What the seamless pattern checker does
The checker repeats your one image across the canvas the same way a printer or a wall would, so you can tell at a glance whether the repeat disappears or leaves a hard line. It also runs a real edge-match test: it reads the pixels along each edge and scores how well opposite edges line up.
Why bother? A seam you overlook on screen turns into a stripe down a finished wall or a bolt of fabric. Checking the tile now can save you a reprint later.
How the check works
- Reading the edges. The tool samples the pixel column on the left edge and compares it with the right edge. Then it does the same for the top and bottom.
- Measuring breaks. You notice a seam because it forms a continuous line. So the verdict is based on the longest unbroken mismatch on each edge. Busy artwork always has small scattered differences. Those print seamlessly, so the tool ignores them.
- Seeing the result. Switch on Tile grid to see how the tiles step in each repeat mode. Switch on Show seams to mark in red the exact spot where an edge breaks.
If your tile passes, it will tile cleanly in full drop, half drop and brick alike. The repeat lives in the edges, not in the layout.
Fixing a seam that won’t line up
A low edge score usually comes down to one of three fixes.
First, move the motif that’s causing trouble so nothing gets cut off at the border. Second, try offset and heal in your image editor: shift the tile by half, then paint out the cross that shows up in the middle.
Third, if your artwork can take it, switch to Mirror mode. Flipping every other tile means the image meets itself at each edge. That’s why mirror always scores clean here.
Full drop, half drop or brick: which repeat should you use?
Full drop lines the tile up in a straight grid. Half drop moves every second column down by half a tile. It’s the classic wallpaper repeat: it hides the grid and suits florals. Brick, also called half-brick, slides alternate rows sideways, like running-bond tile.
All three start from the same seamless tile. The only difference is how that tile steps across the wall. Try each one in the preview above to find the one that fits your motif.