ImageFont 检测丢失的字形(Python Pillow)

问题描述

这是一个简短的示例.

from PIL import ImageFont, ImageDraw绘制 = ImageDraw.Draw(图像)# 使用位图字体font = ImageFont.load("arial.pil")draw.text((10, 10), "你好", font=font)# 使用 truetype 字体font = ImageFont.truetype("arial.ttf", 15)draw.text((10, 25), "world", font=font)

我想知道字体是否缺少渲染文本中的任何字形.

当我尝试渲染丢失的字形时，我得到一个空方块.

draw.text((10, 10), chr(1234), font=font)

• 如何以编程方式确定丢失的字形?
• 如何在 ttf 文件中列出可用的字形?

这两个问题几乎一样.

我更喜欢使用 Pillow 来确定我想要什么.也欢迎来自 PyPI 的其他模块.

解决方案

有'fontTools' 包，其中包含一个用于读取和查询 TrueType 字体的 Python 类.这样的事情是可能的

from fontTools.ttLib import TTFontf = TTFont('/path/to/font/arial.ttf')print(f.getGlyphOrder()) # 顺序中的字形列表# 他们出现了print(f.getReversedGlyphMap() # 从字形名称到 Id 的映射id = f.getGlyphID('Euro') # 欧元字符的内码，# 如果字符，则引发属性错误# 不存在.

从字符到字形的映射通常很复杂，在字体的 cmap 表中定义.这是一个二进制部分，但可以用

检查

f.getTableData('cmap')

一个字体可以有多个 cmap 表.freetype 接口也可以读取 ttf 文件.可以使用 freetype 尝试渲染字符，然后查看结果:这会很慢.

将 freetype 导入为 ftface = ft.Face('arial.ttf')face.set_size(25*32)face.load_char(‽)位图 = face.glyph.bitmap.bufferif bitmap == [255, 255, 255, 255, 0, 255, 255, 0, 255, 255, 0, 255, 255, 0, 255, 255, 0, 255, 255, 255]: 25print("字体中没有interobang")

Here is a short example.

from PIL import ImageFont, ImageDraw

draw = ImageDraw.Draw(image)

# use a bitmap font
font = ImageFont.load("arial.pil")

draw.text((10, 10), "hello", font=font)

# use a truetype font
font = ImageFont.truetype("arial.ttf", 15)

draw.text((10, 25), "world", font=font)

When I try to render a glyph that is missing I get an empty square.

draw.text((10, 10), chr(1234), font=font)

• How to programmatically determine missing glyphs?
• How to list available glyphs in a ttf file?

The two questions are almost the same.

解决方案

There is the 'fontTools' package, that includes a python class for reading and querying TrueType fonts. Something like this is possible

from fontTools.ttLib import TTFont
f = TTFont('/path/to/font/arial.ttf')
print(f.getGlyphOrder())      # a list of the glyphs in the order
                              # they appear
print(f.getReversedGlyphMap() # mapping from glyph names to Id
id = f.getGlyphID('Euro')     # The internal code for the Euro character,
                              # Raises attribute error if the character
                              # isn't present.

The mapping from characters to glyphs is often complex, and is defined in the cmap table of the font. It's a binary section, but can be inspected with

f.getTableData('cmap')

A font can have multiple cmap tables. The freetype interface can also read ttf files. It is possible to use freetype to attempt to render a character, and see the result: this would be slow.

import freetype as ft
face = ft.Face('arial.ttf')
face.set_size(25*32)
face.load_char(‽)
bitmap = face.glyph.bitmap.buffer
if bitmap == [255, 255, 255, 255, 0, 255, 255, 0, 255, 255, 0, 255, 255, 0, 255, 255, 0, 255, 255, 255, 255]:
     print("No interobang in the font")

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