英文:
Resizing PIL rgb image in tkinter application
问题
背景
我正在创建一个小型幻灯片应用程序，允许显示图像。原始图像相当大（2000x2000像素），因此我希望将其重新调整大小以适应屏幕。这方面的工作如预期一样进行。
该图像本质上是一个数组，值范围从0到16位。为了让PIL显示颜色，我复制该数组，分别处理每个通道，转换为图像对象，重新调整大小并显示。在这里，重新调整大小似乎无法正常工作。
方法
我在下面分享了一个重现这个问题的最简代码版本，至少在我的系统上是这样的。
import tkinter as tkimport numpy as npfrom PIL import Image, ImageTkclass MainApplication(tk.Frame):def __init__(self, parent, *args, **kwargs):tk.Frame.__init__(self, parent, *args, **kwargs)self.parent = parentself.images = {}self.load_image()self.show_image()def load_image(self):img = np.zeros((2000,2000))img[100:800, 100:800] = 255self.images[0] = imgdef show_image(self):img = self.images[0]img = np.repeat(img[:,:,np.newaxis], 3, axis=2)img = Image.fromarray(img, 'RGB')img = img.resize((1000,1000))img = ImageTk.PhotoImage(img)self.persistent_img = imgself.canvas = tk.Canvas(self.parent, height=1000, width=1000)self.canvas.grid(row=0, column=0)self.canvas.create_image(0,0,anchor='nw', image=img)if __name__ == '__main__':root = tk.Tk()MainApplication(root)root.mainloop()
预期
实际上，如果只重新调整大小单通道图像，则上述代码可以正常工作：
img = np.zeros((2000,2000))img[100:800, 100:800] = 255self.images[0] = img[...]img = self.images[0]img = Image.fromarray(img)img = img.resize((1000,1000))[...]
实际
这是什么原因，有没有解决方法？非常感谢您的帮助！
英文:
background
I am creating a small slideshow application that allows for displaying an image. The original image is quite large (2000 by 2000 pixels), so I want to rescale it to fit the screen. This works as expected.
The image is essentially an array, with values ranging from 0 to 16 bit.
To get PIL to display colours, I triplicate the array, manipulate each channel individually, convert to an Image object, rescale and display. Here, the rescaling does not seem to work properly.
approach
I am sharing a barebones version of my code that repoduces this issue, at least on my system.
import tkinter as tkimport numpy as npfrom PIL import Image, ImageTkclass MainApplication(tk.Frame):def __init__(self, parent, *args, **kwargs):tk.Frame.__init__(self, parent, *args, **kwargs)self.parent = parentself.images = {}self.load_image()self.show_image()def load_image(self):img = np.zeros((2000,2000))img[100:800, 100:800] = 255self.images[0] = imgdef show_image(self):img = self.images[0]img = np.repeat(img[:,:,np.newaxis], 3, axis=2)img = Image.fromarray(img, 'RGB')img = img.resize((1000,1000))img = ImageTk.PhotoImage(img)self.persistent_img = imgself.canvas = tk.Canvas(self.parent, height=1000, width=1000)self.canvas.grid(row=0, column=0)self.canvas.create_image(0,0,anchor='nw', image=img)if __name__ == '__main__':root = tk.Tk()MainApplication(root)root.mainloop()
expected
In fact, this works with the code above, if I just rescale the one-channel image:
img = np.zeros((2000,2000))img[100:800, 100:800] = 255self.images[0] = img[...]img = self.images[0]img = Image.fromarray(img)img = img.resize((1000,1000))[...]
actual
What is causing this, and is there a way around? Help is highly appreciated!
答案1
得分: 2
应该在np.zeros(...)中设置dtype=uint8以用于图像数据：
np.zeros((2000, 2000), dtype=np.uint8)
英文:
Should set dtype=uint8 in np.zeros(...) for image data:
np.zeros((2000, 2000), dtype=np.uint8)
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