Using a d3 map like this one: http://bl.ocks.org/mbostock/5593150
I would like the map to stay centered on the same spot.
is it possible to de-activate the pan, but keep the zoom active?
Yes, simply ignore any translation in the handler function. The only difficulty is to set the translation such that the center point is the same for different zoom levels (i.e. set the zoom on the projection first):
projection
.scale(zoom.scale() / 2 / Math.PI);
var tiles = tile
.scale(zoom.scale())
.translate(projection([-74.0064, 40.7142]).map(function(x) { return -x; }))
();
Complete demo here.
Related
In Three.js, I have a group of meshes that is loaded from outside with help of FBX loader. The group has six meshes inside. My task is to make this meshes follow pointer when they get hovered. More precisely, I'd like to have a sort of magnetic effect (just like navbar items in this pen, but with meshes in Three.js).
I think, firstly, I have to detect, where currently pointer is, i.e. get position of cursor in world coordinates system, and then translate meshes towards it. But when I try to get the position of cursor, it seems to be wrong.
Having said that, I have two questions:
How to get proper cursor's position relative to the world coordinates?
How to change position of each of the group's meshes so that they get translated against the cursor?
Here is what have I done so far:
Hi everyone.
In Three.js, I have a group of meshes that is loaded from outside with help of FBX loader. The group has six meshes inside. My task is to make this meshes follow pointer when their canvas get hovered. More precisely, I'd like to have a sort of magnetic effect (just like navbar items in this pen, but with meshes of Three.js).
I think, firstly, I have to detect, where currently pointer on canvas is, i.e. get position of cursor in world coordinates system, and then translate meshes towards it. But when I try to get the position of cursor, it seems to be wrong.
Having said that, I have two questions:
How to get proper cursor's position relative to the world coordinates?
How to change position of each of the group's meshes so that they get translated against the cursor?
Here is what have I done so far. Function that translates meshes isn't written yet. Mousemove callback returns pretty big digits, though:
// Load object and play a third-party animation
loader.load("Object_001.fbx", (object) => {
mixer = new THREE.AnimationMixer(object);
const action = mixer.clipAction(object.animations[0]);
action.play();
object.traverse((child) => {
if (child.isMesh) {
child.material.map = texture;
child.material.needsUpdate = true;
}
});
scene.add(object);
});
// log coordinates of the pointer
const mouse = new THREE.Vector3();
const position = new THREE.Vector3();
function onMouseMove(event) {
mouse.set(
(event.clientX / window.innerWidth) * 2 - 1,
-(event.clientY / window.innerHeight) * 2 + 1,
0.5
);
mouse.unproject(camera);
mouse.sub(camera.position).normalize();
const distance = -camera.position.z / mouse.z;
position.copy(camera.position).add(mouse.multiplyScalar(distance));
console.log(position);
}
wrapperElement.addEventListener("mousemove", onMouseMove);
Thanks in advance.
Made a codepen here:
https://codepen.io/cdeep/pen/YzxPPZQ
The cursor only exists in the canvas dom element which is a rendering of the camera view frustum.
The easiest way to make the object follow a mouse is to get the point of intersection of the mouse with another object in the 3d scene and set the object position to the intersection point. The above codepen showcases that.
raycaster.setFromCamera( mouse, camera );
const intersects = raycaster.intersectObjects([ground]);
if(intersects.length) {
const { point } = intersects[0];
cube.position.copy(point.setY(0.5));
}
You could also position it at a fixed distance from the mouse but it looks odd in my opinion:
const distance = 10;
raycaster.setFromCamera( mouse, camera );
const { origin, direction } = raycaster.ray;
cube.position.copy(origin.clone().add(direction.multiplyScalar(distance)));
Documentation for raycaster:
https://threejs.org/docs/index.html?q=ray#api/en/core/Raycaster
Raycasting is used for mouse picking (working out what objects in the
3d space the mouse is over) amongst other things.
I'm developing an application which use d3 for charting. x axis is time scale. User can zoom in/out to expand or shrink x axis. Now I want to add some logic in the event handler based on the direction user is zooming. But I don't find an easy way to know if user is doing zoom and in which direction.
Can someone share some experience here?
