pencilkit

Name: pencilkit
Author: dpearson2699

2.0kinstalls45forks

How to install pencilkit?

dpearson2699/swift-ios-skills/pencilkit

$npx -y skills add dpearson2699/swift-ios-skills --skill pencilkit

Installs into the current project.

Summary

Add Apple Pencil drawing with PKCanvasView, PKToolPicker, PKDrawing serialization/export, stroke inspection, and PencilKit/PaperKit handoffs. Use when building drawing apps, annotation features, handwriting capture, signature fields, content-version-safe ink workflows, or Apple P

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SKILL.md

1	# PencilKit
2
3	Capture Apple Pencil and finger input using `PKCanvasView`, manage drawing
4	tools with `PKToolPicker`, serialize drawings with `PKDrawing`, and wrap PencilKit in SwiftUI.
5
6	## Contents
7
8	- [Setup](#setup)
9	- [Capture-to-Export Workflow](#capture-to-export-workflow)
10	- [PKCanvasView Basics](#pkcanvasview-basics)
11	- [PKToolPicker](#pktoolpicker)
12	- [PKDrawing Serialization](#pkdrawing-serialization)
13	- [Content Version Compatibility](#content-version-compatibility)
14	- [Exporting to Image](#exporting-to-image)
15	- [Stroke Inspection](#stroke-inspection)
16	- [SwiftUI Integration](#swiftui-integration)
17	- [PaperKit Relationship](#paperkit-relationship)
18	- [Common Mistakes](#common-mistakes)
19	- [Review Checklist](#review-checklist)
20	- [References](#references)
21
22	## Setup
23
24	PencilKit requires no entitlements or Info.plist entries. Import `PencilKit`
25	and create a `PKCanvasView`.
26
27	```swift
28	import PencilKit
29	```
30
31	Platform availability: iOS 13+, iPadOS 13+, Mac Catalyst 13.1+, visionOS 1.0+.
32
33	## Capture-to-Export Workflow
34
35	1. Capture: Read `canvasView.drawing` from
36	`canvasViewDrawingDidChange(_:)`; keep the previous persisted revision until
37	the new revision completes the remaining checkpoints.
38	2. Serialize: Create `dataRepresentation()`, write atomically, and run the
39	[decode validate/fix/retry loop](#decode-validatefixretry-loop). Do not mark
40	bytes valid when `PKDrawing(data:)` still throws.
41	3. Version-gate: Apply [Content Version Compatibility](#content-version-compatibility)
42	before editable sync. If the recipient cannot load the drawing, preserve the
43	full-fidelity source and use an existing compatible fallback or read-only
44	preview.
45	4. Sync: Send only validated, compatible data and mark the revision synced
46	after acknowledgement. On transport or conflict failure, retain the pending
47	revision, resolve the cause, and retry without discarding the last good copy.
48	5. Export: Validate a nonempty drawing region and intended scale before
49	calling `image(from:scale:)`; skip export on invalid bounds without altering
