When double-clicking on an OpenLayers map, the screen is momentarily blank while the next zoom level draws.
Is this avoidable? It's not ideal, given that many other mapping APIs show a smooth zooming effect.
[GIS] Do OpenLayers maps always show/flash an empty screen while zooming
openlayers
Related Solutions
You can change the resolution of the displayed tiles. Documentation can be found on the API page of the OpenLayers website. The max resolution will depend on the source. This link will direct you to the tile resolution settings.
extent is the extent of for the view's center constraint, not the extent of the viewable map. You could set an extent on the layer, but that would result in white space inside the view. To maintain a 2km x 2km constraint on the view's edges as could be done in OpenLayers 2 you would need to change the view as the resolution changes (ignoring very small changes to avoid performance issues):
var extent = map.getView().calculateExtent(); // opening coverage
// var extent = [529449 - 1000, 189252 - 1000, 529449 + 1000, 189252 + 1000]; // 2km box
var resolution = 0;
function resChange() {
var newResolution = map.getView().getResolution();
if (resolution == 0 || Math.abs((newResolution-resolution)/resolution) > 0.01) {
resolution = newResolution;
var width = map.getSize()[0] * resolution;
var height = map.getSize()[1] * resolution;
var view = new ol.View({
projection: map.getView().getProjection(),
extent: [extent[0]+(width/2), extent[1]+(height/2), extent[2]-(width/2), extent[3]-(height/2)],
center: map.getView().getCenter(),
resolution: resolution,
maxZoom: map.getView().getMaxZoom(),
minZoom: map.getView().getMinZoom()
});
view.on('change:resolution', resChange);
map.setView(view);
}
}
resChange();
UPDATE: The answer applies OpenLayers 3, 4 and 5. In OpenLayers 6 extent does define the view extent (as in did in Openlayers 2).
Best Answer
You will have to change the layer transitionEffect to 'resize'. According to OpenLayers documentation:
transitionEffect
{String} The transition effect to use when the map is panned or zoomed.
There are currently two supported values
null
No transition effect (the default).
resize
Existing tiles are resized on zoom to provide a visual effect of the zoom having taken place immediately. As the new tiles become available, they are drawn over top of the resized tiles.