Copy Cv Mat

Mat copyto is for when you already have a destination cv mat that may be or is already allocated with the right data size.

Copy cv mat.

Note don t forget to delete cv mat cv matvector and r the mat you get from matvector when you don t want to use them any more. It passes the number of dimensions 1 to the mat constructor but the created array will be 2 dimensional with the number of columns set to 1. The weird thing is that most of times it works correctly. Mat clone is a convenience for when you know you have to allocate a new cv mat.

Making borders for images padding if you want to create a border around the image something like a photo frame you can use cv copymakeborder function. I researched with ptr and at methods available in opencv apis but i could not get proper d. So mat dims is always 2 can also be 0 when the array is empty. Qimage img uchar mat data mat cols mat rows qimage format rgb32.

To convert from cv mat to qimage you could try to use the qimage uchar data int width int height format format constructor as follows mat is a cv mat. Recently i have troubles finding opencv functions to convert from mat to array. But it has more applications for convolution operation zero padding etc. According to the documentation if i return a cv mat it ll have no use because after the function returns the local copy of the cv mat in that function will be destroyed and therefore the one accepting the returned value outside the function should be pointing to some random address.