### Initialize ROS2D.js Viewer and Map Client

Source: https://github.com/robotwebtools/ros2djs/blob/develop/examples/image.html

Sets up the ROS connection, creates a viewer, and initializes an ImageMapClient to display a map. It also includes an event listener to scale and shift the viewer based on the map's dimensions and pose.

```javascript
function init() {
  // Connect to ROS.
  var ros = new ROSLIB.Ros({
    url : 'ws://localhost:9090'
  });

  // Create the main viewer.
  var viewer = new ROS2D.Viewer({
    divID : 'map',
    width : 640,
    height : 480
  });

  // Setup the map client.
  var gridClient = new ROS2D.ImageMapClient({
    ros : ros,
    rootObject : viewer.scene,
    image : 'map.png'
  });

  // Scale the canvas to fit to the map
  gridClient.on('change', function() {
    viewer.scaleToDimensions(gridClient.currentImage.width, gridClient.currentImage.height);
    viewer.shift(gridClient.currentImage.pose.position.x, gridClient.currentImage.pose.position.y);
  });
}
```

--------------------------------

### Initialize ROS2DJS Viewer and Drawing Functionality (JavaScript)

Source: https://github.com/robotwebtools/ros2djs/blob/develop/examples/draw.html

Sets up the main ROS2DJS viewer and defines callback functions for mouse interactions with a polygon. It handles adding, moving, and removing points, as well as splitting lines based on user input like Shift and Ctrl keys.

```javascript
function init() {
  // Create the main viewer.
  var viewer = new ROS2D.Viewer({
    divID : 'map',
    width : 640,
    height : 480,
    context2dOptions: {willReadFrequently: true},
  });

  // Callback functions when there is mouse interaction with the polygon
  var clickedPolygon = false;
  var selectedPointIndex = null;

  var pointCallBack = function(type, event, index) {
    if (type === 'mousedown') {
      if (event.nativeEvent.shiftKey === true) {
        polygon.remPoint(index);
      } else {
        selectedPointIndex = index;
      }
    }
    clickedPolygon = true;
  };

  var lineCallBack = function(type, event, index) {
    if (type === 'mousedown') {
      if (event.nativeEvent.ctrlKey === true) {
        polygon.splitLine(index);
      }
    }
    clickedPolygon = true;
  }

  // Create the polygon
  var polygon = new ROS2D.PolygonMarker({
    lineColor : createjs.Graphics.getRGB(100, 100, 255, 1),
    pointCallBack : pointCallBack,
    lineCallBack : lineCallBack
  });

  // Add the polygon to the viewer
  viewer.scene.addChild(polygon);

  // Event listeners for mouse interaction with the stage
  viewer.scene.mouseMoveOutside = false; // doesn't seem to work

  viewer.scene.addEventListener('stagemousemove', function(event) {
    // Move point when it's dragged
    if (selectedPointIndex !== null) {
      var pos = viewer.scene.globalToRos(event.stageX, event.stageY);
      polygon.movePoint(selectedPointIndex, pos);
    }
  });

  viewer.scene.addEventListener('stagemouseup', function(event) {
    // Add point when not clicked on the polygon
    if (selectedPointIndex !== null) {
      selectedPointIndex = null;
    } else if (viewer.scene.mouseInBounds === true && clickedPolygon === false) {
      var pos = viewer.scene.globalToRos(event.stageX, event.stageY);
      polygon.addPoint(pos);
    }
    clickedPolygon = false;
  });
}
```

--------------------------------

### Initialize ROS2D.js Viewer and Map Client

Source: https://github.com/robotwebtools/ros2djs/blob/develop/examples/map.html

This JavaScript code initializes a connection to a ROS instance via WebSockets, creates a ROS2D viewer for displaying the map, and sets up an OccupancyGridClient to load and display map data. It also includes a callback to scale and shift the viewer to fit the loaded map.

```javascript
function init() {
  // Connect to ROS.
  var ros = new ROSLIB.Ros({
    url : 'ws://localhost:9090'
  });

  // Create the main viewer.
  var viewer = new ROS2D.Viewer({
    divID : 'map',
    width : 640,
    height : 480
  });

  // Setup the map client.
  var gridClient = new ROS2D.OccupancyGridClient({
    ros : ros,
    rootObject : viewer.scene
  });

  // Scale the canvas to fit to the map
  gridClient.on('change', function() {
    viewer.scaleToDimensions(gridClient.currentGrid.width, gridClient.currentGrid.height);
    viewer.shift(gridClient.currentGrid.pose.position.x, gridClient.currentGrid.pose.position.y);
  });
}
```

