Pillow composite

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The Image module of the image processing library Pillow PIL of Python provides composite for compositing two images according to a mask image. Note that composite is a function to composite two images of the same size. Use the paste to composite images of different sizes. There are three parameters for composite. All three must be Image objects, all of the same size.

Pillow composite

If you have two images A and B, you alpha-composite A over B, it will create an effect that you can see both image A and B in the resulting image, as if A has transparency and you can see through A and also see B. Suppose a is the src image, b is the destination image, we composite a over b. The equation for alpha value and pixel value of the generated image are:. So it is easy to see that the resulting pixel value is a linear combination of pixel value from a and b. To test the correctness of the above equations, use the above script. After alpha compositing, the value for channel R and G of im1 should be all 67, for channel B should be all 0, and for alpha channel should be all without rescale, it should be 0. So if we have a large image A and we want to overlay a small image B onto it. How do we do it correctly? We should first add an alpha channel with value for image A. This is the crucial step for correct alpha-compositing. This will not affect the region in A that do not have overlap with image B. Otherwise, you will get a opaque look for those regions. Then we should set proper alpha for image B, depending on how you want to composite. In this case, the pixel value for the resulting image becomes simply:. For example, if you want B to completely dominate the overlapping region, you can set alpha to

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The Image module of the image processing library Pillow PIL of Python provides composite for compositing two images according to a mask image. Note that composite is a function to composite two images of the same size. Use the paste to composite images of different sizes. There are three parameters for composite. All three must be Image objects, all of the same size. ImageDraw and ImageFilter are used when drawing a figure and creating a mask image. When reading an image file and using it as a mask image, they may be omitted.

Pillow composite

Since PIL is no longer under development, Pillow is now widely used. Although advanced image processing face recognition, optical flow, etc. Because Pillow is simpler and easier to understand than OpenCV, it is better to use it depending on the purpose. See the following link for individual articles that explain various processes such as resizing and trimming. Pillow and PIL cannot coexist. If you have installed both, you should uninstall both and reinstall only one. Note that if you are using Python 3, you may have to use pip3 instead of pip depending on your environment. Read the image file. Note that the name of the package to import is PIL , not Pillow. Get meta information such as format, size width, height , mode, etc.

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Contribute to the GeeksforGeeks community and help create better learning resources for all. Related Articles. This is the crucial step for correct alpha-compositing. Interview Experiences. This will not affect the region in A that do not have overlap with image B. Enhance the article with your expertise. Work Experiences. As an example, create a solid image with a value of with Image. So it is easy to see that the resulting pixel value is a linear combination of pixel value from a and b. Submit your entries in Dev Scripter today. Contribute your expertise and make a difference in the GeeksforGeeks portal. For example, if you want B to completely dominate the overlapping region, you can set alpha to How does alpha-compositing work?

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Save Article. The equation for alpha value and pixel value of the generated image are:. LastMod Improve Improve. You will be notified via email once the article is available for improvement. Parameters of Image. You can suggest the changes for now and it will be under the article's discussion tab. Contribute to the GeeksforGeeks community and help create better learning resources for all. We should first add an alpha channel with value for image A. We use cookies to ensure you have the best browsing experience on our website. ImageDraw and ImageFilter are used when drawing a figure and creating a mask image.