Render image attachments

Author: gonzalezreal

Package.swift

@@ -39,7 +39,10 @@ let package = Package(
                 "CommonMarkUI",
                 "SnapshotTesting",
             ],
-            exclude: ["__Snapshots__"]
+            exclude: [
+                "__Fixtures__",
+                "__Snapshots__",
+            ]
         ),
     ]
 )

Sources/CommonMarkUI/Shared/Configuration.swift

@@ -9,5 +9,8 @@ extension NSAttributedString {
         var font: Font
         var codeFont: Font?
         var paragraphStyle: NSParagraphStyle
+        #if !os(watchOS)
+            var attachments: [String: NSTextAttachment] = [:]
+        #endif
     }
 }

Sources/CommonMarkUI/Shared/NSAttributedString+Document.swift

@@ -33,8 +33,16 @@ extension NSAttributedString {
             self.init(inlines: inlines, context: context.strong())
         case let .link(inlines, url, title):
             self.init(inlines: inlines, context: context.link(url, title: title))
-        case .image:
-            fatalError("Not implemented")
+        case let .image(_, url, _):
+            #if os(watchOS)
+                self.init()
+            #else
+                if let attachment = context.attachment(url) {
+                    self.init(attachment: attachment)
+                } else {
+                    self.init()
+                }
+            #endif
         }
     }
 

Sources/CommonMarkUI/Shared/RenderContext.swift

@@ -1,5 +1,11 @@
 import Foundation
 
+#if os(macOS)
+    import AppKit
+#elseif os(iOS) || os(tvOS) || os(watchOS)
+    import UIKit
+#endif
+
 extension NSAttributedString {
     struct RenderContext {
         private(set) var attributes: [Key: Any]
@@ -15,6 +21,12 @@ extension NSAttributedString {
             attributes = [.font: configuration.font]
         }
 
+        #if !os(watchOS)
+            func attachment(_ url: String) -> NSTextAttachment? {
+                configuration.attachments[url]
+            }
+        #endif
+
         func paragraph() -> RenderContext {
             var newContext = self
             newContext.attributes[.paragraphStyle] = configuration.paragraphStyle

Tests/CommonMarkUITests/NSAttributedStringTests.swift

@@ -7,7 +7,10 @@ final class NSAttributedStringTests: XCTestCase {
     private let configuration = NSAttributedString.Configuration(
         font: .custom("Helvetica", size: 16),
         codeFont: .custom("Menlo", size: 16),
-        paragraphStyle: .default
+        paragraphStyle: .default,
+        attachments: [
+            "https://commonmark.org/help/images/favicon.png": makeAttachment(),
+        ]
     )
 
     #if os(macOS)
@@ -113,4 +116,51 @@ final class NSAttributedStringTests: XCTestCase {
 
         assertSnapshot(matching: attributedString, as: .dump, named: platformName)
     }
+
+    func testImage() {
+        let document = Document(
+            #"""
+            CommonMark favicon:
+
+            ![](https://commonmark.org/help/images/favicon.png)
+            """#
+        )!
+
+        let attributedString = NSAttributedString(document: document, configuration: configuration)
+
+        assertSnapshot(matching: attributedString, as: .dump, named: platformName)
+    }
+
+    func testImageWithoutAttachment() {
+        let document = Document(
+            #"""
+            This image does not have an attachment:
+
+            ![](https://commonmark.org/help/images/unknown.png)
+            """#
+        )!
+
+        let attributedString = NSAttributedString(document: document, configuration: configuration)
+
+        assertSnapshot(matching: attributedString, as: .dump, named: platformName)
+    }
+}
+
+private func makeAttachment() -> NSTextAttachment {
+    #if os(macOS)
+        let result = NSTextAttachment()
+        result.image = NSImage(contentsOf: fixtureURL("favicon.png"))
+        return result
+    #elseif os(iOS) || os(tvOS) || os(watchOS)
+        let result = NSTextAttachment()
+        result.image = try! UIImage(data: Data(contentsOf: fixtureURL("favicon.png")))
+        return result
+    #endif
+}
+
+private func fixtureURL(_ fileName: String, file: StaticString = #file) -> URL {
+    URL(fileURLWithPath: "\(file)", isDirectory: false)
+        .deletingLastPathComponent()
+        .appendingPathComponent("__Fixtures__")
+        .appendingPathComponent(fileName)
 }

