# Custom Rviz Overlay > --- name: custom-rviz-overlay description: 'Create custom RViz overlay displays. Use when showing battery status, velocity, or navigation state as 2D overlays in RViz.' --- # Creating Custom RViz Overlay Displays ## Overview RViz overlays render 2D text, plots, and status indicators directly on the 3D viewport. The primary package is `rviz_2d_overlay_plugins` (from `ros-jazzy-rviz-2d-overlay-plugins`). ```bash sudo apt install ros-jazzy-rviz-2d-overlay-plugins ``` ## OverlayText Message ```bash # Message definition: rviz_2d_overlay_msgs/msg/OverlayText # int32 width, height — overlay box size in pixels # int32 left, top — position from viewport edges # std_msgs/ColorRGBA bg_color — background color (use alpha for transparency) # std_msgs/ColorRGBA fg_color — text color # int32 line_width — text line width # int32 text_size — font size in points # string font — font name # string text — content (supports colored HTML) ``` ## Battery Status Overlay Publisher ```python #!/usr/bin/env python3 """Publish battery status as an RViz overlay with color-coded voltage.""" import rclpy from rclpy.node import Node from rclpy.qos import QoSProfile, ReliabilityPolicy, DurabilityPolicy from sensor_msgs.msg import BatteryState from rviz_2d_overlay_msgs.msg import OverlayText from std_msgs.msg import ColorRGBA class BatteryOverlayPublisher(Node): def __init__(self): super().__init__("battery_overlay_publisher") sensor_qos = QoSProfile( reliability=ReliabilityPolicy.BEST_EFFORT, durability=DurabilityPolicy.VOLATILE, depth=5, ) self.sub = self.create_subscription( BatteryState, "/battery_state", self.battery_callback, sensor_qos ) self.pub = self.create_publisher(OverlayText, "/overlay/battery", 10) def battery_callback(self, msg: BatteryState): overlay = OverlayText() overlay.width = 280 overlay.height = 100 overlay.left = 10 overlay.top = 10 overlay.text_size = 14 overlay.font = "DejaVu Sans Mono" overlay.bg_color = ColorRGBA(r=0.0, g=0.0, b=0.0, a=0.6) voltage = msg.voltage current = abs(msg.current) pct = msg.percentage * 100 # Color code: green > 50%, yellow 20-50%, red < 20% if pct > 50: overlay.fg_color = ColorRGBA(r=0.2, g=1.0, b=0.2, a=1.0) elif pct > 20: overlay.fg_color = ColorRGBA(r=1.0, g=1.0, b=0.0, a=1.0) else: overlay.fg_color = ColorRGBA(r=1.0, g=0.2, b=0.2, a=1.0) status_str = {0: "UNKNOWN", 1: "CHARGING", 2: "DISCHARGING", 3: "NOT_CHARGING", 4: "FULL"}.get(msg.power_supply_status, "?") overlay.text = ( f"Battery: {pct:.0f}%\n" f"Voltage: {voltage:.1f}V\n" f"Current: {current:.1f}A\n" f"Status: {status_str}" ) self.pub.publish(overlay) def main(): rclpy.init() node = BatteryOverlayPublisher() rclpy.spin(node) node.destroy_node() rclpy.shutdown() if __name__ == "__main__": main() ``` ## Multi-Info Dashboard Node ```python #!/usr/bin/env python3 """Dashboard overlay: velocity, nav state, WiFi, CPU.""" import psutil import rclpy from rclpy.node import Node from geometry_msgs.msg import Twist from std_msgs.msg import String from rviz_2d_overlay_msgs.msg import OverlayText from std_msgs.msg import ColorRGBA class DashboardOverlay(Node): def __init__(self): super().