import * as Cesium from "cesium";
/**
* DrawPolygon class for drawing a polygon in a Cesium viewer.
* @class DrawPolygon
* @param {Cesium.Viewer} viewer - The Cesium viewer instance.
* @param {Object} [options] - Options for the drawing tool.
* @param {Cesium.Color} [options.color] - The color of the polygon.
* @param {boolean} [options.clampToGround] - Whether to clamp the polygon to the ground.
* @example
* const drawPolygon = new DrawPolygon(viewer, { color: Cesium.Color.RED });
* drawPolygon.on();
* // To disable the drawing tool and clear entities
* drawPolygon.off();
*/
export class DrawPolygon {
constructor(viewer, options = {}) {
this.viewer = viewer;
this.scene = viewer.scene;
this.handler = new Cesium.ScreenSpaceEventHandler();
this.color = options.color || Cesium.Color.LIGHTGRAY;
this.clampToGround = options.clampToGround || false;
this.status = false;
this.cartesians = undefined;
this.endCartesian = undefined;
this.polygonEntity = undefined;
this.polylineEntity = undefined;
this.pointEntities = [];
}
/**
* Enables the polygon drawing tool.
* Left click to add points, right click to finish.
* @function
* @type {boolean} Continue - Whether to continue measuring after the first click.
* @returns {void}
*/
on = (isContinue = false) => {
this.scene.canvas.style.cursor = "crosshair";
const viewer = this.viewer;
const scene = viewer.scene;
const handler = this.handler;
const mouseLeftClickHandler = (event) => {
if (!this.status) {
this.status = true;
// Clear previous entities
this.recentPositions = this.cartesians.slice();
if (this.recentPositions && this.recentPositions.length > 0) {
this.recentPositions.push(this.recentPositions[0]);
}
this.clearEntities(viewer);
this.clearCartesians();
scene.screenSpaceCameraController.enableRotate = true;
scene.screenSpaceCameraController.enableTranslate = true;
scene.screenSpaceCameraController.enableZoom = true;
scene.screenSpaceCameraController.enableTilt = true;
scene.screenSpaceCameraController.enableLook = true;
}
this.pickedObject = scene.pick(event.position);
let pickedEllipsoidPosition;
if (scene.pickPositionSupported) {
pickedEllipsoidPosition = viewer.scene.pickPosition(
event.position);
}
if (!pickedEllipsoidPosition) {
pickedEllipsoidPosition = viewer.camera.pickEllipsoid(
event.position,
scene.globe.ellipsoid,
);
const cartographic = Cesium.Cartographic.fromCartesian(
pickedEllipsoidPosition);
const height = viewer.scene.globe.getHeight(
Cesium.Cartographic.fromRadians(cartographic.longitude,
cartographic.latitude, 0));
pickedEllipsoidPosition = Cesium.Cartesian3.fromRadians(
cartographic.longitude, cartographic.latitude, height);
}
this.cartesians.push(pickedEllipsoidPosition);
this.endCartesian = pickedEllipsoidPosition;
const pointEntity = viewer.entities.add({
position: pickedEllipsoidPosition,
point: {
show: false,
color: this.color,
pixelSize: 4,
disableDepthTestDistance: Number.POSITIVE_INFINITY,
},
});
this.pointEntities.push(pointEntity);
if (this.cartesians.length <= 1) {
this.polylineEntity = viewer.entities.add({
polyline: {
positions: new Cesium.CallbackProperty(() => {
const cartesianPositions = this.cartesians.slice();
cartesianPositions.push(this.endCartesian);
cartesianPositions.push(this.cartesians[0]);
return cartesianPositions;
}, false),
width: 3,
depthFailMaterial: this.color,
material: this.color.withAlpha(0.8),
clampToGround: this.clampToGround,
},
});
this.polygonEntity = viewer.entities.add({
polygon: {
hierarchy: new Cesium.CallbackProperty(() => {
const cartesianPositions = this.cartesians.slice();
cartesianPositions.push(this.endCartesian);
return new Cesium.PolygonHierarchy(
cartesianPositions);
}, false),
material: this.color.withAlpha(0.5),
perPositionHeight: !this.clampToGround,
