zoom in to mouse point

CesiumJS
1

Hi,

I came across this code for zooming to mouse point, instead of the map center point:
https://gist.github.com/scothis/c9f2695f03380ca5dd96

It works fine for 3D but not for 2D. you can check it in sandcastle.

Can you please tell me what should I do to get this work in 2D?
If you have a better way for zooming to mouse point in 2D,
I would be very grateful to know about it.

Thanks!

2

I don’t have a complete code sample handy, but here is some pseudocode where you need to modify

eventHandler.setInputAction(function (wheelZoomAmount) {
var cameraHeight, directionToZoom, zoomAmount;
if (mousePosition) {
cameraHeight = viewer.scene.globe.ellipsoid.cartesianToCartographic(camera.position).height || Number.MAX_VALUE;
zoomAmount = wheelZoomAmount * cameraHeight / 1000;

    if (scene.mode !== Cesium.SceneMode.SCENE3D) {
        //Determine Camera position https://groups.google.com/d/msg/cesium-dev/QSFf3RxNRfE/XotNBSBdFQgJ

        //calculate the vector between camera ground position and mouse ground position so you can calculate a
        //moveLeft amount and a moveForward amount;  This will need probably have a scaling factor based on height
        //similar to the zoomAmount;

        camera.zoomIn (zoomAmount);
        camera.moveLeft(leftAmount);
        camera.moveForward(forwardAmount);
    } else {
        directionToZoom = camera.getPickRay(mousePosition).direction;
        camera.move(directionToZoom, zoomAmount);
    }
}

}, Cesium.ScreenSpaceEventType.WHEEL);

``

3

I finally wrote something that works in 2D

here is a link to that code https://github.com/erezy/cesium-2D-zoom-in/blob/master/src/zoom-in.js

you can copy&paste it in Sandcastle.

Don’t forget to change the map to 2D.

4

Thanks for sharing the code sample.

5

FYI to people interested in this feature, a pull request is open to do this official and make it the default zoom behavior: https://github.com/AnalyticalGraphicsInc/cesium/pull/2810

6

This feature (#2810) was just merged into master and will be in Cesium 1.11 on July 1.

If you have the same experience I did, you will quickly get use to it and will not want to go back to the old zoom.

Patrick

7

Any chance there will ever be zoom out on mouse position?

8

Is July first soon enough?

Cheers,

-Mike

9

Mike, the July 1st release does not have zoom out on mouse position, though I agree with Denver in that we should absolutely support it.

There is already an issue open for it here: https://github.com/AnalyticalGraphicsInc/cesium/issues/2834

Depending on how hard it is, it might go into July 1st, but I have to refer to Dan, since he’s the one that knows this area of the code.