Clean up ahead of PR.

Signal.xcodeproj/project.pbxproj

@@ -235,7 +235,7 @@
 		34BECE2B1F74C12700D7438D /* DebugUIStress.m in Sources */ = {isa = PBXBuildFile; fileRef = 34BECE2A1F74C12700D7438D /* DebugUIStress.m */; };
 		34BECE2E1F7ABCE000D7438D /* GifPickerViewController.swift in Sources */ = {isa = PBXBuildFile; fileRef = 34BECE2D1F7ABCE000D7438D /* GifPickerViewController.swift */; };
 		34BECE301F7ABCF800D7438D /* GifPickerLayout.swift in Sources */ = {isa = PBXBuildFile; fileRef = 34BECE2F1F7ABCF800D7438D /* GifPickerLayout.swift */; };
-		34BEDB0E21C405B0007B0EAE /* ImageEditor.swift in Sources */ = {isa = PBXBuildFile; fileRef = 34BEDB0D21C405B0007B0EAE /* ImageEditor.swift */; };
+		34BEDB0E21C405B0007B0EAE /* ImageEditorModel.swift in Sources */ = {isa = PBXBuildFile; fileRef = 34BEDB0D21C405B0007B0EAE /* ImageEditorModel.swift */; };
 		34BEDB1121C41E71007B0EAE /* ImageEditorTest.swift in Sources */ = {isa = PBXBuildFile; fileRef = 34BEDB1021C41E71007B0EAE /* ImageEditorTest.swift */; };
 		34BEDB1321C43F6A007B0EAE /* ImageEditorView.swift in Sources */ = {isa = PBXBuildFile; fileRef = 34BEDB1221C43F69007B0EAE /* ImageEditorView.swift */; };
 		34BEDB1621C80BCA007B0EAE /* OWSAnyTouchGestureRecognizer.h in Headers */ = {isa = PBXBuildFile; fileRef = 34BEDB1421C80BC9007B0EAE /* OWSAnyTouchGestureRecognizer.h */; settings = {ATTRIBUTES = (Public, ); }; };
@@ -911,7 +911,7 @@
 		34BECE2A1F74C12700D7438D /* DebugUIStress.m */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.objc; path = DebugUIStress.m; sourceTree = "<group>"; };
 		34BECE2D1F7ABCE000D7438D /* GifPickerViewController.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = GifPickerViewController.swift; sourceTree = "<group>"; };
 		34BECE2F1F7ABCF800D7438D /* GifPickerLayout.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = GifPickerLayout.swift; sourceTree = "<group>"; };
-		34BEDB0D21C405B0007B0EAE /* ImageEditor.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = ImageEditor.swift; sourceTree = "<group>"; };
+		34BEDB0D21C405B0007B0EAE /* ImageEditorModel.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = ImageEditorModel.swift; sourceTree = "<group>"; };
 		34BEDB1021C41E71007B0EAE /* ImageEditorTest.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = ImageEditorTest.swift; sourceTree = "<group>"; };
 		34BEDB1221C43F69007B0EAE /* ImageEditorView.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = ImageEditorView.swift; sourceTree = "<group>"; };
 		34BEDB1421C80BC9007B0EAE /* OWSAnyTouchGestureRecognizer.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = OWSAnyTouchGestureRecognizer.h; sourceTree = "<group>"; };
@@ -1873,8 +1873,8 @@
 		34BEDB0C21C405B0007B0EAE /* ImageEditor */ = {
 			isa = PBXGroup;
 			children = (
-				34BEDB0D21C405B0007B0EAE /* ImageEditor.swift */,
 				34BEDB1821C82AC5007B0EAE /* ImageEditorGestureRecognizer.swift */,
+				34BEDB0D21C405B0007B0EAE /* ImageEditorModel.swift */,
 				34BEDB1221C43F69007B0EAE /* ImageEditorView.swift */,
 			);
 			path = ImageEditor;
@@ -3356,7 +3356,7 @@
 				34AC09E9211B39B100997B47 /* OWSTableViewController.m in Sources */,
 				346129F51FD5F31400532771 /* OWS102MoveLoggingPreferenceToUserDefaults.m in Sources */,
 				45194F8F1FD71FF500333B2C /* ThreadUtil.m in Sources */,
-				34BEDB0E21C405B0007B0EAE /* ImageEditor.swift in Sources */,
+				34BEDB0E21C405B0007B0EAE /* ImageEditorModel.swift in Sources */,
 				451F8A3B1FD71297005CB9DA /* UIUtil.m in Sources */,
 				450C800F20AD1AB900F3A091 /* OWSWindowManager.m in Sources */,
 				454A965A1FD6017E008D2A0E /* SignalAttachment.swift in Sources */,

SignalMessaging/ViewControllers/AttachmentApprovalViewController.swift

@@ -60,6 +60,7 @@ class SignalAttachmentItem: Hashable {
 
     let attachment: SignalAttachment
 
+    // This might be nil if the attachment is not a valid image.
     var imageEditorModel: ImageEditorModel?
 
     init(attachment: SignalAttachment) {

SignalMessaging/Views/ImageEditor/ImageEditorGestureRecognizer.swift

@@ -34,6 +34,7 @@ class ImageEditorGestureRecognizer: UIGestureRecognizer {
 
         if state == .possible,
             touchType(for: touches, with: event) == .valid {
+            // If a gesture starts with a valid touch, begin stroke.
             state = .began
         } else {
             state = .failed
@@ -48,10 +49,13 @@ class ImageEditorGestureRecognizer: UIGestureRecognizer {
         case .began, .changed:
             switch touchType(for: touches, with: event) {
             case .valid:
+                // If a gesture continues with a valid touch, continue stroke.
                 state = .changed
             case .invalid:
                 state = .failed
             case .outside:
+                // If a gesture continues with a valid touch _outside the canvas_,
+                // end stroke.
                 state = .ended
             }
         default:
@@ -67,6 +71,7 @@ class ImageEditorGestureRecognizer: UIGestureRecognizer {
         case .began, .changed:
             switch touchType(for: touches, with: event) {
             case .valid, .outside:
+                // If a gesture ends with a valid touch, end stroke.
                 state = .ended
             case .invalid:
                 state = .failed

SignalMessaging/Views/ImageEditor/ImageEditorModel.swift

@@ -114,6 +114,9 @@ public class ImageEditorStrokeItem: ImageEditorItem {
 
 // MARK: -
 
+// ImageEditorContents represents a snapshot of canvas
+// state.
+//
 // Instances of ImageEditorContents should be treated
 // as immutable, once configured.
 public class ImageEditorContents: NSObject {

SignalMessaging/Views/ImageEditor/ImageEditorView.swift

@@ -4,6 +4,8 @@
 
 import UIKit
 
+// A view for editing outgoing image attachments.
+// It can also be used to render the final output.
 @objc
 public class ImageEditorView: UIView, ImageEditorModelDelegate {
     private let model: ImageEditorModel