Random Dot-to-Dot Drawing Generator

Description

Place numbered waypoints along a supplied open or closed outline with order-preserving arc-length jitter, explicit endpoints, and geometric evidence.

Procedural artwork expresses a visual idea through coordinates, repeated motifs, colors, or explicit placement constraints. A coordinate plan can be checked and reproduced before rendering, while physical material behavior and fabrication require separate information.

Place numbered waypoints along a supplied open or closed outline with order-preserving arc-length jitter, explicit endpoints, and geometric evidence.

When to use this tool

Use this generator to create reproducible dot to dot drawing cases from the supplied model or bank. Inspect the returned evidence before using cases in a test or exercise.

How to use the tool and how it works

Supply outline, closed, count, jitterFraction in the field shapes below. Set seed when you need an explicit replay.
Run the tool and correct any input error. For generated controls, distinguish a successful fixture containing an invalid case from failure to generate the fixture.
Read closed, points, outlineLength, drawingLength, boundingBox. Use the conventions below. Keep answer-bearing fields separate when presenting an exercise.

Measure a supplied polyline's arclength and place sequential numbered points near regular fractions with bounded jitter. Preserve open endpoints, omit a repeated closing endpoint for closed outlines, and return original and connected-point lengths plus bounds.^[1]

Delegated operations used for this result: polyline length; bounding box. Their calculation or parsing conventions apply to the corresponding result fields.^{[2, 3]}

Input field	Meaning and units	Accepted input
outline	Outline	Required. Array of Object; no unknown keys.; minimum items 2; maximum items 128.
outline[].x	X	Required. Finite number.
outline[].y	Y	Required. Finite number.
closed	Closed	Required. Boolean.
count	Count	Required. Safe integer; minimum 2; maximum 256.
jitterFraction	Jitter Fraction	Required. Finite number; minimum 0; strictly below 1.
seed	Optional numeric seed; takes precedence over context randomness. Without either, use the fixed tool.io default seed.	Optional. Safe integer.

Output field	Interpretation	Returned shape
closed	Closed	Required. Boolean.
points	Points	Required. Array of Object; no unknown keys.; minimum items 2; maximum items 256.
points[].number	Number	Required. Safe integer; minimum 1; maximum 256.
points[].x	X	Required. Finite number.
points[].y	Y	Required. Finite number.
points[].arcLength	Arc Length	Required. Finite number.
points[].segmentIndex	Segment Index	Required. Safe integer; minimum 0; maximum 127.
outlineLength	Outline Length	Required. Finite number.
drawingLength	Drawing Length	Required. Finite number.
boundingBox	Bounding Box	Required. Object; no unknown keys.
boundingBox.minX	Min X	Required. Finite number.
boundingBox.minY	Min Y	Required. Finite number.
boundingBox.maxX	Max X	Required. Finite number.
boundingBox.maxY	Max Y	Required. Finite number.
boundingBox.width	Width	Required. Finite number.
boundingBox.height	Height	Required. Finite number.
randomness	Replay source and normalized 32-bit seed, or null seed for an advancing context source.	Required. Object; no unknown keys.
randomness.seed	Optional safe-integer replay seed; normalization and precedence are explained below.	Required. Safe integer. or Null.
randomness.source	Source	Required. Text; one of "context", "seed".

An explicit safe-integer seed takes precedence over injected context randomness and is normalized to an unsigned 32-bit integer. With no seed and no context source, replay uses the fixed tool.io default seed. A context source must return finite values from zero inclusive to one exclusive; its advancing state must be retained separately. randomness records the source and normalized seed, or null for context. These generators are not cryptographic random sources.

json

{
  "input": {
    "outline": [
      {
        "x": 0,
        "y": 0
      },
      {
        "x": 3,
        "y": 0
      },
      {
        "x": 3,
        "y": 4
      }
    ],
    "closed": false,
    "count": 3,
    "jitterFraction": 0,
    "seed": 42
  },
  "output": {
    "closed": false,
    "points": [
      {
        "number": 1,
        "x": 0,
        "y": 0,
        "arcLength": 0,
        "segmentIndex": 0
      },
      {
        "number": 2,
        "x": 3,
        "y": 0.5,
        "arcLength": 3.5,
        "segmentIndex": 1
      },
      {
        "number": 3,
        "x": 3,
        "y": 4,
        "arcLength": 7,
        "segmentIndex": 1
      }
    ],
    "outlineLength": 7,
    "drawingLength": 6.541381265149109,
    "boundingBox": {
      "minX": 0,
      "minY": 0,
      "maxX": 3,
      "maxY": 4,
      "height": 4,
      "width": 3
    },
    "randomness": {
      "seed": 42,
      "source": "seed"
    }
  }
}

Limitations and assumptions

Points advance in arclength but can shortcut corners when connected, so drawingLength can differ from outlineLength. This is a sampled outline exercise, not exact continuous-curve reconstruction or physical tracing guidance.
A replay requires the same complete input and implementation. The stated sampling convention applies within its eligible space. A finite draw does not exhaust all possible outputs; repeats remain possible unless a distinct-selection rule is explicit.
The field tables state structural bounds; cross-field constraints and bounded search or output budgets also apply. Unknown keys are rejected where the object contract disallows them. Input errors are distinct from null fields and deliberate invalid controls in a successful output.

Alternative or Complementary methods

For a supplied example, inspect the returned construction or delegated check directly. To evaluate a consumer, also test cases chosen for its own boundaries; a generated finite corpus does not establish exhaustive coverage.

References

Tool behavior and example: Random Dot-to-Dot Drawing Generator — tool.io
Calculation or validation: geometry/polyline-length — tool.io
Calculation or validation: geometry/bounding-box — tool.io

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