Window Manager

The WindowManager is the core system responsible for managing all window operations in Time Capsule. It handles window lifecycle, positioning, dragging, focus management, z-index ordering, and workspace assignment.

Overview

WindowManager is implemented as a singleton module pattern with private state and exposed public methods:

const WindowManager = (() => {
  let zIndex = CONFIG.WINDOW.BASE_Z_INDEX;
  let highestWindowZIndex = CONFIG.WINDOW.BASE_Z_INDEX;
  let highestModalZIndex = 90000;
  let currentWorkspace = '1';
  let lastFocusedWindowId: string | null = null;
  const dragState: DragState = { /* ... */ };

  // Public API
  return {
    init,
    drag,
    focusWindow,
    registerWindow,
    centerWindow,
    switchWorkspace,
    showWindow,
    getNextZIndex,
    getTopZIndex,
  };
})();

Key Concepts

Window Registration

All windows must be registered with WindowManager to enable management features:

function registerWindow(win: HTMLElement): void {
  if (win.hasAttribute('data-cde-registered')) return;

  const id = win.id;
  const titlebar = document.getElementById(`${id}Titlebar`) || 
                   win.querySelector('.titlebar');

  if (titlebar) {
    // Restore session position if available
    const session = settingsManager
      .getSection('session')
      .windows[id];
      
    if (session && session.left && session.top) {
      win.style.left = session.left;
      win.style.top = session.top;
      if (session.maximized) {
        win.classList.add('maximized');
      }
    } else {
      // First time: normalize position
      setTimeout(() => {
        normalizeWindowPosition(win);
      }, CONFIG.TIMINGS.NORMALIZATION_DELAY);
    }

    // Enable dragging
    titlebar.style.touchAction = 'none';
    titlebar.addEventListener(
      'pointerdown', 
      titlebarDragHandler
    );
    
    win.setAttribute('data-cde-registered', 'true');
  }
}

Dynamic Scanning

WindowManager uses a MutationObserver to automatically detect and register new windows:

function initDynamicScanning(): void {
  // Scan existing windows
  const windows = document.querySelectorAll(
    '.window, .cde-retro-modal'
  );
  windows.forEach((el) => registerWindow(el as HTMLElement));

  // Observe for new windows
  const observer = new MutationObserver((mutations) => {
    mutations.forEach((mutation) => {
      mutation.addedNodes.forEach((node) => {
        if (node instanceof HTMLElement) {
          if (node.classList.contains('window') || 
              node.classList.contains('cde-retro-modal')) {
            registerWindow(node);
          }
          // Scan children
          node.querySelectorAll('.window, .cde-retro-modal')
            .forEach((el) => registerWindow(el as HTMLElement));
        }
      });
    });
  });

  observer.observe(document.body, { 
    childList: true, 
    subtree: true 
  });
}

Z-Index Management

Layered Z-Index System

Z-indexes are managed in separate layers to prevent conflicts:

// Layer allocation
const BASE_WINDOW_Z = 10000;  // Regular windows
const BASE_MODAL_Z = 90000;   // Modal dialogs
const DROPDOWN_Z = 20000;     // Dropdown menus

let highestWindowZIndex = CONFIG.WINDOW.BASE_Z_INDEX;
let highestModalZIndex = 90000;

function getNextZIndex(isModal: boolean = false): number {
  if (isModal) {
    return ++highestModalZIndex;
  }
  return ++highestWindowZIndex;
}

function getTopZIndex(): number {
  return Math.max(highestWindowZIndex, highestModalZIndex);
}

Focus and Z-Index

Focusing a window assigns it the highest z-index in its layer:

function focusWindow(id: string): void {
  if (id === lastFocusedWindowId) return;

  const win = document.getElementById(id);
  if (!win) return;

  if (!dragState.isDragging) {
    // Remove active class from previous window
    if (lastFocusedWindowId) {
      const prevWin = document.getElementById(
        lastFocusedWindowId
      );
      if (prevWin) prevWin.classList.remove('active');
    }

