Semantics

The default semantic of the Frame class ensures that the memory ownership is preserved when creating a new instance of a Frame object. That means that the new Frame object will be the owner of the image content (by creating a copy) if the source Frame is also the owner of the image content. The new Frame object will not be the owner of the image content if the source Frame is also not the owner of the image content. For example:

Frame sourceFrameOwningTheMemory = ...;
Frame newFrameWithCopiedMemory = sourceFrameOwningTheMemory;

Frame sourceFrameNotOwningTheMemory = ...;
Frame newFrameAlsoNotOwningTheMemory = sourceFrameNotOwningTheMemory;

// memory ownership of source and new frames will be identical
assert(sourceFrameOwningTheMemory.isOwner() == newFrameWithCopiedMemory.isOwner());
assert(sourceFrameNotOwningTheMemory.isOwner() == newFrameAlsoNotOwningTheMemory.isOwner());

However, when using the copy constructor of Frame with explicit copy mode, the copy behavior can be customized.

Frame sourceFrame = ...;

// Using memory, not making a copy, the padding layout is preserved.
Frame newFrame(sourceFrame, Frame::ACM_USE_KEEP_LAYOUT);

// Make a copy of the memory,
// but the new memory will be continuous and the source padding data is not touched
Frame newFrame(sourceFrame, Frame::ACM_COPY_REMOVE_PADDING_LAYOUT);

// Make a copy of the memory,
// the new memory will have the same padding layout as the source image,
// but the actual padding data is not copied
Frame newFrame(sourceFrame, Frame::ACM_COPY_KEEP_LAYOUT_DO_NOT_COPY_PADDING_DATA);

// Make a copy of the memory,
// the new memory will have the same padding layout as the source image,
// the padding data is copied as well
Frame newFrame(sourceFrame, Frame::ACM_COPY_KEEP_LAYOUT_COPY_PADDING_DATA);