[Discussions] What is the practical sense for needRotate boolean?

[bambinoua]

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What is the practical sense for needRotate boolean? If I just need to know the size of the image? Width and height are enough to know image orientation - portrait or landscape.

[CaiJingLong]

The exif of jpeg maybe contains orientation attr.

A example to know it: https://developer.mozilla.org/en-US/docs/Web/CSS/image-orientation

See the attr info to read wiki.

This value range is 1~8, but only 1, 3, 6 and 8 can be seen when using.

A document of MIT: https://www.media.mit.edu/pia/Research/deepview/exif.html#orientation

From load to render graph:

graph TD;
    A[Load Image] --> B{exif orientation = 6 or 8?};
    B -- 6 --> C[Rotate counterclockwise by 90 degrees];
    B -- 8 --> D[Rotate clockwise by 90 degrees];
    B -- other values --> E[No rotation];
    C --> F[Render rotated image];
    D --> F;
    E --> F;

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This is image size getter about the attribute:

graph TD;
    A[Read metadata] --> B[Get image width and height];
    B --> C[Determine if rotation is needed];
    C --> D{Need rotation?};
    D -- Yes --> E[Rotate image];
    D -- No --> F[Do not rotate image];
    E --> G[ Return Size with needRotation=true];
    F --> H[Return Size with needRotation=false];

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