    // Periodic cleanup of stale classes
    if (Math.random() < 0.05) {
      document.querySelectorAll('.active').forEach((el) => {
        if (el.id !== id) el.classList.remove('active');
      });
    }

    win.classList.add('active');
    lastFocusedWindowId = id;

    zIndex = getNextZIndex();
    win.style.zIndex = String(zIndex);

    if (window.AudioManager) window.AudioManager.click();
  }
}

Drag and Drop

Drag State Management

interface DragState {
  element: HTMLElement | null;
  offsetX: number;
  offsetY: number;
  startX: number;
  startY: number;
  startLeft: number;
  startTop: number;
  lastX: number;
  lastY: number;
  isDragging: boolean;
}

Pointer-Based Dragging

Dragging uses PointerEvents for unified mouse/touch support:

function drag(e: PointerEvent, id: string): void {
  // Disable drag on mobile
  if (isMobile()) {
    logger.log(
      `[WindowManager] Drag disabled on mobile for: ${id}`
    );
    return;
  }

  if (!e.isPrimary) return;

  const el = document.getElementById(id);
  if (!el) return;

  e.preventDefault();
  e.stopPropagation();

  // Normalize position if transform is applied
  if (window.getComputedStyle(el).transform !== 'none') {
    normalizeWindowPosition(el);
  }

  focusWindow(id);

  const rect = el.getBoundingClientRect();
  dragState.element = el;
  dragState.offsetX = e.clientX - rect.left;
  dragState.offsetY = e.clientY - rect.top;
  dragState.lastX = e.clientX;
  dragState.lastY = e.clientY;
  dragState.isDragging = true;

  // Capture pointer for reliable tracking
  el.setPointerCapture(e.pointerId);

  // X11-style move cursor
  document.documentElement.style.setProperty(
    '--cde-cursor-override',
    "url('/icons/cursors/cursor-move.svg') 12 12, move"
  );
  document.body.style.cursor = 
    "url('/icons/cursors/cursor-move.svg') 12 12, move";

  // Performance optimization
  el.style.willChange = 'transform, left, top';

  el.addEventListener('pointermove', move, { passive: false });
  el.addEventListener('pointerup', stopDrag, { passive: false });
  el.addEventListener('pointercancel', stopDrag, { passive: false });
}

Mouse Acceleration

Mouse movement supports configurable acceleration:

function move(e: PointerEvent): void {
  if (!dragState.element || !dragState.isDragging) return;

  e.preventDefault();
  e.stopPropagation();

  // Get acceleration from CSS variable
  const accelStr = getComputedStyle(document.documentElement)
    .getPropertyValue('--mouse-acceleration');
  const acceleration = parseFloat(accelStr) || 1;

  // Calculate delta
  const deltaX = e.clientX - dragState.lastX;
  const deltaY = e.clientY - dragState.lastY;

  // Apply acceleration
  let currentLeft = parseFloat(
    dragState.element.style.left || '0'
  );
  let currentTop = parseFloat(
    dragState.element.style.top || '0'
  );

  let left = currentLeft + deltaX * acceleration;
  let top = currentTop + deltaY * acceleration;

  // Update tracking
  dragState.lastX = e.clientX;
  dragState.lastY = e.clientY;

  // Apply constraints (shown in next section)
  // ...

  dragState.element.style.left = left + 'px';
  dragState.element.style.top = top + 'px';
}

Viewport Constraints

Windows are constrained to stay within viewport bounds:

function move(e: PointerEvent): void {
  // ... delta calculation ...

  const winWidth = dragState.element.offsetWidth;
  const winHeight = dragState.element.offsetHeight;
  const viewportWidth = window.innerWidth;
  const viewportHeight = window.innerHeight;
  const TOP_BAR_HEIGHT = CONFIG.WINDOW.TOP_BAR_HEIGHT;
  const PANEL_HEIGHT = isMobile() ? 65 : 85;

  // Define bounds
  const minX = 0;
  const maxX = Math.max(0, viewportWidth - winWidth);
  const minY = TOP_BAR_HEIGHT;
  const maxY = Math.max(
    minY, 
    viewportHeight - winHeight - PANEL_HEIGHT
  );

  // Clamp position
  left = Math.max(minX, Math.min(left, maxX));
  top = Math.max(minY, Math.min(top, maxY));

  dragState.element.style.left = left + 'px';
  dragState.element.style.top = top + 'px';
}

Opaque vs Wireframe Dragging

function move(e: PointerEvent): void {
  // ...
  
