Python ImageTk.PhotoImage 使用 alpha 通道缓慢加载 png答案

【问题标题】：Python ImageTk.PhotoImage slow loading of png with alphachannelPython ImageTk.PhotoImage 使用 alpha 通道缓慢加载 png
【发布时间】：2022-02-10 00:57:28
【问题描述】：

我写了一个小程序来加载和显示图像。一切正常，直到我到达示例中的 png 文件 (shade.png)。

显示这张小图片需要 7 七秒。

PhotoImage 中是否有错误或我错过了一些参数？

这是我的示例代码：

from PIL import Image, ImageTk
from six.moves import tkinter

import time
start = time.process_time()
print(time.process_time() - start)

root = tkinter.Tk()

img = Image.open('shade.png')
img = img.convert("RGBA")  # make sure, it has alphachannel

print(time.process_time() - start, "after image.open")


img = ImageTk.PhotoImage(img)
print(time.process_time() - start, "after PhotoImage")

【问题讨论】：

标签： python tkinter png alpha-transparency

【解决方案1】：

在我的研究中，我发现这个
是 Tk() 中的一个古老的已知错误，尤其是在 Tk_PhotoPutBlock 中。 https://core.tcl-lang.org/tk/tktview/b9827ece14da1cd186c5816dc45abc29cf9b8a9c

当我发现在某些情况下有帮助的解决方法时，
我想把它贴在这里。
为了进一步测试和寻找错误。

import time  # only to stop the time

from PIL import Image, ImageTk, ImageDraw
from six.moves import tkinter


HAVE_PIC = "no"  # "yes" # or let create a pic if you have none

root = tkinter.Tk()


def masking_1(image):  # faster

    mask = image.copy()
    mask.putalpha(1)

    mask.paste(image, (0, 0), image)

    # img.paste(img,(0, 0), mask)

    image = mask.copy()
    return image


def masking_2(image):  # better quality

    datas = image.getdata()

    newData = []
    for item in datas:
        if item[3] == 0:
            newData.append((item[0], item[1], item[2], 1))
        else:
            newData.append(item)

    image.putdata(newData)

    return image


def image_draw():  # creates the test pic

    width = 300  # the bigger the slower
    height = 300
    colour = "green"  # "#519ae7"
    image = Image.new('RGBA', (width, height))
    imd = ImageDraw.Draw(image, 'RGBA')

    y = 0
    while y < height:
        x = y % 2
        while x < width:
            imd.point((x, y), colour)
            x += 2
        y += 1
    return image


if HAVE_PIC == "yes":
    img = Image.open('shade.png')  # insert your problem pic
    img = img.convert("RGBA")  # make sure, it has alphachannel
else:
    img = image_draw()  # creates test pic


start = time.process_time()
print(time.process_time() - start, "after image.open")
# img.show()  # to show that it is the same image
photo_image = ImageTk.PhotoImage(img, master=root)  # too slow
print(time.process_time() - start, "after PhotoImage")


start = time.process_time()
print(time.process_time() - start, "before masking_1")
pic = masking_1(img)
# pic.show()
photo_image = ImageTk.PhotoImage(pic, master=root)
print(time.process_time() - start, "after masking_1")

start = time.process_time()
print(time.process_time() - start, "before masking_2")
pic = masking_2(img)
# pic.show()
photo_image = ImageTk.PhotoImage(pic, master=root)
print(time.process_time() - start, "after masking_2")

在我的电脑上输出：
0.0 后 image.open
9.734375 后 PhotoImage
屏蔽前 0.0_1
屏蔽后 0.0_1
掩蔽前 0.0_2
屏蔽后0.03125_2

【讨论】：