[Init] Initial commit - NetMesh terminal manager

components/terminal/runtime/terminalFontZoom.ts

@@ -0,0 +1,61 @@
+import {
+  DEFAULT_FONT_SIZE,
+  MAX_FONT_SIZE,
+  MIN_FONT_SIZE,
+} from "../../../infrastructure/config/fonts";
+
+type WheelLike = Pick<WheelEvent, "ctrlKey" | "metaKey" | "deltaY">;
+
+const TERMINAL_FONT_SIZE_ACTIONS = new Set([
+  "increaseTerminalFontSize",
+  "decreaseTerminalFontSize",
+  "resetTerminalFontSize",
+]);
+
+export const terminalFontSizeWheelListenerOptions = {
+  passive: false,
+  capture: true,
+} as const satisfies AddEventListenerOptions;
+
+export const clampTerminalFontSize = (fontSize: number): number =>
+  Math.max(MIN_FONT_SIZE, Math.min(MAX_FONT_SIZE, fontSize));
+
+export const isTerminalFontSizeAction = (action: string): boolean =>
+  TERMINAL_FONT_SIZE_ACTIONS.has(action);
+
+export const shouldHandleTerminalFontSizeAction = (
+  action: string,
+  disabled = false,
+): boolean => isTerminalFontSizeAction(action) && !disabled;
+
+export const nextTerminalFontSizeForAction = (
+  action: string,
+  currentFontSize: number,
+  disabled = false,
+): number | null => {
+  if (disabled) return null;
+  switch (action) {
+    case "increaseTerminalFontSize":
+      return clampTerminalFontSize(currentFontSize + 1);
+    case "decreaseTerminalFontSize":
+      return clampTerminalFontSize(currentFontSize - 1);
+    case "resetTerminalFontSize":
+      return DEFAULT_FONT_SIZE;
+    default:
+      return null;
+  }
+};
+
+export const nextTerminalFontSizeForWheel = (
+  event: WheelLike,
+  currentFontSize: number,
+  isMac: boolean,
+  disabled = false,
+): number | null => {
+  if (disabled) return null;
+  const hasZoomModifier = isMac
+    ? event.metaKey && !event.ctrlKey
+    : event.ctrlKey && !event.metaKey;
+  if (!hasZoomModifier || event.deltaY === 0) return null;
+  return clampTerminalFontSize(currentFontSize + (event.deltaY < 0 ? 1 : -1));
+};