  // Check if opaque dragging is enabled
  const opaque = document.documentElement
    .getAttribute('data-opaque-drag') !== 'false';
    
  if (!opaque) {
    // Wireframe mode: lighter rendering
    dragState.element.classList.add('dragging-wireframe');
  }
  
  // ...
}

Drag Completion

function stopDrag(e: PointerEvent): void {
  if (!dragState.element || !dragState.isDragging) return;

  e.preventDefault();
  e.stopPropagation();

  const el = dragState.element;
  el.releasePointerCapture(e.pointerId);
  el.removeEventListener('pointermove', move);
  el.removeEventListener('pointerup', stopDrag);
  el.removeEventListener('pointercancel', stopDrag);

  // Clear performance hints
  el.style.willChange = 'auto';

  // Restore cursor
  document.body.style.cursor = '';

  el.classList.remove('dragging-wireframe');
  dragState.isDragging = false;

  // Persist position
  settingsManager.updateWindowSession(el.id, {
    left: el.style.left,
    top: el.style.top,
    maximized: el.classList.contains('maximized'),
  });

  dragState.element = null;
}

Window Operations

Minimize

function minimizeWindow(id: string): void {
  const win = document.getElementById(id);
  if (!win) return;

  if (win.style.display !== 'none') {
    // Save state before hiding
    windowStates[id] = {
      display: win.style.display,
      left: win.style.left,
      top: win.style.top,
      width: win.style.width,
      height: win.style.height,
      maximized: win.classList.contains('maximized'),
    };

    // Animate closing
    win.classList.add('window-closing');
    if (window.AudioManager) {
      window.AudioManager.windowMinimize();
    }

    // Hide after animation
    win.addEventListener(
      'animationend',
      () => {
        win.style.display = 'none';
        win.classList.remove('window-closing');
      },
      { once: true }
    );
  }
}

Maximize

function maximizeWindow(id: string): void {
  const win = document.getElementById(id);
  if (!win || win.hasAttribute('data-no-maximize')) return;

  if (win.classList.contains('maximized')) {
    // Restore
    win.classList.remove('maximized');
    if (window.AudioManager) {
      window.AudioManager.windowMaximize();
    }

    // Update icon
    const maxBtnImg = win.querySelector('.max-btn img') as 
      HTMLImageElement;
    if (maxBtnImg) {
      maxBtnImg.src = '/icons/ui/maximize-inactive.png';
    }

    // Restore saved size/position
    if (windowStates[id]) {
      win.style.left = windowStates[id].left || '';
      win.style.top = windowStates[id].top || '';
      win.style.width = windowStates[id].width || '';
      win.style.height = windowStates[id].height || '';
    }
    
    settingsManager.updateWindowSession(id, { 
      maximized: false 
    });
  } else {
    // Maximize
    windowStates[id] = {
      left: win.style.left,
      top: win.style.top,
      width: win.style.width,
      height: win.style.height,
      maximized: false,
    };
    
    win.classList.add('maximized');
    if (window.AudioManager) {
      window.AudioManager.windowMaximize();
    }

    // Update icon
    const maxBtnImg = win.querySelector('.max-btn img') as 
      HTMLImageElement;
    if (maxBtnImg) {
      maxBtnImg.src = '/icons/ui/maximize-toggled-inactive.png';
    }
    
    settingsManager.updateWindowSession(id, { 
      maximized: true 
    });
  }
  
  WindowManager.focusWindow(id);
}

Window Shading

Double-click titlebar to “shade” (roll up) a window:

function shadeWindow(id: string): void {
  const win = document.getElementById(id);
  if (!win) return;

  const titlebar = win.querySelector('.titlebar') as HTMLElement;
  if (!titlebar) return;

  const isMaximized = win.classList.contains('maximized');

  if (win.classList.contains('shaded')) {
    // Unshade: restore height
    win.classList.remove('shaded');

    if (isMaximized) {
      win.style.height = '';
    } else if (windowStates[id]?.height) {
      win.style.height = windowStates[id].height!;
    }

    if (window.AudioManager) {
      window.AudioManager.windowShade();
    }
  } else {
    // Shade: save height and collapse
    if (!isMaximized) {
      windowStates[id] = {
        ...windowStates[id],
        height: win.style.height || 
                getComputedStyle(win).height,
      };
    }

    win.classList.add('shaded');
    win.style.height = titlebar.offsetHeight + 'px';

    if (window.AudioManager) {
      window.AudioManager.windowShade();
    }
  }
}

Focus Management

Focus Modes

Two focus modes are supported:

