Using imgproc::find_contours ?

[Tramac]

// gray_image_slice is slice &[u8]
let gray_image = image::GrayImage::from_raw(240, 360, gray_image_slice.to_vec()).unwrap();
// gray_image.save(&"gray_image.png");

let mut contours_cv = VectorOfVectorOfPoint::new();
imgproc::find_contours(
    &gray_image, 
    &mut contours_cv, 
    imgproc::RETR_EXTERNAL,
    imgproc::CHAIN_APPROX_SIMPLE,
    core::Point::new(0, 0),
).unwrap();

The following error occurred when compiling：

The gray_image is type of ImageBuffer, but imgproc::find_contours need ToInputArray, I have no idea how to convert ImageBuffer to ToInputArray format, help please.

[twistedfall]

The easiest way is to use OpenCV function imgcodecs::imread to load image, like in this example: https://github.com/twistedfall/opencv-rust/blob/master/examples/window.rs

[Tramac]

Thanks for your reply, but there is no way to load image locally, only slice given.

[twistedfall]

If you only have a byte slice then you'd need to manually make a Mat and copy the data over into it. I'm planning to make a release later today with the helper function for that. Alternatively you can use the rel branch and call the Mat::from_slice_rows_cols() function (https://github.com/twistedfall/opencv-rust/blob/rel/src/manual/core/mat.rs#L172). It should look something like this for your case:

let gray_image = Mat::from_slice_rows_cols(gray_image_slice, 360, 240).unwrap();

[twistedfall]

This should now be available in 0.76.3 release