Mouse Actions

Many operations on control points and images may be carried out with a combination of mouse and keyboard actions. 

Note:

All keys except the arrow keys must be pressed before a mouse button is pressed, and they must be held down until after the mouse button is released, or nothing happens.  You can use this feature to cancel an operation simply by releasing the key before releasing the mouse button.

Left Mouse Button:

No Key: 

If two images with at least four control points each are loaded, then a black-rimmed magnifier appears when the left button is pressed, and a green-rimmed magnifier appears in the opposite image and tracks the position of the black rim magnifier when the mouse is dragged.

Shift:

The nearest corner of the blinking white and red quadrilateral is captured by the mouse, and it may be dragged to set a primary control point at a new position.  Three additional primary control points are set at the other three corners of the quadrilateral.

Ctrl:

A red rimmed magnifier appears which can be dragged to a new position. When the left mouse button is released, a control point is set at the position given by the centre of the magnifier and marked on the image in either black or white depending on the brightness of the background along with an identification number.

Alt:

Hold down the left button while Alt is pressed and drag the mouse to draw a red/white blinking line on the image. Release the left button and repeat to set a control point at the intersection of the two lines drawn.  If the intersection is outside of the image, a square will be drawn along with the identification number at the nearest point on a side of the image in the direction of the intersection.

Mouse Wheel or Middle Button:

No Key: 

Zoom into or out of the image which has the focus with the wheel, zoom in with the middle button.  

Shift: 

Zoom out of the image.

Right Mouse Button:

No Key: 

Display an overview of the image which has the focus and showing at larger than minimum zoom. Moving the mouse in the overview moves a frame. A left mouse click  will display the portion of the image shown in the frame, centered in the window.

Shift:

If two images are loaded with at least 4 control points each, then two magnifiers appear, one cyan rimmed, the other magenta rimmed. The cyan rimmed magnifier tracks the mouse when it is dragged. Releasing the right button enters two control points simultaneously in both images. If the cyan magnifier is held on a control point which has a corresponding point in the other image and the button released, both control points will be deleted.

Ctrl:

A blue rimmed magnifier appears and when placed over a control point and the button released, the control point is disabled and changes its colour to blue. If a corresponding control point in another image exists, it too will be disabled.  Repeat the operation to re-enable disabled control points.

Alt:

A light blue rimmed magnifier appears. Drag this to a control point and release the button.  The control point colour changes to red. You can now move the control point a pixel at a time with the arrow keys on the numeric keypad.  The original red marker is retained for reference. Press Enter on the keyboard, and the control point is moved to the new position selected with the arrow keys and the red marker is turned off.