Most colorwork charting tools are still desktop programs: you install them, they target one operating system, and older ones have stopped working on current machines entirely. ArtPatt runs as a web application instead. There is nothing to download, nothing to license per machine, and the same URL works on a laptop and a tablet — which matters when the chart is being read next to the project rather than at a desk.
It is genuinely two tools in one. The engine converts a source image into a craft-correct chart, and a built-in editor lets you change that chart afterwards. The editor works stitch by stitch: pencil, eraser, and a fill with exact, close, or broad tolerance; straight line, rectangle, filled rectangle, and ellipse for larger shapes; an eyedropper that picks up a color already in the chart; and a text tool that stamps lettering into the grid. Brush size, horizontal symmetry, and up to 30 steps of undo and redo are available while you work.
You can also start from a blank grid and simply draw. Nothing in the editor requires a photo, so it doubles as a plain chart editor for motifs, monograms, borders, and colorwork designed from scratch. Editing is free and needs no account — payment applies to exporting the finished pattern, not to designing it.