Fill tool
Recolour a shape, flood an area enclosed by lines, or fill pixels: the bucket picks the right one from what you click.
The Fill tool (K) applies the active colour from the Color panel. The hover cursor is a small grey circle: there is no size to set, because the bucket fills the whole region you click, not a footprint.
Which region that is depends on what is under the cursor. The bucket tries these in order, and stops at the first one that applies.
| K | Fill tool |
What the bucket fills
- Click on a vector shape: that shape is recoloured outright. With Color 1 active it gets a solid fill; with Color 2 active it gets the stroke colour.
- Click inside a closed shape that has no fill yet, a brushed ring or an outline you have only stroked: that shape gets a fill, rather than a second shape being laid behind it.
- Click on empty space while a Shape or Drawing layer is selected: the bucket finds the area enclosed by the lines on the current frame and fills it, placing the fill behind the drawing.
- Click anywhere else: the bucket floods pixels on the selected Raster or Pixel layer, creating a raster layer if the project has none.
Options
| Setting | Default | What it does |
|---|---|---|
| Source | This layer | Which pixels the fill READS. This layer, Layer above, Layer below, or All visible composited together. The colour still lands on the layer you have selected. |
| Tolerance | 16% | How far a pixel's colour may differ from the one you clicked and still be filled. 0% fills only exact matches. |
| Expand | 0 px | Grow the finished region outward, or shrink it with a negative value. From -16 to 16 px. |
| Gap | 0 px | The widest break in the outline the fill may treat as closed, measured across the break itself. Up to 64 px. 0 is off, where one hole floods the whole layer. |
| Contiguous | On | On, the fill spreads outward from the click and stops at any edge. Off, it fills every similar-coloured pixel in the image, wherever it sits. |
| Anti-alias | Off | Give the finished edge a one-pixel ramp so it meets an anti-aliased line without a visible step. |
| Output | Vector Cells | Only on a vector or drawing layer: whether a fill produces a traced shape (Vector Cells) or pixels (Pixel). A raster target has no choice to make. |
| Opacity | 100% | How opaque the deposited colour is. |
| Expand mode | To darkest pixel | Live only while Expand is positive. Rectangle grows in a square, Round grows in a circle, and To darkest pixel grows under a soft line edge and stops at its dark core. |
| Fill narrow areas | On | Live only while Gap is above 0. A sliver no wider than its own opening is filled along with the region it hangs off, so sealing a gap does not leave the pocket behind the seal unpainted. |
The tool opens on its old behaviour with every new capability off, so a click does exactly what it did before until you ask for more. Leave Source, Gap and Output alone on a vector layer and the fill works on the real curves rather than on a rendered picture, which is both faster and resolution independent.
Colouring under line art
Source is the setting the tool exists for. Ink your lines on one layer, select the layer you want the colour on, and set Source to read the ink layer: the fill is bounded by lines it does not paint, so the colour goes under them and the line work is untouched.
Reading is never the raw bitmap. The source layer is rendered first, so a vector layer's ink counts as a wall exactly like painted pixels do, and a group is read as it composites. All visible flattens the whole scene and bounds the fill with everything you can see.
Gaps and haloes
Gap is the width of the break the fill may treat as closed. Raise it until the leak stops. It works by joining the two stroke ends the break sits between, so the line keeps its own weight everywhere else and only that opening closes. The bridge is not painted into the picture either: it bounds the fill and then it is gone.
Expand answers the pale outline an anti-aliased line leaves behind, where the flood stops several pixels short of the line's opaque core. Push it up two or three pixels and the colour reaches the line. Expand mode decides the shape of that growth: Rectangle spreads in a square, Round spreads in a circle, and To darkest pixel, the default, crawls under the soft edge and stops at the core so the growth cannot punch through a thin stroke to the far side.
Filling ink drawings
On a Shape or Drawing layer the bucket unions all the ink on the current frame, finds the innermost enclosed area containing your click, and inserts the fill as a new shape behind the lines. Holes inside that area stay holes. Because the result is ordinary vector geometry you can restyle it later, animate it, or edit its outline with the Node tool. The outline is refitted as bezier curves rather than traced as a dense polygon, so a fill against curved lines comes back with a point count you can actually work with.
Set Output to Pixel and the same click deposits pixels instead, on the nearest editable raster layer or a new one. That is the way to flat-colour a vector drawing without accumulating one shape per region.
Filling pixels
The pixel flood compares colours channel by channel against your Tolerance. Dragging with the button held re-runs the fill continuously for the region under the cursor, which is a quick way to flat-colour several small areas in one pass.
An active pixel selection bounds the fill on any layer, vector included, so you can constrain a messy fill by marqueeing the area first.
Limits
- Recolouring a shape and filling an enclosed vector area are geometric operations and ignore Tolerance entirely.
- Nothing happens if the colour you click already matches the fill colour.
- There are no modifier keys, no double-click behaviour and no snapping.