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Karnav Shah
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Docs(imgcodecs): clarify animation frame duration units #28176 ### Pull Request Readiness Checklist See details at https://github.com/opencv/opencv/wiki/How_to_contribute#making-a-good-pull-request - [x] I agree to contribute to the project under Apache 2 License. - [x] To the best of my knowledge, the proposed patch is not based on a code under GPL or another license that is incompatible with OpenCV - [x] The PR is proposed to the proper branch - [x] There is a reference to the original bug report and related work - [x] There is accuracy test, performance test and test data in opencv_extra repository, if applicable Patch to opencv_extra has the same branch name. - [x] The feature is well documented and sample code can be built with the project CMake Docs-only change. No code or tests affected.
95 lines
2.9 KiB
Markdown
95 lines
2.9 KiB
Markdown
Handling Animated Image Files {#tutorial_animations}
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===========================
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@tableofcontents
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| Original author | Suleyman Turkmen (with help of ChatGPT) |
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| Compatibility | OpenCV >= 4.11 |
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Goal
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----
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In this tutorial, you will learn how to:
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- Use `cv::imreadanimation` to load frames from animated image files.
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- Understand the structure and parameters of the `cv::Animation` structure.
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- Display individual frames from an animation.
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- Use `cv::imwriteanimation` to write `cv::Animation` to a file.
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Source Code
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-----------
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@add_toggle_cpp
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- **Downloadable code**: Click
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[here](https://github.com/opencv/opencv/tree/4.x/samples/cpp/tutorial_code/imgcodecs/animations.cpp)
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- **Code at a glance:**
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@include samples/cpp/tutorial_code/imgcodecs/animations.cpp
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@end_toggle
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@add_toggle_python
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- **Downloadable code**: Click
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[here](https://github.com/opencv/opencv/tree/4.x/samples/python/tutorial_code/imgcodecs/animations.py)
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- **Code at a glance:**
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@include samples/python/tutorial_code/imgcodecs/animations.py
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@end_toggle
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Explanation
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-----------
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## Initializing the Animation Structure
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Initialize a `cv::Animation` structure to hold the frames from the animated image file.
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@add_toggle_cpp
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@snippet cpp/tutorial_code/imgcodecs/animations.cpp init_animation
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@end_toggle
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@add_toggle_python
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@snippet python/tutorial_code/imgcodecs/animations.py init_animation
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@end_toggle
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## Loading Frames
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Use `cv::imreadanimation` to load frames from the specified file. Here, we load all frames from an animated WebP image.
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@add_toggle_cpp
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@snippet cpp/tutorial_code/imgcodecs/animations.cpp read_animation
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@end_toggle
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@add_toggle_python
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@snippet python/tutorial_code/imgcodecs/animations.py read_animation
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@end_toggle
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## Displaying Frames
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Each frame in the `animation.frames` vector can be displayed as a standalone image. This loop iterates through each frame, displaying it in a window with a short delay to simulate the animation.
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> **Note:** Frame durations in `cv::Animation` are expressed in milliseconds.
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> When displaying frames manually using `cv::waitKey`, make sure to use the corresponding duration value to preserve the original animation timing.
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@add_toggle_cpp
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@snippet cpp/tutorial_code/imgcodecs/animations.cpp show_animation
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@end_toggle
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@add_toggle_python
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@snippet python/tutorial_code/imgcodecs/animations.py show_animation
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@end_toggle
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## Saving Animation
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@add_toggle_cpp
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@snippet cpp/tutorial_code/imgcodecs/animations.cpp write_animation
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@end_toggle
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@add_toggle_python
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@snippet python/tutorial_code/imgcodecs/animations.py write_animation
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@end_toggle
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## Summary
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The `cv::imreadanimation` and `cv::imwriteanimation` functions make it easy to work with animated image files by loading frames into a `cv::Animation` structure, allowing frame-by-frame processing.
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With these functions, you can load, process, and save frames from animated image files like GIF, AVIF, APNG, and WebP.
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