QuickShape
Draw-and-hold shape fitting — the hold threshold, every shape it fits, the chip, the handles, and what undo returns.
Reference
- Tool
- Draw
- Panel
- Tool Options
- Section
- Smart Shape
- Gesture
- Draw and hold
QuickShape fits a clean shape to a stroke you have just drawn, without leaving the stroke. Draw the shape freehand and hold the pen still; after the hold threshold elapses the stroke is replaced by the fitted shape.
What replaces the stroke is not a new kind of object. The fitted shape is a description that generates a set of points, and those points replace the ones you drew. The brush, the 3D surface it is bound to, the eraser, sculpting, fill and export all keep treating it as the ordinary stroke it still is.
The interaction
Draw the shape freehand
Hold the pen still
Keep the pen down and stop moving. Travel of more than 9 points from where the hold began restarts the clock — that reads as the pen travelling, not holding.
The shape is fitted
After the threshold — 0.4 seconds by default — the stroke is replaced by the fitted shape and a light haptic fires. If the stroke is not shape-like, nothing happens: the stroke is left exactly as drawn, with no chip and no snap.
Steer it, still holding
The pen is still down and the shape is still yours to place. Pulling away from the shape's centre grows it; pulling in shrinks it.
Lift
Handles appear on the shape and the chip appears near the bottom of the canvas, clear of your hand.
End the session
Tap the chip's ✓ to commit, tap Raw to put your own stroke back, or drag a handle to keep editing. Once committed it is an ordinary stroke from then on.
The threshold is a clock rather than an event because iOS sends no movement events while a finger is perfectly still — "has the pen stopped?" cannot be answered by waiting for something to arrive. The 9-point tolerance exists because the Pencil reports movement on essentially every frame from force jitter alone, even parked on glass.
Settings
Tool Options ▸ Smart Shape, on the Draw and Shape tools.
The master switch. Off, a held stroke is just a held stroke — nothing below applies.
Regularises the fit: a near-circle becomes a circle, a near-square a square, a near-regular polygon a regular one, and a line within a few degrees of a 15° multiple snaps to that angle.
Off means fit exactly what I drew, only clean it up — the shape is still recognised and still fitted, but its proportions and angles are left as you made them. Shown only when Draw and hold to snap is on.
How long the pen must be still before the shape is fitted. Displayed to two decimal places. Shown only when Draw and hold to snap is on.
Every shape it fits
Ten kinds are recognised. The name in the first column is the name on the chip.
| Name | What it is |
|---|---|
| Line | A straight segment between two endpoints. |
| Circle | An ellipse whose radii matched. |
| Ellipse | An ellipse whose radii did not match, at whatever rotation you drew it. |
| Square | A rectangle whose sides matched. |
| Rectangle | A rectangle whose sides did not match, at whatever rotation you drew it. |
| Triangle | A closed three-cornered polygon. |
| Polygon | A closed regular polygon of any corner count other than three. |
| Shape | A closed irregular polygon — corners you drew, kept where you drew them. |
| Lines | An open polyline: a run of straight segments that does not close. |
| Curve | Your own curve, cleaned up. The universal fallback. |
Two of those names run against the intuition and are worth committing to memory: the regular polygon is called Polygon, and the irregular closed polygon is called Shape.
The chip
The chip appears while a shape is fitted and shows, left to right:
- The recognised shape's name, with a wand icon.
- Its alternatives — two or three plain buttons, chosen for this shape. Tapping one re-fits the stroke as that kind.
- Raw, in orange. Puts your original stroke back.
- ✓. Commits.
The alternatives are not a fixed set. They are the kinds you are most likely to have meant instead, given what was recognised, and they are ordered by that likelihood.
| Recognised | Alternatives offered |
|---|---|
| Circle | Ellipse · Polygon · Curve |
| Ellipse | Circle · Rectangle · Curve |
| Square | Rectangle · Circle · Curve |
| Rectangle | Square · Ellipse · Curve |
| Triangle | Polygon · Shape · Curve |
| Polygon | Shape · Circle · Curve |
| Shape | Polygon · Rectangle · Curve |
| Lines | Line · Curve |
| Line | Lines · Curve |
| Curve | Line · Ellipse · Shape |
Every row but the last ends in Curve — just clean up my line is always one tap away. The Curve row is the exception because Curve is already what was recognised.
Handles
After the pen lifts, the shape carries draggable handles. The nearest handle within 30 points of the touch takes the drag.
| Shape | Handles |
|---|---|
| Line | Two, one at each endpoint. |
| Ellipse, Circle, Rectangle, Square | Four box corners plus a rotation handle beyond the top edge. |
| Triangle, Polygon, Shape, Lines | One per corner. |
| Curve | A sampled ring of up to about twelve. A smoothed curve can hold hundreds of points; handles on all of them would be unusable. |
Four rules govern what a drag does:
The kind never changes on a drag. Dragging a circle's corner keeps it a circle. You picked circle; a drag is a resize, not a re-classification.
A box resize pins the opposite corner and is computed in the shape's own rotated frame, so a turned rectangle resizes along its own axes rather than the screen's. A square stays square.
Dragging a polygon's vertex makes it irregular — a hand-moved corner is no longer regular, and the shape becomes Shape.
Dragging a curve's point moves its neighbourhood, with a falloff, so the curve stays smooth instead of growing a spike at the one point you moved.
What undo returns
This is the rule worth knowing before you use the gesture on real work.
Undo once and your original freehand stroke comes back, exactly as you drew it. Undo twice and it is gone.
Fitting the shape lays down two history entries before it bakes: the layer without the stroke at all, and then the layer with your raw stroke on it. The fitted shape sits on top of both. So the stack reads: no stroke → your stroke → the fitted shape.
Everything you do during the edit session is free. Steering, tapping an alternative, dragging a handle and tapping Raw all cost no undo step — the whole session is one edit sitting on top of those two checkpoints. Reverting to Raw is not an undo; as far as the history is concerned the snap never happened.
It fits in canvas space
The shape is fitted where you drew it, in the canvas, not on the screen.
A circle drawn on a curved surface is fitted as a circle on that surface: it follows the curve, and it stays correct from every angle you orbit to. It is not a flat disc pasted over the top that only reads as a circle from where you were standing.
When it refuses
A stroke is never fitted if it is fewer than 6 sample points or shorter than 24 points of travel. A dot, a tap or a twitch must never silently become a shape.
Beyond that, the recogniser refuses when nothing fits well enough — and when it refuses, it leaves your stroke alone. The fallback is Curve, which is your own line cleaned up rather than a shape imposed on it.