},
});
}
};
const mouseMoveHandler = (moveEvent) => {
if (!this.status) {
return;
}
// pickedObject = scene.pick(moveEvent.endPosition);
let pickedEllipsoidPosition;
if (scene.pickPositionSupported) {
pickedEllipsoidPosition = viewer.scene.pickPosition(
moveEvent.endPosition);
}
if (!pickedEllipsoidPosition) {
pickedEllipsoidPosition = viewer.camera.pickEllipsoid(
moveEvent.endPosition,
scene.globe.ellipsoid,
);
const cartographic = Cesium.Cartographic.fromCartesian(
pickedEllipsoidPosition);
const height = viewer.scene.globe.getHeight(
Cesium.Cartographic.fromRadians(cartographic.longitude,
cartographic.latitude, 0));
pickedEllipsoidPosition = Cesium.Cartesian3.fromRadians(
cartographic.longitude, cartographic.latitude, height);
}
this.endCartesian = pickedEllipsoidPosition;
};
const mouseRightClickHandler = (event) => {
if (!this.status) {
return;
}
this.status = false;
this.pickedObject = scene.pick(event.position);
let pickedEllipsoidPosition;
if (scene.pickPositionSupported) {
pickedEllipsoidPosition = viewer.scene.pickPosition(
event.position);
}
if (!pickedEllipsoidPosition) {
pickedEllipsoidPosition = viewer.camera.pickEllipsoid(
event.position,
scene.globe.ellipsoid,
);
const cartographic = Cesium.Cartographic.fromCartesian(
pickedEllipsoidPosition);
const height = viewer.scene.globe.getHeight(
Cesium.Cartographic.fromRadians(cartographic.longitude,
cartographic.latitude, 0));
pickedEllipsoidPosition = Cesium.Cartesian3.fromRadians(
cartographic.longitude, cartographic.latitude, height);
}
this.cartesians.push(pickedEllipsoidPosition);
const pointEntity = viewer.entities.add({
position: pickedEllipsoidPosition,
point: {
show: false,
color: this.color,
pixelSize: 4,
disableDepthTestDistance: Number.POSITIVE_INFINITY,
},
});
this.pointEntities.push(pointEntity);
scene.screenSpaceCameraController.enableRotate = true;
scene.screenSpaceCameraController.enableTranslate = true;
scene.screenSpaceCameraController.enableZoom = true;
scene.screenSpaceCameraController.enableTilt = true;
scene.screenSpaceCameraController.enableLook = true;
};
handler.setInputAction(mouseLeftClickHandler,
Cesium.ScreenSpaceEventType.LEFT_CLICK);
handler.setInputAction(mouseMoveHandler,
Cesium.ScreenSpaceEventType.MOUSE_MOVE);
handler.setInputAction(mouseRightClickHandler,
Cesium.ScreenSpaceEventType.RIGHT_CLICK);
handler.setInputAction(mouseRightClickHandler,
Cesium.ScreenSpaceEventType.LEFT_DOUBLE_CLICK);
};
/**
* Disables the polygon drawing tool. and clears the entities.
* @function
* @returns {void}
*/
off = () => {
this.getPositions();
this.scene.canvas.style.cursor = "default";
this.status = false;
this.clearEntities();
const handler = this.handler;
if (handler) {
handler.removeInputAction(Cesium.ScreenSpaceEventType.LEFT_CLICK);
handler.removeInputAction(Cesium.ScreenSpaceEventType.MOUSE_MOVE);
handler.removeInputAction(Cesium.ScreenSpaceEventType.RIGHT_CLICK);
handler.removeInputAction(
Cesium.ScreenSpaceEventType.LEFT_DOUBLE_CLICK);
}
};
/**
* get position of the polygon
* @function
* @returns {Array} cartesians - Array of Cesium.Cartesian3 positions
*/
getPositions = () => {
if (this.polygonEntity) {
const positions = this.recentPositions;
console.log("getPositions", positions);
return positions;
} else {
console.warn("No positions found");
return [];
}
};
clearEntities = () => {
this.viewer.entities.remove(this.polylineEntity);
this.viewer.entities.remove(this.polygonEntity);
this.pointEntities.forEach(entity => {
this.viewer.entities.remove(entity);
});
this.polylineEntity = undefined;
this.polygonEntity = undefined;
this.pointEntities = [];
this.cartesians = [];
this.endCartesian = undefined;
};
clearCartesians = () => {
this.cartesians = [];
this.endCartesian = undefined;
};
}