--------------------------------

### Initialize ROS2D.js Viewer and Map Client

Source: https://github.com/robotwebtools/ros2djs/blob/develop/examples/continuous.html

Sets up the connection to the ROS WebSocket server and initializes the ROS2D.js viewer and OccupancyGridClient. The client is configured for continuous updates, and an event listener scales and shifts the viewer to match the map dimensions and pose.

```javascript
function init() {
  // Connect to ROS.
  var ros = new ROSLIB.Ros({
    url : 'ws://localhost:9090'
  });

  // Create the main viewer.
  var viewer = new ROS2D.Viewer({
    divID : 'map',
    width : 640,
    height : 480
  });

  // Setup the map client.
  var gridClient = new ROS2D.OccupancyGridClient({
    ros : ros,
    rootObject : viewer.scene,
    // Use this property in case of continuous updates
    continuous: true
  });

  // Scale the canvas to fit to the map
  gridClient.on('change', function() {
    viewer.scaleToDimensions(gridClient.currentGrid.width, gridClient.currentGrid.height);
    viewer.shift(gridClient.currentGrid.pose.position.x, gridClient.currentGrid.pose.position.y);
  });
}
```

--------------------------------

### Initialize and Use ROS2D Viewer

Source: https://context7.com/robotwebtools/ros2djs/llms.txt

Demonstrates how to create a ROS2D Viewer instance, add visual objects like navigation arrows, and adjust the view to fit map dimensions. It requires a DOM element with the specified 'divID' and utilizes EaselJS for rendering.

```javascript
var viewer = new ROS2D.Viewer({
  divID: 'map-container',
  width: 800,
  height: 600,
  background: '#2d2d2d'
});

var arrow = new ROS2D.NavigationArrow({
  size: 0.5,
  fillColor: createjs.Graphics.getRGB(0, 255, 0)
});
arrow.x = 2.5;
arrow.y = 1.0;
viewer.addObject(arrow);

viewer.scaleToDimensions(20.0, 15.0);
viewer.shift(-5.0, -3.0);
```

--------------------------------

### Load Static Map via Service Call

Source: https://context7.com/robotwebtools/ros2djs/llms.txt

Illustrates using OccupancyGridSrvClient to retrieve a static map by calling the map_server's GetMap service. This is efficient for static environments as it avoids continuous topic subscriptions. The viewer is configured upon successful map retrieval.

```javascript
var ros = new ROSLIB.Ros({
  url: 'ws://localhost:9090'
});

var viewer = new ROS2D.Viewer({
  divID: 'static-map',
  width: 800,
  height: 600
});

var srvClient = new ROS2D.OccupancyGridSrvClient({
  ros: ros,
  service: '/static_map',
  rootObject: viewer.scene
});

srvClient.on('change', function(currentGrid) {
  viewer.scaleToDimensions(currentGrid.width, currentGrid.height);
  viewer.shift(currentGrid.pose.position.x, currentGrid.pose.position.y);
  console.log('Map loaded: ' + currentGrid.width + 'm x ' + currentGrid.height + 'm');
});
```

