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Process Stroke Data

Process handwriting stroke coordinates directly, without needing to generate an image first. Supports the same options as image processing but with lower latency.

Send stroke data​

Send stroke data to the v3/strokes endpoint. Strokes are represented as arrays of x and y coordinates, where each sub-array is one continuous stroke.

info

The request body has a double-nested strokes key:

  • The outer strokes is the API parameter name
  • The inner strokes contains the coordinate data (x and y arrays)

The example below sends four strokes that form the handwritten expression 3x23x^2:

Visualization of the four strokes in the example request. Each polyline is one continuous stroke rendered from the x and y coordinate arrays.
{
  "strokes": {
    "strokes": {
      "x": [
        [131,131,130,130,131,133,136,146,151,158,161,162,162,162,162,159,155,147,142,137,136,138,143,160,171,190,197,202,202,202,201,194,189,177,170,158,153,150,148],
        [231,231,233,235,239,248,252,260,264,273,277,280,282,283],
        [273,272,271,270,267,262,257,249,243,240,237,235,234,234,233,233],
        [296,296,297,299,300,301,301,302,303,304,305,306,306,305,304,298,294,286,283,281,281,282,284,284,285,287,290,293,294,299,301,308,309,314,315,316]
      ],
      "y": [
        [213,213,212,211,210,208,207,206,206,209,212,217,220,227,230,234,236,238,239,239,239,239,239,239,241,247,252,259,261,264,266,269,270,271,271,271,270,269,268],
        [231,231,232,235,238,246,249,257,261,267,270,272,273,274],
        [230,230,230,231,234,240,246,258,268,273,277,281,281,283,283,284],
        [192,192,191,189,188,187,187,187,188,188,190,193,195,198,200,205,208,213,215,215,215,214,214,214,214,216,218,220,221,223,223,223,223,221,221,220]
      ]
    }
  }
}
Example response
{
  "request_id": "cea6b8e4-0ab4-550a-c467-ce2eb00430be",
  "is_printed": false,
  "is_handwritten": true,
  "auto_rotate_confidence": 0.0020149118193977245,
  "auto_rotate_degrees": 0,
  "confidence": 1,
  "confidence_rate": 1,
  "latex_styled": "3 x^{2}",
  "text": "\\( 3 x^{2} \\)",
  "version": "SuperNet-109p4"
}

In the example response, the latex_styled field renders as:

3x23 x^{2}

Live stroke sessions​

For live digital ink with updating results (e.g., in a mobile app), use app tokens with stroke sessions:

  1. Get an app_token with strokes_session_id from your server:
POST /v3/app-tokens
{
  "include_strokes_session_id": true,
  "expires": 300
}
  1. Use the app_token and strokes_session_id in client requests to v3/strokes.

Live stroke sessions are billed differently from standalone requests — see pricing. You are billed the first time strokes are sent for a session, not when requesting the token.

Next steps​