'Exporting' 一个 tkinter canvas 到带有 Pillow 的 .png 并导致极低的分辨率

Question

我正在尝试 'export' tkinter canvas 到 png 文件，如以下答案所示：

我创建了一个示例 canvas 和一个触发函数以将其导出为 png 的按钮：

import tkinter as tk
from PIL import Image

def save_as_png(canvas, fileName):
    canvas.postscript(file='./' + fileName + '.eps', colormode='color')
    img = Image.open(fileName + '.eps')
    img.convert()
    img.save(fileName + '.png', 'png')


root = tk.Tk()
canvas = tk.Canvas(root, width=100, height=100)
text = canvas.create_text(50, 50, anchor='center', text='Some text')
button = tk.Button(root, text='Save canvas', command=lambda: save_as_png(canvas, 'my canvas'))
canvas.pack()
button.pack()

root.mainloop()

不过，生成的图像分辨率极低。我花了一段时间才明白 'Some text' 实际上是这样写的：

我尝试摆弄 open 和 save 方法的参数（dpi、quality、compression_level），但没有成功.

Answer 1

根据 .postscript() 的 pagewidth or pageheight 上的 tkdoc：

Specifies that the Postscript should be scaled in both x and y so that the printed area is size high on the Postscript page. Size consists of a floating-point number followed by c for centimeters, i for inches, m for millimeters, or p or nothing for printer's points (1/72 inch). Defaults to the height of the printed area on the screen. If both -pageheight and -pagewidth are specified then the scale factor from -pagewidth is used (non-uniform scaling is not implemented).

# set the output width to 1000 pixels
canvas.postscript(file='./'+fileName+'.eps', colormode='color', pagewidth=1000)

'Exporting' 一个 tkinter canvas 到带有 Pillow 的 .png 并导致极低的分辨率

'Exporting' a tkinter canvas to .png with Pillow and results in extremely low resolution

png

tkinter

ghostscript

python-imaging-library

tkinter-canvas