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OnPaintCrosshair Method

Summary

Occurs when the Magnifying Glass crosshair is redrawn.

Syntax

C++

protected virtual void OnPaintCrosshair( 
   Graphics graphics, 
   Point centerPoint 
)

  
Protected Overridable Sub OnPaintCrosshair( _ 
   ByVal graphics As Graphics, _ 
   ByVal centerPoint As Point _ 
)

protected: 
virtual void OnPaintCrosshair(  
   Graphics^ graphics, 
   Point centerPoint 
)

Parameters

graphics
The Graphics object used to paint.

centerPoint
The center point of the Magnifying Glass rectangle

Remarks

You can override this method in order to paint your own crosshair for the Magnifying Glass. Call the base class implementation for the default behavior.

Example

using Leadtools.WinForms; 
using Leadtools; 
using Leadtools.Codecs; 
using Leadtools.ImageProcessing.Color; 
using Leadtools.Drawing; 
 
class MyRasterMagnifyGlass : RasterMagnifyGlass 
{ 
   public MyRasterMagnifyGlass() 
   { 
      Shape = RasterMagnifyGlassShape.Border3D; 
   } 
 
   protected override void OnPaintBorder(Graphics graphics, Point centerPoint) 
   { 
      int width = (Size.Width - 2) / 2; 
      int height = (Size.Height - 2) / 2; 
 
      Rectangle rc = new Rectangle(centerPoint.X - width, centerPoint.Y - height, 2 * width, 2 * height); 
      graphics.DrawRectangle(Pens.Blue, rc); 
   } 
 
   protected override void OnPaintCrosshair(Graphics graphics, Point centerPoint) 
   { 
      int width = (Size.Width - 2) / 2; 
      int height = (Size.Height - 2) / 2; 
      Point p1 = new Point(centerPoint.X - width, centerPoint.Y - height); 
      Point p2 = new Point(centerPoint.X + width, centerPoint.Y + height); 
      graphics.DrawLine(Pens.Red, p1, p2); 
 
      p1 = new Point(centerPoint.X + width, centerPoint.Y - height); 
      p2 = new Point(centerPoint.X - width, centerPoint.Y + height); 
      graphics.DrawLine(Pens.Red, p1, p2); 
   } 
} 
 
private void viewer_MagnifyGlassChanged(object sender, EventArgs e) 
{ 
   MessageBox.Show("Custom Magnify Glass being used -- red X for crosshair, blue for border"); 
} 
 
public void RasterImageViewer_MagnifyGlass(RasterImageViewer viewer) 
{ 
   viewer.MagnifyGlassChanged += new EventHandler(viewer_MagnifyGlassChanged); 
   viewer.MagnifyGlass = new MyRasterMagnifyGlass(); 
   viewer.InteractiveMode = RasterViewerInteractiveMode.MagnifyGlass; 
 
   viewer.MagnifyGlassChanged -= new EventHandler(viewer_MagnifyGlassChanged); 
}

Imports Leadtools.WinForms 
Imports Leadtools 
Imports Leadtools.Codecs 
Imports Leadtools.ImageProcessing.Color 
Imports Leadtools.Drawing 
 
Private Class MyRasterMagnifyGlass : Inherits RasterMagnifyGlass 
   Public Sub New() 
      Shape = RasterMagnifyGlassShape.Border3D 
   End Sub 
 
   Protected Overrides Sub OnPaintBorder(ByVal graphics As Graphics, ByVal centerPoint As Point) 
      Dim width As Integer = (Size.Width - 2) \ 2 
      Dim height As Integer = (Size.Height - 2) \ 2 
 
      Dim rc As Rectangle = New Rectangle(centerPoint.X - width, centerPoint.Y - height, 2 * width, 2 * height) 
      graphics.DrawRectangle(Pens.Blue, rc) 
   End Sub 
 
   Protected Overrides Sub OnPaintCrosshair(ByVal graphics As Graphics, ByVal centerPoint As Point) 
      Dim width As Integer = (Size.Width - 2) \ 2 
      Dim height As Integer = (Size.Height - 2) \ 2 
      Dim p1 As Point = New Point(centerPoint.X - width, centerPoint.Y - height) 
      Dim p2 As Point = New Point(centerPoint.X + width, centerPoint.Y + height) 
      graphics.DrawLine(Pens.Red, p1, p2) 
 
      p1 = New Point(centerPoint.X + width, centerPoint.Y - height) 
      p2 = New Point(centerPoint.X - width, centerPoint.Y + height) 
      graphics.DrawLine(Pens.Red, p1, p2) 
   End Sub 
End Class 
 
Private Sub viewer_MagnifyGlassChanged(ByVal sender As Object, ByVal e As EventArgs) 
   MessageBox.Show("Custom Magnify Glass being used -- red X for crosshair, blue for border") 
End Sub 
 
Public Sub RasterImageViewer_MagnifyGlass(ByVal viewer As RasterImageViewer) 
   AddHandler viewer.MagnifyGlassChanged, AddressOf viewer_MagnifyGlassChanged 
   viewer.MagnifyGlass = New MyRasterMagnifyGlass() 
   viewer.InteractiveMode = RasterViewerInteractiveMode.MagnifyGlass 
 
   RemoveHandler viewer.MagnifyGlassChanged, AddressOf viewer_MagnifyGlassChanged 
End Sub

Requirements

Target Platforms

Reference

RasterMagnifyGlass Class

RasterMagnifyGlass Members

Help Version 19.0.2017.10.27

Leadtools.WinForms Assembly

Introduction

Getting Started

Namespaces

Leadtools.WinForms Namespace

Assemblies