A small utility to convert an image to an SVG knitting chart. It samples the image and scales it down to a specified number of stitches by picking the most frequent colour in the area covered by the stitch meaning that it never adds any colours that aren’t in the original image. The non-rectangular aspect ratio of the stitches is respected so that the piece can be knitted without stretching or shrinking the image on the piece. The stitches are grouped together into sections that can be knit with intarsia knitting and a stitch count for each section is shown in order to help create the bobbins.
If you have a rust compiler installed, after checking out the repository you can build and run it like so:
cargo run -- -i your-image.png -o chart.svgYou can specify the number of stitches that you want to cast on with the -s option. By default this will be 22. The number of rows to knit will be calculated automatically based on the number of cast-on stitches and the aspect ratio of the source image.
If you want the image to be more precise you can specify your knitting gauge using the --gauge-stitches and --gauge-rows options. This would usually be the number stitches and rows in a 10cm×10cm square. The gauge is used to calculate the aspect ratio of the box representing a stitch and the approximate length of yarn needed for each bobbin.
If you don’t want to use a 10cm square you can specify the number of stitches or rows for a different measurement. For example, --gauge-stitches=30/15cm means 30 stitches measures 15cm, or --gauge-rows=10/4in means that 10 rows measures 4 inches.
If you are going to use the pattern to do garter stitch, you can specify the -g option. This will make it so that the generated chart will only change colour on odd rows. This is important for garter stitch because otherwise the colour change will look weird on the right side if the colour changes on even rows.
If you are doing fair isle knitting then you don’t need the letters on the chart. You can remove them easily by opening the generated SVG in Inkscape. Press Ctrl+Shift+L to open the layers list, look for the group called “box-threads” and then delete it.
If you want to tweak the colours in the generated image, you can do so by editing the colours of the boxes in Inkscape. If you then want to regenerate the stitch counts, one option could be to delete everything from the chart except the “boxes” group and then re-export it as a PNG. If you then rerun the program using this PNG it will recreate the diagram with the updated colours.
If you pass the --mitre option the program will try to generate a pattern that is suitable for knitting a mitre square. That is, it will be a square that is knit in garter stitch by starting with enough stitches for the right and bottom sides of the square and then doing two reductions per pair of rows so that it sort of forms two triangles that join up along the hypotenuse to make a square. If you use this option the gauge will be ignored and the image will be sampled as squares. This only really works properly if the source image is a square too.
