update at 2026-03-16 09:00:35

calendar/scripts/export-kindle-background.sh

@@ -18,6 +18,7 @@ trap 'kill "$SERVER_PID" 2>/dev/null || true' EXIT INT TERM
 
 sleep 1
 /usr/bin/swift "$CALENDAR_DIR/scripts/export-kindle-background.swift" "$URL" "$OUT_PNG" "$OUT_REGION"
+
 node "$CALENDAR_DIR/scripts/generate-dashboard-manifest.mjs" >/dev/null
 
 cat "$OUT_REGION"

calendar/scripts/export-kindle-background.swift

@@ -2,6 +2,8 @@
 
 import AppKit
 import Foundation
+import ImageIO
+import UniformTypeIdentifiers
 import WebKit
 
 enum ExportError: Error, CustomStringConvertible {
@@ -29,7 +31,8 @@ final class SnapshotExporter: NSObject, WKNavigationDelegate {
   private let pngOutputURL: URL
   private let regionOutputURL: URL
   private let completion: (Result<Void, Error>) -> Void
-  private let targetSize = CGSize(width: 1024, height: 600)
+  // 直接按 Kindle Voyage 的系统屏保尺寸导出，避免额外旋转和补边。
+  private let targetSize = CGSize(width: 1072, height: 1448)
 
   private lazy var window: NSWindow = {
     let window = NSWindow(
@@ -129,16 +132,52 @@ final class SnapshotExporter: NSObject, WKNavigationDelegate {
     image.draw(in: NSRect(origin: .zero, size: targetSize))
     normalizedImage.unlockFocus()
 
-    guard
-      let tiffRepresentation = normalizedImage.tiffRepresentation,
-      let bitmap = NSBitmapImageRep(data: tiffRepresentation),
-      let pngData = bitmap.representation(using: .png, properties: [:])
-    else {
+    guard let sourceCGImage = normalizedImage.cgImage(forProposedRect: nil, context: nil, hints: nil) else {
+      throw ExportError.pngEncodingFailed(url.path)
+    }
+
+    let width = Int(targetSize.width)
+    let height = Int(targetSize.height)
+    let colorSpace = CGColorSpaceCreateDeviceGray()
+
+    // 输出 8-bit 灰度 PNG，但页面本身仍按纯白底和纯黑字设计，避免额外灰阶装饰。
+    guard let context = CGContext(
+      data: nil,
+      width: width,
+      height: height,
+      bitsPerComponent: 8,
+      bytesPerRow: 0,
+      space: colorSpace,
+      bitmapInfo: CGImageAlphaInfo.none.rawValue
+    ) else {
+      throw ExportError.pngEncodingFailed(url.path)
+    }
+
+    context.setFillColor(gray: 1, alpha: 1)
+    context.fill(CGRect(x: 0, y: 0, width: width, height: height))
+    context.interpolationQuality = .high
+    context.draw(sourceCGImage, in: CGRect(x: 0, y: 0, width: width, height: height))
+
+    guard let grayscaleImage = context.makeImage() else {
       throw ExportError.pngEncodingFailed(url.path)
     }
 
     try FileManager.default.createDirectory(at: url.deletingLastPathComponent(), withIntermediateDirectories: true)
-    try pngData.write(to: url)
+
+    guard let destination = CGImageDestinationCreateWithURL(
+      url as CFURL,
+      UTType.png.identifier as CFString,
+      1,
+      nil
+    ) else {
+      throw ExportError.pngEncodingFailed(url.path)
+    }
+
+    CGImageDestinationAddImage(destination, grayscaleImage, nil)
+
+    guard CGImageDestinationFinalize(destination) else {
+      throw ExportError.pngEncodingFailed(url.path)
+    }
   }
 
   private func saveRegion(region: [String: NSNumber]) throws {