--------------------------------

### Complete ros2djs Robot Monitoring Interface

Source: https://context7.com/robotwebtools/ros2djs/llms.txt

This HTML and JavaScript code demonstrates a complete ros2djs application. It connects to a ROS instance, displays an occupancy grid map, visualizes the robot's current pose and trail, and allows users to set navigation goals by clicking on the map. It relies on easeljs, eventemitter2, roslib, and ros2djs libraries.

```html
<!DOCTYPE html>
<html>
<head>
  <script src="https://cdn.jsdelivr.net/npm/easeljs@1/lib/easeljs.min.js"></script>
  <script src="https://cdn.jsdelivr.net/npm/eventemitter2@6/lib/eventemitter2.min.js"></script>
  <script src="https://cdn.jsdelivr.net/npm/roslib@1/build/roslib.min.js"></script>
  <script src="https://cdn.jsdelivr.net/npm/ros2d@0/build/ros2d.min.js"></script>
</head>
<body>
  <div id="map"></div>
  <script>
    // Connect to ROS
    var ros = new ROSLIB.Ros({ url: 'ws://localhost:9090' });

    // Create viewer
    var viewer = new ROS2D.Viewer({
      divID: 'map',
      width: 800,
      height: 600,
      background: '#222222'
    });

    // Load occupancy grid map
    var gridClient = new ROS2D.OccupancyGridClient({
      ros: ros,
      rootObject: viewer.scene,
      continuous: true
    });

    gridClient.on('change', function() {
      viewer.scaleToDimensions(
        gridClient.currentGrid.width,
        gridClient.currentGrid.height
      );
      viewer.shift(
        gridClient.currentGrid.pose.position.x,
        gridClient.currentGrid.pose.position.y
      );
    });

    // Robot pose marker
    var robotMarker = new ROS2D.NavigationArrow({
      size: 0.5,
      fillColor: createjs.Graphics.getRGB(0, 200, 0),
      pulse: false
    });
    viewer.addObject(robotMarker);

    // Robot trail
    var robotTrace = new ROS2D.TraceShape({
      strokeColor: createjs.Graphics.getRGB(0, 150, 0, 0.5),
      maxPoses: 100
    });
    viewer.addObject(robotTrace);

    // Subscribe to robot pose
    var poseTopic = new ROSLIB.Topic({
      ros: ros,
      name: '/amcl_pose',
      messageType: 'geometry_msgs/PoseWithCovarianceStamped'
    });

    poseTopic.subscribe(function(msg) {
      var pose = msg.pose.pose;
      robotMarker.x = pose.position.x;
      robotMarker.y = pose.position.y;
      robotMarker.rotation = viewer.scene.rosQuaternionToGlobalTheta(pose.orientation);
      robotTrace.addPose(new ROSLIB.Pose(pose));
    });

    // Click to set navigation goal
    viewer.scene.addEventListener('stagemouseup', function(event) {
      var pos = viewer.scene.globalToRos(event.stageX, event.stageY);
      var goalTopic = new ROSLIB.Topic({
        ros: ros,
        name: '/move_base_simple/goal',
        messageType: 'geometry_msgs/PoseStamped'
      });
      goalTopic.publish(new ROSLIB.Message({
        header: { frame_id: 'map' },
        pose: { position: { x: pos.x, y: pos.y, z: 0 }, orientation: { w: 1 } }
      }));
    });
  </script>
</body>
</html>
```

--------------------------------

### Display Occupancy Grid Map from Topic

Source: https://context7.com/robotwebtools/ros2djs/llms.txt

Shows how to use OccupancyGridClient to subscribe to a ROS occupancy grid topic and render it as a bitmap. It requires a running rosbridge instance and a ROS topic publishing map data. The viewer is automatically scaled and shifted upon map changes.

```javascript
var ros = new ROSLIB.Ros({
  url: 'ws://localhost:9090'
});

var viewer = new ROS2D.Viewer({
  divID: 'map',
  width: 640,
  height: 480
});

var gridClient = new ROS2D.OccupancyGridClient({
  ros: ros,
  topic: '/map',
  rootObject: viewer.scene,
  continuous: false
});

gridClient.on('change', function() {
  var width = gridClient.currentGrid.width;
  var height = gridClient.currentGrid.height;
  var pose = gridClient.currentGrid.pose;

  viewer.scaleToDimensions(width, height);
  viewer.shift(pose.position.x, pose.position.y);
});
```

--------------------------------

### Display Custom PNG Map with ROS Metadata - ROS2DJS

Source: https://context7.com/robotwebtools/ros2djs/llms.txt

The ImageMapClient displays a custom PNG image as a map, scaled according to ROS map metadata from the /map_metadata topic. It requires a ROS connection and a viewer instance. The client listens for map metadata changes to rescale and reposition the viewer.

```javascript
var ros = new ROSLIB.Ros({
  url: 'ws://localhost:9090'
});

var viewer = new ROS2D.Viewer({
  divID: 'image-map',
  width: 640,
  height: 480
});

// Load custom image map
var imageClient = new ROS2D.ImageMapClient({
  ros: ros,
  topic: '/map_metadata',     // Topic for map metadata (default: '/map_metadata')
  image: 'custom_map.png',    // URL or path to the map image
  rootObject: viewer.scene
});

// Scale viewer when metadata is received
imageClient.on('change', function() {
  viewer.scaleToDimensions(
    imageClient.currentImage.width,
    imageClient.currentImage.height
  );
  viewer.shift(
    imageClient.currentImage.pose.position.x,
    imageClient.currentImage.pose.position.y
  );
});
```

