修复双面打印

electron/main.js

@@ -301,9 +301,11 @@ ipcMain.handle("print-pdf", async (event, pdfDataOrUrl, printOptions = {}) => {
     }
 
     const duplexMode = printOptions?.duplex;
+    // pdf-to-printer 使用 side 选项，而不是 duplex
+    // side 可选值: "simplex" | "duplex" | "duplexshort" | "duplexlong"
+    const sideOption = duplexMode ? "duplex" : "simplex";
     log.info(
-      `准备打印PDF: ${pdfFilePath}, 打印机: ${
-        targetPrinterName || "默认打印机"
+      `准备打印PDF: ${pdfFilePath}, 打印机: ${targetPrinterName || "默认打印机"
       }, 双面打印: ${duplexMode ? "是" : "否"}`
     );
 
@@ -311,7 +313,7 @@ ipcMain.handle("print-pdf", async (event, pdfDataOrUrl, printOptions = {}) => {
     const printOptions_ptp = {
       printer: targetPrinterName || undefined,
       silent: true, // 静默打印
-      duplex: duplexMode || false, // 双面打印选项
+      side: sideOption, // 双面打印选项
     };
 
     await ptp.print(pdfFilePath, printOptions_ptp);