Preferences Dialog

Application Tab

Controls on the Application tab are used to set application wide defaults.

The Language combo-box lists the translations available in QtiPlot. Select a language from this list. Control names, program labels, etc., will be displayed in this language.

The Style combo-box defines the style used by QtiPlot for the window decorations. These include stylistic aspects of buttons, dialog boxes, window borders and titles, etc. Available styles are those currently available in the Qt library.

The Font chooser selects the font used in the GUI (menus, dialogs, etc). It doesn't apply to plots.

The Default Scripting Language combo-box is used to set the scripting language. muParser is the default. Python will also be available if Python support has been compiled into QtiPlot.

The Undo Stack Size is the number of operations that can be undone/redone. By default it is set to ten operations. A high value for this parameter can be very costly in terms of memory consumption, especially for large matrices.

The Endline character combo-box defines the end of line convention used by QtiPlot for copy/paste operations and for exporting matrices/tables to ASCII files. The end of line convention can be set to any one of the following: Line Feed (LF), Carriage Return + Line Feed (CRLF) or Carriage Return (CR) only.

The Start New Project combo-box is used to select what type of child window, if any, is created when a new project is started. The default is for new projects to contain an empty Table window.

The Import Excel files using option allows to specify the method used by QtiPlot when trying to import Excel files. Depending on the operating system QtiPlot provides four methods. The first one (the ExcelFormat library) can fail for certain files, therefore QtiPlot provides a second solution which needs LibreOffice installed on your computer. The third solution which uses OpenOffice is obsolete and users that employed it in older versions of QtiPlot are strongly encouraged to install LibreOffice since it is much faster (the path to the soffice executable must be correctly set in the File Locations tab). Finally, on Windows platforms, if you choose the option Locally installed Excel, QtiPlot uses Microsoft Excel as a server application in order to import the data sheets and also the plots.

The Clipboard Image Format option allows to specify the method used by QtiPlot when copying plot images to clipboard. When the first method (Bitmap) is chosen QtiPlot stores the plots as raster images, while the other methods use vectorial image formats: Enhanced Metafile (.emf), the default format on Windows platforms, Encapsulated Postscript (.eps), the default on Linux platforms and Scalable Vector Graphics (.svg).

The Preview check box allows to enable/disable the display of a preview image in the project explorer when the user hovers the mouse over the name of a project window. The size of the preview can be customized using the spin box on the right. The preview image is scaled to a rectangle preserving the aspect ratio of the window and having the shorter side equal to the value displayed in the spin box. When the Preview box is not checked, the display of the preview image is disabled during mouse hover events, but the user can still preview the window using the context menu of the window item. The context menu is displayed with a right-click.

The Save Every check box is used to turn the auto-save feature on(checked) or off(unchecked). The associated textbox/spin button is used to set the autosave interval. The interval is in minutes. The textbox only accepts positive integer numeric input. All other input is ignored.

The Theme list box can be used in order to choose a Light or a Dark color theme for the user interface. On macOS, starting with release 10.14 (Mojave), if the selected theme is Auto, QtiPlot honours the system preferences. On Linux and Windows operating systems and on macOS versions lower than 10.14, Auto and Light themes are equivalent. Also, on these operating systems, when changing the color theme to Dark, QtiPlot automatically changes the style of the interface to Fusion since it provides the best compatibility. Please note that the Style defined for the application interface has precedence over the chosen color theme, e.g. setting the Light theme with the Kvantum style would still result in a dark color theme being used by QtiPlot.

If the option Backup project before saving is checked, QtiPlot creates a backup copy of the current project before saving any changes. This option is checked by default. The QtiPlot backup files have the extension *.qti~. If QtiPlot closes unexpectedly, the current project file might be corrupted, but it is still possible to recover the initial state of the file which is stored in the .qti~ backup copy. This file can be opened using the Open... command and selecting the option Backup files (*.qti~) from the list of supported file types.

When checked, the Check for new versions at startup option will look for program updates on the internet each time the program is started. The default is disabled. Alternatively, if you wish to be informed when new QtiPlot releases are available, you can also subscribe to our mailing list.

When checked, the Open last project at startup option enables the feature that reloads the last active project when QtiPlot is restarted. The default is enabled.

When checked, the Enable Autocompletion option enables the autocompletion feature of QtiPlot. Autocompletion is enabled by default in all QtiPlot editors (Notes, Script Windows, and values dialogs for matrices and tables). Completion suggestions are automatically popped-up for words that have more than two characters, but you can trigger autocompletion at any time using the shortcut Ctrl+U. Autocompletion can be disabled by unchecking the Enable autocompletion option.

