Merge commit '7621e2f8dec938cf48181c8b10afc9b01f444e68' into beta

submodules/Pdf/BUILD

@@ -0,0 +1,18 @@
+load("@build_bazel_rules_swift//swift:swift.bzl", "swift_library")
+
+swift_library(
+    name = "Pdf",
+    module_name = "Pdf",
+    srcs = glob([
+		"Sources/**/*.swift",
+    ]),
+    copts = [
+        "-warnings-as-errors",
+    ],
+    deps = [
+    	"//submodules/Display:Display",
+    ],
+    visibility = [
+        "//visibility:public",
+    ],
+)

submodules/Pdf/Sources/PDF.swift

@@ -0,0 +1,33 @@
+import Foundation
+import UIKit
+import Display
+
+public func generatePdfPreviewImage(url: URL, size: CGSize) -> UIImage? {
+    guard let data = try? Data(contentsOf: url, options: .mappedIfSafe) else { return nil }
+    return generatePdfPreviewImage(data: data, size: size)
+}
+
+public func generatePdfPreviewImage(data: Data, size: CGSize) -> UIImage? {
+    guard let provider = CGDataProvider(data: data as CFData) else { return nil }
+    guard let document = CGPDFDocument(provider) else { return nil }
+    guard let firstPage = document.page(at: 1) else { return nil }
+    
+    guard let context = DrawingContext(size: size) else {
+        return nil
+    }
+    context.withContext { c in
+        var pageRect = firstPage.getBoxRect(.mediaBox)
+        let pdfScale = 320.0 / pageRect.size.width
+        pageRect.size = CGSize(width: pageRect.size.width * pdfScale, height: pageRect.size.height * pdfScale)
+        pageRect.origin = CGPoint.zero
+        
+        c.setFillColor(UIColor.white.cgColor)
+        c.fill(pageRect)
+        
+        c.translateBy(x: 0.0, y: pageRect.size.height)
+        c.scaleBy(x: 1.0, y: -1.0)
+        c.concatenate(firstPage.getDrawingTransform(.mediaBox, rect: pageRect, rotate: 0, preserveAspectRatio: true))
+        c.drawPDFPage(firstPage)
+    }
+    return context.generateImage()
+}