Once initialised, or if a visibility map has been loaded, the image can be resized through this function:

This function decides automatically whether it can use the already computed visibility map, it has to update it or waste it completely and start afresh. This last event occurs when the map was computed for horizontal resizing and a vertical resize has been requested, or vice versa, and also when the required enlargment is bigger than the enlargement step value (see Setting the enlargement step). Note that only initialised carvers can update or change the visibility map; if this is not the case, an error is returned.

The function also takes advantage of the fact that the enlargment process mirrors the shrink process. For example, if the original size of the image is (w0, h0) and lqr_carver_resize is invoked with (w0 - 100, h0) as an argument, then subsequent calls to the function will allow on-the-fly resizing in the whole range from (w0 - 100, h0) to (w0 + 100, h0). (But note that this may be overcome if w0 + 100 is bigger than the enlargement step.)

In order to resize in more than one step, the image can be flattened in its current state, thrugh this function:

The return value is FALSE in case of insufficient memory, TRUE otherwise.

This function destroys the current visibility map and reinitialises the multi-size image from its current state.

The resizing and flattening operations can be aborted using this function:

This function can be invoked asynchronously, from a different thread with respect to the one in which the resizing or flattening methods were called. If successful, this function will return LQR_OK, and any ongoing resizing or flattening functions will immidiately abort and return the special value LQR_USRCANCEL; however, this function will have no effect if no operation was in progress when calling it.

This function can be called multiple times.