using System;
using SystemDrawing;
using SystemCollections;
using SystemComponentModel;
using SystemWindowsForms;
using SystemData;
using SystemRuntimeInteropServices;
namespace RubberBands
{
/// <summary>
/// Summary description for Form
/// </summary>
public class RubberBandForm : SystemWindowsFormsForm
{
/// API Declarations
private struct POINTAPI {
public int x;
public int y;
}
[DllImport(gdiDLL)]
private static extern Int SetROP(IntPtr hDC
int nDrawMode);
[DllImport(gdidll)]
private static extern bool MoveToEx(IntPtr hDC
int x
int y
POINTAPI lpPoint);
[DllImport(gdidll)]
private static extern bool LineTo(IntPtr hDC
int x
int y);
[DllImport(gdidll)]
private static extern IntPtr CreatePen(int nPenStyle
int nWidth
int crColor);
[DllImport(gdidll)]
private static extern IntPtr SelectObject(IntPtr hDC
IntPtr hObject);
[DllImport(gdidll)]
private static extern bool DeleteObject(IntPtr hObject);
private const int R_NOT = ;
private const int R_XORPEN = ;
private const int PS_DOT = ;
/// <summary>
/// Required designer variable
/// </summary>
private SystemComponentModelContainer components = null;
private SystemDrawingGraphics m_oDrawingSurface;
private POINTAPI m_ptsStart = new POINTAPI();
private POINTAPI m_ptsPrevious;
public RubberBandForm()
{
//
// Required for Windows Form Designer support
//
InitializeComponent();
//Add any initialization after the InitializeComponent() call
m_oDrawingSurface = thisCreateGraphics();
}
/// <summary>
/// Clean up any resources being used
/// </summary>
protected override void Dispose( bool disposing )
{
if( disposing )
{
if (components != null)
{
componentsDispose();
}
}
baseDispose( disposing );
}
protected override void OnMouseDown(MouseEventArgs e) {
// Check whether the left mouse button
// has generated the associated event
if (eButton == MouseButtonsLeft) {
// Store the starting point for your rubberband line
m_ptsStartx = eX;
m_ptsStarty = eY;
// Store the previous end point for your rubberband line
m_ptsPrevious = m_ptsStart;
}
baseOnMouseDown (e);
}
protected override void OnMouseMove(MouseEventArgs e) {
// Check if the left mouse button is pressed
if( eButton == MouseButtonsLeft) {
// Declare local variables
// handle to an appropriate device context obtained
// from m_oDrawingSurface
IntPtr hDC;
// previous mix mode; returned from SetROP
Int Mix ;
// temporary variables used for rubberbanding logic
POINTAPI ptsCurrent;
POINTAPI ptsOld = new POINTAPI();
// determines whether MoveToEx and LineTo calls are successful
Boolean Success;
// Store the current end point of your rubberband line
ptsCurrentx = eX;
ptsCurrenty = eY;
// Perform the requisite graphical operations
// Obtain a handle to an appropriate device context
hDC = m_oDrawingSurfaceGetHdc();
// Set the raster mode to invert the screen color
Mix = SetROP(hDC R_NOT);
// Move to the starting point of the rubberband line
Success = MoveToEx(hDC m_ptsStartx m_ptsStarty ptsOld);
// Erase the previous line
Success = LineTo(hDC m_ptsPreviousx m_ptsPreviousy);
// Move to the starting point of the rubberband line
Success = MoveToEx(hDC m_ptsStartx m_ptsStarty ptsOld);
// Draw the new line
Success = LineTo(hDC ptsCurrentx ptsCurrenty);
// Release the obtained handle to a device context
m_oDrawingSurfaceReleaseHdc(hDC);
// Store the current end point for the next erase operation
m_ptsPrevious = ptsCurrent;
}
baseOnMouseMove (e);
}
#region Windows Form Designer generated code
/// <summary>
/// Required method for Designer support do not modify
/// the contents of this method with the code editor
/// </summary>
private void InitializeComponent()
{
//
// RubberBandForm
//
thisAutoScaleBaseSize = new SystemDrawingSize( );
thisBackColor = SystemDrawingSystemColorsWindow;
thisClientSize = new SystemDrawingSize( );
thisName = RubberBandForm;
thisText = Using Unmanaged APIs;
}
#endregion
/// <summary>
/// The main entry point for the application
/// </summary>
[STAThread]
static void Main()
{
ApplicationRun(new RubberBandForm());
}
}
}