__init__("dashboard_overlay") self.vel_linear = 0.0 self.vel_angular = 0.0 self.nav_state = "IDLE" self.create_subscription(Twist, "/cmd_vel", self.vel_cb, 10) self.create_subscription(String, "/nav_state", self.nav_cb, 10) # Velocity overlay — top right self.vel_pub = self.create_publisher(OverlayText, "/overlay/velocity", 10) # System overlay — bottom left self.sys_pub = self.create_publisher(OverlayText, "/overlay/system", 10) self.create_timer(0.5, self.publish_overlays) def vel_cb(self, msg: Twist): self.vel_linear = msg.linear.x self.vel_angular = msg.angular.z def nav_cb(self, msg: String): self.nav_state = msg.data def publish_overlays(self): # Velocity overlay vel = OverlayText() vel.width = 240 vel.height = 70 vel.left = -250 # negative = from right edge (not all plugins support this) vel.top = 10 vel.text_size = 14 vel.font = "DejaVu Sans Mono" vel.bg_color = ColorRGBA(r=0.0, g=0.0, b=0.0, a=0.5) vel.fg_color = ColorRGBA(r=0.9, g=0.9, b=0.9, a=1.0) vel.text = ( f"Linear: {self.vel_linear:+.2f} m/s\n" f"Angular: {self.vel_angular:+.2f} rad/s\n" f"Nav: {self.nav_state}" ) self.vel_pub.publish(vel) # System overlay cpu = psutil.cpu_percent() mem = psutil.virtual_memory().percent sys_overlay = OverlayText() sys_overlay.width = 200 sys_overlay.height = 50 sys_overlay.left = 10 sys_overlay.top = 120 # below battery overlay sys_overlay.text_size = 12 sys_overlay.font = "DejaVu Sans Mono" sys_overlay.bg_color = ColorRGBA(r=0.0, g=0.0, b=0.0, a=0.5) color_r = min(1.0, cpu / 100.0) sys_overlay.fg_color = ColorRGBA(r=color_r, g=1.0 - color_r, b=0.0, a=1.0) sys_overlay.text = f"CPU: {cpu:.0f}% MEM: {mem:.0f}%" self.sys_pub.publish(sys_overlay) def main(): rclpy.init() rclpy.spin(DashboardOverlay()) rclpy.shutdown() ``` ## RViz Config for Overlays Add these displays to your `.rviz` config: ```yaml - Class: rviz_2d_overlay_plugins/OverlayText Name: BatteryOverlay Enabled: true Topic: Value: /overlay/battery Depth: 5 Reliability Policy: Reliable - Class: rviz_2d_overlay_plugins/OverlayText Name: VelocityOverlay Enabled: true Topic: Value: /overlay/velocity Depth: 5 Reliability Policy: Reliable - Class: rviz_2d_overlay_plugins/OverlayText Name: SystemOverlay Enabled: true Topic: Value: /overlay/system Depth: 5 Reliability Policy: Reliable ``` ## Marker-Based HUD Alternative When `rviz_2d_overlay_plugins` isn't available, use `visualization_msgs/Marker` with `TEXT_VIEW_FACING` type. These appear in 3D space (not screen-fixed) but can be placed relative to the robot: ```python from visualization_msgs.msg import Marker marker = Marker() marker.header.frame_id = "base_link" marker.type = Marker.TEXT_VIEW_FACING marker.action = Marker.ADD marker.pose.position.z = 1.0 # float above robot marker.scale.z = 0.15 # text height in meters marker.color.a = 1.0 marker.color.g = 1.0 marker.text = f"Battery: {pct:.0f}%" ``` ## jsk_rviz_plugins Alternative The `jsk_rviz_plugins` package provides additional overlay types: pie charts, bounding boxes, pictograms, and status indicators. Install with `sudo apt install ros-jazzy-jsk-rviz-plugins` (if available for your distro). ## Dashboard Layout ``` ┌─────────────────────────────────────────┐ │ [Battery: 78% ] ←top-left [Vel]→ │ │ [Voltage: 12.4V ] top-right │ │ [CPU: 45% MEM:62%] │ │ │ │ 3D Viewport │ │ │ │ │ │ [Nav: NAVIGATING] [Plot]→ │ │ bottom-left bottom-right │ └─────────────────────────────────────────┘ ```