Field settings
Introduction
An Autograph field is a channel field like any other. Create it under Developer › Fields, choose Autograph as the type, and assign its field group to the channels that need a signature.
Autograph fields can be used as ordinary channel fields, and as member fields. They can't be used inside Grid or Fluid fields.
Settings
Each Autograph field has four settings, under Field Options:
| Setting | Default | What it does |
|---|---|---|
| Canvas Width | 400 | The width of the signing pad, in pixels. Required. |
| Canvas Height | 200 | The height of the signing pad, in pixels. Required. |
| Pen Color | Black | The colour of the ink. Picked with ExpressionEngine's colour picker. |
| Save in Control Panel | Off | Whether editors can sign on the publish form. See Control panel. |
The canvas size is also the size of the saved image, and the size {field_name} gives the <img> it outputs. If you change it after signatures have been saved, existing signatures are drawn at the new size, stretched if the shape changed.
The signature is saved as a PNG image inside the entry. A bigger canvas makes a bigger image, and the column it's saved in holds about 64 KB. 400 × 200 leaves plenty of room. See Long signatures are cut off.
Required fields
Mark the field Required in its field settings to make a signature mandatory. An untouched or cleared pad submits an empty value, so ExpressionEngine refuses the entry as it would any other empty required field.
What gets saved
Every signature is saved as a PNG data URL, a line of text beginning data:image/png;base64,, in the field's own column on the entry. Nothing is written to an upload directory. The background is transparent.
Because it's text, the signature travels with the entry: it's copied when the entry is duplicated, included in entry exports, and deleted with the entry.