如何將圖像繪製到pictureBox？

Question

在Form1頂部，我有：

Bitmap bitmap; 

在構造函數中：

bitmap = (Bitmap)sc.CaptureScreen(); 

創建100個截圖：

for (int i = 0; i < 100; i++) 
{ 
    bitmap.Save(@"D:\ffmpegtorun\ffmpeg-20130509-git-13cb6ed-win32-static\bin\Screenshots\" + "Screenshot" + i.ToString("D6") + ".Jpg", ImageFormat.Jpeg); 
} 

把截圖給pictureBox1：

pictureBox1.Image = bitmap = new Bitmap(@"D:\ffmpegtorun\ffmpeg-20130509-git-13cb6ed-win32-static\bin\Screenshots\Screenshot000000.jpg"); 

然後在pictureBox1油漆事件我做：

private void pictureBox1_Paint(object sender, PaintEventArgs e) 
{ 
    int width = pictureBox1.Width; 
    int height = pictureBox1.Height; 

    // Draw the image with no shrinking or stretching. 
    e.Graphics.InterpolationMode = InterpolationMode.HighQualityBicubic; 
    e.Graphics.DrawImage(
       bitmap, 
       new Rectangle(0, 0, width, height), // destination rectangle 
       0, 
       0,   // upper-left corner of source rectangle 
       width,  // width of source rectangle 
       height,  // height of source rectangle 
       GraphicsUnit.Pixel, 
       null); 

} 

這是截圖課堂，它採取的截圖：

using System; 
using System.Runtime.InteropServices; 
using System.Drawing; 
using System.Drawing.Imaging; 
namespace ScreenShotDemo 
{ 
    /// <summary> 
    /// Provides functions to capture the entire screen, or a particular window, and save it to a file. 
    /// </summary> 
    public class ScreenCapture 
    { 
     /// <summary> 
     /// Creates an Image object containing a screen shot of the entire desktop 
     /// </summary> 
     /// <returns></returns> 
     public Image CaptureScreen() 
     { 
      return CaptureWindow(User32.GetDesktopWindow()); 
     } 
     /// <summary> 
     /// Creates an Image object containing a screen shot of a specific window 
     /// </summary> 
     /// <param name="handle">The handle to the window. (In windows forms, this is obtained by the Handle property)</param> 
     /// <returns></returns> 
     public Image CaptureWindow(IntPtr handle) 
     { 
      // get te hDC of the target window 
      IntPtr hdcSrc = User32.GetWindowDC(handle); 
      // get the size 
      User32.RECT windowRect = new User32.RECT(); 
      User32.GetWindowRect(handle, ref windowRect); 
      int width = windowRect.right - windowRect.left; 
      int height = windowRect.bottom - windowRect.top; 
      // create a device context we can copy to 
      IntPtr hdcDest = GDI32.CreateCompatibleDC(hdcSrc); 
      // create a bitmap we can copy it to, 
      // using GetDeviceCaps to get the width/height 
      IntPtr hBitmap = GDI32.CreateCompatibleBitmap(hdcSrc, width, height); 
      // select the bitmap object 
      IntPtr hOld = GDI32.SelectObject(hdcDest, hBitmap); 
      // bitblt over 
      GDI32.BitBlt(hdcDest, 0, 0, width, height, hdcSrc, 0, 0, GDI32.SRCCOPY); 
      // restore selection 
      GDI32.SelectObject(hdcDest, hOld); 
      // clean up 
      GDI32.DeleteDC(hdcDest); 
      User32.ReleaseDC(handle, hdcSrc); 
      // get a .NET image object for it 
      Image img = Image.FromHbitmap(hBitmap); 
      // free up the Bitmap object 
      GDI32.DeleteObject(hBitmap); 
      return img; 
     } 
     /// <summary> 
     /// Captures a screen shot of a specific window, and saves it to a file 
     /// </summary> 
     /// <param name="handle"></param> 
     /// <param name="filename"></param> 
     /// <param name="format"></param> 
     public void CaptureWindowToFile(IntPtr handle, string filename, ImageFormat format) 
     { 
      Image img = CaptureWindow(handle); 
      img.Save(filename, format); 
     } 
     /// <summary> 
     /// Captures a screen shot of the entire desktop, and saves it to a file 
     /// </summary> 
     /// <param name="filename"></param> 
     /// <param name="format"></param> 
     public void CaptureScreenToFile(string filename, ImageFormat format) 
     { 
      Image img = CaptureScreen(); 
      img.Save(filename, format); 
     } 