When the option Enable window changelog is checked, the information displayed in the undo/redo stack is logged internally for each table or matrix window in the project and saved into the project file. This information can be viewed at any time by pressing the Changelog... button in the Window Properties dialog of each table/matrix window.

The option Disable in-place editing has an effect when editing axis labels and texts from 2D/3D plot windows. When checked, a local, in-place text editor is created after a double-click on the text to be edited, otherwise the editing process can only be performed by opening the properties editor of each text object.

The option Enable high DPI scaling was introduced in release 1.1.3 and is disabled by default. It is useful when working with multiple screens having different pixel densities. When this option is checked, the application window can be moved from a high DPI screen lo a low DPI screen, or vice versa, and the user interface is automatically scaled based on the monitor's pixel density. This check box is not available on macOS computers because scaling is handled internally by the operating system. After modifying this option QtiPlot needs to be manually closed and reopened before the change becomes effective.

Confirmations Tab

The General Preferences: Confirmations tab contains a set of check boxes that enable/disable various warning prompts. The first six are warnings given when deleting folders or closing project windows (Tables, Matrices, 2D Plots, 3D Plots and Notes).

The remaining warnings are given when renaming or appending windows with names that are already used in the current project, when pasting values to tables, when evaluating multi-line expressions using muParser, when attempting to overwrite an existing file and when modifying data points using the 2D plot tools. All warnings are enabled by default.

Colors Tab

Using the controls from the General group box, it is possible to change the default color for the QtiPlot workspace, the panel background color and the general color of the text. Panels refer for example to the Log Window or the Project explorer.

The controls from the Tool tips group box can be used to change the default background and text colors for the tool tips, the help messages that are displayed when the mouse pointer is placed over a button or menu icon.

The controls from the Matrix group box can be used to change the default background and text colors for matrix windows.

Numeric Format Tab

The Numeric Format tab allows customizing several aspects of numeric formatting used by QtiPlot. The Number of Decimal Digits specifies the default precision used for any calculations applied to your data in Tables and Matrices. The Decimal Separators fields allow selection of the characters used as the decimal point and the thousands separator. By default, QtiPlot uses the locale settings detected on your system. Separate fields are provided for data in tables/matrices and data copied to the clipboard. The thousands separator can be eliminated completely from tables and matrices by checking the Omit Thousands Separator option. QtiPlot will convert all the existing data in your project to the new settings when you click the Apply button.

If the option muParser uses C locale settings is checked operations like setting column/matrix values or plotting function curves require that all the data input parameters are written using the standard convention for the C programming language: the decimal point is the dot character and the thousands separator is omited. Uncheck this option in order to use the numeric format settings specified above.

File Locations Tab

The File Locations tab allows you to define custom locations for the folders containing the translation files, the manual files and the Python configuration files (qtiplotrc.py and qtiUtil.py) if QtiPlot was built with Python scripting support.

The folder entry Startup Scripts is empty by default. This control is only visible if QtiPlot was built with Python scripting support and if the Default scripting language is set to Python in the Application tab of this dialog. In this folder one may place all the Python script files (*.py) that should be loaded and executed when QtiPlot starts.

The LaTeX Compiler and LaTeX Preamble fields are useful if you want to add TeX formated equations to 2D plots and you prefer to generate them using a compiler installed on your computer. The LaTeX Preamble field is optional, you may leave it blank.

In the LaTeX Compiler field you must provide the path to the LaTeX executable. On Linux this path is set by default to /usr/bin/latex. On Windows operating systems you need to choose the location of the latex.exe file. A very popular LaTeX compiler for Windows is MiKTeX. On macOS you can use the LaTeX distribution provided by the MacPorts project. In this case the path to the LaTeX executable is probably /opt/local/bin/latex.

Keyboard Tab

The Keyboard tab makes possible to define custom shortcuts for all actions in the menus and toolbars of QtiPlot.

Internet Connections Tab

Settings on the Internet Connection tab are only needed if you connect to the internet via a proxy server. If you don't now how to set these options, contact your Network Administrator or other suitably knowledgeable person.

Options Tab

Selecting the Tables icon opens the second page of the preferences dialog which allows customizing default aspects of tables: background, text colors and fonts for tables and labels.

Descriptive Statistics Tab

Via this tab you can select the quantities to be computed and displayed in the columns of the result tables generated by the Statistics -> Descriptive Statistics -> Statistics on Columns and Statistics -> Descriptive Statistics -> Statistics on Rows commands.

