The line measurement tool allows you to position two crosshairs anywhere on the screen and measure the positions, distance and other information for the line connecting them. Both the data window attached to the crosshairs and Meazure’s tool information section will display the measurement information. The magnifier window will show the area around the crosshair that is being moved as well as the color of the pixel at the center of the crosshair.

The tool information section displays the following measurements for the Line tool:

• X1, Y1 - The position of the Point 1 crosshair
• X2, Y2 - The position of the Point 2 crosshair
• W, H - The width and height of the bounding rectangle for the line. W = |X2 - X1| + 1, H = |Y2 - Y1| + 1
• D - The length of the line connecting the two crosshairs. D = sqrt(W² + H²)
• A - The angle of the line relative to the x-axis. Using the default coordinate system, positive angles are measured clockwise from the positive x-axis to the line from Point 1 to Point 2
• Ar - The area of the bounding rectangle for the line. Ar = (W * H)

Note that the calculation of W, H, D and Ar is always performed in pixel units and the result is converted to the currently selected display units.

The mouse or keyboard can be used to position the crosshairs and fine adjustment can be made with the up/down buttons adjacent to the position text fields. When using the mouse to drag a crosshair, the SHIFT key can be used to lock the line to the horizontal or vertical direction. In addition, the entire line can be moved by pressing the CTRL key while dragging one of the crosshairs.

To select the Line tool choose the Line item on the Tools menu or click on the Line tool icon on the toolbar.