Rect... button MLx Home | MLx menu | MLx buttons | Widgets | Index | What's New

This tool is for setting a rectangular region in an image (or stack).

Uses of the Rect... tool

The tool is used in conjunction with the pixels... button to examine portions of an image. The Rect... button defines a rectangle of a set size. This rectangle is then used as a cursor to show a blow up, statistics, a chart of pixel values, and the like.

This tool is used with the pixels... button and the duplicate button to make copies of pieces of images in register.

The tool is used in the stacks widget to select an area for an averaged profile, or to crop the stack when saving it as a raw format file.


The rectangle (crop_bdr parameter) will be draggable by the mouse, as long as the button is held down. Will display new position in the window as a yellow border.

Note that the crop_bdr is not associated with any particular image, although it is shown on whatever image it is made. If it is to be moved using another image, the starting position will become visible upon holding the mouse button down. Alternatively, the position of the rectangle (crop_bdr) can be shown using the Show command above.

Burn in

This is for drawing the bounding rectangle right on an image so that its position can be documented.

Value of rectangle defaults to image max, but can be any value allowed for the pixel data type. A one pixel border with the value you input is written into the image array, destroying the data in those pixels. Don't save this file on top of your original data.

The one pixel border is part of the rectangle - not outside it.

Changing the Rect

The size of the rectangle (and its position) do not change until a new rectangle is moused, or new values are typed in using the Parameters... button.

Cropping images

Images can be cropped using either rect...->crop button. The previously moused rectangle will be used for both size and position. A duplicate image is made from the area inside the rectangle - the original image is not changed. This is NOT like the crop function in Photoshop, which changes the original.

To cut pieces of images of the same size but different positions, use the pixels...->Blow Up button along with the Duplicate button - the duplicate of the 'blow up' will be of the original size - not the zoomed size shown in the blow up.

Note that for convenience, there are two crop options - one for each Rect... button. The one in the central collumn is for cropping a group of images all at the same time. The one in the right collumn is for cropping only one image.