Add frame rate limit setting

Lets the frame rate be capped at 30, 15 or 10 fps to find out whether the
occasional random-colour flashes on single keys depend on the update rate.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

README.md

@@ -9,7 +9,8 @@ product ID or have a K87 layout, so the keyboard is ignored without this plugin.
 Copy `Womier_K87_EVision.js` to `%USERPROFILE%\Documents\WhirlwindFX\Plugins\` and restart SignalRGB.
 
 The device settings have a "Key test" option (column or row sweep) to check the LED map,
-and "Low frame-rate mode" in case the keyboard drops frames at full speed.
+"Low frame-rate mode" in case the keyboard drops frames at full speed, and a "Frame rate limit"
+(Unlimited / 30 / 15 / 10 fps). Known issue: single keys occasionally flash a random colour for a moment.
 
 ## Protocol
 

Womier_K87_EVision.js

@@ -17,6 +17,7 @@ LightingMode:readonly
 forcedColor:readonly
 lowFPS:readonly
 keyTest:readonly
+frameLimit:readonly
 */
 export function ControllableParameters() {
 	return [
@@ -24,6 +25,7 @@ export function ControllableParameters() {
 		{property:"LightingMode", group:"lighting", label:"Lighting Mode", description: "Determines where the device's RGB comes from. Canvas will pull from the active Effect, while Forced will override it to a specific color", type:"combobox", values:["Canvas", "Forced"], default:"Canvas"},
 		{property:"forcedColor", group:"lighting", label:"Forced Color", description: "The color used when 'Forced' Lighting Mode is enabled", min:"0", max:"360", type:"color", default:"#009bde"},
 		{property:"lowFPS", group:"lighting", label:"Low frame-rate mode", description: "Sends smaller packets with pauses in between, can improve stability", type:"boolean", default:false},
+		{property:"frameLimit", group:"lighting", label:"Frame rate limit", description: "Maximum frames per second sent to the keyboard", type:"combobox", values:["Unlimited", "30", "15", "10"], default:"Unlimited"},
 		{property:"keyTest", group:"lighting", label:"Key test", description: "Sweeps a white line across the keys to check the LED map", type:"combobox", values:["Off", "Column sweep", "Row sweep"], default:"Off"},
 	];
 }
@@ -67,7 +69,18 @@ export function Initialize() {
 	device.setControllableLeds(vLedNames, vLedPositions);
 }
 
+let lastFrameTime = 0;
+
 export function Render() {
+	// The keyboard falls back to its own effect after about a second without frames,
+	// so the lowest limit (10 fps) still keeps it under plugin control
+	const now = Date.now();
+
+	if (frameLimit !== "Unlimited" && now - lastFrameTime < 1000 / parseInt(frameLimit)) {
+		return;
+	}
+
+	lastFrameTime = now;
 	sendColors();
 }