Where the bucket lives, and what it actually does
The rail is grouped. The Paint Bucket sits in the paint slot together with Gradient, Mesh Gradient and Spray, and Gradient is the slot's default occupant. Click the small triangle on that slot to open the flyout and pick the bucket, or just press K.
It works on geometry. When you click, the bucket collects the drawn paths near your cursor, builds a planar map of every region they enclose, and fills the one you clicked in. The new fill is a real path with the artwork's own anchors: pour inside a circle and you get four curves, not a thirty point polyline.
It does not recolour the shape you clicked. It adds a new filled path underneath the lines that bound it, so the lines stay fully visible and the region reads as painted. Click the same region again and it recolours that fill rather than stacking a second copy.
Pouring a region
- Pick the tool Press K, or open the paint slot's flyout and choose Paint Bucket.
- Set the colour you are about to pour Press, to open the colour picker. X toggles which paint is active, Shift+X swaps fill and stroke, D resets to the default white fill with a black stroke, and . switches the active paint to a gradient.
- Click inside the region Click once inside the enclosed area. Hover first if you like: the region you are about to fill is outlined before you commit. The pour lands as a new path under the lines.
- Judge the edges, then adjust If nothing filled, the boundary has a gap: raise Close gaps. If the fill sits too far under the lines or too far off them, change Grow/shrink by. Undo with Ctrl+Z and click again, the settings apply to the next pour.
The option bar
Pick the Paint Bucket and the context bar gives you six controls:
- Paint: Faces or Edges. Faces pours the region your click sits in. Edges paints the piece of line between two crossings.
- Fill by and Threshold: these belong to images. They are a colour channel and a colour tolerance, and a region bounded by paths has no use for either, so they only affect a pour on a photo. The bar labels them so.
- Grow/shrink by: how far the fill runs past the lines, in screen pixels. Positive tucks it further under the ink, negative pulls it back and leaves a margin you can see. It means the same distance at any zoom.
- Close gaps: None, Small, Medium or Large. How wide a break in an outline the pour is allowed to bridge.
Close gaps is the setting worth understanding. Hand drawn outlines rarely meet exactly, and a two pixel opening is enough for the pour to find no closed region at all. Step the setting up until it fills. Small is the default and handles most line art.
Edges: painting the line, not the region
Switch Paint to Edges and the bucket stops filling regions and starts painting lines. Hover and it outlines the piece of line under your cursor, from one crossing to the next. Click and that piece takes your current stroke colour and width.
It replaces the line rather than drawing over it. The span is taken out of the path it belonged to and re-added as its own object, so a thin light stroke on a thick black line leaves page behind it, not a black edge either side. Draw a grid, paint one wall of one cell, and only that wall changes.
A shape with a fill is left alone, because its outline is also its fill boundary and cutting a piece out would destroy the shape. Those get the paint on top instead, and the tool tells you.
The fill follows the lines
A pour is not a frozen copy of the region it filled. It remembers the point it was poured from, so when you move, resize or reshape the lines around it, the fill re-derives itself and follows them. Nudge a divider and the colour either side moves with it.
Open a wall and the fill stays where it is rather than vanishing, and it re-derives the moment the region closes again. Undo restores the lines and the fill catches up on its own.
Keys worth knowing here
| K | Paint Bucket |
| G | Gradient (the paint slot's default) |
| , | Open the colour picker |
| X | Toggle the active paint between fill and stroke |
| Shift+X | Swap fill and stroke |
| D | Default paint: white fill, black stroke |
| / | Set the active paint to none |
| . | Set the active paint to a gradient |
| Ctrl+Z | Undo the pour |
Common questions
I clicked and nothing happened. Why?
The region was not closed, so there was nothing to fill, and the bucket says so rather than flooding your page. Raise Close gaps from Small to Medium or Large and click again. If it still refuses, the opening is genuinely large and the path needs closing.
The bucket made a new shape instead of colouring my rectangle. Is that a bug?
No, that is the design. A pour is a new filled path, placed under the lines that bound it, so the lines stay visible. To change an existing object's own colour, select it with the Select tool (V) and set the fill in the colour picker instead. To recolour one piece of its outline, use Edges.
What is the difference between Faces and Edges?
Faces fills the area your artwork encloses. Edges paints one piece of the artwork itself, from one crossing to the next. Both read the same geometry, so neither has a threshold to guess at. Use Faces to colour a region in, and Edges to recolour or re-weight a single line without touching the rest of the path it belongs to.
Can I pour a gradient?
Press . to set the active paint to a gradient before you pour. For editing a gradient directly on an object, the Gradient tool (G) is the better route: drag on the object, then drag the on-canvas handles.
I moved a line and the fill moved with it. Can I stop that?
That is the fill working as intended: it re-derives from the point you poured it at, so it keeps matching the region it was poured into. If you want a fill that stays put, pour it and then move it out of the region, or paint the shape directly rather than pouring into it. Painted edges do not follow anything, they are ordinary paths from the moment you make them.