     /// <summary> 
     /// Helper class containing Gdi32 API functions 
     /// </summary> 
     private class GDI32 
     { 

      public const int SRCCOPY = 0x00CC0020; // BitBlt dwRop parameter 
      [DllImport("gdi32.dll")] 
      public static extern bool BitBlt(IntPtr hObject, int nXDest, int nYDest, 
       int nWidth, int nHeight, IntPtr hObjectSource, 
       int nXSrc, int nYSrc, int dwRop); 
      [DllImport("gdi32.dll")] 
      public static extern IntPtr CreateCompatibleBitmap(IntPtr hDC, int nWidth, 
       int nHeight); 
      [DllImport("gdi32.dll")] 
      public static extern IntPtr CreateCompatibleDC(IntPtr hDC); 
      [DllImport("gdi32.dll")] 
      public static extern bool DeleteDC(IntPtr hDC); 
      [DllImport("gdi32.dll")] 
      public static extern bool DeleteObject(IntPtr hObject); 
      [DllImport("gdi32.dll")] 
      public static extern IntPtr SelectObject(IntPtr hDC, IntPtr hObject); 
     } 

     /// <summary> 
     /// Helper class containing User32 API functions 
     /// </summary> 
     private class User32 
     { 
      [StructLayout(LayoutKind.Sequential)] 
      public struct RECT 
      { 
       public int left; 
       public int top; 
       public int right; 
       public int bottom; 
      } 
      [DllImport("user32.dll")] 
      public static extern IntPtr GetDesktopWindow(); 
      [DllImport("user32.dll")] 
      public static extern IntPtr GetWindowDC(IntPtr hWnd); 
      [DllImport("user32.dll")] 
      public static extern IntPtr ReleaseDC(IntPtr hWnd, IntPtr hDC); 
      [DllImport("user32.dll")] 
      public static extern IntPtr GetWindowRect(IntPtr hWnd, ref RECT rect); 
     } 
    } 
} 

結果是這樣的：

https://skydrive.live.com/redir?resid=EB1C71C44C3976D5!270&authkey=!ANAKzbwJI-3TQqE

圖像不適合pictureBox。

但是如果我用放大鏡玻璃移過，現在在PictureBox我看到它平滑，但圖像不適合在PictureBox：

https://skydrive.live.com/redir?resid=EB1C71C44C3976D5!271&authkey=!ALizvsyxrMuyVTk

這是放大鏡玻璃表單代碼：

using System; 
using System.Collections.Generic; 
using System.ComponentModel; 
using System.Data; 
using System.Drawing; 
using System.Text; 
using System.Windows.Forms; 
using System.Drawing.Drawing2D; 
using System.IO; 
using System.Drawing.Imaging; 

namespace Magnifier20070401 
{ 
    public partial class MagnifierForm : Form 
    { 
     private bool _doMove; 

     public MagnifierForm() 
     { 
      InitializeComponent(); 

      _doMove = true; 
      FormBorderStyle = FormBorderStyle.None; 
      ShowInTaskbar = false; 
      TopMost = true; 
      Width = 150; 
      Height = 150; 
      GraphicsPath gp = new GraphicsPath(); 
      gp.AddEllipse(ClientRectangle); 
      Region = new Region(gp); 
      mTimer = new Timer(); 
      mTimer.Enabled = true; 
      mTimer.Interval = 20; 
      mTimer.Tick += new EventHandler(HandleTimer); 
      mScreenImage = new Bitmap(Screen.PrimaryScreen.Bounds.Width, 
            Screen.PrimaryScreen.Bounds.Height); 
      mStartPoint = new Point(500, 500); 
      mTargetPoint = new Point(500, 500); 
      speed = 0.35F; 
      zoom = 3.0F; 
      hidecursor = false; 
      hue = 30; 
     } 

     public MagnifierForm(bool MoveTheGlass, bool InTaskBar, int MagnifierWidth, int MagnifierHeight, Point MagnifierStartPoint, float SpeedFactor, float ChangeZoom, bool HideMouseCursor, float AdjustHue) 
     { 
      InitializeComponent(); 

