Random Bullet Journal Spread Layout Generator

Description

Stack supplied tracker, note and calendar blocks on two dimensioned pages with gutter and legal-side constraints, without accessing journal content.

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.

Stack supplied tracker, note and calendar blocks on two dimensioned pages with gutter and legal-side constraints, without accessing journal content.

When to use this tool

Use this generator to create reproducible bullet journal spread layout 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 pageWidth, pageHeight, gutter, blocks 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 placements, spreadWidth, spreadHeight, paperArea. Use the conventions below. Keep answer-bearing fields separate when presenting an exercise.

Use bounded backtracking to place each block on an allowed side of a two-page spread. Stack blocks vertically from each page's top, check width and cumulative height, and return coordinates, spread width including gutter, and paper area excluding gutter.^[1]

Input field	Meaning and units	Accepted input
pageWidth	Page Width	Required. Finite number; strictly above 0.
pageHeight	Page Height	Required. Finite number; strictly above 0.
gutter	Gutter	Required. Finite number; minimum 0.
blocks	Blocks	Required. Array of Object; no unknown keys.; minimum items 1; maximum items 16.
blocks[].id	Literal identifier used independently of display labels.	Required. Text; minimum UTF-16 length 1; maximum UTF-16 length 80.
blocks[].kind	Kind	Required. Text; one of "tracker", "note", "calendar".
blocks[].width	Width	Required. Finite number; strictly above 0.
blocks[].height	Height	Required. Finite number; strictly above 0.
blocks[].allowedSides	Allowed Sides	Required. Array of Text; one of "left", "right".; minimum items 1; maximum items 2.
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
placements	Placements	Required. Array of Object; no unknown keys.; minimum items 1; maximum items 16.
placements[].id	Literal identifier used independently of display labels.	Required. Text; minimum UTF-16 length 1; maximum UTF-16 length 80.
placements[].kind	Kind	Required. Text; one of "tracker", "note", "calendar".
placements[].side	Side	Required. Text; one of "left", "right".
placements[].x	X	Required. Finite number.
placements[].y	Y	Required. Finite number.
placements[].width	Width	Required. Finite number; strictly above 0.
placements[].height	Height	Required. Finite number; strictly above 0.
placements[].area	Area	Required. Finite number; strictly above 0.
spreadWidth	Spread Width	Required. Finite number; strictly above 0.
spreadHeight	Spread Height	Required. Finite number; strictly above 0.
paperArea	Paper Area	Required. Finite number; strictly above 0.
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": {
    "pageWidth": 4,
    "pageHeight": 6,
    "gutter": 2,
    "blocks": [
      {
        "id": "habit",
        "kind": "tracker",
        "width": 4,
        "height": 2,
        "allowedSides": [
          "left"
        ]
      },
      {
        "id": "ideas",
        "kind": "note",
        "width": 4,
        "height": 3,
        "allowedSides": [
          "right"
        ]
      }
    ],
    "seed": 42
  },
  "output": {
    "placements": [
      {
        "id": "habit",
        "kind": "tracker",
        "side": "left",
        "x": 0,
        "y": 0,
        "width": 4,
        "height": 2,
        "area": 8
      },
      {
        "id": "ideas",
        "kind": "note",
        "side": "right",
        "x": 6,
        "y": 0,
        "width": 4,
        "height": 3,
        "area": 12
      }
    ],
    "spreadWidth": 10,
    "spreadHeight": 6,
    "paperArea": 48,
    "randomness": {
      "seed": 42,
      "source": "seed"
    }
  }
}

Limitations and assumptions

Blocks are not rotated or packed side by side. A feasible stack is not optimal use of area and does not account for handwriting, typography, binding, paper thickness, or fabrication.
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 Bullet Journal Spread Layout Generator — tool.io

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