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jpg lossless rotation - what is a 'perfect' transformation?
jpg lossless rotation - what is a 'perfect' transformation?
When doing lossless jpg rotation in thumbnails view, you get the option to do perfect transformations only. What does this mean? And what are the consequences of setting/unsetting it?
Simplified answer because there is a lot math behing. Jpeg does not store pixels. The conversion to jpeg works on tiles of a given size. A lossless jpeg operation does not modify the stored image data instead you are just manipulating the transformation. The size of a perfect jpeg is an exact multiple of the tile size. If you rotate a non perfect jpeg you will modify the resulting size.
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