Normalize pointer movement across resolutions

src/main/input/pointer-profile.test.ts

@@ -3,7 +3,7 @@ import { MAX_POINTER_DELTA } from '../../shared/protocol';
 import { createPointerMovementProfile } from './pointer-profile';
 
 describe('createPointerMovementProfile', () => {
-  it('creates sensible deltas for a 1280x720 display at 1.5 scale', () => {
+  it('creates display-relative deltas for a 1280x720 display at 1.5 scale', () => {
     const profile = createPointerMovementProfile({
       cursor: { x: 100, y: 100 },
       display: {
@@ -18,17 +18,17 @@ describe('createPointerMovementProfile', () => {
       bounds: { x: 0, y: 0, width: 1280, height: 720 },
       maxDelta: MAX_POINTER_DELTA,
       recommendedDeltas: {
-        small: 32,
-        medium: 85,
-        large: 187
+        small: 21,
+        medium: 57,
+        large: 125
       },
       capabilities: {
         noAckMouseMove: true
       }
     });
   });
 
-  it('returns native target deltas on a 1x display', () => {
+  it('preserves current feel on a 1920x1080 display at 1x scale', () => {
     expect(
       createPointerMovementProfile({
         cursor: { x: 100, y: 100 },
@@ -38,25 +38,57 @@ describe('createPointerMovementProfile', () => {
         }
       }).recommendedDeltas
     ).toEqual({
-      small: 48,
-      medium: 128,
-      large: 280
+      small: 49,
+      medium: 130,
+      large: 281
     });
   });
 
-  it('returns small logical deltas on a 3x display', () => {
+  it('returns larger clamped deltas on a 4K display at 1x scale', () => {
     expect(
       createPointerMovementProfile({
         cursor: { x: 100, y: 100 },
         display: {
-          bounds: { x: 0, y: 0, width: 1920, height: 960 },
-          scaleFactor: 3
+          bounds: { x: 0, y: 0, width: 3840, height: 2160 },
+          scaleFactor: 1
+        }
+      }).recommendedDeltas
+    ).toEqual({
+      small: 97,
+      medium: 259,
+      large: MAX_POINTER_DELTA
+    });
+  });
+
+  it('uses the short edge for ultrawide displays', () => {
+    expect(
+      createPointerMovementProfile({
+        cursor: { x: 100, y: 100 },
+        display: {
+          bounds: { x: 0, y: 0, width: 3440, height: 1440 },
+          scaleFactor: 1
+        }
+      }).recommendedDeltas
+    ).toEqual({
+      small: 65,
+      medium: 173,
+      large: 374
+    });
+  });
+
+  it('still divides by scale factor on high-DPI displays', () => {
+    expect(
+      createPointerMovementProfile({
+        cursor: { x: 100, y: 100 },
+        display: {
+          bounds: { x: 0, y: 0, width: 3840, height: 2160 },
+          scaleFactor: 2
         }
       }).recommendedDeltas
     ).toEqual({
-      small: 16,
-      medium: 43,
-      large: 93
+      small: 49,
+      medium: 130,
+      large: 281
     });
   });
 

src/main/input/pointer-profile.ts

@@ -3,10 +3,10 @@ import { MAX_POINTER_DELTA, NO_ACK_CONTROL_COMMAND_TYPES, type PointerMovementPr
 type Point = { x: number; y: number };
 type Bounds = { x: number; y: number; width: number; height: number };
 
-const TARGET_NATIVE_DELTAS = {
-  small: 48,
-  medium: 128,
-  large: 280
+const TARGET_DISPLAY_FRACTIONS = {
+  small: 0.045,
+  medium: 0.12,
+  large: 0.26
 };
 
 export function createPointerMovementProfile(input: {
@@ -21,16 +21,17 @@ export function createPointerMovementProfile(input: {
   const scaleFactor =
     Number.isFinite(input.display.scaleFactor) && input.display.scaleFactor > 0 ? input.display.scaleFactor : 1;
   const maxDelta = input.maxDelta ?? MAX_POINTER_DELTA;
+  const targetNativeDeltas = targetNativeDeltasForDisplay(bounds);
 
   return {
     displayId: `${bounds.x}:${bounds.y}:${bounds.width}:${bounds.height}:${scaleFactor}`,
     scaleFactor,
     bounds,
     maxDelta,
     recommendedDeltas: {
-      small: toLogicalDelta(TARGET_NATIVE_DELTAS.small, scaleFactor, maxDelta),
-      medium: toLogicalDelta(TARGET_NATIVE_DELTAS.medium, scaleFactor, maxDelta),
-      large: toLogicalDelta(TARGET_NATIVE_DELTAS.large, scaleFactor, maxDelta)
+      small: toLogicalDelta(targetNativeDeltas.small, scaleFactor, maxDelta),
+      medium: toLogicalDelta(targetNativeDeltas.medium, scaleFactor, maxDelta),
+      large: toLogicalDelta(targetNativeDeltas.large, scaleFactor, maxDelta)
     },
     capabilities: {
       noAckMouseMove: true,
@@ -39,6 +40,15 @@ export function createPointerMovementProfile(input: {
   };
 }
 
+function targetNativeDeltasForDisplay(bounds: Bounds): { small: number; medium: number; large: number } {
+  const referenceSize = Math.min(bounds.width, bounds.height);
+  return {
+    small: Math.round(referenceSize * TARGET_DISPLAY_FRACTIONS.small),
+    medium: Math.round(referenceSize * TARGET_DISPLAY_FRACTIONS.medium),
+    large: Math.round(referenceSize * TARGET_DISPLAY_FRACTIONS.large)
+  };
+}
+
 function normalizeBounds(bounds: Bounds): Bounds {
   return {
     x: finiteOr(bounds.x, 0),