Replace hard cutoff with graduated falloff for column-count estimate#26
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Malcolmnixon merged 2 commits intoJul 17, 2026
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July 16, 2026 18:45
…nt estimate ContainmentLayoutAlgorithm.ComputeContentWidth's column-count-based width candidate was gated by MaxColumnEstimateSizeRatio = 2.0: the candidate was skipped entirely unless widest/narrowest <= 2.0 for both width and height. This cliff is far too strict for realistic box sets - ordinary, differently-named identifiers routinely exceed a 2x width ratio just from label-length variance, disabling the heuristic and collapsing a balanced multi-column grid into one degenerate column (observed with a real 9-box set, widths 168-351px, ratio 2.08 - barely over the cutoff - rendering as one long column instead of packing 2-3 per row). Since the candidate is combined via Math.Max, it can only ever widen the final budget, never narrow it below the widest-box/area-based floor. Given that asymmetry, replace the hard <= 2.0 cutoff with a graduated linear falloff: full weight at or below ColumnEstimateFullWeightSizeRatio (2.0), zero weight at or above ColumnEstimateZeroWeightSizeRatio (6.0), interpolating linearly in between. Over-applying the estimate costs at most some extra whitespace; under-applying it (the old cliff's failure mode) had no bound on how degenerate the resulting single-column layout got. - Renamed MaxColumnEstimateSizeRatio to ColumnEstimateFullWeightSizeRatio and added ColumnEstimateZeroWeightSizeRatio. - Added ComputeColumnEstimateWeight (graduated falloff) and ComputeSizeRatio (zero-safe ratio) helpers, both made internal (alongside ComputeContentWidth) for direct unit testing. - Added regression coverage spanning the old cliff boundary (ratios just below/above 2.0), the new upper falloff bound (6.0), the interpolated midrange, and an end-to-end test reproducing the exact reported 9-box scenario (ratio ~2.08) now packing into multiple rows/columns instead of collapsing into one column. - Updated design doc and doc comments describing the new graduated behavior instead of the old hard threshold.
The 12 module-name boxes in this diagram vary in width just enough (driven by label length) that the column-count-based content-width candidate previously fell just over the old hard 2.0 size-ratio cutoff and was skipped entirely, collapsing the layout into a single narrow column (332x444). With the graduated falloff fix, the candidate still contributes substantial weight at this ratio, producing the intended balanced multi-column grid (452x296).
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This pull request improves the containment layout algorithm by replacing a hard cutoff with a graduated falloff for the column-count-based content width estimate, making the algorithm more robust to moderate variance in box sizes. This change ensures that ordinary variance (such as label-driven width differences) does not collapse multi-column layouts into a single column, and only suppresses the column estimate in truly pathological cases. The update is thoroughly documented and covered by new, detailed tests.
Containment layout algorithm improvements:
Replaced the hard cutoff for applying the column-count-based content width estimate with a graduated, linear falloff between two configurable size-ratio bounds (
ColumnEstimateFullWeightSizeRatio = 2.0,ColumnEstimateZeroWeightSizeRatio = 6.0). This allows moderately non-uniform box sets to still benefit from multi-column packing, while only suppressing the estimate for extremely non-uniform sets. (docs/design/rendering-layout/containment-layout-algorithm.md[1] [2];src/DemaConsulting.Rendering.Layout/ContainmentLayoutAlgorithm.cs[3] [4] [5]Added
ComputeSizeRatioandComputeColumnEstimateWeighthelper methods to encapsulate the new graduated weighting logic and handle degenerate cases robustly. (src/DemaConsulting.Rendering.Layout/ContainmentLayoutAlgorithm.cssrc/DemaConsulting.Rendering.Layout/ContainmentLayoutAlgorithm.csL277-R375)Testing and regression coverage:
test/DemaConsulting.Rendering.Layout.Tests/ContainmentLayoutAlgorithmTests.cstest/DemaConsulting.Rendering.Layout.Tests/ContainmentLayoutAlgorithmTests.csR379-R513)These changes make the layout algorithm more resilient and user-friendly, especially for real-world data where some variance in box sizes is expected.