Calculate hash of an Image?

[harshita]

hi all,

i am trying to compare 2 images in an efficient manner using Qt/c++, how can i find the hash of an image?

i found this class QCryptographicHash that can be used but i am not sure, if this can be used then how do i convet the image say a Qimage to QByteArray?

Is there any thing similar available in c++?

thank u

[stampede]

how do i convet the image say a Qimage to QByteArray?
QImage has constBits() (http://doc.qt.nokia.com/latest/qimage.html#constBits) method that returns the pixel data, you can use it to construct the QByteArray (http://doc.qt.nokia.com/stable/qbytearray.html#QByteArray-2), which you can pass to QCrypthographicHash.

Is there any thing similar available in c++?
C++ is a programming language, it has no built-in support for image processing.

[mnutt]

If you're just comparing images, QImage::cacheKey may be what you're looking for.