将打印页图形转换为位图 C#

Question

我有一个应用程序，用户可以在其中以发票的形式打印所选项目的文档。一切正常，但是在 PrintDocument 的PrintPage事件中，我想捕获文档或图形，将其转换为位图，以便我可以保存一个.bmp以供以后使用/查看。（注：本文档有多个页面）我把它设置成这样：

PrintDocument doc = new PrintDocument();
doc.PrintPage += new PrintPageEventHandler(doc_PrintPage);
doc.Print();

然后在PrintPage事件中：

private void doc_PrintPage(object sender, PrintPageEventArgs ev)
{
    // Use ev.Graphics to create the document
    // I create the document here
    // After I have drawn all the graphics I want to get it and turn it into a bitmap and save it.
}

我已经删除了所有ev.Graphics代码，因为它有很多行。有没有办法在不更改将图形绘制到PrintDocument上的任何代码的情况下将图形转换为位图？或者做类似的事情，也许复制文档并将其转换为位图？

Answer 1

实际上，您应该将页面绘制到位图中，然后使用 ev。用于在页面上绘制该位图的图形。

private void doc_PrintPage(object sender, PrintPageEventArgs ev)
{
    var bitmap = new Bitmap((int)graphics.ClipBounds.Width,
                            (int)graphics.ClipBounds.Height);
    using (var g = Graphics.FromImage(bitmap))
    {
        // Draw all the graphics using into g (into the bitmap)
        g.DrawLine(Pens.Black, 0, 0, 100, 100);
    }
    // And maybe some control drawing if you want...?
    this.label1.DrawToBitmap(bitmap, this.label1.Bounds);
    ev.Graphics.DrawImage(bitmap, 0, 0);
}

Answer 2

实际上，Yorye Nathan 在 6 月 3'12 7：33 的回答是正确的，这是帮助我的起点。 但是，我无法让它按原样工作，所以我做了一些更正，使其在我的应用程序中工作。 更正是从 PrintPgeEventArgs.Graphics 设备上下文中获取打印机的页面大小，并将 PrintPage 图形作为第三个参数包含在新的 Bitmap（...） 构造中。

private void doc_PrintPage(object sender, PrintPageEventArgs ppea)
{
  // Retrieve the physical bitmap boundaries from the PrintPage Graphics Device Context
  IntPtr hdc = ppea.Graphics.GetHdc();
  Int32 PhysicalWidth = GetDeviceCaps(hdc, (Int32)PHYSICALWIDTH);
  Int32 PhysicalHeight = GetDeviceCaps(hdc, (Int32)PHYSICALHEIGHT);
  ppea.Graphics.ReleaseHdc(hdc);
  // Create a bitmap with PrintPage Graphic's size and resolution
  Bitmap myBitmap = new Bitmap(PhysicalWidth, PhysicalHeight, ppea.Graphics);
  // Get the new work Graphics to use to draw the bitmap
  Graphics myGraphics = Graphics.FromImage(myBitmap);
  // Draw everything on myGraphics to build the bitmap
  // Transfer the bitmap to the PrintPage Graphics
  ppea.Graphics.DrawImage(myBitmap, 0, 0);
  // Cleanup 
  myBitmap.Dispose();
}
////////
// Win32 API GetDeviceCaps() function needed to get the DC Physical Width and Height
const int PHYSICALWIDTH = 110;  // Physical Width in device units           
const int PHYSICALHEIGHT = 111; // Physical Height in device units          
// This function returns the device capability value specified
// by the requested index value.
[DllImport("GDI32.DLL", CharSet = CharSet.Auto, SetLastError = true)]
public static extern Int32 GetDeviceCaps(IntPtr hdc, Int32 nIndex);

再次感谢Yorye Nathan提供原始答案。AJ