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).

• Mouse 'Mouse' a rectangle by dragging. Sets the crop_bdr parameter, which can be read with the Parameters button. This is the faster way to mouse a rectangle.
• Mouse Adjust 'Mouse' a rectangle by dragging. If control key is held down, the rectangle will be initialized to the crop_bdr parameter, ie., to the last moused rectangle -- release the control key to adjust further: After the rectangle is 'moused', the four sides are adjustable by dragging each side with the mouse. The rectangle is fixed when the go-away square of the PINK message bar, wich lies on top of the image window title bar, is clicked. Sets the crop_bdr parameter, which can be read with the Parameters button.
• Move Drag the rectangle with the mouse without changing its size.
• Clear Clears the crop_bdr parameter. (Can also be cleared and otherwise changed via the parameters button, but this is faster.) Some operations will work with the rectangular region ONLY, if this parameter is set.
• Burn in Permanently put the rectangle into a gray scale image.
• -> Square Force the rectangle to be a square.
• Show Show the rectangle in the image. Clicking on the grow box will redraw the image window, showing this rectangle. The graphics in the window can be cleared with the Clear ->Graphics button. This is independent of the crop_bdr parameter.
• Crop Image Crop the image (making a new one) to the size of the rectangle.
• Area Displays and prints the area of the rectangle. Use the parameters button to show the actual coordinates of the crop_bdr parameter. (The four numbers are the locations from the upper left corner of the image in pixels).

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.

Move

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.