A mosaic chart has two colors, A and B. Each row is worked in one color, alternating A and B from the first (bottom) row up. A stitch of the other color is a long stitch from the row below, so it's only possible where the stitches above and below it are that color too.

1. Start a chart

• From scratch: open Chart Size/Gauge, set the width and height in stitches and rows (or in inches, from your gauge), and click New Blank Chart. The chart starts all Color A.
• From an existing chart: drop an image file onto the chart area, or choose it under Load/Save → Chart / Drawing Layer. Each pixel becomes one stitch, so a chart saved with Save Raw Image loads back exactly.
• From a picture: choose it under Load/Save → Reference Image. MoYa makes a blank chart the same size and switches the View to Trace Mode, showing your chart over the picture. Set the size you want in Chart Size/Gauge and click Resize Chart, which resizes the picture too. Then draw over the picture, or let MoYa turn it into a chart (below).

Turning a picture into a chart

Both commands are in Image Processing + Validation. Each replaces the whole chart with one stitch per pixel of the reference picture, so set the size first. Ctrl+Z undoes them.

• Threshold looks at how light each pixel is. Pixels at least as light as the Threshold value become Color A; darker ones become Color B. Raise the value for more B, lower it for more A. Shading is lost: every area is either A or B. Threshold doesn't follow the mosaic rules, so validate afterward.
• Dither keeps shading. For each stitch it picks whichever of your Color A and Color B is closer to the pixel, then passes the difference on to the stitches next to it, so a gray area becomes a mix of A and B stitches.
  • Dither to chooses the two colors it matches against. Black and white goes by lightness alone: light areas become A and dark areas B, whatever your colors are. Color A and Color B matches against your display colors, so set them to your yarns first (in the Draw menu); this can follow the picture's colors better when your yarns differ in hue as well as lightness.
  • Dither Strength is how much of the difference is passed on: at 100% you get the most shading; at 0% each stitch is just the closer color, much like Threshold.
  • Serpentine Scan works alternate rows in opposite directions, which avoids diagonal streaks.
  • Validate while Dithering steers the result toward a chart that can be worked: the top and bottom rows are kept in their row colors, and a stitch may take the other color only where it can be a long stitch. Validate afterward to check.

2. Draw

• Pick a Mode in the toolbar. Toggle (X) flips a clicked stitch between A and B; a drag paints the color the first stitch flipped to. A (A) and B (B) paint that color; hold Alt to paint the other one.
• The Draw menu sets the brush size ([ and ]), the display colors of A and B, and fills the whole chart with A or B.
• Symmetry (also in the Draw menu) copies what you draw across the chart. Mirror L/R and Mirror T/B reflect it. 4x and 8x turn it into a rotationally symmetric design that is worked in rows; validation checks the whole chart. 4x In-The-Round and 8x In-The-Round are for work in the round, where every wedge is worked the same way up, so only the drawing wedge is validated. The 4x and 8x modes need a square chart.
• The bar at the bottom of the chart shows what a click or drag will do right now.
• Ctrl+Z undoes and Ctrl+Y redoes any change.

3. Move around

• The mouse wheel (or I / O) zooms; hold Space and drag to pan; F fits the chart to the window. ? lists every shortcut.
• The View list switches between the chart, the reference picture, and Trace Mode (T).
• The Display menu turns on grid lines, rulers, non-square stitches (from your gauge), and chart markings.

4. Check that it can be worked

• First row, under Information, sets whether the first (bottom) row is Color A or Color B. Rows alternate from there, and the markers to the right of the chart show each row's color.
• Validate (V, or Validate Chart in Image Processing + Validation) checks every stitch against its row's color. A stitch in its row's color is fine. A stitch in the other color is fine only as a long stitch: the stitches directly above and below it must both be in its color, so the first and last rows can't have any. Every other stitch is outlined in red, and the counts appear under Information. After you validate once, MoYa checks again after every change.
• With symmetry, 4x and 8x check the whole chart, each quarter with its rows running along its outer edge. In-The-Round checks only the drawing wedge; its diagonal edge stitches are increases, with no stitch below them.
• Toggle All Invalid Stitches flips every red stitch to its row's color. That fixes those stitches, but it can leave a neighbor that was part of a long stitch without its partner, so MoYa checks again and outlines any new problems. Press it again, or fix the rest by hand; Ctrl+Z undoes it.
• Chart markings in the Display menu mark the anchors of each long stitch, for knitting (up) or crochet (down).

5. Save

• In Load/Save: Save Raw Image (one pixel per stitch), Save Chart As Image, or Save Chart As PDF to print in black and white, with rulers and markings. For In-The-Round, the PDF has just the drawing wedge, the part that is worked.
• MoYa starts fresh each time it opens. To keep working on a chart later, save it with Save Raw Image and load it again as an existing chart.