Usage

Starting PyGRA

pygra

Interface overview

Left panel

  • Load files — opens one or more data files

  • Series selector — dropdown menu to quickly navigate between loaded series without scrolling through tabs

  • Series tabs — one tab per loaded series; each tab has column selectors, mode selector (Series / Histogram / Histogram 2D), Appearance button, visibility checkbox, and a close button (✕)

  • Fit & interpolation layers — lists active fit curves with visibility toggle, remove button, and double-click to edit style

  • Axis settings — labels, title, log scale, limits

  • Plot — renders the figure (also Ctrl+Enter)

  • Double-click on a curve in the plot to automatically switch to the corresponding series tab in the left panel

Toolbar

  • 🔍 Zoom — click and drag to zoom into a region

  • ✋ Pan — click and drag to pan the view

  • ⌂ Reset — restore the original view

  • ↺ Legend — reset the legend to its automatic position

  • ✎ Text — add a draggable text annotation to the plot

  • Coordinate display — x and y values under the cursor, shown in real time on the right side of the toolbar when hovering over the plot

Plot modes

Each series can be displayed in one of three modes, selectable via radio buttons in the series tab:

Series — standard x/y line or scatter plot with optional error bars.

Histogram — 1D histogram of a selected column. Options in Appearance:

  • Bin count (manual or auto) and normalisation (count / density / probability)

  • Horizontal orientation

  • Color by value — bars colored using a matplotlib colormap based on height

  • Percentage labels with configurable font size and bold option

  • Show/hide percentages

Histogram 2D — 2D density map of two columns. Options in Appearance:

  • Bins x / bins y (manual or auto)

  • Colormap (viridis, plasma, coolwarm, etc.)

  • Normalisation (count / density)

  • Log scale for the color axis

  • Colorbar on/off

Text annotations

Click ✎ Text in the toolbar to add a text annotation to the plot. A dialog allows you to set:

  • Text content (Shift+Enter for newline)

  • Font size and bold

  • Color

  • Rotation angle (degrees)

Once placed, annotations can be:

  • Dragged — click and drag to reposition

  • Edited — double-click to reopen the dialog

  • Deleted — right-click → Delete

Annotation positions are preserved across replots and saved in sessions.

Color picker

The color picker uses the Qt dialog (same appearance on all platforms). The Basic colors grid can be replaced with any scientific palette via View → Color palette. A checkmark indicates the active palette, and the name of the active palette is shown in the color picker itself (“Basic colors palette (active: …)”). The chosen palette is saved in preferences and restored at next launch.

On Linux, the Pick Screen Color button captures any color visible on screen. On macOS and Windows this button is hidden, as platform security restrictions prevent capturing colors outside the dialog window.

Custom colors added via Add to Custom Colors are saved in preferences and restored at next launch on all platforms.

Draggable legend

After plotting, click and drag the legend to reposition it anywhere on the figure. The position is preserved across subsequent plots. Click ↺ Legend in the toolbar to reset to automatic positioning.

Legend style options are available in View → Style settings: frame on/off, background transparency, number of columns, symbol size, default position, and show/hide toggle.

Style settings

View → Style settings (Ctrl+,) controls global appearance:

  • Font sizes for title, axis labels, ticks, and legend

  • Bold text options for each element independently

  • Major/minor tick spacing and grid

  • Plot theme (default, dark, seaborn, ggplot, bmh, grayscale)

  • Figure size and DPI for saving

  • Legend options (position, frame, transparency, columns, symbol size)

User preferences

PyGRA saves preferences automatically to ~/.config/pygra/preferences.json when you close the application. These include:

  • Window geometry and panel proportions

  • Style settings (fonts, grid, theme, DPI, figure size)

  • Last used color palette

  • Custom colors

Use View → Save preferences to save at any time, or View → Reset preferences to restore defaults.

File format

Files should be whitespace-delimited with one data point per row. Lines starting with # are treated as comments and ignored.

# x   y    dy
0     1.0  0.05
1     2.3  0.08
2     1.8  0.06