--------------------------------

### ROS2D.TraceShape: Visualize Robot Trail

Source: https://context7.com/robotwebtools/ros2djs/llms.txt

Records and displays a trail of robot poses with configurable history and distance-based filtering. It visualizes the robot's traveled path. Dependencies include ROSLIBJS and CreateJS.

```javascript
var robotTrace = new ROS2D.TraceShape({
  strokeSize: 2,
  strokeColor: createjs.Graphics.getRGB(255, 165, 0),  // Orange trace
  maxPoses: 200,        // Maximum poses to keep (0 for infinite)
  minDist: 0.1          // Minimum distance between recorded poses (meters)
});

viewer.addObject(robotTrace);

var poseTopic = new ROSLIB.Topic({
  ros: ros,
  name: '/robot_pose',
  messageType: 'geometry_msgs/Pose'
});

poseTopic.subscribe(function(message) {
  var pose = new ROSLIB.Pose({
    position: message.position,
    orientation: message.orientation
  });
  robotTrace.addPose(pose);
});

robotTrace.addPose(new ROSLIB.Pose({
  position: { x: 1.0, y: 2.0, z: 0 }
}));
```

--------------------------------

### Implement Zoom Functionality with ROS2D.ZoomView

Source: https://context7.com/robotwebtools/ros2djs/llms.txt

This snippet demonstrates how to set up and use the ROS2D.ZoomView helper to enable zoom functionality centered on a specific point. It handles mouse wheel events to adjust the zoom level while preserving the view's center. Dependencies include the ROS2D library and a viewer instance.

```javascript
var zoomView = new ROS2D.ZoomView({
  rootObject: viewer.scene,
  minScale: 0.001     // Minimum zoom scale to maintain precision
});

var currentZoom = 1.0;

// Handle mouse wheel zoom
viewer.scene.canvas.addEventListener('wheel', function(event) {
  event.preventDefault();

  // Calculate zoom factor
  var zoomDelta = event.deltaY > 0 ? 0.9 : 1.1;
  currentZoom *= zoomDelta;

  // Start zoom centered on mouse position
  zoomView.startZoom(event.offsetX, event.offsetY);
  zoomView.zoom(currentZoom);
});
```

--------------------------------

### ROS2D.PanView: Enable Scene Panning

Source: https://context7.com/robotwebtools/ros2djs/llms.txt

Provides click-and-drag panning functionality for the visualization scene. It tracks mouse movements to translate the stage. Dependencies include CreateJS.

```javascript
var panView = new ROS2D.PanView({
  rootObject: viewer.scene
});

var isPanning = false;

viewer.scene.addEventListener('stagemousedown', function(event) {
  if (event.nativeEvent.button === 1) {  // Middle mouse button
    isPanning = true;
    panView.startPan(event.stageX, event.stageY);
  }
});

viewer.scene.addEventListener('stagemousemove', function(event) {
  if (isPanning) {
    panView.pan(event.stageX, event.stageY);
  }
});

viewer.scene.addEventListener('stagemouseup', function(event) {
  isPanning = false;
});
```

