Charts

The toolbar every chart carries and what each button does, the scale, statistics and reference-line panels, the detached chart window, where charts appear in the app, and the one engine behind all of them.

View as Markdown

Every chart in the application is drawn by one engine (ECharts) through one chart view, whatever put it on screen: the Line chart, Bar chart and Pie chart components on a dashboard, the Channels card of a unit panel, the live chart of a run on the Process page, the datalog chart of a recorded run in Histories, the recipe profile preview in a recipe or a procedure, the criterion preview of an evaluation, and the two detached windows below. What differs between them is where the configuration comes from, never the drawing: a gap in the data is always a hole in the line, never a bridge, and every number and instant the chart writes follows the station's own localization. The PDF report renders the same drawing without any of the tools on this page.

A chart carries a row of buttons over its plot: the same bar everywhere, told per chart which buttons to draw. On a dashboard component that list is the Toolbox section of its properties (The dashboard editor); a surface with nobody to ask (a recorded run, a recipe preview) offers every tool a time chart can honour. With no tool at all no bar is drawn.

Button (its tooltip)	What it does	Offered on	On by default on a screen
Open in another window	Opens the same chart in a window of its own (see below). Only where the chart has an address of its own: a recorded run in Histories, a recipe profile. Never on a chart placed on a screen.	Recorded runs, recipe profiles	not offered
Select an area to zoom	Arms box-select zoom: the next drag over the plot frames the box it draws instead of panning. The button stays lit while armed.	Time charts	yes
Reset zoom	Returns the frame to the whole of what is plotted.	Time charts	yes
Set the scale by hand	Opens the scale panel below. Lit while anything is pinned, so a scale that stopped following the data says so without being opened.	Time charts	no
Minimum, average and maximum of the window shown	Opens the statistics panel below. Measured only while the panel is open.	Time charts	no
Draw a reference line	Opens the reference-line panel below. Lit while any line is drawn.	Time charts	no
Save PNG	Downloads the drawing as a PNG at twice the screen resolution, on the theme's background, named after the chart's title ("chart" when it has none).	All charts	yes
Copy PNG	Puts the same PNG on the clipboard. A browser that refuses clipboard writes does nothing, in silence.	All charts	yes
Show or hide series	Opens a list of the plotted series with a tick box each, read straight off the chart; unticking hides a series for as long as the screen stays open. "No series" when nothing is plotted.	Time charts	yes
The tooltip is off / The tooltip is on	Turns the hover readout on or off. It opens off, so a hand crossing the plot never covers it with a box nobody asked for; the choice lasts for the session.	Time charts	yes
Full screen	Fills the window with this one chart, through the browser's element fullscreen; pressing it again, or Esc, hands the window back. On a dashboard already full screen it expands the chart, and Esc leaves the chart before it leaves the dashboard.	All charts	yes

A Bar chart or Pie chart can honour only the PNG pair and Full screen: a comparison read at this instant has no axis to walk, no window to measure and nothing to lay a line on. Only one panel is open at a time, and a press anywhere else closes it.

Zooming and panning themselves are the chart's Navigation setting (a fixed frame, wheel and drag, or wheel and drag plus a navigation bar under the plot showing where the frame sits in the whole recording); a chart with stacked plots moves every plot together, because they share one time axis. A gesture never touches what is stored: the chart draws what reaches the canvas from the visible range, so zooming in always reveals the real data, and a corner mark can say whether the picture is the measurement or a reduction of it (Line chart).

Set the scale by hand

The panel pins a period of the time axis and a range of the value axis, each side independently. Every field commits when you leave it; an empty field is a side left free, still fitting itself.

Field	What it takes
Period / Period (s from now) / Samples	The two ends of the time axis, asked in the words the axis is drawn in: two date-and-time pickers on a clock axis, two numbers of seconds on a relative axis, two sample counts on a sample axis.
Value axis, minimum and maximum	The ends of the chart's own value axis. On a chart with stacked plots this is the top plot's ruler alone; the time period moves every plot together.
Automatic (one per axis)	Hands that axis back to the frame the chart built: a rolling window rolls again, an axis authored with held ends returns to them, one authored with none returns to its free fit. Greyed while nothing is pinned on that axis.
Load the window shown	Fills all four fields from the frame really on screen, after every zoom and pan you made, so pinning what you are looking at costs one press.