Tests/CommonMarkUITests/__Fixtures__/favicon.png

@@ -0,0 +1,8 @@
+- CommonMark favicon:{
+    NSFont = "\"Helvetica 16.00 pt. P [] () fobj=, spc=4.45\"";
+    NSParagraphStyle = "Alignment 4, LineSpacing 0, ParagraphSpacing 0, ParagraphSpacingBefore 0, HeadIndent 0, TailIndent 0, FirstLineHeadIndent 0, LineHeight 0/0, LineHeightMultiple 0, LineBreakMode 0, Tabs (\n    28L,\n    56L,\n    84L,\n    112L,\n    140L,\n    168L,\n    196L,\n    224L,\n    252L,\n    280L,\n    308L,\n    336L\n), DefaultTabInterval 0, Blocks (\n), Lists (\n), BaseWritingDirection -1, HyphenationFactor 0, TighteningForTruncation YES, HeaderLevel 0 LineBreakStrategy 0";
+}
+{
+}{
+    NSAttachment = "<NSTextAttachment>";
+}

Tests/CommonMarkUITests/__Snapshots__/NSAttributedStringTests/testImage.AppKit.txt

@@ -0,0 +1,8 @@
+- CommonMark favicon:{
+    NSFont = "<UICTFont> font-family: \"Helvetica\"; font-weight: normal; font-style: normal; font-size: 16.00pt";
+    NSParagraphStyle = "Alignment 4, LineSpacing 0, ParagraphSpacing 0, ParagraphSpacingBefore 0, HeadIndent 0, TailIndent 0, FirstLineHeadIndent 0, LineHeight 0/0, LineHeightMultiple 0, LineBreakMode 0, Tabs (\n    28L,\n    56L,\n    84L,\n    112L,\n    140L,\n    168L,\n    196L,\n    224L,\n    252L,\n    280L,\n    308L,\n    336L\n), DefaultTabInterval 0, Blocks (\n), Lists (\n), BaseWritingDirection -1, HyphenationFactor 0, TighteningForTruncation NO, HeaderLevel 0 LineBreakStrategy 0";
+}
+{
+}{
+    NSAttachment = "<NSTextAttachment>";
+}

Tests/CommonMarkUITests/__Snapshots__/NSAttributedStringTests/testImage.UIKit.txt

@@ -0,0 +1,6 @@
+- This image does not have an attachment:{
+    NSFont = "\"Helvetica 16.00 pt. P [] () fobj=, spc=4.45\"";
+    NSParagraphStyle = "Alignment 4, LineSpacing 0, ParagraphSpacing 0, ParagraphSpacingBefore 0, HeadIndent 0, TailIndent 0, FirstLineHeadIndent 0, LineHeight 0/0, LineHeightMultiple 0, LineBreakMode 0, Tabs (\n    28L,\n    56L,\n    84L,\n    112L,\n    140L,\n    168L,\n    196L,\n    224L,\n    252L,\n    280L,\n    308L,\n    336L\n), DefaultTabInterval 0, Blocks (\n), Lists (\n), BaseWritingDirection -1, HyphenationFactor 0, TighteningForTruncation YES, HeaderLevel 0 LineBreakStrategy 0";
+}
+{
+}

Tests/CommonMarkUITests/__Snapshots__/NSAttributedStringTests/testImageWithoutAttachment.AppKit.txt

@@ -0,0 +1,6 @@
+- This image does not have an attachment:{
+    NSFont = "<UICTFont> font-family: \"Helvetica\"; font-weight: normal; font-style: normal; font-size: 16.00pt";
+    NSParagraphStyle = "Alignment 4, LineSpacing 0, ParagraphSpacing 0, ParagraphSpacingBefore 0, HeadIndent 0, TailIndent 0, FirstLineHeadIndent 0, LineHeight 0/0, LineHeightMultiple 0, LineBreakMode 0, Tabs (\n    28L,\n    56L,\n    84L,\n    112L,\n    140L,\n    168L,\n    196L,\n    224L,\n    252L,\n    280L,\n    308L,\n    336L\n), DefaultTabInterval 0, Blocks (\n), Lists (\n), BaseWritingDirection -1, HyphenationFactor 0, TighteningForTruncation NO, HeaderLevel 0 LineBreakStrategy 0";
+}
+{
+}