Click-to-Focus
Point-to-Focus

Default mode. Windows receive focus when clicked.

document.addEventListener('pointerdown', (e) => {
  if (dragState.isDragging) return;
  
  const target = e.target as HTMLElement;
  const win = target.closest('.window, .cde-retro-modal');
  if (win) {
    focusWindow(win.id);
  }
});

X11-style: Windows receive focus when mouse enters.

document.addEventListener('pointerenter', (e) => {
  const mode = document.documentElement
    .getAttribute('data-focus-mode');
  if (mode !== 'point') return;

  const target = e.target as HTMLElement;
  const win = target.closest('.window, .cde-retro-modal');
  if (win) {
    focusWindow(win.id);
  }
}, true);

Workspace Management

Virtual Desktops

WindowManager supports 4 virtual workspaces:

function switchWorkspace(id: string): void {
  if (id === currentWorkspace) return;

  AudioManager.click();

  const windows = document.querySelectorAll(
    '.window, .cde-retro-modal'
  );

  // Hide windows from current workspace
  windows.forEach((win) => {
    const el = win as HTMLElement;
    const winWorkspace = el.getAttribute('data-workspace');

    if (winWorkspace === currentWorkspace) {
      const isVisible = 
        window.getComputedStyle(el).display !== 'none';
      
      if (isVisible) {
        el.setAttribute('data-was-opened', 'true');
        el.style.display = 'none';
      }
    }
  });

  currentWorkspace = id;

  // Show windows from new workspace
  windows.forEach((win) => {
    const el = win as HTMLElement;
    const winWorkspace = el.getAttribute('data-workspace');

    if (winWorkspace === currentWorkspace) {
      if (el.getAttribute('data-was-opened') === 'true') {
        el.style.display = 'flex';
      }
    }
  });

  // Update pager UI
  const pagerItems = document.querySelectorAll(
    '.pager-workspace'
  );
  pagerItems.forEach((item) => {
    if ((item as HTMLElement).dataset.workspace === id) {
      item.classList.add('active');
    } else {
      item.classList.remove('active');
    }
  });
}

Workspace Assignment

Windows are automatically assigned to the current workspace when opened:

function showWindow(id: string): void {
  const win = document.getElementById(id);
  if (!win) return;

  // Assign workspace on first show
  if (!win.getAttribute('data-workspace')) {
    win.setAttribute('data-workspace', currentWorkspace);
  }

  // Mark as opened
  win.setAttribute('data-was-opened', 'true');

  win.style.display = 'flex';
  win.classList.add('window-opening');

  // Center on mobile
  if (isMobile()) {
    centerWindow(win);
  }

  focusWindow(id);
  AudioManager.windowOpen();

  win.addEventListener(
    'animationend',
    () => {
      win.classList.remove('window-opening');
    },
    { once: true }
  );
}

Mobile Considerations

Disabled Features

Certain features are disabled on mobile for better UX:

function isMobile(): boolean {
  return window.innerWidth < 768;
}

// Drag disabled on mobile
function drag(e: PointerEvent, id: string): void {
  if (isMobile()) {
    logger.log('[WindowManager] Drag disabled on mobile');
    return;
  }
  // ...
}

Automatic Centering

Windows are automatically centered on mobile devices:

function centerWindow(win: HTMLElement): void {
  const winWidth = win.offsetWidth;
  const winHeight = win.offsetHeight;
  const viewportWidth = window.innerWidth;
  const viewportHeight = window.innerHeight;
  const TOP_BAR_HEIGHT = CONFIG.WINDOW.TOP_BAR_HEIGHT;
  const PANEL_HEIGHT = isMobile() ? 65 : 85;

  let left = (viewportWidth - winWidth) / 2;
  let top = (viewportHeight - winHeight) / 2;