The following Moments can be computed by QtiPlot:

Before computing the following Quantiles, QtiPlot sorts the input dataset in ascending order.

Options Tab

The Options tab may be used to customize the general behavior of the plot layers. Most of the changes made to these options will be applied only to newly created plots. Changing the options from the General group box: Autoscaling, scaling of fonts and the behavior on resize events will affect existant plots.

If the Legend box is checked, QtiPlot adds a legend opbject to each new plot layer you create, otherwise no legend is added. You may choose the type of information displayed by default in the legend from the drop list box on the right side. If the Indexed Colors box is checked, each line of the legend is wrapped in a \cn(), color syntax specifier, where n is the index of a color from the ordered color list defined in the Curves tab of the Preferences dialog. An example of the default text of a legend object created with this option enabled is given below:

\l(1)\c1(%(1))
\l(2)\c2(%(2))
\l(3)\c3(%(3))

The controls in the Layer group box can be used in order to set a default background and a solid border for each 2D plot layer and to customise the Canvas Color, where the canvas is the drawing area for 2D plot curves.

The controls in the Window group box can be used in order to set a default background and a frame for each newly created 2D plot window.

The controls in the Data Drawing Options group box can be used in order to set the default drawing options that can be modified later on for each plot layer via the Layer Display tab of the Plot Details dialog.

If the Margins box is checked QtiPlot automatically adds some amount of space before and after the data values along each axis scale. The effect of this option is mainly visible when creating new plots from table columns or when rescaling a plot layer so that all data on the graph is visible, using the Graph -> Rescale To Show All command.

The names of the other options in this group box should be self explaining.

Curves Tab

The Curves tab contains a number of controls that define the default style used when creating a new plot.

The controls in the Indexed Colors group box can be used in order to customize the incremental list of default colors used by QtiPlot when plotting a group of data sets or for filling the segments of pie charts. The Palettes box provides four color lists: Default, LibreOffice, Origin1 and Origin2. These palettes can be loaded into the color list editor by pressing the Apply button next to the Palettes list box.

The indexed color list can be edited using the tool buttons on the right side: the New Color button, the Delete Color button, the Move Color Up button and the Move Color Down button. It is possible to save a custom indexed color list to a text file (*.txt), by pressing the Save As... button. The structure of this file is very simple: the colors are saved one per line, using the RGB format #RRGGBB. The text file can be loaded later on into the color list editor by pressing the Open File... button.

Symbol Tab

The Symbol tab contains a number of controls that define the default 2D symbol style used when creating a new plot.

The controls in the Indexed Symbols group box can be used in order to customize the incremental list of default symbols used by QtiPlot when plotting a group of data sets. The indexed symbol list can be edited using the arrow buttons on the right side: the Move Symbol Up button and the Move Symbol Down button. The default symbols list can be reloaded by pressing the Load Default button.

Error Bars Tab

The Error Bars tab contains the controls that define the default style used when adding error bars to a 2D plot curve.

Axes Tab

The first panel in this tab allows to specify the dominant stylistic aspects of the plot axes like their Thickness, the visibility of the backbone line (with the help of the Draw backbones check box) and the space between the axes and their title and between the major ticks and their corresponding labels.

The Synchronize scale divisions box is checked by default, meaning that the scale range and the tick divisions of the opposite layer axes (left/right and bottom/top) are automatically forced to have the same values when you modify any of them. If you need to represent different data ranges for each axis you should uncheck this box. This option can also be set for individual 2D plot layers using the Synchronize scales box from the Layer tab of the Plot details dialog.

If you want that the axes intersect in the center of the plot layer you should check the Crossing axes layout box. With the help of the controls from this panel it is possible to precisely define the positions of the Horizontal and Vertical axes either in percentages of the plot canvas dimensions (width and height) or by specifying a custom scale value.

Using the controls in the Arrow group box it is possible to define a default end arrow shape for the Horizontal and Vertical axes only. The Left, Right, Bottom and Top axes cannot display arrows at their end point.

The Enabled axes panel controls which axes and more precisely which axes elements will be visible in a new plot layer. With the use of the Show check box it is possible to enable/disable a plot axis. The display of the major tick labels is controlled with the Labels check box. If you want to disable the display of an axis title you simply remove the text in the Title edit box.

Ticks Tab

The Ticks tab can be used to define the type of scale ticks drawn on newly created plots.

The drop down list boxes from the Style controls group make possible to customize the default tick style for each side axis of a plot layer (Left, Right, Bottom or Top), as well as for the central axes (Horizontal and Vertical), in case you prefer a crossing axes layout.

