The crosshair lines are movable lines that can be used to specify and measure positions on the spectrum. One or two horizontal, and one or two vertical, crosshair lines may be displayed. Two or four crosshair lines can be used to specify a region of the spectrum to be used for some subsequent action, such as to display an expansion of the spectrum. Each of the four possible crosshair lines may be enabled or disabled. With 1D spectra, only the two vertical crosshair lines are enabled by default. The crosshairs can be positioned when the cursor is in the "crosshair" mode. Click the cross button near the lower left corner of the window.
To display the crosshairs:
Click the left mouse button with the pointer positioned at the location you want the first crosshair line(s) to appear.
Click the middle mouse button to get the second crosshairs (red).
To move an existing crosshair:
Press and hold the left mouse button with the pointer near the first crosshair. Keep the button down as you drag the crosshair to a new position. If you first position the pointer near the intersection of two croshairs lines, then both crosshairs will move. If you position the point near a single crosshair line (vertical or horizon- tal), then only that crosshair will move. Use the middle mouse button to position the second crosshair.
To remove the crosshairs:
Click the redraw button in the control panel to the right of the spectrum. When the spectrum is redrawn the crosshairs will not be displayed.
To move the spectrum region
Hold down the Command key (Mac OS X) or Control key (Windows or Linux) and click and drag with the left mouse button. The spectrum will pan left and right along with the cursor. With 2D spectra you can also pan the spectrum region vertically.
Status panel displays crosshair positions
As the crosshair lines are moved around the spectrum the status panel is continuously updated with their positions (in PPM). The horizontal distance (in Hz) between the two vertical crosshair lines is also displayed. This can be useful for the manual measurement of couplings. The crosshair positions can be precisely adjusted by typing a value into the status panel entries for each of the crosshair lines. After entering a value, hit the Return key to move the crosshair to the new position. This is useful to, for example, set up expansions of the spectrum.
Selector mode can be used when the cursor is in the "selector" mode. Click the arrow button near the lower left corner of the window.
To expand the spectrum view
Press and hold the left mouse button with the cursor at the position you want to start the expansion at. Keep the button down as you drag the crosshair to a new position. When you release the mouse button the window will expand to display the selected region.
To move the spectrum region
Hold down the Command key (Mac OS X) or Control key (Windows or Linux) and click and drag with the left mouse button. The spectrum will pan left and right along with the cursor. With 2D spectra you can also pan the spectrum region vertically.
To add or adjust a spectrum region
Use the same protocol as above to expand the view, but press and hold the Alt key on the keyboard while performing the actions. If you do this in an area that doesn't overlap any previously existing regions, a new region will be added to the spectrum. If the area does overlap a region, then that region will be adjusted so the limits correspond to the selected area.