50	the serialized drawing.
51
52	## PKCanvasView Basics
53
54	`PKCanvasView` is a `UIScrollView` subclass that captures Apple Pencil and
55	finger input and renders strokes.
56
57	```swift
58	import PencilKit
59	import UIKit
60
61	class DrawingViewController: UIViewController, PKCanvasViewDelegate {
62	let canvasView = PKCanvasView()
63
64	override func viewDidLoad() {
65	super.viewDidLoad()
66	canvasView.delegate = self
67	canvasView.drawingPolicy = .anyInput
68	canvasView.tool = PKInkingTool(.pen, color: .black, width: 5)
69	canvasView.frame = view.bounds
70	canvasView.autoresizingMask = [.flexibleWidth, .flexibleHeight]
71	view.addSubview(canvasView)
72	}
73
74	func canvasViewDrawingDidChange(_ canvasView: PKCanvasView) {
75	// Drawing changed -- save or process
76	}
77	}
78	```
79
80	### Drawing Policies
81
82	\| Policy \| Behavior \|
83	\|---\|---\|
84	\| `.default` \| Respects `UIPencilInteraction.prefersPencilOnlyDrawing` when the tool picker is visible; otherwise Pencil-only \|
85	\| `.anyInput` \| Both pencil and finger draw \|
86	\| `.pencilOnly` \| Only Apple Pencil touches draw on the canvas \|
87
88	```swift
89	canvasView.drawingPolicy = .pencilOnly
90	```
91
92	Use `.default` for system-standard Pencil-primary canvases when the tool
93	picker's drawing-policy control should follow the user's Pencil preference. Use
94	`.anyInput` for signature pads, whiteboards, or explicit finger-drawing modes.
95	Use `.pencilOnly` when finger input should never create strokes.
96
97	### Configuring the Canvas
98
99	```swift
100	// Set a large drawing area (scrollable)
101	canvasView.contentSize = CGSize(width: 2000, height: 3000)
102
103	// Enable/disable the ruler
104	canvasView.isRulerActive = true
105
106	// Set the current tool programmatically
107	canvasView.tool = PKInkingTool(.pencil, color: .blue, width: 3)
108	canvasView.tool = PKEraserTool(.vector)
109	```
110
111	## PKToolPicker
112
113	`PKToolPicker` displays a floating palette of drawing tools. The canvas
114	automatically adopts the selected tool.
115
116	```swift
117	class DrawingViewController: UIViewController {
118	let canvasView = PKCanvasView()
119	let toolPicker = PKToolPicker()
120
121	override func viewDidAppear(_ animated: Bool) {
122	super.viewDidAppear(animated)
123	toolPicker.addObserver(canvasView)
124	toolPicker.setVisible(true, forFirstResponder: canvasView)
125	canvasView.becomeFirstResponder()
126	}
127	}
128	```
129
130	### Custom Tool Picker Items
131
132	Create a tool picker with specific tools. `PKToolPicker(toolItems:)` and
133	custom tool picker item classes require iOS/iPadOS 18+, Mac Catalyst 18+, and
134	visionOS 2+; those item classes are available on macOS starting