The option Max Number can be used in order to set a limit for the number of major ticks that are displayed on each axis if the plot layer is rescaled automatically, for example after using the Rescale To Show All command.

Grid Tab

The Grid tab defines the default aspect of plot layer grids.

Geometry Tab

The Geometry tab defines the default size for the drawing area of a plot layer and the margins around the layers. When the Keep aspect ratio option is checked, changing either the width or height will proportionally change the other dimension. Also, the aspect of the plot canvas (ratio between width and height) will remain unchanged for all future plot layers when you manually resize a graph window.

Speed Tab

The Speed tab lets the user enable/disable antialiasing when drawing/redrawing 2D plots. Antialiasing is a major source of slow-down when rendering 2D plots. Unchecking the Antialiasing checkbox disables antialiasing for all curves, which probably will only be needed in extreme circumstances. Checking the Disable for curves with more than checkbox will disable antialiasing only for curves having data sets larger than the threshold set with the textbox to the right of the Disable for curves with more than checkbox. Disabling this option is probably not a good idea. The default is for both of these options to be enabled, with a threshold of 1000 data points. Proper setting of these options is essential to keeping the application responsive.

The controls from the Speed Mode, Skip Points if needed group box can be used to customize the default speed mode for all new 2D plot layers.

By default, the speed mode uses the Douglas-Peucker algorithm, the purpose of which is to take a curve composed of line segments (or points) and find a new curve with fewer points that is not too dissimilar from the original curve. The algorithm defines 'not too dissimilar' as a function of the maximum distance, the Tolerance, between the original curve and the new curve. The new curve then consists of a subset of the line segments (or points) that defined the original curve.

The Pro edition of QtiPlot provides other two data decimation/downsampling algorithms for easier visualization of large data sets: the Max-Min algorithm and the LTTB (Largest Triangle Three Buckets) algorithm.

The LTTB algorithm works by dividing the input data into buckets or bins (the term used in QtiPlot) and then finding and keeping from each bin the data point that forms the largest triangle with two other data points from the neighbouring left and right bins. The number of bins is equal to the number of points remaining in the filtered data curve. QtiPlot uses a straightforward C++ port of the reference implementation of the LTTB algorithm described in the paper Downsampling time series for visual representation by Sveinn Steinarsson.

The Max-Min algorithm is a much simpler and more agressive filtering algorithm that should be used for very large data sets. It filters the input data curves by keeping from each bin the data points having the maximum and minimum Y values. If the number of decimation bins is set to zero the curves are not filtered, all data points are drawn.

When the speed mode is enabled, filtering of the data is activated only for those curves having more data points than specified in the Apply to curves with more than input box.

The option Disable mouse tracking for curves with more than ... data points can be used to stop detecting the position of the mouse pointer for curves with a very large number of data points. Data tools like the Data Reader command or the Select Data Range command will no longer work for the curves with more data points than the value defined for this option, but the application will be more responsive.

Fonts Tab

The Fonts tab defines the default fonts used when creating new plots. Options are provided for the plot Title, plot Legend, Axes Labels, and Axes Numbers.

Print Tab

The Print tab allows you to control a few default options that are used when printing 2D plots. If you want layers to be printed with their original dimensions, you must be sure to uncheck the Scale layers to paper size option. Checking the Print Cropmarks option ensures that some visible marks will be drawn around the borders of the plot.

Options Tab

Selecting the 3D Plots icon opens the fourth section of the preferences dialog. This set of options is used to customize default aspects of three dimensional plots.

The first page in this section is the Options tab, which allows to set a default size for 3D plot windows as well as default rotation angles around the three axes. Please note that the default size is the canvas size, it doesn't include the window frame.

The color buttons in the Colors group box help define the aspect of the various plot elements like the axes, the scale numbers, the window background, etc... Their meaning should be self-explanatory.

The Smooth Line check box from the General controls group can be used to enable/disable the OpenGL GL_LINE_SMOOTH option: if enabled, QtiPlot draws antialiased lines, otherwise all lines are aliased.

The Multisampling box can be used in order to enable/disable the use of the OpenGL multisampling feature. If the Multisampling box is checked, QtiPlot automatically enables the spin box on the left side, used to defines the number of samples. If unchecked, the number of samples is set to zero. A high number of samples improves the quality of the lines and polygon edges but comes with a performance cost. Please note that any changes to the multisampling settings are only visible after you close and restart QtiPlot.

If the Autoscaling option is checked, QtiPlot will automatically update the scale ranges for the three axes when the source data sets of the 3D curves/surfaces in a 3D plot are modified.

