Control study-> enlarge the image area when the mouse moves over the image

(1). Description

Point the cursor to an area of an image. This area is enlarged to make it clearer.
Class: Graphics implementation.

(2). Image example

(3 ).Code

Using system;
Using system. drawing;
Using system. collections;
Using system. componentmodel;
Using system. Windows. forms;
Using system. Data;
Using system. Drawing. drawing2d;

Resize the image area using namespace
{
/// <Summary>
/// Summary of form1.
/// </Summary>
Public class form1: system. Windows. Forms. Form
{
Private system. Windows. Forms. picturebox picturebox1;
/// <Summary>
/// Required designer variables.
/// </Summary>
Private system. componentmodel. Container components = NULL;
Private system. Windows. Forms. Button button1;
// Private cursor mycursor;
Cursor mycursor = new cursor ("... // .. // magnify. cur"); // custom mouse
Graphics g;
Image myimage;

Public form1 ()
{
//
// Required for Windows Form Designer support
//
Initializecomponent ();

//
// Todo: add Any constructor code after initializecomponent calls
//
}

/// <Summary>
/// Clear all resources in use.
/// </Summary>
Protected override void dispose (bool disposing)
{
If (disposing)
{
If (components! = NULL)
{
Components. Dispose ();
}
}
Base. Dispose (disposing );
}

# Region code generated by Windows Form Designer
/// <Summary>
/// The designer supports the required methods-do not use the code editor to modify
/// Content of this method.
/// </Summary>
Private void initializecomponent ()
{
System. Resources. ResourceManager resources = new system. Resources. ResourceManager (typeof (form1 ));
This. picturebox1 = new system. Windows. Forms. picturebox ();
This. button1 = new system. Windows. Forms. Button ();
This. suspendlayout ();
//
// Picturebox1
//
This. picturebox1.backcolor = system. Drawing. systemcolors. controltext;
This. picturebox1.image = (system. Drawing. Image) (resources. GetObject ("picturebox1.image ")));
This. picturebox1.location = new system. Drawing. Point (24, 16 );
This. picturebox1.name = "picturebox1 ";
This. picturebox1.size = new system. Drawing. Size (440,384 );
This. picturebox1.tabindex = 0;
This. picturebox1.tabstop = false;
This. picturebox1.mousemove + = new system. Windows. Forms. mouseeventhandler (this. picturebox#mousemove );
//
// Button1
//
This. button1.location = new system. Drawing. Point (384, 96 );
This. button1.name = "button1 ";
This. button1.tabindex = 1;
This. button1.text = "button1 ";
This. button1.click + = new system. eventhandler (this. button#click );
//
// Form1
//
This. autoscalebasesize = new system. Drawing. Size (6, 14 );
This. backcolor = system. Drawing. systemcolors. inactivecaptiontext;
This. clientsize = new system. Drawing. Size (472,406 );
This. Controls. Add (this. button1 );
This. Controls. Add (this. picturebox1 );
This. Name = "form1 ";
This. Text = "form1 ";
This. Load + = new system. eventhandler (this. form#load );
This. mousemove + = new system. Windows. Forms. mouseeventhandler (this. form1_mousemove );
This. resumelayout (false );

}
# Endregion

/// <Summary>
/// ApplicationProgram.
/// </Summary>
[Stathread]
Static void main ()
{
Application. Run (New form1 ());
}

Private void picturebox#mousemove (Object sender, system. Windows. Forms. mouseeventargs E)
{
Cursor. Current = mycursor;
Rectangle sourcerectangle = new rectangle (E. X-10, E. Y-10, 20, 20); // area to zoom in
// Rectangle destrectangle = new rectangle (E. X-20, E. Y-20, 40, 40 );
Rectangle destrectangle = new rectangle (picturebox1.width-150, picturebox1.height-150, picturebox1.width, picturebox1.height); // zoom in ratio
G. drawimage (myimage, destrectangle, sourcerectangle, graphicsunit. pixel );
}

Private void form=mousemove (Object sender, system. Windows. Forms. mouseeventargs E)
{
Cursor. Current = cursors. default;
}

Private void form1_load (Object sender, system. eventargs E)
{
G = This. picturebox1.creategraphics ();

Myimage = This. picturebox1.image;
}

Private void button#click (Object sender, system. eventargs E)
{
// Graphics G = This. picturebox1.creategraphics ();
Graphics G = picturebox1.creategraphics ();
G. drawline (new pen (color. Red, 5), 20, 20, 50, 50 );
}
}
}

(4). Sample download

Http://www.cnblogs.com/files/chengking/magnification .rar