Configuration

Sizer has two parts to configure: the charts you build and reuse, and the two wording settings that control the text shoppers see. Everything is under WooCommerce → Size Guides, which has two tabs, Settings and Size charts. There is intentionally no display-style, trigger-style or placement choice: the guide is always a button rendered after the add-to-cart button that opens a modal.

Settings

The Settings tab has exactly two fields, stored together in the sizer_settings option.

Link wording

The clickable text on the product page that opens the chart, the value of trigger_label. Keep it short; Size guide, Size chart or Find my fit all read well next to the price. Leave it blank and Sizer falls back to Size guide. A small preview of the storefront button is shown under the field so you can see the wording without leaving the page.

Pop-up heading

The heading shown at the top of the dialog once it opens, the value of modal_title. Leave it blank to reuse the Link wording above, so by default the button and the heading read the same.

Both fields are sanitised with sanitize_text_field on save. The settings page (and the chart manager) require the manage_woocommerce capability.

Building a chart

On the Size charts tab a chart is a labelled table, for example sizes down the side (S, M, L) and measurements across the top (Chest, Waist, Length). Each chart has:

• id, a slug generated from the name (or a random chart-xxxxxxxx fallback); you do not edit it directly.
• name, required, used in the assignment dropdown and as the table’s screen-reader caption.
• caption, optional text shown below the table on the storefront.
• columns, the header cells.
• rows, one list of cells per row; the first cell renders as a row header (<th scope="row">).

Charts are stored together in the single sizer_charts option (not autoloaded). Saving the form replaces the whole set, so the page is the source of truth, there is no per-chart save. Empty rows and unnamed charts are stripped during save.

Assigning a chart

A chart only appears once it is assigned to a product. Edit the product, open Product data → Size guide, and pick the chart in the Size chart select. The choice is stored as the _sizer_chart_id post meta and saved with a nonce and an edit_product capability check. Choosing - No chart - removes the meta, so the guide disappears from that product.

There is no category-level or store-wide assignment in the free edition. A store-wide default chart (one chart for every product with no explicit assignment) is the single shipped Sizer Pro feature; it works through the sizer/resolved_chart_id filter described in Using size guides.

Theming and overrides

• Templates, Sizer loads its storefront markup through a theme-overridable loader. Copy any of templates/single-product/trigger.php, dialog.php or chart-table.php into your theme at yourtheme/sizer/single-product/<file>.php; the theme copy wins over the plugin’s. Overrides survive plugin updates.
• CSS, the storefront stylesheet is built on custom properties so you can re-theme without touching markup. On the trigger: --sizer-accent, --sizer-accent-ink, --sizer-accent-contrast, --sizer-tape and --sizer-radius. On the dialog: --sizer-dialog-bg, --sizer-dialog-fg, --sizer-border and --sizer-head-bg. A prefers-color-scheme: dark block re-points the dialog colours, and entry animations and the size-row highlight are gated behind prefers-reduced-motion: no-preference.

What is fixed by design

A few behaviours are deliberately not settings, so the guide stays correct:

• The button is always rendered on woocommerce_after_add_to_cart_button at priority 15, there is no placement option.
• The trigger is always a styled button (.sizer-trigger--button); there is no text-link variant.
• The chart always opens in a native <dialog> modal; there is no inline product-tab display.
• A product with no assigned chart renders nothing at all.

Storage and cleanup

Settings live in sizer_settings, charts in sizer_charts, and a schema marker in sizer_db_version. Per-product assignments live in the _sizer_chart_id post meta. Deleting the plugin runs the uninstall routine, which removes the three options but leaves the post meta in place, so reinstalling keeps your existing per-product assignments. Everything stays in your own database.