The Scale Fonts option enables the automatic change of the font sizes used for the various 3D plot elements with the size of the plot window. By default, this option is disabled, since it might lead to wrong results in some special cases.

Curves Tab

The second page in this section is the Curves tab, which allows to set the default preferences for 3D curves and surfaces.

The Style list box can be used to define the default appearance for 3D analytical functions or parametrical surfaces. Available styles are: Wireframe, Hidden line, Polygon only, Mesh + Filled polygons, Scatter and Bars.

The Floor style list box allows to define the floor projection of a 3D surface. One can enable a full 2D projection or only display the isolines. The following floor projection styles are available: Empty (the default), Isolines (the isoline projections are visible) and Projection (the 2D projected polygons are visible). If the floor style is set to Isolines, the number of projected isolines can be customised using the Isolines input box bellow.

The Shading defines the way the 3D polygons are rendered. The following shading styles are available:

If the Legend option is checked, QtiPlot automatically displays a legend item for each curve or surface added to a 3D plot window. The text of the legend item has the syntax %(index), where the % character is an alias for the name of the data set and the integer value between the round brackets is the index of the curve/surface. The drop list box on the right becomes available only is the Legend box is checked and allows to select the translation mode for the % character.

The Y drop list box can be used in order to specify the way to calculate the Y values that are used for XYY plot curves. In the Auto mode the Y value is equal to the index of the 3D XYY curve. In the case of the other modes: Long Name, Units and Comments, QtiPlot reads the Y values from the corresponding fields of the Y column used to create the XYY curve.

The controls in the Mesh group box define the aspect of the lines that are drawn in the case of 3D curves or surfaces having the Wireframe, Hidden line, Mesh + Filled polygons or Line + Symbols style.

The controls in the Fill area under curve group box define the default color used to fill the area bellow a 3D curve drawn by the Waterfall Plot and Waterfall Plot (Color Mapped) commands, as well as the possibility to draw the Side Lines and the Baseline.

The Skip Points option from the Data Drawing Option control box is more or less akin to a speed drawing mode, which can be very useful when working with large data sets. Larger values of the Skip Points option result in fewer data points being drawn on 3D plots, and therefore a higher drawing speed. When Skip Points is set to 0, all data points are drawn.

If the Margins box is checked, QtiPlot automatically adds some amount of space before and after the data values along each axis scale, in an attempt to find reasonable scale ranges. The effect of this option is mainly visible when creating new plots from table columns or when rescaling a plot layer so that all data on the graph is visible, using the Graph -> Rescale To Show All command.

Axes Tab

Using the Axes tab it is possible to fully customize the appearance of the coordinates system in a 3D plot.

The following coordinate system styles are available:

By default, the three axes decorated with ticks and numbers are X1, Y1 and Z1. By setting the Enabled axes option to Custom, it is possible to specify which axes should be decorated, using the X, Y and Z drop lists that are enabled in this case.

The perspective view mode can be enabled/disabled by default using the Orthogonal box.

Grids Tab

If the coordinate system is visible, you can enable the display of a default grid for each of its six sides, by checking the corresponding boxes from the Show group box.

The default color, pen style and line width can be customized for both major and minor grid lines, using the controls from the Format group box.

Planes Tab

Using the Planes tab, it is possible to set a color filling for the six sides of the coordinate system. Please note that transparency of these planes is not correctly handled when exporting 3D plots to vectorial image formats (*.EPS, *PDF or *.SVG files). It is also possible to set a default colored Border for the sides of the coordinate system.

Colors Tab

The Colors tab makes possible to define a default color map to be used for rendering 3D surfaces with style set to Polygon only or Mesh + Filled polygons and for the symbols of 3D curves.

If the Scale Colors box is checked, a Z value will be represented by a color defined as a linear interpolation between the adjacent values in the color table.

It is possible to load or store a colormap from/to a XML file by pressing the Open file and Save buttons.

A click on the Level column header opens the Set Equidistant Levels dialog, which allows to quickly edit the color map levels by specifying their total number and an intensity range.

A click on the Color column header opens the Gradient Fill dialog, which allows to quickly customize the colors in the map.

The Opacity slider can be used in order to modify the alpha channel of the color map from 0 % (totally transparent) to 100 % (fully opaque).

Fonts Tab

Using the controls in the Fonts tab you can customize with just a few clicks the fonts for the various elements in a 3D plot: title, axes labels and scale numbers. The Labels font, the last in the list, is used by QtiPlot for new legend items and text objects, as well as for the curve labels that can be displayed near each data point.