Brush Tool

Paint stitches with a round brush. Fast fills, partial stitches with smart Merge, symmetry, two-color texture, and keyboard-precise placement.

Shortcut: B Location: Left toolbar → Brush
Keyboard & modifiers
W S
Increase / decrease Brush size
Q E
Next / previous color in the palette
X
Swap primary (left mouse) and secondary (right mouse) colors
D
Toggle erase mode (paint vs erase)
Shift
Draw a straight line (hold while dragging)
Alt Option
Pick color from canvas (set as Primary)
Cmd Ctrl
Fill area with Primary color
Arrows Enter Delete
Precision mode: move with arrows, paint with Enter, erase with Delete

Basics

Brush is a round stamp that previews where it'll land. It has two paint sources (Primary / Secondary), three power overlays (Merge, Symmetry, Two-color texture), and one surgical mode (Precision keyboard). Nothing commits until you finish the stroke — and undo is always one stroke.

Brush basics — paint, tweak size, undo

Shortcuts are shown above. Here are the core workflows:

  • Paint & erase: Primary (LMB) / Secondary (RMB) — one color to build, one to erase or shade.
  • Lines: Hold Shift, click start, drag end; release Shift to exit.
  • Fill: Hold Cmd/Ctrl, click to fill an area with Primary; release to snap back.
  • Surgery: Precision mode (arrow keys + Enter/Delete) for cleanup; Esc or click elsewhere to exit.

How to paint clean shapes

  1. Pick Primary color (LMB or palette).
  2. Set Brush size (W / S or bottom slider).
  3. Use Replace for full stitches; Merge for partial stitches (building a cell from parts).
  4. Hold Shift for straight lines.
  5. Use Precision mode (arrows + Enter/Delete) for crisp edges and cleanup.

For crisp edges: zoom in 200–400% and use size 1–2.

Brush size

  • Default: 2 · Range: 1–20 · Change: W / S or the bottom toolbar slider.

When to use:

  • 1–2: Edges, cleanup, tight corners.
  • 3–6: Blocking in shapes fast.
  • 7–20: Big fills and rough silhouette; then refine with a smaller size.
Resize + paint — bump size with W/S

Preview behavior

Brush shows two kinds of preview.

Before you paint: Hover shows the outline of the round brush and which cells would be affected. It's light and responsive.

While you paint: Once you start (drag, Shift line, or arrow keys), Brush shows a full preview of what will be placed — Replace vs Merge, symmetry, two-color texture, and smooth strokes (no gaps when you move fast). Nothing commits until you finish the stroke.

Note: The hover outline is not the final result when texture, symmetry, or Merge are on — it's just the footprint. Start the stroke to see the real result.

Preview while painting — the "real" result preview

Primary / Secondary colors

Brush always has two colors ready: Primary (LMB) and Secondary (RMB). Defaults: Primary = selected palette color; Secondary = Eraser (empty cell). X swaps them; Q / E step through the palette; D toggles Paint vs Erase. One color to build, one to erase or shade — without switching tools.

Pro tip: Keep Secondary = Eraser. It turns Brush into paint and cleanup in one tool.

Primary/Secondary workflow — paint with LMB, erase with RMB, hit X to swap
Bottom toolbar — Primary/Secondary + erase toggle

Stitch types

Brush can place full stitches and partial stitches. Choose stitch type from the bottom toolbar (pop-up panel).

Mental model: Full · Half · Quarter · Three-quarter. Diagonal direction matters. Half-filled is “block halves” (top, bottom, left, right). The picker shows a grid of options.

Stitch type picker
Canvas close-up — mixed partial stitches

Replace vs Merge

In the stitch-type panel you choose how Brush treats existing stitches in a cell.

Replace (default): Brush overwrites the cell with your current stitch type and color.

Merge: For partial stitches. Brush keeps any partials that can share the cell and adds the new partial (e.g. half diagonal-left in A + half diagonal-right in B → one cell with both). If the combo can't be combined, it'll just Replace that cell.

When to use:

  • Replace when you want certainty — full stitches, cleanup, or a full redo.
  • Merge when you're building a cell from parts (partial stitches).
  • If Merge seems to “do nothing”, the combo is likely incompatible → Brush replaces that cell.
Merge in action — partial A + partial B in one cell
Replace vs Merge toggle

Symmetry

Symmetry repeats your stroke across a mirror or rotation. It stacks with stitch type, Merge, and texture. Modes: Mirror (vertical, horizontal, 4-way, 8-way); Rotate (2-way, 4-way, 8-way).

Mirror 4-way — paint once, it repeats
Symmetry selector

Two-color texture

Turn this on for a soft speckled look or to blend two colors without doing it by hand. Brush distributes Primary and Secondary in the round brush area; the density slider (default 50%) controls the mix. Secondary = Eraser → light, airy texture. Secondary = a real color → two-color texture in one stroke.

When to use:

  • Breaking up large flat areas (less posterized).
  • Faux shading without manual dithering.
  • Secondary = Eraser → dusting or worn-fabric vibe.
Two-color texture — change density, paint again
Texture density slider + preview

Precision keyboard mode

Use the arrow keys and Brush enters precision mode. The UI shows a crosshair and cell coordinates. Arrow keys move the hovered cell; Enter paints; Delete erases. Use it for calm, deliberate cleanup — like placing stitches with tweezers. If your hand is shaky or you're zoomed way in, precision mode keeps you honest.

Exit: Esc or click elsewhere on the canvas.

Keyboard precision — arrows move, Enter paints, Delete erases
Precision cursor + coordinate label

Momentary modes

Hold a key to temporarily switch; release to snap back to Brush.

  • Alt/Option: Eyedropper — click a cell to set its color as Primary. Release Alt/Option to exit.
  • Cmd/Ctrl: Fill — click to fill an area with Primary. Release to exit.
  • Shift: Line mode — click start, drag end; release Shift to exit.
Momentary modes — pick → fill → line

Undo

Every Brush action is undoable. Infinite undo. One stroke = one undo step.

Undo cadence — stroke → undo → redo

Pencil is Brush with two differences: size fixed at 1 cell, and clean, crisp lines (no double diagonals). Use Pencil for strict single-cell lines; use Brush for speed, filling in areas, and Merge, symmetry, and texture.

Pencil vs Brush — line behavior

Tips & gotchas

  • Merge is for partial stitches. For full stitches, Replace is usually simpler.
  • Some partial combos can't merge. In that case Brush will Replace that cell.
  • Secondary doesn't have to be Eraser. Try Secondary as a second color for shading, then X to swap.
  • Texture loves symmetry. For “intentional randomness”, mirror it.
  • Fast drag still no holes. Stroke interpolation keeps strokes smooth when you move the brush quickly.