Cesiumjs - Rotate text - text

Question

I want to add a label that doesn't always face the camera. Instead, I want it to follow a defined path. Similar to how street names follow the direction of their streets in google maps (they aren't always horizontal).
I can think of 2 possible implementations for rotating text but haven't had any luck.
That Label() or label : have a rotation property I haven't found. IE something like this:
viewer.entities.add({
position : Cesium.Cartesian3.fromDegrees(-75.1641667, 39.9522222),
label : {
text : 'Philadelphia'
//rotation : Cesium.Math.toRadians(-45)
}
});
or this
var labels = scene.primitives.add(new Cesium.LabelCollection());
var l = labels.add({
position : Cesium.Cartesian3.fromRadians(longitude, latitude, height),
text : 'Hello World',
font : '24px Helvetica'
//rotation: Cesium.Math.toRadians(-45)
});
Create Pictures of each label in photoshop and import them as an image, then rotate the image (or use it as a material and rotate the entity). Very labor intensive if you have a lot of labels (like street names).
Or perhaps there is a way for cesiumjs to recognize text as a fixed position 2D object and skew it appropriately as the view angle changes.
Any ideas?

Answer 1

If your text doesn't change, You can use an image, and load it by Cesium.SingleTileImageryProvider .
If your text does change, you can use a billboard.image, set an HTML canvas to it, and rotate the canvas like so:
var c = document.getElementById("myCanvas");
var ctx = c.getContext("2d");
ctx.font = "20px Georgia";
ctx.fillText("Hello World!", 10, 50);
ctx.font = "30px Verdana";
// Create gradient
var gradient = ctx.createLinearGradient(0, 0, c.width, 0);
gradient.addColorStop("0", "magenta");
gradient.addColorStop("0.5", "blue");
gradient.addColorStop("1.0", "red");
// Fill with gradient
ctx.rotate(20*Math.PI/180);
ctx.fillStyle = gradient;
ctx.fillText("Big smile!", 10, 90);
billboard.image = ctx;

Answer 2

The only way I know how to rotate a label is like #Henri Aloni said with canvas.
Cesium has already a function called: writeTextToCanvas.
example in typescript :
viewer.entities.add({
position: Cartesain3.fromDegrees(34, 32, 0),
billboard: {
image: writeTextToCanvas('baruch', {
font: '30px sans-serif'
}),
rotation: 45
}
});