You want to add an event handler to the zoom.
To run a function whenever the zoom changes, you can add an event handler for zoom as follows:
zoom.on("zoom", function () {
var scale = d3.event.scale;
var translate = d3.event.translate;
// Do your processing
});
If you want to tell the direction of the zoom, you can save the translate each time, and compare the current one to the previous.
Direction of zoom : Zooming in or zooming out
In version 4 of d3, ZoomEvent contains WheelEvent as sourceEvent property. So to have the direction i'am doing :
zoom.on("zoom", () => {
-1 * Math.sign(d3.event.sourceEvent.deltaY)
});
d3.event.sourceEvent.deltaY gives nigative values when you zooming in, for me i use negative values when i zoom out that's why i'am multipling by -1.
The value of d3.event.deltaY works only in wheelDelta method of the zoom (see code below) but it gives mes values in v3 when i called it in the handler of zoom.
d3
.zoom()
.wheelDelta((ev, i, g) => {
return -d3.event.deltaY * (d3.event.deltaMode ? 120 : 1) / 500;
})
.on('zoom', () => {
// ...
});
I developed an script to display 2 layers ob base map.
but it is not zooming properlly.
I am using following code
can you please suggest me
<script type="text/javascript">
var map, layer, select, hover, control;
function init(){
map = new OpenLayers.Map('map', {
controls: [
new OpenLayers.Control.PanZoom(),
new OpenLayers.Control.Permalink(),
new OpenLayers.Control.Navigation()
]
});
layer = new OpenLayers.Layer.WMS(
"States WMS/WFS",
"http://localhost:8080/geoserver/topp/wms",
{layers: 'topp:india_road',transparent: true}
);
select = new OpenLayers.Layer.Vector("Selection", {styleMap:
new OpenLayers.Style(OpenLayers.Feature.Vector.style["select"])
});
hover = new OpenLayers.Layer.Vector("Hover");
map.addLayers([layer, hover, select]);
var wmsLayer = new OpenLayers.Layer.Google('Google Layer',{} );
map.addLayer(wmsLayer);
map.setCenter(new OpenLayers.Bounds(143.83482400000003,-43.648056,148.47914100000003,-39.573891).getCenterLonLat(), 5);
}
</script>
What do you mean by not zooming properly?
Are you finding that they are not matching up with the google maps when zooming in as far as you can go, or the zoom work until you try to pan and then the layers don't stay lined up with google maps? If this is the case then you are probably zooming in further than is supported by the Google map service. There is no easy way to fix this and I recommend you alter allowed scales and zoom with the following settings
minScale - float -- the minimum scale value at which the layer should display
maxScale - float -- the maximum scale value at which the layer should display
numZoomLevels - int -- Total number of zoom levels
Also please see this link on more information about google zoom scales.
If you are finding that none of your layers match the google background. I.E. they look like they are zoomed in out or offset then it is likely that your data is in a different projection to the google maps layer. Google maps uses EPSG:900913 as their SRS. The eisiest way to do this is to let geoserver do the re projection for you. Go to your layer setting in geoserver make sure you have the native projection set correctly and set the declared SRS to EPSG:900913.
If that doesn't help then I think we need more information on exactly what the problem is.
I've managed to make a d3.js line+area graph sync with focus/context brushing and pan/zoom, with a small example here:
http://jsfiddle.net/MtXvx/8/
I'm having trouble limiting the panning to stop at the original domain boundaries, while also working nicely with the brush. This is to prevent users from losing the graph in their view.
While I have tried manually detecting when panning has exceeded boundaries and then setting zoom.translate([0,0]), such as in these examples:
d3.js scatter plot - zoom/drag boundaries, zoom buttons, reset zoom, calculate median
Limiting domain when zooming or panning in D3.js
d3.js scatter plot - zoom/drag boundaries, zoom buttons, reset zoom, calculate median
...as I do here at line 183:
//If exceed original domain, limit panning by resetting translate
if (x.domain()[0] < x0.domain()[0]) {
zoom.translate([0, 0]);
}
The problem occurs when:
1) Create a brush region in the small context graph
2) Pan the big focus graph all the way towards the earliest date
3) Graph jumps when panning is almost at the boundary
Would appreciate any help to prevent the jumping from happening, or if there is any other way to limit the panning (and eventually the zooming out too) to the original domain boundaries.
