From b45b6a5fd2cb1e2a4cdecd49c45a48b4cffd9f05 Mon Sep 17 00:00:00 2001
From: "Joshua A. Horton" <joshua_horton@sil.org>
Date: Mon, 24 Jun 2024 08:55:09 +0700
Subject: [PATCH 1/2] fix(web): use fat-finger data with simple keypresses

Cherry-pick-of: #11854
---
 web/src/engine/osk/src/visualKeyboard.ts | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/web/src/engine/osk/src/visualKeyboard.ts b/web/src/engine/osk/src/visualKeyboard.ts
index 4dcd9e655c..af8324f03e 100644
--- a/web/src/engine/osk/src/visualKeyboard.ts
+++ b/web/src/engine/osk/src/visualKeyboard.ts
@@ -637,7 +637,7 @@ export default class VisualKeyboard extends EventEmitter<EventMap> implements Ke
           try {
             shouldLockLayer && this.lockLayer(true);
             // Once the best coord to use for fat-finger calculations has been determined:
-            keyResult = this.modelKeyClick(gestureStage.item, coord);
+            keyResult = this.modelKeyClick(gestureStage.item, coord, correctionKeyDistribution);
           } finally {
             shouldLockLayer && this.lockLayer(false);
           }

From 469e1037d7682fb90c334d65e1a2a7abf6e3b7f6 Mon Sep 17 00:00:00 2001
From: "Joshua A. Horton" <joshua_horton@sil.org>
Date: Mon, 24 Jun 2024 09:26:22 +0700
Subject: [PATCH 2/2] change(web): better div-by-zero fudge factor for
 fat-fingering

---
 common/web/input-processor/src/corrections.ts | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/common/web/input-processor/src/corrections.ts b/common/web/input-processor/src/corrections.ts
index fa9b77036f..39c5ae2ef3 100644
--- a/common/web/input-processor/src/corrections.ts
+++ b/common/web/input-processor/src/corrections.ts
@@ -80,7 +80,12 @@ export function distributionFromDistanceMaps(squaredDistMaps: Map<ActiveKeyBase,
     for(let key of squaredDistMap.keys()) {
       // We've found that in practice, dist^-4 seems to work pretty well.  (Our input has dist^2.)
       // (Note:  our rule of thumb here has only been tested for layout-based distances.)
-      const entry = 1 / (Math.pow(squaredDistMap.get(key), 2) + 1e-6); // Prevent div-by-0 errors.
+      //
+      // The 3e-5 fudge-factor may seem a bit high, but it has two purposes:
+      // 1. Prevent div-by-0 errors
+      // 2. Ensures that the main key's probability doesn't get SO high that we don't
+      //    consider correcting to immediate neighbors, even if perfectly accurate.
+      const entry = 1 / (Math.pow(squaredDistMap.get(key), 2) + 3e-5);
       totalMass += entry;
 
       // In case of duplicate key IDs; this can occur if multiple sets are specified.