// 设置缩放比例
pd.DefaultPageSettings.Landscape = false;
pd.DefaultPageSettings.PaperSize = new PaperSize("A4", 827, 1169);
pd.DefaultPageSettings.Margins = new Margins(100, 100, 100, 100); // 左上右下边距

试一试

using System;
using System.Drawing;
using System.Drawing.Printing;
using System.Windows.Forms;

public class PrintExample : Form
{
private PrintDocument printDocument;
private Button printButton;

public PrintExample()
{
    printDocument = new PrintDocument();
    printDocument.PrintPage += new PrintPageEventHandler(printDocument_PrintPage);

    printButton = new Button();
    printButton.Text = "Print";
    printButton.Click += new EventHandler(printButton_Click);

    Controls.Add(printButton);
}

private void printButton_Click(object sender, EventArgs e)
{
    PrintDialog printDialog = new PrintDialog();
    printDialog.Document = printDocument;

    if (printDialog.ShowDialog() == DialogResult.OK)
    {
        // 获取用户选择的打印机
        PrinterSettings printerSettings = printDialog.PrinterSettings;

        // 设置打印机首选项，这里设置缩放为0.5（50%）
        printerSettings.DefaultPageSettings.Scale = 0.5f;

        // 开始打印
        printDocument.Print();
    }
}

private void printDocument_PrintPage(object sender, PrintPageEventArgs e)
{
    // 在打印页面上绘制内容
    Graphics g = e.Graphics;
    Font font = new Font("Arial", 12);
    g.DrawString("Hello, World!", font, Brushes.Black, 100, 100);
}

[STAThread]
static void Main()
{
    Application.EnableVisualStyles();
    Application.Run(new PrintExample());
}

}