The pin belongs to this chart on this connection: it is never saved with the screen, another browser looking at the same chart has its own, and closing the screen releases it. A pinned frame that holds none of the samples still draws, and says so under the plot: "Nothing was measured inside the scale you pinned."

Minimum, average and maximum

The panel is a table with one row per plotted series (a series the screen's author turned off is not on the screen and not in the table; one hidden with the legend still is), coloured by its ink, with Minimum, Average and Maximum over the samples inside the window shown, written the way the station writes numbers. The line above the table says which window that is: "The window shown, up to the newest sample." or "The window shown. The newest sample is past its right edge." when you walked back into the history. A row's tooltip says how many of the window's samples were readings; a gap counts as a sample the window held and as nothing in the three numbers, so no average is taken across a hole. A row with nothing to read writes gaps and says which silence it is: "Nothing of this series was sampled in the window shown." or "Every sample of this series in the window shown is a gap." The numbers follow the live data while the panel is open and are measured over the samples themselves, never over the reduced drawing.

Reference lines

A reference line is a line at a value across the plot, or at an instant down it, with words for why it is there and a colour to tell it from the next. The panel lists what is drawn, each with its ✕, and Remove all; under the list one small form draws the next:

Field	What it takes
Which axis	At a value, or the time axis in its own words: At an instant (a date-and-time picker), At a second (from now) or At a sample. Changing the axis empties the position, since a value and an instant are not the same number.
Where the line goes	The position on that axis. Draw the line is greyed until it holds one.
What the line says	Optional text drawn on the line.
The line's color	A colour picker; a line starts amber.
Draw the line	Draws it. The position and the text empty for the next line; the axis and the colour stay.

Lines belong to the chart in front of you and to nothing else: they are not saved, the screen's author is never told, another connection does not see them, and closing the screen ends them. An annotation that has to outlive the looking belongs to a run, where the run's own file records it (Runs and comments).

The detached chart window

Open in another window opens the chart's own route in a new window: a real window of the application on the station, a new tab in a remote browser. Pressing it again brings the existing window forward instead of opening a second one. Two routes exist:

Route	What it shows	Opened from
`/chart/run/{id}`	The datalog chart of one recorded run, reloaded from the run file: its series, annotations, comments and the approved bands of its procedure as currently configured. "Run not found" when the id resolves to nothing.	The chart of a run in Histories
`/chart/recipe/{id}`	The Step, Ramp and Soak profile of one recipe, rebuilt from the saved models. "Recipe not found" when the id resolves to nothing.	The recipe editor and a procedure's recipe preview

The window renders without the shell: no rail, no title bar, no status bar, just a top bar with the chart's title and Sync X with the main chart ("Mirror the X axis zoom and pan with the main chart"), on by default, over the chart with its full toolbar. While the sync is on the window joins a channel keyed by its route and follows the main chart's zoom and pan on the time axis; turned off, it navigates on its own. Each route demands what admits an identity to what it draws: the run window asks for View histories, the same permission that admits the recorded-run browser it is opened from, and the recipe window asks for the Process page's own policy, which any of the four Process switches or View histories opens. A role without what its own route asks, or one demoted while the window is open, cannot read that chart by its address. The window is read-only: comments and annotations are edited in Histories, not here.

What the tools do not do

Nothing on the bar changes the screen: a hidden series, a pin, a line and the tooltip state are all state of this chart on this connection, and a screen reopened tomorrow opens clean. Nothing on the bar reaches a report: the PDF renders the drawing its own producer builds, without pins, lines or tools. The bar exports no data, only pictures: the numbers of a run leave through the exports of Histories. And the bar offers no tool the drawing cannot honour: a comparison of categories never gets zoom, scale, statistics or lines, and a chart on a screen never gets a window of its own.