OpticalFit Manual 18.06	Table of contents	Spectrum plot	« Last page	Next page »

Spectrum display options

The ‘Spectrum options’ window (shown below) may be used to control the appearance of each spectrum in the plot window, including the display name , drawing style , interpolation mode , colour(s), line width , and smoothing of each spectrum. Additionally, the ‘Spectrum options’ window has buttons to save spectra as files, and to clear (remove) spectra from the current OpticalFit plot.

The ‘Spectrum options’ window.

To open the ‘Spectrum options’ window, select the ‘Spectrum→Spectrum options...’ menu option, as shown below:

Selecting the ‘Spectrum→Spectrum options...’ menu option.

Name

The text used to label each spectrum in the plot legend may be edited by double left-clicking in the ‘Name’ column. If no text is set, a default name will be applied (e.g. “Spectrum 1”).

Style

Spectra in OpticalFit may be plotted in a number of different styles, which may be selected by double left-clicking in the ‘Style’ column to open a drop-down list of style options, as shown below:

The ‘Style’ drop-down list.

‘Line’ and ‘Fill’ styles

The ‘Line’ style draws the spectrum as a single line (shown below left), with a line width given by the ‘Width’ column. The ‘Fill’ style draws the spectrum as a solid-filled area between the spectrum intensity value and the x-axis, as shown below right.

Drawing spectra in the ‘Line’ and ‘Fill’ styles.

If multiple spectra are drawn in the ‘Fill’ style, the later spectra in the spectrum list will overdraw the earlier spectra (as shown above right). However, it is possible to use ‘Fill’ and ‘Line’ styles for different spectra to prevent this over-drawing, as line spectra are always drawn on top of fill spectra (as shown below). Alternatively, you may select the ‘Fill + Outline’ style, in which spectra are drawn first as solid fill, and then as line drawings, resulting in the spectrum line always being visible.

A combination of 'Line' and 'Fill' styles.

Another combination of 'Line' and 'Fill' styles.

Two combinations of ‘Line’ and ‘Fill’ styles.

‘Fill + Outline’ style

The ‘Fill + Outline’ style is a combination of the ‘Line’ and ‘Fill’ styles; the spectrum is first drawn as a solid fill (along with other solid fill spectra), and then over-drawn as a line afterwards. This style ensures the spectrum is always visible, even when 'behind' other solid-filled spectra. Note that the colour of the line and fill may be set independently.

The ‘Fill + outline’ style, which ensures spectra are always visible when 'behind' other solid fill spectra.

Interpolation

When the spectrum view is zoomed in on a small spectral range, each spectrum channel may occupy more than the width of one screen pixel, which requires OpticalFit to interpolate the intensity values between the measured spectral data points. OpticalFit has two interpolation modes:

Continuous, in which a straight line is drawn from one channel's x/y coordinates to the next (below left), and;
Discrete, in which values are not interpolated, but instead presented as a discrete bar graph with a constant y-value within each bar, centred on the channel's x-value (below right).

Continuous (left) and discrete (right) interpolation modes.

The interpolation mode of each spectrum may be changed by double left-clicking on the value in the ‘Interpolation’ column. This opens a drop-down list (shown below) with the options ‘Auto’, ‘Continuous’, and ‘Discrete’. The ‘Auto’ mode uses continuous interpolation when the draw style is ‘Line’, and discrete interpolation when the draw style is ‘Fill’ or ‘Fill+outline’.

Selecting interpolation modes in the ‘Spectrum options’ window.

Fill and Line colour

The colour of the line and/or solid fill used to draw the spectrum may be set by double left-clicking in the ‘Fill’ and ‘Line’ cells, which opens a standard Windows colour-picking dialog box.

For spectra displayed with the ‘Fill + Outline’ style, the fill and line colours may be set independently, as shown below:

Using different fill and line colours with the 'Fill + Outline' style'

Using different fill (grey) and line (black) colours with the ‘Fill + Outline’ style.

Line width

The width of the line used to draw the spectrum in ‘Line’ and ‘Fill + outline’ display styles is set using the ‘Width’ column. In the example below, three spectra are drawn with line widths of 1, 2 and 3 pixels. The default line with is 2 pixels, and the maximum supported line with is 10 pixels.

Setting different line widths in the ‘Spectrum options’ window.

Smoothing

The ‘Smoothing’ column may be used to apply Gaussian smoothing to spectra. For more information, please refer to the smoothing multiple spectra section.

The ‘Save’ button

The ‘Save’ allows you to save one or more spectra as EMSA, CSV, or TAB/TXT files. If multiple spectra are selected in the spectrum list, you will be asked to give the file name of each spectrum one by one in a succession of file saving dialog boxes.

The ‘Clear’ and ‘Clear all’ buttons

The ‘Clear’ button allows you to remove one or more spectra from the OpticalFit plot, depending on how many spectra are selected in the spectrum list. The ‘Clear all’ button removes all spectra from the plot.