Bitmap.LockBits 方法

來源:

Bitmap.cs

來源:

Bitmap.cs

來源:

Bitmap.cs

public:
 System::Drawing::Imaging::BitmapData ^ LockBits(System::Drawing::Rectangle rect, System::Drawing::Imaging::ImageLockMode flags, System::Drawing::Imaging::PixelFormat format);

public System.Drawing.Imaging.BitmapData LockBits (System.Drawing.Rectangle rect, System.Drawing.Imaging.ImageLockMode flags, System.Drawing.Imaging.PixelFormat format);

member this.LockBits : System.Drawing.Rectangle * System.Drawing.Imaging.ImageLockMode * System.Drawing.Imaging.PixelFormat -> System.Drawing.Imaging.BitmapData

Public Function LockBits (rect As Rectangle, flags As ImageLockMode, format As PixelFormat) As BitmapData

參數

傳回

BitmapData，包含這個鎖定作業的相關資訊。

例外狀況

範例

下列程式代碼範例示範如何使用、、 和屬性、LockBits和 UnlockBits 方法，以及 ImageLockMode 列舉。Scan0WidthHeightPixelFormat 此範例的設計目的是要與 Windows Forms 搭配使用。 此範例並非設計來正確處理所有像素格式，而是提供如何使用 方法的 LockBits 範例。 若要執行此範例，請將它貼到表單中，並藉由呼叫 方法來處理表單Paint的事件，並e傳遞為 PaintEventArgs。LockUnlockBitsExample

void LockUnlockBitsExample( PaintEventArgs^ e )
{
   // Create a new bitmap.
   Bitmap^ bmp = gcnew Bitmap( "c:\\fakePhoto.jpg" );

   // Lock the bitmap's bits.  
   Rectangle rect = Rectangle(0,0,bmp->Width,bmp->Height);
   System::Drawing::Imaging::BitmapData^ bmpData = bmp->LockBits( rect, System::Drawing::Imaging::ImageLockMode::ReadWrite, bmp->PixelFormat );

   // Get the address of the first line.
   IntPtr ptr = bmpData->Scan0;

   // Declare an array to hold the bytes of the bitmap.
   // This code is specific to a bitmap with 24 bits per pixels.
   int bytes = Math::Abs(bmpData->Stride) * bmp->Height;
   array<Byte>^rgbValues = gcnew array<Byte>(bytes);

   // Copy the RGB values into the array.
   System::Runtime::InteropServices::Marshal::Copy( ptr, rgbValues, 0, bytes );

   // Set every third value to 255.  
   for ( int counter = 2; counter < rgbValues->Length; counter += 3 )
      rgbValues[ counter ] = 255;

   // Copy the RGB values back to the bitmap
   System::Runtime::InteropServices::Marshal::Copy( rgbValues, 0, ptr, bytes );

   // Unlock the bits.
   bmp->UnlockBits( bmpData );

   // Draw the modified image.
   e->Graphics->DrawImage( bmp, 0, 150 );
}

private void LockUnlockBitsExample(PaintEventArgs e)
    {

        // Create a new bitmap.
        Bitmap bmp = new Bitmap("c:\\fakePhoto.jpg");

        // Lock the bitmap's bits.  
        Rectangle rect = new Rectangle(0, 0, bmp.Width, bmp.Height);
        System.Drawing.Imaging.BitmapData bmpData =
            bmp.LockBits(rect, System.Drawing.Imaging.ImageLockMode.ReadWrite,
            bmp.PixelFormat);

        // Get the address of the first line.
        IntPtr ptr = bmpData.Scan0;

        // Declare an array to hold the bytes of the bitmap.
        int bytes  = Math.Abs(bmpData.Stride) * bmp.Height;
        byte[] rgbValues = new byte[bytes];

        // Copy the RGB values into the array.
        System.Runtime.InteropServices.Marshal.Copy(ptr, rgbValues, 0, bytes);

        // Set every third value to 255. A 24bpp bitmap will look red.  
        for (int counter = 2; counter < rgbValues.Length; counter += 3)
            rgbValues[counter] = 255;

        // Copy the RGB values back to the bitmap
        System.Runtime.InteropServices.Marshal.Copy(rgbValues, 0, ptr, bytes);

        // Unlock the bits.
        bmp.UnlockBits(bmpData);

