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cache optimizations

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This commit is contained in:
Jörg Breitbart
2023-07-31 20:07:40 +02:00
parent c796514de8
commit c79aa542c9
1 changed files with 13 additions and 8 deletions
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src/browser/renderer/dom/WidthCache.ts
+13 -8
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@@ -17,11 +17,15 @@ const enum CacheSettings {
export class WidthCache implements IDisposable {
// flat cache for regular variant up to CacheSettings.FLAT_SIZE
// NOTE: ~4x faster access than holey (serving >>80% of terminal content)
// It has a small memory footprint (only 1MB for full BMP caching),
// still the sweet spot is not reached before touching 32k different codepoints,
// thus we store the remaining <<20% of terminal data in a holey structure.
private _flat = new Float32Array(CacheSettings.FLAT_SIZE);
// holey cache for bold, italic and bold&italic for any string
// FIXME: can grow really big over time, so a shared API across terminals is needed
private _holey = new Map<string, number>();
// FIXME: can grow really big over time (~8.5 MB for full BMP caching),
// so a shared API across terminals is needed
private _holey: Map<string, number> | undefined;
private _font = '';
private _fontSize = 0;
@@ -67,9 +71,9 @@ export class WidthCache implements IDisposable {
}
public dispose(): void {
this._container.remove();
this._measureElements.length = 0;
this._holey.clear(); // also free memory
this._container.remove(); // remove elements from DOM
this._measureElements.length = 0; // release element refs
this._holey = undefined; // free cache memory via GC
}
/**
@@ -77,7 +81,8 @@ export class WidthCache implements IDisposable {
*/
public clear(): void {
this._flat.fill(CacheSettings.FLAT_UNSET);
this._holey.clear();
// .clear() has some overhead, re-assign instead (>3 times faster)
this._holey = new Map<string, number>();
}
/**
@@ -124,13 +129,13 @@ export class WidthCache implements IDisposable {
let key = c;
if (bold) key += 'B';
if (italic) key += 'I';
let width = this._holey.get(key);
let width = this._holey!.get(key);
if (width === undefined) {
let variant = 0;
if (bold) variant |= 1;
if (italic) variant |= 2;
width = this._measure(c, variant);
this._holey.set(key, width);
this._holey!.set(key, width);
}
return width;
}