The MVIEW program enables the user to inspect multidimensional NMR data interactively. The data is show as a 2D bitmap display. For spectra with a dimension greater than 2, planes can be extracted with all possible dimensions along the two axes. The program can only display its graphics on a screen with at least 128 user selectable colors (PseudoColor mode). It has been tested without problems on the Silicon Graphics Personal Iris, the Stardent 1500 machine, and on the SUN SPARC station.
The MVIEW program is called as follows:
<Machine ID>mview <name> <expno> <procno> <disk> <user>
The main part of the MVIEW window is occupied with a bitmap display of the spectrum. When the program is started up with a 2D spectrum as input, the whole spectrum will be shown in the window. If the input is a 3D spectrum, the window will contain the first plane in the slowest dimension (number 2).
The mapping of values to colors is controlled with the two sliders to the left. The left slider controls the low value, and the right slider controls the contrast (i.e. the difference in values between the black and the most intense display). Positive values are mapped to red, negative to blue.
The stop button terminates the MVIEW program.
The two rows of dimension buttons select the dimension to be shown along the x- and y-axis, respectively. If a value is chosen for the x-axis, the same value cannot be used for the y-axis.
If a spectrum with a dimension higher than two is used as input, one or more index lines appear under the dimension buttons. If the spectrum has n dimensions, n-2 lines will appear. Each line is used to select the index number for the dimension(s) not shown along the x- or y-axis. If the fastest (0) axis is shown along the x-axis, and the slow axis (1) along the y-axis, one field for entering the plane number in the slowest dimension appears. Enter a value, from zero to the number of planes minus one, and press enter in the box to fetch another slice.
Pressing the left mouse button while the mouse is located in the graphics display stores the current coordinates in the editors to the right of the x- and y-axis selection. These fields can also be specified manually.
After pressing this button, the currently selected slice will be fetched and displayed in a separate window. The slice will be fetched from the dimension selected with the working dimension buttons. The slice will be presented in a separate window. The x-axis of the slice will correspond to the current state of the scale buttons. Each slice window can be scaled separately.
When the program is started, the whole spectrum or plane will be shown in the bitmap display. To select only a part of the spectrum/plane, use the scale buttons. You can only scale the display in powers of two, and the limits of the display will always be a multiple of the size of the window. Thus, if the size of the spectrum is 1024 x 1024, scaling 4 times will enables you to select one out of 16 squares of the spectrum, the x and y ranges being 0-255, 256-511, 512-767, or 768-1023. If you decrease the scaling value (zooming out), the bigger window containing the previous view will be selected. If scaling is increased (zooming in), the area around the point last selected will be displayed.
The working dimension is selected either as the current x dimension or as the current y dimension. The working dimension is the dimension in which to select slices and subsequently perform phase correction interactively. As soon as a slice has been selected, you cannot switch working dimension unless you manually exits all the slices currently opened.
If zerofilling is set to a value greater than 1, slices displayed in the slice windows will first be reversed FFT'ed (using a Hilbert transformation), zerofilled to the selected size, and FFT'ed again. This value can be changed after slices have been selected, and the displays will change accordingly. The usefulness of this feature is limited.
The slices selected can be phase corrected interactively. A Hilbert transformation is used to regenerate the imaginary part of the complex points, even though a dimension is selected for which the imaginary part still exists in the data file. Before doing any phase correction, select the zero point for the linear phase correction in the bitmap display. This is simply done by pressing the Select Phase Offset button, and the current x- and y-position is selected as the zero point. A crosshair is always shown at the zero point, unless the display is zoomed to a part of the spectrum that neither contains the x- nor the y-value of the crosshair. Click the buttons in the 0-order phase list to change the constant phase, and the buttons in the 1-order list to change the linear phase.
When you have obtained the proper values for the phase correction in one dimension, exit the program, and adjust the phases of the whole spectrum in that dimension using the MPHASE program. Reenter the MVIEW program and go on with the next dimension.