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BeforeDrawingObjects Event

Summary

Occurs during drawing before the objects are drawn.

Syntax

C++

public event EventHandler<AnnPaintEventArgs> BeforeDrawingObjects

  
Public Event BeforeDrawingObjects As EventHandler(Of AnnPaintEventArgs)

public: 
event EventHandler<AnnPaintEventArgs^>^ BeforeDrawingObjects

Event Data

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.

Remarks

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

Example

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

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); 
   } 
}

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

Requirements

Target Platforms

Reference

AnnContainer Class

AnnContainer Members

Help Version 19.0.2017.10.27

Leadtools.Annotations Assembly

Introduction

Getting Started

Namespaces

Leadtools.Annotations Namespace

Assemblies