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pencilkit

2.0kinstalls45forks

View on GitHub

How to install pencilkit?

dpearson2699/swift-ios-skills/pencilkit

$npx -y skills add dpearson2699/swift-ios-skills --skill pencilkit

Installs into the current project.

Summary

Files · 1

View on GitHub

SKILL.md

1	# PencilKit
2
3	Capture Apple Pencil and finger input using `PKCanvasView`, manage drawing
4	tools with `PKToolPicker`, serialize drawings with `PKDrawing`, and wrap PencilKit in SwiftUI.
5
6	## Contents
7
8	- [Setup](#setup)
9	- [Capture-to-Export Workflow](#capture-to-export-workflow)
10	- [PKCanvasView Basics](#pkcanvasview-basics)
11	- [PKToolPicker](#pktoolpicker)
12	- [PKDrawing Serialization](#pkdrawing-serialization)
13	- [Content Version Compatibility](#content-version-compatibility)
14	- [Exporting to Image](#exporting-to-image)
15	- [Stroke Inspection](#stroke-inspection)
16	- [SwiftUI Integration](#swiftui-integration)
17	- [PaperKit Relationship](#paperkit-relationship)
18	- [Common Mistakes](#common-mistakes)
19	- [Review Checklist](#review-checklist)
20	- [References](#references)
21
22	## Setup
23
24	PencilKit requires no entitlements or Info.plist entries. Import `PencilKit`
25	and create a `PKCanvasView`.
26
27	```swift
28	import PencilKit
29	```
30
31	Platform availability: iOS 13+, iPadOS 13+, Mac Catalyst 13.1+, visionOS 1.0+.
32
33	## Capture-to-Export Workflow
34
35	1. Capture: Read `canvasView.drawing` from
36	`canvasViewDrawingDidChange(_:)`; keep the previous persisted revision until
37	the new revision completes the remaining checkpoints.
38	2. Serialize: Create `dataRepresentation()`, write atomically, and run the
39	[decode validate/fix/retry loop](#decode-validatefixretry-loop). Do not mark
40	bytes valid when `PKDrawing(data:)` still throws.
41	3. Version-gate: Apply [Content Version Compatibility](#content-version-compatibility)
42	before editable sync. If the recipient cannot load the drawing, preserve the
43	full-fidelity source and use an existing compatible fallback or read-only
44	preview.
45	4. Sync: Send only validated, compatible data and mark the revision synced
46	after acknowledgement. On transport or conflict failure, retain the pending
47	revision, resolve the cause, and retry without discarding the last good copy.
48	5. Export: Validate a nonempty drawing region and intended scale before
49	calling `image(from:scale:)`; skip export on invalid bounds without altering
50	the serialized drawing.
51
52	## PKCanvasView Basics
53
54	`PKCanvasView` is a `UIScrollView` subclass that captures Apple Pencil and
55	finger input and renders strokes.
56
57	```swift
58	import PencilKit
59	import UIKit
60
61	class DrawingViewController: UIViewController, PKCanvasViewDelegate {
62	let canvasView = PKCanvasView()
63
64	override func viewDidLoad() {
65	super.viewDidLoad()
66	canvasView.delegate = self
67	canvasView.drawingPolicy = .anyInput
68	canvasView.tool = PKInkingTool(.pen, color: .black, width: 5)
69	canvasView.frame = view.bounds
70	canvasView.autoresizingMask = [.flexibleWidth, .flexibleHeight]
71	view.addSubview(canvasView)
72	}
73
74	func canvasViewDrawingDidChange(_ canvasView: PKCanvasView) {
75	// Drawing changed -- save or process
76	}
77	}
78	```
79
80	### Drawing Policies
81
82	\| Policy \| Behavior \|
83	\|---\|---\|
84	\| `.default` \| Respects `UIPencilInteraction.prefersPencilOnlyDrawing` when the tool picker is visible; otherwise Pencil-only \|
85	\| `.anyInput` \| Both pencil and finger draw \|
86	\| `.pencilOnly` \| Only Apple Pencil touches draw on the canvas \|
87
88	```swift
89	canvasView.drawingPolicy = .pencilOnly
90	```
91
92	Use `.default` for system-standard Pencil-primary canvases when the tool
93	picker's drawing-policy control should follow the user's Pencil preference. Use
94	`.anyInput` for signature pads, whiteboards, or explicit finger-drawing modes.
95	Use `.pencilOnly` when finger input should never create strokes.
96
97	### Configuring the Canvas
98
99	```swift
100	// Set a large drawing area (scrollable)
101	canvasView.contentSize = CGSize(width: 2000, height: 3000)
102
103	// Enable/disable the ruler
104	canvasView.isRulerActive = true
105
106	// Set the current tool programmatically
107	canvasView.tool = PKInkingTool(.pencil, color: .blue, width: 3)
108	canvasView.tool = PKEraserTool(.vector)
109	```
110
111	## PKToolPicker
112
113	`PKToolPicker` displays a floating palette of drawing tools. The canvas
114	automatically adopts the selected tool.
115
116	```swift
117	class DrawingViewController: UIViewController {
118	let canvasView = PKCanvasView()
119	let toolPicker = PKToolPicker()
120
121	override func viewDidAppear(_ animated: Bool) {
122	super.viewDidAppear(animated)
123	toolPicker.addObserver(canvasView)
124	toolPicker.setVisible(true, forFirstResponder: canvasView)
125	canvasView.becomeFirstResponder()
126	}
127	}
128	```
129
130	### Custom Tool Picker Items
131
132	Create a tool picker with specific tools. `PKToolPicker(toolItems:)` and
133	custom tool picker item classes require iOS/iPadOS 18+, Mac Catalyst 18+, and
134	visionOS 2+; those item classes are available on macOS starting

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