ShapeStripCache class
Content-keyed cache of rasterized stroke/fill strips, replayed by StripGenerator.fillPath and StripGenerator.strokePath.
The glyph cache's design (relocatable strip blobs, subpixel-phase quantization with the y phase kept inside the 4-px strip row, cache-on-second-sight) applied to geometry without shared object identity: dense CAD sheets redraw the same hatch strokes, dimension arrows, and symbol fills thousands of times as distinct PdfPath instances, so the key is the shape's content - segment opcodes + point deltas from the first point quantized to 1/64 px, stroke/fill parameters, flatten tolerance, and the anchor's subpixel phase. Quantization moves geometry by at most 1/16 px (anchor snap) + 1/128 px (deltas) - half the glyph cache's budget, because snapping a fill shifts whole edges rather than one glyph.
Only paths with at most maxSegments segments attempt the cache (the content walk costs one transform pass + hash, which huge one-off clip/boundary paths must not pay), and - like glyphs - shapes larger than maxShapeSide device px or not fully inside the viewport bypass to the direct unquantized raster.
Constructors
- ShapeStripCache({int maxEntries = 131072, int maxBytes = 64 << 20})
Properties
- bypasses ↔ int
-
getter/setter pair
- collisions ↔ int
-
Draws whose 32-bit content hash matched a stored entry with different
content; rendered directly (correctness never rides on the hash).
getter/setter pair
- dataBytes → int
-
no setter
- entryCount → int
-
no setter
- firstSights ↔ int
-
First-sight draws that rendered directly (cache-on-second-sight gate).
getter/setter pair
- hashCode → int
-
The hash code for this object.
no setterinherited
- hits ↔ int
-
getter/setter pair
- maxBytes → int
-
Byte budget over CachedShapeStrips.dataBytes (strip blob + content),
across both generations.
final
- maxEntries → int
-
Live-entry cap across both generations. Dense CAD documents carry
~25-40k distinct small-shape keys per 10-page render; each generation
(half this cap) must hold a whole document's working set or its own
render rotates its early keys out and every recurrence turns into a
full rebuild (measured slower than no cache at all on ly9-far-cad at
a 16k cap). Steady state on the heavy corpus is ~40k entries /
~20 MB; the cap is headroom, not expected occupancy.
final
- misses ↔ int
-
getter/setter pair
- runtimeType → Type
-
A representation of the runtime type of the object.
no setterinherited
- viewportCulls ↔ int
-
Small shapes rejected by the cache probe because their padded device
bounds lie wholly outside the current viewport. These draws are complete
no-ops and do not fall through to the direct flatten/raster path.
getter/setter pair
Methods
-
clear(
) → void -
noSuchMethod(
Invocation invocation) → dynamic -
Invoked when a nonexistent method or property is accessed.
inherited
-
resetStats(
) → void -
toString(
) → String -
A string representation of this object.
inherited
Operators
-
operator ==(
Object other) → bool -
The equality operator.
inherited
Static Properties
-
Process-wide default instance.
final
Constants
- maxSegments → const int
- Paths with more segments than this never attempt the cache: the content walk + hash would tax every huge one-off boundary path, and plotted symbols/hatches stay far below it.
- maxShapeSide → const int
- Shapes larger than this on either side (device px, stroke pad included) bypass the cache.