BeforeDrawingObjects Event

C#
Visual Basic
Objective-C
Java
C++

public event EventHandler<AnnPaintEventArgs> BeforeDrawingObjects

'Declaration
 
Public Event BeforeDrawingObjects As EventHandler(Of AnnPaintEventArgs)

'Usage
 
Dim instance As AnnContainer
Dim handler As EventHandler(Of AnnPaintEventArgs)
 
AddHandler instance.BeforeDrawingObjects, handler

public:
event EventHandler<AnnPaintEventArgs^>^ BeforeDrawingObjects

The event handler receives an argument of type AnnPaintEventArgs containing data related to this event. The following AnnPaintEventArgs properties provide information specific to this event.

Property	Description
Graphics	Gets the graphics used to paint.

You can prevent the AnnContainer from raising this event by calling DisableDrawObjectEvents. You can re-enable the raising of this event by calling EnableDrawObjectEvents.

This example will draw a grid 100 pixels apart on the surface of the viewer before the container is drawn.

C#
Visual Basic
WinRT C#
WinRT JavaScript
Silverlight C#
Silverlight VB

Copy Code

Imports Leadtools
Imports Leadtools.Annotations
Imports Leadtools.Codecs
Imports Leadtools.WinForms

Public theContainer As AnnContainer
Public Sub AnnContainer_BeforeDrawingObjects(ByVal container As AnnContainer)
   ' theContainer is set so that it can be accessed in the container_BeforeDrawingObjects event
   theContainer = container
   AddHandler container.BeforeDrawingObjects, AddressOf container_BeforeDrawingObjects
End Sub
Private Sub container_BeforeDrawingObjects(ByVal sender As Object, ByVal e As AnnPaintEventArgs)
   ' draw a grid, 100 pixels apart

   Dim graphics As Graphics = e.Graphics

   ' set the current transform from the container
   graphics.MultiplyTransform(theContainer.Transform)

   ' get the bounds in pixels
   Dim rc As AnnRectangle = theContainer.Bounds.ConvertTo(theContainer.UnitConverter, AnnUnit.Pixel)

   Dim p As Pen = New Pen(Color.FromArgb(128, 255, 255, 255))
   Try
      ' draw the grid
      Dim x As Single = rc.Left
      Do While x <= rc.Right
         graphics.DrawLine(p, x, 0, x, rc.Bottom)
         x += 100
      Loop

      Dim y As Single = rc.Top
      Do While y <= rc.Bottom
         graphics.DrawLine(p, 0, y, rc.Right, y)
         y += 100
      Loop
   Finally
      CType(p, IDisposable).Dispose()
   End Try
End Sub

using Leadtools;
using Leadtools.Annotations;
using Leadtools.Codecs;
using Leadtools.WinForms;

public AnnContainer theContainer;
public void AnnContainer_BeforeDrawingObjects(AnnContainer container)
{
   // theContainer is set so that it can be accessed in the container_BeforeDrawingObjects event
   theContainer = container;
   container.BeforeDrawingObjects += new EventHandler<AnnPaintEventArgs>(container_BeforeDrawingObjects);
}
private void container_BeforeDrawingObjects(object sender, AnnPaintEventArgs e)
{
   // draw a grid, 100 pixels apart

   Graphics graphics = e.Graphics;

   // set the current transform from the container
   graphics.MultiplyTransform(theContainer.Transform);

   // get the bounds in pixels
   AnnRectangle rc = theContainer.Bounds.ConvertTo(theContainer.UnitConverter, AnnUnit.Pixel);

   using (Pen p = new Pen(Color.FromArgb(128, 255, 255, 255)))
   {
      // draw the grid
      for (float x = rc.Left; x <= rc.Right; x += 100)
         graphics.DrawLine(p, x, 0, x, rc.Bottom);

      for (float y = rc.Top; y <= rc.Bottom; y += 100)
         graphics.DrawLine(p, 0, y, rc.Right, y);
   }
}

Target Platforms

Reference

AnnContainer Class
AnnContainer Members