The settings dialog

Declare a setting by its kind and the dialog draws the right control: one page per thing you can declare, in the order you meet them.

One rule

A setting is one declaration users can change without editing code. param.<kind>(name, default, options?) names the kind of value, and the overlay's settings dialog on the chart draws the control that kind calls for: a number field, a toggle, a menu, a color picker, a market button, a session strip. The value you read once in onStart() drives your logic, and changing it reruns the indicator over the loaded bars without recompiling. This is how you ship a configurable indicator: an adjustable period, a threshold, a multiplier, an on/off switch, a picked market.

param.int("length", 20, { min: 2, max: 200 });
param.bool("show_bands", true);
let n: i32 = 20;
let bands = true;
function onStart(): void { n = i32(p_length()); bands = pb_show_bands(); }

Every kind keeps the contract of plain param(name, default, { required, min, max, description }): a top-level statement, a literal default, and a generated reader, readable from onStart() on. Plain param(...) still declares a number field, and a file that uses it runs exactly as before.

The dialog, labelled

The tour's dialog on its two pages. On the left, the rail: one entry per page(...), then a Chart caption with the chart's own entries. Across the top of a page, the presets strip. Below it the rows, grouped by sections: one carries its toggle in its header, one starts folded with its row count in the header. Each row is the label, a hint glyph when the declaration has one, a dot and a reset button once the value differs from its default, and the control the kind names.

Pages on the rail

page(title) starts a page. Pages are entries in the dialog's left rail, in order, above a Chart caption that holds the chart's own entries: the plot settings, visibility and price marker pages follow the pages you declare. Settings declared before the first page(...) land on General. A file with no layout word and no group keeps one flat list. The layout words are on Pages, sections, dividers, notes.

Rows and their controls

Every param.<kind> you declare is a row, drawn as the control its kind names (Setting kinds has all fifteen). The row's name is its label; without one the row shows description, else the name read as words (show_bands reads "Show Bands"). A hint puts words behind a small glyph after the label, shown on hover. Rows that name the same row word share one line of the dialog, and a row whose when toggle is off is dimmed, or hidden with hide (Options on a setting).

The dialog adds the rest by itself. A row that differs from its default shows a dot and a reset button that names the default, and a dialog with more than twelve settings gets a filter box over every page.

The presets strip

presets({ Name: { setting: value, ... }, ... }) ships named sets of values with the indicator. The dialog offers them as chips after Default; picking one fills every setting it names in one step, and editing a row afterwards shows Custom (Presets).

The Style page

Every output you draw gets a row on the dialog's Style page without a declaration: visible, width, line style and color for a line; opacity beside them for an area, and for a column with a static color; visible, width and color for a mark. A spot the file binds to a setting (color: "@basis_color") is that setting's row instead, so a look never has two controls (The Style page).

Browser or cloud

Most settings are numbers the module reads, and every place that runs an indicator hands them to onStart() the same way: your browser, OpenMarket's servers for an indicator published as Protected, and the alerts engine. A setting's value on the chart is the overlay's own, read once in onStart(): the chart runs every setting from the dialog, or from the default when none is set, and changing one reruns the indicator over the loaded bars. An alert on a published indicator runs with the settings of the overlay you set it from (Alerts).

Three kinds are applied by the chart instead: param.source picks the field an input reads, and param.timeframe and param.symbol pin an input. For now the chart applies them only when the indicator runs in your browser.

An indicator that runs on OpenMarket's servers has no Style page either. The lanes in full, with the picks and the 128-setting cap: Picks, lanes, the cap.

Where to go next