Interactive Viewer

An HTML page written by foresight is the SVG plot plus a small embedded script. The page is self-contained — no network, no external files — and works opened straight from the disk.

Controls

Input	Action
mouse wheel	zoom around the cursor
shift + wheel	zoom x only
ctrl + wheel	zoom y only
left drag	pan
right drag	zoom to the box
u	undo the last box zoom or autoscale
a	autoscale: back to the original view
g	toggle the grid
click on a key entry	hide or show its series
l	link or unlink the x zoom of the panels sharing their x axis (linked by default)
f	follow the end of the data: see below
h or ?	show or hide the help

The cursor coordinates, in data values, show at the bottom left while the pointer is over a plot (with the y2 value when the panel has a second y axis). In a multiplot the mouse acts on the panel under the pointer, keys on the last panel hovered.

Hiding a series

A click on an entry of the key hides its series — lines, points, error bars — and dims the entry; another click shows it again. A series without a title has no entry and stays shown. Hiding does not rescale the axes: a box zoom fits what remains.

Linked panels

Panels whose x axis is the same — same range, same scale, as the panels of a dashboard plotting the same iterations — zoom and pan their x together: a box zoom on the residuals shows the same iterations in the forces panel, each panel keeping its own y. u undoes the zoom on all of them. An inset, with its own x range, stays independent. l unlinks them (and links them again).

Following a live run

On a page that reloads with new data (--watch), zoom to the window you want to watch — the last 200 iterations, say — and press f: the window slides to the end of the x axis, keeping its width, and the y range fits the points shown, gnuplot's autoscale within the window. At each reload the window moves to the new end of the data: a scrolling view of the recent past, as feedgnuplot --xlen. f again stops following; a shows the whole run.

What happens on zoom

The data are never re-plotted: they live in a nested SVG whose coordinates span the unit square, and zooming changes its viewBox only. Line widths stay constant thanks to vector-effect="non-scaling-stroke". What does change is regenerated:

• ticks, tick labels and grid (y2 ticks included), with a line-by-line port of the Fortran tick rules (src/js/viewer.js mirrors src/lib/foresight_ticks.F90), so labels stay exact decimals;
• error bar caps and point type markers (pt), kept at their pixel size in separate overlays.

Back at the original view (a), the ticks written by Fortran are restored exactly.

State in the URL

Zoom, grid and hidden series are kept in the page URL, as data values:

monitor.html#g=1&x=10,30&y=1e-4,1e-1          first panel
monitor.html#g=0&g1=1&x1=2,6&y1=0.9,1.1       second panel zoomed
monitor.html#f=1&g=0&x=900,1000&y=1e-6,1e-3   following the end of the data
monitor.html#g=0&s=2,3                        series 2 and 3 hidden (numbered in plot order, from 1)
monitor.html#l=0&g=0&g1=0                     panels zoomed independently

A reload restores the view, which is what makes live pages usable: when new data change the autoscaled range, the zoom still shows the same data window. Such a URL can be bookmarked or shared along with the file.

Limits

• Tick labels regenerated after a zoom can be wider than the margin reserved by Fortran for the original ones.
• Log and linear scales cannot be toggled in the page: the data are written already mapped to the axis scale.
• Points on the border are clipped to the plot area, as matplotlib does (gnuplot shows them whole).
• Hiding a series does not rescale the axes, and following fits y to every shown series of the panel, on either y axis.