Mixing WMTS sources having TileMatrix using different TileOrigin and Resolution.
With the new client zoom from OpenLayers, it is now possible to mix tiles using different extent defintiion and different resolution.
In this example, we superpose the canton's border layer (ch.swisstopo.gg25-kanton-flaeche.fill) using resolutions [10000, 5000, 2500, 1000, 500, 200, 100, 50, 25, 10, 5, 2, 1, 0.5] on the top of a base layer (ch.swisstopo.pixelkarte-farbe) using the standard GeoAdmin resolution ([650.0, 500.0, 250.0, 100.0, 50.0, 20.0, 10.0, 5.0, 2.5, 2.0, 1.5, 1.0, 0.5]).
So if the gridResolution of a layer doesn't not match the one of the map, the tiles are stretch, hence the variations in the canton's border width and the blurry apsect at certain scales.
The used projections however, have to be the same.
View the wmts-resolution.js source to see how this is done.