Скачать или смотреть How to Pass the Result of a tkinter Button Click to Another Button in Python

Learn how to pass the image path from one `tkinter` button to another to display images using `cv2` in a Python GUI application.
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How to Pass the Result of a tkinter Button Click to Another Button in Python

Creating a graphical user interface (GUI) in Python using tkinter can sometimes pose challenges, especially when one button's action needs to be dependent on another button's output. In this guide, we will explore how to select an image using one button and then display that image using another button using the OpenCV library.

The Problem

Imagine a scenario where you have two buttons in your GUI:

Select Button: This button allows users to select an image file from their system.

Show Button: This button is intended to display the selected image using cv2.imshow.

However, the challenge arises when trying to maintain the file path of the selected image when trying to display it. Here's a simplified understanding of the current issue:

You want to ensure that when the Show Button is pressed, it can access the path chosen by the Select Button.

Let’s dive into the code and see how we can create a smooth functioning interface.

Analyzing the Initial Code

Here’s a short look at what your initial code looks like:

[[See Video to Reveal this Text or Code Snippet]]

The Issue:

In this code, the func2 lambda function does not correctly pass the selected image path to show_image. This happens because func1 is called instead of retrieving its value.

The Solution

To effectively achieve the desired functionality, we need to store the file path in a way that the Show Button can access it later. Here’s a step-by-step guide on how to modify the initial code.

Step 1: Use a Global Variable

To store the selected file path, we will define a global variable. This allows both button commands to access the file path easily.

Step 2: Create Separate Functions for Button Actions

We'll create two clear functions: one for updating the file path when the select button is clicked and another for displaying the image.

Revised Code:

Here’s the revamped code structure using these principles:

[[See Video to Reveal this Text or Code Snippet]]

Explanation of the Changes:

Global Variable: A variable selected_filepath is introduced to store the image path from the select function.

Separated Functions: We now have update_filepath() to update the global variable when the Select Button is clicked, and display_image() to show the image if a file has been selected.

Conclusion

With these modifications, we now have a functioning GUI where one button can reliably select an image file and another button can properly display that image using OpenCV. This approach not only solves our original problem but also promotes better readability and maintainability of the code.

If you’re interested in crafting your own image viewing application, try out this code snippet and feel free to customize it to suit your needs!