      FormBorderStyle = FormBorderStyle.None; 
      TopMost = true; 
      GraphicsPath gp = new GraphicsPath(); 
      gp.AddEllipse(ClientRectangle); 
      Region = new Region(gp); 
      mTimer = new Timer(); 
      mTimer.Enabled = true; 
      mTimer.Interval = 20; 
      mTimer.Tick += new EventHandler(HandleTimer); 
      mScreenImage = new Bitmap(Screen.PrimaryScreen.Bounds.Width, 
            Screen.PrimaryScreen.Bounds.Height); 

      _doMove = MoveTheGlass; 
      ShowInTaskbar = InTaskBar; 
      Width = MagnifierWidth; 
      Height = MagnifierHeight; 
      mStartPoint = MagnifierStartPoint; 
      mTargetPoint = MagnifierStartPoint; 
      speed = SpeedFactor; 
      zoom = ChangeZoom; 
      hidecursor = HideMouseCursor; 
      hue = AdjustHue; 
     } 

     protected override void OnShown(EventArgs e) 
     { 
      RepositionAndShow(); 
     } 

     private delegate void RepositionAndShowDelegate(); 

     private void RepositionAndShow() 
     { 
      if (InvokeRequired) 
      { 
       Invoke(new RepositionAndShowDelegate(RepositionAndShow)); 
      } 
      else 
      { 
       Graphics g = Graphics.FromImage(mScreenImage); 
       g.CopyFromScreen(0, 0, 0, 0, new Size(mScreenImage.Width, mScreenImage.Height)); 
       HSLAdjust.BitmapFunctions bf = new HSLAdjust.BitmapFunctions((Bitmap)mScreenImage); 
       bf.Hue(hue); 
       bf.Dispose(); 
       g.Dispose(); 

       if (hidecursor == true) 
       { 
        Cursor.Hide(); 
       } 
       else 
       { 
        Cursor = Cursors.Cross; 
       } 
       Capture = true; 
       mCurrentPoint = Cursor.Position; 
       Show(); // to add here the bool of the Mouse Cursor to hide or not to hide 
      } 
     } 

     void HandleTimer(object sender, EventArgs e) 
     { 
      float dx = speed * (mTargetPoint.X - mCurrentPoint.X); 
      float dy = speed * (mTargetPoint.Y - mCurrentPoint.Y); 

      if (mFirstTime) 
      { 
       mFirstTime = false; 

       mCurrentPoint.X = mTargetPoint.X; 
       mCurrentPoint.Y = mTargetPoint.Y; 

       Left = (int)mCurrentPoint.X - Width/2; 
       Top = (int)mCurrentPoint.Y - Height/2; 

       return; 
      } 

      mCurrentPoint.X += dx; 
      mCurrentPoint.Y += dy; 

      if (Math.Abs(dx) < 1 && Math.Abs(dy) < 1) 
      { 
       mTimer.Enabled = false; 
      } 
      else 
      { 
       // Update location 
       Left = (int)mCurrentPoint.X - Width/2; 
       Top = (int)mCurrentPoint.Y - Height/2; 
       mLastMagnifierPosition = new Point((int)mCurrentPoint.X, (int)mCurrentPoint.Y); 
      } 

      Refresh(); 
     } 


     protected override void OnMouseDown(MouseEventArgs e) 
     { 
      mOffset = new Point(Width/2 - e.X, Height/2 - e.Y); 
      mCurrentPoint = PointToScreen(new Point(e.X + mOffset.X, e.Y + mOffset.Y)); 
      mTargetPoint = mCurrentPoint; 
      mTimer.Enabled = true; 

