compare to the base new_base = recursive_order(tree_base, new_geo) ## If it is not None, we're valid and we can keep going if new_base: tree_base = new_base ## If it's None, we have non-intersecting polygons so we bump them ## right back to the end of the list, and re-try with the same base else: geos_tree.append(new_geo) ## Collapse hierarchy by intersecting contained geometries ########################################################## final_geo = recursive_collapse(tree_base) ## Corrective transformations ############################# ## Translate baseline shifted = affinity.translate(final_geo, yoff=Y_BASELINE) ## Flip on y axis and shrink to unit size accounting for baseline scaled = affinity.scale(shifted, xfact=SHRINK_FACT, yfact=-SHRINK_FACT, origin=(0,0)) ## Export ######### wkt_dict[char] = scaled.wkt ## Return all WKT strings return wkt_dict ############################################################################### if __name__ == "__main__": ## Generate WKT strings wkts = text2wkt(font_family="Mindfuct NBP", # input_chars="1234", ) ## Dump to file with open("out.json", "w", encoding="utf-8") as out_file: json.dump(wkts, out_file, ensure_ascii=False, indent=4)