Performance Sprite Bounds Row Scan

Sprite bounds row scans

SpriteArtBounds.TryGetLocalArtBounds scans each row from its two edges. Once it finds both visible ends, interior pixels cannot change that row's bounds. It preserves the same alpha thresholds, pivots, transparent result and coordinate calculation.

On Windows x64 Unity 6000.6.7f1 Editor Mono, three alternating baseline/candidate process pairs measured 256×256 inputs. Each process warmed 64 calls, calibrated batches to at least 20 ms, and retained 21 rounds for each workload. Times below are medians of process medians. Ratios show the range of the three paired process ratios; lower is faster.

Input	API	Before, µs	After, µs	Paired after / before
Opaque	Existing mask	38.02	0.54	0.0136–0.0148
Single column	Existing mask	25.86	26.06	0.977–1.050
Transparent	Existing mask	22.90	24.49	1.063–1.087
Opaque	Readable sprite	295.79	72.14	0.240–0.379
Single column	Readable sprite	276.78	259.57	0.875–1.006
Transparent	Readable sprite	258.46	255.15	0.982–1.457

Dense inputs benefit most. Transparent cached masks were 6–9% slower; the transparent sprite measurements varied enough to prevent a stable speed claim. The sprite path still copies texture pixels. A separate controlled allocation check recorded 32 allocation events for 32 direct queries and 64 when explicitly building masks first. These event counts do not measure bytes or retained memory.

All six timing processes passed six shape checks, exited zero, ended both output streams, and retained matching source and loaded-method identities. The existing bounds fixture plus 72 new pixel-oracle cases passed all 116 cases. No IL2CPP, other editor version, arbitrary texture size or universal timing margin is claimed.

Replay sources, raw rounds and receipts retain every sample and identify both source variants. Earlier runs whose NUnit progress output was discarded remain excluded from the timing result.