Mosaic engine guide

Help

Short answers to what goes wrong most often.

The page stops for a moment when I build

The tool does all its work in one go on the page itself, so the page waits until a build is done. The line under the Image buttons shows how long the last build took.

Delaunay and Voronoi slow down fast as Cell count rises: at 10,000 points a build can take several seconds. Lower Cell count, or use a grid mode, for quick changes.

Cell count stops at 3,000 on my phone

On a narrow screen or a touch screen the most points the tool will scatter is 3,000, and pictures are fit to 1,000 pixels instead of 1,600. Every mode, preset, animation and export still works. The Pointillism preset draws 3,000 dots there instead of 5,000.

My picture came out smaller

Big pictures are fit to 1,600 pixels on their long side, or 1,000 on a phone, before they are broken up. The line under the Image buttons shows the working size, and the PNG is that size.

The layout changed when I moved a slider

Letting go of a slider builds the picture again, and Delaunay, Voronoi, Circle and any jittered mode scatter new random points each time. Change Color under Stroke, or Background, to recolour without moving the cells.

The edges of the picture are empty or ragged

Delaunay can only fill the ground inside its outermost points, so thin gaps of background can show along the edges and in the corners. Voronoi drops some cells at the edge for the same reason. Raise Cell count, lower Edge weight, or set Background to a colour you like there. The grid modes always reach the edges.

Dominant color looks close to Average color

In a cell that is all one colour the two agree. They part where a cell crosses an edge: Average color mixes both sides into an in-between colour, while Dominant color keeps the colour of the bigger side. Lower Cell count for bigger cells to see the difference, or use Center sample for a livelier fill.

The picture did not load

The tool takes picture files only, and nothing happens with any other file. If the browser cannot open a picture, for example some HEIC photos, nothing changes either. Save it as a PNG or JPEG and try again.

The PNG has no animation

Save PNG stops the animation first and saves the finished picture. Copy takes the canvas as it is, so pressed during an animation it copies that moment.

Copy did nothing

Some browsers do not let a page put a picture on the clipboard. The tool then says Copy failed; use Save PNG instead.

Does it need WebGL or a strong graphics card?

No. It draws on a plain 2D canvas, so any current browser can run it. Big cell counts need a fast processor, not a graphics card.

Is my picture uploaded?

No. The picture is read and broken up on your device and never leaves it.

Why is a picture from another tool here?

Pictures you add are kept on this device for every lab tool that takes one, so you need not add them again. Press × on a tile to forget that picture; the sample comes back.

Are there keyboard shortcuts?

The tool has none of its own. Anywhere in the lab, Ctrl K, or Cmd K on a Mac, opens the list of all tools.

Why does the video stop by itself?

Record video keeps exactly one sweep, Seconds a cycle long, so the clip loops when it plays. It is an MP4 in H.264, the kind phones, Photos and Instagram play.