BitmapData.Scan0 Properti
Penting
Beberapa informasi terkait produk prarilis yang dapat diubah secara signifikan sebelum dirilis. Microsoft tidak memberikan jaminan, tersirat maupun tersurat, sehubungan dengan informasi yang diberikan di sini.
Mendapatkan atau mengatur alamat data piksel pertama di bitmap. Ini juga dapat dianggap sebagai baris pemindaian pertama di bitmap.
public:
property IntPtr Scan0 { IntPtr get(); void set(IntPtr value); };
public IntPtr Scan0 { get; set; }
member this.Scan0 : nativeint with get, set
Public Property Scan0 As IntPtr
nativeint
Alamat data piksel pertama dalam bitmap.
Contoh kode berikut menunjukkan cara menggunakan PixelFormatproperti , , Height, Widthdan Scan0 ; LockBits metode dan UnlockBits ; dan ImageLockMode enumerasi. Contoh ini dirancang untuk digunakan dengan Formulir Windows. Untuk menjalankan contoh ini, tempelkan ke dalam formulir dan tangani peristiwa Paint formulir dengan memanggil LockUnlockBitsExample
metode , meneruskannya e
sebagai PaintEventArgs.
Catatan
Contoh kode berikut dibuat untuk digunakan dengan gambar dengan Format24bppRgb format .
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
Produk | Versi |
---|---|
.NET Framework | 1.1, 2.0, 3.0, 3.5, 4.0, 4.5, 4.5.1, 4.5.2, 4.6, 4.6.1, 4.6.2, 4.7, 4.7.1, 4.7.2, 4.8, 4.8.1 |
Windows Desktop | 3.0, 3.1, 5, 6, 7, 8, 9 |
Umpan balik .NET
.NET adalah proyek sumber terbuka. Pilih tautan untuk memberikan umpan balik: