Demonstrates image manipulation using the [!INCLUDEwinsdklong].

The following topics demonstrate the use of the xref:System.Drawing.Image?displayProperty=fullName class to perform image manipulation.

The following code example modifies the OnPaint event handler to retrieve a pointer to the xref:System.Drawing.Graphics object for the main form. The xref:System.Windows.Forms.Form.OnPaint%2A function is intended for a Windows Forms application, most likely created with a Visual Studio application wizard.

The image is represented by the xref:System.Drawing.Image class. The image data is loaded from a .jpg file using the xref:System.Drawing.Image.FromFile%2A?displayProperty=fullName method. Before the image is drawn to the form, the form is resized to accommodate the image. The drawing of the image is performed with the xref:System.Drawing.Graphics.DrawImage%2A?displayProperty=fullName method.

The xref:System.Drawing.Graphics and xref:System.Drawing.Image classes are both in the xref:System.Drawing?displayProperty=fullName namespace.

#using <system.drawing.dll>  
  
using namespace System;  
using namespace System::Drawing;  
  
protected:  
virtual Void Form1::OnPaint(PaintEventArgs^ pe) override  
{  
    Graphics^ g = pe->Graphics;  
    Image^ image = Image::FromFile("SampleImage.jpg");  
    Form::ClientSize = image->Size;  
    g->DrawImage( image, 0, 0, image->Size.Width, image->Size.Height );  
}  

The following code example uses the xref:System.Drawing.Graphics class to modify the xref:System.Windows.Forms.Form.OnPaint%2A event handler to retrieve a pointer to the xref:System.Drawing.Graphics object for the main form. This pointer is then used to set the background color of the form and draw a line and an arc using the xref:System.Drawing.Graphics.DrawLine%2A?displayProperty=fullName and xref:System.Drawing.Graphics.DrawArc%2A methods.

#using <system.drawing.dll>  
using namespace System;  
using namespace System::Drawing;  
// ...  
protected:   
virtual Void Form1::OnPaint(PaintEventArgs^ pe ) override  
{  
   Graphics^ g = pe->Graphics;  
   g->Clear(Color::AntiqueWhite);  
  
   Rectangle rect = Form::ClientRectangle;  
   Rectangle smallRect;  
   smallRect.X = rect.X + rect.Width / 4;  
   smallRect.Y = rect.Y + rect.Height / 4;  
   smallRect.Width = rect.Width / 2;  
   smallRect.Height = rect.Height / 2;  
  
   Pen^ redPen = gcnew Pen(Color::Red);  
   redPen->Width = 4;  
   g->DrawLine(redPen, 0, 0, rect.Width, rect.Height);  
  
   Pen^ bluePen = gcnew Pen(Color::Blue);  
   bluePen->Width = 10;  
   g->DrawArc( bluePen, smallRect, 90, 270 );  
}  

The following code example demonstrates the use of the xref:System.Drawing.Image?displayProperty=fullName class to load an image from disk, rotate it 90 degrees, and save it as a new .jpg file.

#using <system.drawing.dll>  
  
using namespace System;  
using namespace System::Drawing;  
  
int main()  
{  
   Image^ image = Image::FromFile("SampleImage.jpg");  
   image->RotateFlip( RotateFlipType::Rotate90FlipNone );  
   image->Save("SampleImage_rotated.jpg");  
   return 0;  
}  

The following code example demonstrates the xref:System.Drawing.Image?displayProperty=fullName class and the xref:System.Drawing.Imaging.ImageFormat?displayProperty=fullName enumeration used to convert and save image files. The following code loads an image from a .jpg file and then saves it in both .gif and .bmp file formats.

#using <system.drawing.dll>  
  
using namespace System;  
using namespace System::Drawing;  
using namespace System::Drawing::Imaging;  
  
int main()  
{  
   Image^ image = Image::FromFile("SampleImage.jpg");  
   image->Save("SampleImage.png", ImageFormat::Png);  
   image->Save("SampleImage.bmp", ImageFormat::Bmp);  
  
   return 0;  
}  

Getting Started with Graphics Programming

About GDI+ Managed Code

.NET Programming with C++/CLI (Visual C++)

xref:System.Drawing