--------------------------------

### Convert Coordinates using ROS2D Viewer Utilities

Source: https://context7.com/robotwebtools/ros2djs/llms.txt

This code illustrates how to leverage ROS2D.Viewer's extended createjs.Stage methods for coordinate transformations. It shows converting screen coordinates (from mouse events) to ROS world coordinates and vice-versa, as well as converting ROS quaternions to canvas rotation angles. This is crucial for tasks like navigation goal setting and displaying robot positions.

```javascript
var viewer = new ROS2D.Viewer({
  divID: 'map',
  width: 640,
  height: 480
});

// After setting up map scaling...
viewer.scaleToDimensions(20.0, 15.0);

// Convert screen click to ROS coordinates
viewer.scene.addEventListener('stagemouseup', function(event) {
  // Convert global stage coordinates to ROS world coordinates
  var rosPos = viewer.scene.globalToRos(event.stageX, event.stageY);
  console.log('Clicked at ROS position: x=' + rosPos.x + ', y=' + rosPos.y);

  // Use for sending navigation goals
  var goal = new ROSLIB.Pose({
    position: { x: rosPos.x, y: rosPos.y, z: 0 },
    orientation: { w: 1, x: 0, y: 0, z: 0 }
  });
});

// Convert ROS position to screen coordinates
var robotRosPos = { x: 5.0, y: 3.0 };
var screenPos = viewer.scene.rosToGlobal(robotRosPos);
console.log('Robot on screen at: x=' + screenPos.x + ', y=' + screenPos.y);

// Convert ROS quaternion to canvas rotation
var orientation = { w: 0.707, x: 0, y: 0, z: 0.707 };
var degrees = viewer.scene.rosQuaternionToGlobalTheta(orientation);
console.log('Rotation: ' + degrees + ' degrees');
```

--------------------------------

### ROS2D.PathShape: Visualize nav_msgs/Path

Source: https://context7.com/robotwebtools/ros2djs/llms.txt

Renders a nav_msgs/Path message as a connected line. It can be initialized with path data or updated via subscription to a ROS topic. Dependencies include ROSLIBJS and CreateJS.

```javascript
var pathShape = new ROS2D.PathShape({
  strokeSize: 2,
  strokeColor: createjs.Graphics.getRGB(0, 100, 255)  // Blue path
});

viewer.addObject(pathShape);

var pathTopic = new ROSLIB.Topic({
  ros: ros,
  name: '/move_base/NavfnROS/plan',
  messageType: 'nav_msgs/Path'
});

pathTopic.subscribe(function(message) {
  pathShape.setPath(message);
});

var manualPath = {
  poses: [
    { pose: { position: { x: 0, y: 0 } } },
    { pose: { position: { x: 2, y: 1 } } },
    { pose: { position: { x: 4, y: 1.5 } } },
    { pose: { position: { x: 6, y: 3 } } }
  ]
};
pathShape.setPath(manualPath);
```

--------------------------------

### ROS2D.PolygonMarker: Interactive Polygon Editor

Source: https://context7.com/robotwebtools/ros2djs/llms.txt

Creates an interactive and editable polygon shape for defining regions. Users can add, remove, and drag points with mouse events. Supports callbacks for point and line interactions. Dependencies include ROSLIBJS and CreateJS.

```javascript
var viewer = new ROS2D.Viewer({
  divID: 'polygon-editor',
  width: 640,
  height: 480
});

var selectedPointIndex = null;

var polygon = new ROS2D.PolygonMarker({
  lineSize: 2,
  lineColor: createjs.Graphics.getRGB(100, 100, 255, 1),
  pointSize: 8,
  pointColor: createjs.Graphics.getRGB(255, 0, 0, 0.8),
  fillColor: createjs.Graphics.getRGB(0, 255, 0, 0.3),
  pointCallBack: function(type, event, index) {
    if (type === 'mousedown') {
      if (event.nativeEvent.shiftKey) {
        polygon.remPoint(index);
      } else {
        selectedPointIndex = index;
      }
    }
  },
  lineCallBack: function(type, event, index) {
    if (type === 'mousedown' && event.nativeEvent.ctrlKey) {
      polygon.splitLine(index);
    }
  }
});

viewer.addObject(polygon);

viewer.scene.addEventListener('stagemousemove', function(event) {
  if (selectedPointIndex !== null) {
    var pos = viewer.scene.globalToRos(event.stageX, event.stageY);
    polygon.movePoint(selectedPointIndex, pos);
  }
});

viewer.scene.addEventListener('stagemouseup', function(event) {
  if (selectedPointIndex !== null) {
    selectedPointIndex = null;
  } else {
    var pos = viewer.scene.globalToRos(event.stageX, event.stageY);
    polygon.addPoint(pos);
  }
});
```

--------------------------------

### Display Custom Image as Navigation Marker - ROS2DJS

Source: https://context7.com/robotwebtools/ros2djs/llms.txt

The NavigationImage displays a custom image as a navigation marker, useful for robot icons or waypoint markers. It allows for customizable size, image source, opacity, and an optional pulsing effect. The marker can be positioned and rotated within the viewer.

```javascript
// Create image-based robot marker
var robotMarker = new ROS2D.NavigationImage({
  size: 50,                    // Desired size in pixels
  image: 'robot_icon.png',     // URL to marker image
  pulse: false,                // Optional pulsing effect
  alpha: 1.0                   // Opacity (0-1)
});

// Position at robot location
robotMarker.x = 4.2;
robotMarker.y = 3.1;
robotMarker.rotation = 45;  // Rotation in degrees

viewer.addObject(robotMarker);

// Create semi-transparent waypoint marker
var waypoint = new ROS2D.NavigationImage({
  size: 30,
  image: 'waypoint.png',
  alpha: 0.7,
  pulse: true
});
waypoint.x = 6.0;
waypoint.y = 4.5;
viewer.addObject(waypoint);
```

--------------------------------

### ROS2D.Grid: Visualize Coordinate Grid

Source: https://context7.com/robotwebtools/ros2djs/llms.txt

Draws a coordinate grid overlay for debugging and scale reference. It features centered axes and configurable grid lines. Dependencies include CreateJS.

```javascript
var grid = new ROS2D.Grid({
  size: 20,           // Grid extent from center (grid spans -20 to +20)
  cellSize: 1.0,      // Size of each grid cell in meters
  lineWidth: 0.01     // Width of grid lines
});

viewer.addObject(grid);
```

--------------------------------

### Create Navigation Arrow for Robot Pose/Goals - ROS2DJS

Source: https://context7.com/robotwebtools/ros2djs/llms.txt

The NavigationArrow creates a triangular arrow shape for representing robot pose or navigation goals. It supports customizable colors, sizes, and an optional pulsing animation. The arrow can be positioned and rotated using ROS coordinates and quaternions.

```javascript
// Create a navigation arrow for robot pose
var robotPose = new ROS2D.NavigationArrow({
  size: 15,                                           // Arrow size in pixels
  strokeSize: 2,                                      // Outline width
  strokeColor: createjs.Graphics.getRGB(0, 0, 0),     // Black outline
  fillColor: createjs.Graphics.getRGB(0, 200, 0),    // Green fill
  pulse: false                                        // Pulsing animation
});

// Position the arrow at robot's location (ROS coordinates)
robotPose.x = 3.5;   // X position in meters
robotPose.y = 2.0;   // Y position in meters

// Set rotation from ROS quaternion
var orientation = { w: 0.707, x: 0, y: 0, z: 0.707 };  // 90 degrees
robotPose.rotation = viewer.scene.rosQuaternionToGlobalTheta(orientation);

viewer.addObject(robotPose);

// Create a pulsing goal marker
var goalMarker = new ROS2D.NavigationArrow({
  size: 20,
  fillColor: createjs.Graphics.getRGB(255, 100, 0),
  pulse: true   // Enable pulsing animation
});
goalMarker.x = 8.0;
goalMarker.y = 5.0;
viewer.addObject(goalMarker);
```

--------------------------------

### Create Directional Arrow Shape - ROS2DJS

Source: https://context7.com/robotwebtools/ros2djs/llms.txt

The ArrowShape creates a directional arrow with a line body and triangular head, suitable for displaying vectors or directions. It points to the right at 0 degrees rotation by default. The shape can be customized with size, stroke, fill color, and pulsing animation.

```javascript
// Create direction arrow
var directionArrow = new ROS2D.ArrowShape({
  size: 25,                                           // Total arrow length
  strokeSize: 2,                                      // Line thickness
  strokeColor: createjs.Graphics.getRGB(50, 50, 50),  // Dark gray stroke
  fillColor: createjs.Graphics.getRGB(255, 0, 0),     // Red arrowhead
  pulse: false                                        // Pulsing animation
});

// Position and rotate
directionArrow.x = 5.0;
directionArrow.y = 3.0;
directionArrow.rotation = 135;  // Point to upper-left

viewer.addObject(directionArrow);
```

=== COMPLETE CONTENT === This response contains all available snippets from this library. No additional content exists. Do not make further requests.