     } 

     protected override void OnMouseMove(MouseEventArgs e) 
     { 
      if (_doMove == true) 
      { 
       mTargetPoint = PointToScreen(new Point(e.X + mOffset.X, e.Y + mOffset.Y)); 
       mTimer.Enabled = true; 
      } 

     } 

     protected override void OnPaintBackground(PaintEventArgs e) 
     { 
      /*if (mConfiguration.DoubleBuffered) 
      { 
       // Do not paint background (required for double buffering)! 
      } 
      else 
      { 
       base.OnPaintBackground(e); 
      }*/ 
      base.OnPaintBackground(e); 
     } 

     protected override void OnPaint(PaintEventArgs e) 
     { 
      if (mBufferImage == null) 
      { 
       mBufferImage = new Bitmap(Width, Height); 
      } 
      Graphics bufferGrf = Graphics.FromImage(mBufferImage); 

      Graphics g; 

      /*if (mConfiguration.DoubleBuffered) 
      { 
       g = bufferGrf; 
      } 
      else 
      {*/ 
       g = e.Graphics; 
      //} 

      if (mScreenImage != null) 
      { 
       Rectangle dest = new Rectangle(0, 0, Width, Height); 
       int w = (int)(Width/zoom);//mConfiguration.ZoomFactor); 
       int h = (int)(Height/zoom);//mConfiguration.ZoomFactor); 
       int x = Left - w/2 + Width/2; 
       int y = Top - h/2 + Height/2; 

       g.DrawImage(
        mScreenImage, 
        dest, 
        x, y, 
        w, h, 
        GraphicsUnit.Pixel); 
      } 
       e.Graphics.DrawImage(mBufferImage, 0, 0, Width, Height);  
     } 


     //--- Data Members --- 
     #region Data Members 
     private bool hidecursor; 
     private float zoom; 
     private float hue; 
     private float speed; 
     private Timer mTimer; 
     private Image mBufferImage = null; 
     private Image mScreenImage = null; 
     private Point mStartPoint; 
     private PointF mTargetPoint; 
     private PointF mCurrentPoint; 
     private Point mOffset; 
     private bool mFirstTime = true; 
     private static Point mLastMagnifierPosition = Cursor.Position; 
     #endregion 


     // New code \\ 

     protected override void OnMouseEnter(EventArgs e) 
     { 
      base.OnMouseEnter(e); 

      Point pt = Control.MousePosition; 
      int eX = pt.X - this.Left; 
      int eY = pt.Y - this.Top; 

      mOffset = new Point(0, 0); 
      mCurrentPoint = PointToScreen(new Point(eX + mOffset.X, eY + mOffset.Y)); 
      mTargetPoint = mCurrentPoint; 
      mTimer.Enabled = true; 
      this.Capture = true; 
     } 

     protected override void OnMouseLeave(EventArgs e) 
     { 
      base.OnMouseLeave(e); 

      if (_doMove) 
      { 
       Left = (int)mCurrentPoint.X - Width/2; 
       Top = (int)mCurrentPoint.Y - Height/2; 
      } 
     } 

     protected override void OnMouseClick(MouseEventArgs e) 
     { 
      base.OnMouseClick(e); 
      if (_doMove == true) 
      { 
       _doMove = false; 
      } 
      else 
      { 
       _doMove = true; 
      } 
     } 
    } 
} 

Answer 1

您可以將e.Graphics.InterpolationMode設置爲InterpolationMode.HighQualityBicubic。繪製圖像之前

e.Graphics.InterpolationMode = InterpolationMode.HighQualityBicubic; 

：
因此，使用這條線。這可以平滑圖像。

不要忘記：

using System.Drawing.Drawing2D; 

編輯：
而不是使用這個的：

int width = bitmap.Width; 
int height = bitmap.Height; 

使用的是：

int width = pictureBox1.Width; 
int height = pictureBox1.Height; 

於所繪製的位圖的大小調整爲PictureBox的大小。

編輯＃2：
您必須使用DrawImage方法的不同過載：

e.Graphics.DrawImage(bitmap, new Rectangle(0, 0, width, height)); 

Answer 2

您可以使用sizemode的picturebox屬性。

或將圖像轉換爲bytearray並使用預定義大小或圖像大小創建新圖像。