Rule of Thirds Composition Grid Checker
Distance of an actual normalized focal point to nearest thirds grid line, not intersection distance, automatic image focal point or composition quality.
Description
A rule-of-thirds grid places lines at one third and two thirds of normalized image dimensions.
A rule-of-thirds grid places lines at one third and two thirds of normalized image dimensions.1
This tool measures an independently chosen focal point's distance to the nearest line without judging composition quality.
When to use Rule of Thirds Composition Grid Checker
Use this tool to measure an independently chosen focal point's distance to the nearest line without judging composition quality.
How to use Rule of Thirds Composition Grid Checker and how it works
- Establish the observations, units, reference context and assumptions described below.
- Enter normalizedFocalX, normalizedFocalY, callerPermittedGridDistance and run the tool.
- Read result.nearestThirdsLineDistance, result.withinCallerLineDistance using the meanings and sign conventions below.
- Correct any rejected inputs and rerun; independently review the result under the stated scope.
| Input field | Meaning | Value type | Requirement |
|---|---|---|---|
| normalizedFocalX | Independently identified horizontal focal coordinate divided by image width; 0–1 inclusive. | number | Required; finite; fraction 0–1 inclusive; branch conditions below |
| normalizedFocalY | Independently identified vertical focal coordinate divided by image height; 0–1 inclusive. | number | Required; finite; fraction 0–1 inclusive; branch conditions below |
| callerPermittedGridDistance | Nonnegative normalized distance tolerance to a grid line, not an intersection. | number | Required; finite; nonnegative; branch conditions below |
Supply normalized focal x and y coordinates from zero to one inclusive and a nonnegative caller-permitted line distance. Find the minimum absolute difference between either coordinate and one third or two thirds; return that distance and whether it is at most the tolerance. This measures proximity to any grid line, not distance to a grid intersection or automatic focal detection.
distance=min(abs(x-1/3),abs(x-2/3),abs(y-1/3),abs(y-2/3)); within=(distance<=tolerance) Use the stated ordering, units and branch conditions.
| Output field | Meaning | Value type |
|---|---|---|
| result | Object containing the fields below. | object |
| result.nearestThirdsLineDistance | Minimum normalized distance to any vertical or horizontal thirds line. | number |
| result.withinCallerLineDistance | True when nearest-line distance is at most the caller tolerance. | boolean |
{
"input": {
"normalizedFocalX": 0.3333333333333333,
"normalizedFocalY": 0.5,
"callerPermittedGridDistance": 0.02
},
"output": {
"result": {
"nearestThirdsLineDistance": 0,
"withinCallerLineDistance": true
}
}
}Limitations and assumptions
The calculation depends on independently established observations, coefficients and the matching units. It does not collect data, choose a treatment or target, establish model applicability or provide a validated forecast. Interpret its result within the branch conditions and assumptions above.
Supply explicit values and dense aligned arrays. Unexpected fields, wrong types and nonfinite scalar values are rejected; fixed-token, alignment and other branch conditions are explained above. A successful false flag, empty match list or unknown-evidence list differs from an input error. Extremely large inputs or nonrepresentable results may fail.
Alternative or Complementary methods
Use Visual Rhythm Motif Repetition Interval Counter for a related operation: Visual repetition can be summarized through intervals between independently identified instances of one motif.
Use Focal Point Dominance Hierarchy Guide Lookup for a related operation: Focal hierarchy depends on relationships among contrast, scale, position and viewing context.
References
-
Rule of Thirds Composition Grid Checker — tool.io
Similar or alternative tools
- Visual Rhythm Motif Repetition Interval Counter
Visual repetition can be summarized through intervals between independently identified instances of one motif.
- Focal Point Dominance Hierarchy Guide Lookup
Focal hierarchy depends on relationships among contrast, scale, position and viewing context.