Regarding limiting the zoom-out, setting:
var zoom = d3.behavior.zoom().x(x).scaleExtent([1,10]).on("zoom", zoomed);
...does not work nicely because the zoom-out would be limited to the brush region instead of the full extent of the graph data.
Much thanks!
I had similar problems combining D3 Brushing and Zoom & Pan, but figured it out eventually. I found the key to limit the panning is to reset the translate of the zoom behavior object. Specifically, here is my zoom callback function:
function zoomed() {
var t = d3.event.translate;
var s = d3.event.scale;
var size = width*s;
t[0] = Math.min(t[0], 0);
t[0] = Math.max(t[0], width-size);
zoom.translate(t);
focus.select(".area").attr("d", area);
focus.select(".x.axis").call(xAxis);
var brushExtent = [x.invert(0), x.invert(width)];
context.select(".brush").call(brush.extent(brushExtent));
}
While not part of your question, also an important part to make the whole demo work right is to update the zoom translate and scale when brushing is done, so here is my brushed callback:
function brushed() {
x.domain(brush.empty() ? x2.domain() : brush.extent());
focus.select(".area").attr("d", area);
focus.select(".x.axis").call(xAxis);
var s = x.domain();
var s_orig = x2.domain();
var newS = (s_orig[1]-s_orig[0])/(s[1]-s[0]);
var t = (s[0]-s_orig[0])/(s_orig[1]-s_orig[0]);
var trans = width*newS*t;
zoom.scale(newS);
zoom.translate([-trans,0]);
}
Here is a complete example based one of D3 examples: http://bl.ocks.org/sbreslav/be9af0d809b49864b7d8
to limit the extent of the panning on the graph you could use clamp, although I couldn't see where or if you were using a scale in that fiddle (actually it didn't appear to be working). Here's a simple example in a fiddle
I've written a home-brew view_port class for a 2D strategy game. The panning (with arrow keys) and zooming (with mouse wheel) work fine, but I'd like the view to also home towards wherever the cursor is placed, as in Google Maps or Supreme Commander
I'll spare you the specifics of how the zoom is implemented and even what language I'm using: this is all irrelevant. What's important is the zoom function, which modifies the rectangle structure (x,y,w,h) that represents the view. So far the code looks like this:
void zoom(float delta, float mouse_x, float mouse_y)
{
zoom += delta;
view.w = window.w/zoom;
view.h = window.h/zoom;
// view.x = ???
// view.y = ???
}
Before somebody suggests it, the following will not work:
view.x = mouse_x - view.w/2;
view.y = mouse_y - view.h/2;
This picture illustrates why, as I attempt to zoom towards the smiley face:
As you can see when the object underneath the mouse is placed in the centre of the screen it stops being under the mouse, so we stop zooming towards it!
If you've got a head for maths (you'll need one) any help on this would be most appreciated!
I managed to figure out the solution, thanks to a lot of head-scratching a lot of little picture: I'll post the algorithm here in case anybody else needs it.
Vect2f mouse_true(mouse_position.x/zoom + view.x, mouse_position.y/zoom + view.y);
Vect2f mouse_relative(window_size.x/mouse_pos.x, window_size.y/mouse_pos.y);
view.x = mouse_true.x - view.w/mouse_relative.x;
view.y = mouse_true.y - view.h/mouse_relative.y;
This ensures that objects placed under the mouse stay under the mouse. You can check out the code over on github, and I also made a showcase demo for youtube.
In my concept there is a camera and a screen.
The camera is the moving part. The screen is the scalable part.
I made an example script including a live demo.
The problem is reduced to only one dimension in order to keep it simple.
https://www.khanacademy.org/cs/cam-positioning/4772921545326592
var a = (mouse.x + camera.x) / zoom;
// now increase the zoom e.g.: like that:
zoom = zoom + 1;
var newPosition = a * zoom - mouse.x;
camera.setX(newPosition);
screen.setWidth(originalWidth * zoom);
For a 2D example you can simply add the same code for the height and y positions.