        // Draw the modified image.
        e.Graphics.DrawImage(bmp, 0, 150);
    }

Private Sub LockUnlockBitsExample(ByVal e As PaintEventArgs)

    ' Create a new bitmap.
    Dim bmp As New Bitmap("c:\fakePhoto.jpg")

    ' Lock the bitmap's bits.  
    Dim rect As New Rectangle(0, 0, bmp.Width, bmp.Height)
    Dim bmpData As System.Drawing.Imaging.BitmapData = bmp.LockBits(rect, _
        Drawing.Imaging.ImageLockMode.ReadWrite, bmp.PixelFormat)

    ' Get the address of the first line.
    Dim ptr As IntPtr = bmpData.Scan0

    ' Declare an array to hold the bytes of the bitmap.
    ' This code is specific to a bitmap with 24 bits per pixels.
    Dim bytes As Integer = Math.Abs(bmpData.Stride) * bmp.Height
    Dim rgbValues(bytes - 1) As Byte

    ' Copy the RGB values into the array.
    System.Runtime.InteropServices.Marshal.Copy(ptr, rgbValues, 0, bytes)

    ' Set every third value to 255. A 24bpp image will look red.
    For counter As Integer = 2 To rgbValues.Length - 1 Step 3
        rgbValues(counter) = 255
    Next

    ' Copy the RGB values back to the bitmap
    System.Runtime.InteropServices.Marshal.Copy(rgbValues, 0, ptr, bytes)

    ' Unlock the bits.
    bmp.UnlockBits(bmpData)

    ' Draw the modified image.
    e.Graphics.DrawImage(bmp, 0, 150)

End Sub

備註

LockBits使用 方法來鎖定系統記憶體中的現有點陣圖，以便以程序設計方式加以變更。 您可以使用 方法來變更影像 SetPixel 的色彩，不過 LockBits 此方法可為大規模變更提供更佳的效能。

BitmapData指定的屬性Bitmap，例如大小、圖元格式、記憶體中像素數據的起始位址，以及每個掃描線的長度 () 。

呼叫此方法時，您應該使用列舉的成員 System.Drawing.Imaging.PixelFormat ，其中包含每個圖元的特定位 (BPP) 值。 使用 System.Drawing.Imaging.PixelFormat 與之類的IndexedGdi值會擲回 System.ArgumentException。 此外，傳遞點陣圖不正確的圖格式會擲回 System.ArgumentException。

來源:

Bitmap.cs

來源:

Bitmap.cs

來源:

Bitmap.cs

public:
 System::Drawing::Imaging::BitmapData ^ LockBits(System::Drawing::Rectangle rect, System::Drawing::Imaging::ImageLockMode flags, System::Drawing::Imaging::PixelFormat format, System::Drawing::Imaging::BitmapData ^ bitmapData);

public System.Drawing.Imaging.BitmapData LockBits (System.Drawing.Rectangle rect, System.Drawing.Imaging.ImageLockMode flags, System.Drawing.Imaging.PixelFormat format, System.Drawing.Imaging.BitmapData bitmapData);

member this.LockBits : System.Drawing.Rectangle * System.Drawing.Imaging.ImageLockMode * System.Drawing.Imaging.PixelFormat * System.Drawing.Imaging.BitmapData -> System.Drawing.Imaging.BitmapData

Public Function LockBits (rect As Rectangle, flags As ImageLockMode, format As PixelFormat, bitmapData As BitmapData) As BitmapData

參數

傳回

BitmapData，包含鎖定作業的相關資訊。

例外狀況

備註

LockBits使用 方法來鎖定系統記憶體中的現有點陣圖，以便以程序設計方式加以變更。 您可以使用 方法來變更影像 SetPixel 的色彩，不過 LockBits 此方法可為大規模變更提供更佳的效能。

呼叫此方法時，您應該使用列舉的成員 System.Drawing.Imaging.PixelFormat ，其中包含每個圖元的特定位 (BPP) 值。 使用 System.Drawing.Imaging.PixelFormat 與之類的IndexedGdi值會擲回 System.ArgumentException。 此外，傳遞點陣圖不正確的圖格式會擲回 System.ArgumentException。

這個版本的 LockBits 方法旨在與的值ImageLockMode.UserInputBuffer搭配flags使用。