  // Clamp to viewport
  const minX = 0;
  const maxX = Math.max(0, viewportWidth - winWidth);
  const minY = TOP_BAR_HEIGHT;
  const maxY = Math.max(
    minY, 
    viewportHeight - winHeight - PANEL_HEIGHT
  );

  left = Math.max(minX, Math.min(left, maxX));
  top = Math.max(minY, Math.min(top, maxY));

  win.style.position = 'absolute';
  win.style.left = `${left}px`;
  win.style.top = `${top}px`;
  win.style.transform = 'none';
}

Resize Handling

Windows are normalized when viewport resizes:

window.addEventListener('resize', () => {
  clearTimeout(resizeTimer);
  resizeTimer = window.setTimeout(() => {
    logger.log(
      '[WindowManager] Viewport resized, ' + 
      'normalizing positions...'
    );
    
    document.querySelectorAll('.window, .cde-retro-modal')
      .forEach((win) => {
        if (win instanceof HTMLElement) {
          if (isMobile()) {
            centerWindow(win);
          } else {
            normalizeWindowPosition(win);
          }
        }
      });
  }, CONFIG.TIMINGS.NORMALIZATION_DELAY);
});

Global Exposure

WindowManager functions are exposed globally for legacy compatibility:

declare global {
  interface Window {
    drag: (e: PointerEvent, id: string) => void;
    focusWindow: (id: string) => void;
    centerWindow: (win: HTMLElement) => void;
    minimizeWindow: typeof minimizeWindow;
    maximizeWindow: typeof maximizeWindow;
    shadeWindow: typeof shadeWindow;
    WindowManager: typeof WindowManager;
  }
}

window.drag = WindowManager.drag;
window.focusWindow = WindowManager.focusWindow;
window.centerWindow = WindowManager.centerWindow;
window.minimizeWindow = minimizeWindow;
window.maximizeWindow = maximizeWindow;
window.shadeWindow = shadeWindow;
window.WindowManager = WindowManager;

Best Practices

Always Register Windows

Ensure windows have proper structure and are registered:

<div id="myWindow" class="window">
  <div id="myWindowTitlebar" class="titlebar">
    <span class="titlebar-text">My Window</span>
    <div class="titlebar-buttons">
      <button class="min-btn" 
              onclick="minimizeWindow('myWindow')">
        <img src="/icons/ui/shade-inactive.png" />
      </button>
      <button class="max-btn" 
              onclick="maximizeWindow('myWindow')">
        <img src="/icons/ui/maximize-inactive.png" />
      </button>
      <button class="close-btn" 
              onclick="document.getElementById('myWindow').style.display='none'">
        <img src="/icons/ui/close-inactive.png" />
      </button>
    </div>
  </div>
  <div class="window-content">
    <!-- Content -->
  </div>
</div>

Persist Window State

Use updateWindowSession after position/state changes:

settingsManager.updateWindowSession(id, {
  left: win.style.left,
  top: win.style.top,
  maximized: win.classList.contains('maximized'),
});

Handle Mobile Gracefully

Check isMobile() before drag/resize operations:

if (isMobile()) {
  centerWindow(win);
  return; // Skip desktop-specific operations
}

Architecture

Overall system architecture overview

Storage

Window session persistence mechanism

Virtual Filesystem

File operations in window contexts

Development

Build applications using WindowManager

Documentation Index

​Window Manager

​Overview

​Key Concepts

​Window Registration

​Dynamic Scanning

​Z-Index Management

​Layered Z-Index System

​Focus and Z-Index

​Drag and Drop

​Drag State Management

​Pointer-Based Dragging

​Mouse Acceleration

​Viewport Constraints

​Opaque vs Wireframe Dragging

​Drag Completion

​Window Operations

​Minimize

​Maximize

​Window Shading

​Focus Management

​Focus Modes

​Workspace Management

​Virtual Desktops

​Workspace Assignment

​Mobile Considerations

​Disabled Features

​Automatic Centering

​Resize Handling

​Global Exposure

​Best Practices

​Related Documentation