Take the following steps to start a project and to add some code
that draws lines and shapes on an image:
- Start Visual Studio .NET.
- Choose File->New->Project… from the menu.
- In the New Project dialog box, choose either "Visual C# Projects" or "Visual Basic Projects" in the Projects Type List, and choose "Windows Application " in the Templates List.
- Type the project name as "Drawing Simple Lines and Shapes" in the Project Name field, and then choose OK. If desired, type a new location for your project or select a directory using the Browse button, and then choose OK
- In the "Solution Explorer" window, right-click on the "References"
folder, and select "Add Reference…" from the context menu. In
the "Add Reference" dialog box, select the ".NET"
tab and browse to Leadtools For .NET "\LEAD Technologies\LEADTOOLS 15\Bin\DotNet\Win32
" folder and select the following DLLs:
- Leadtools.dll
- Leadtools.Codecs.dll
- Leadtools.WinForms.dll
- Make sure Form1 is in design view. Go to the toolbox (View->Toolbox) and Drag and drop an instance of RasterImageViewer to the form. If you do not have RasterImageViewer in your toolbox, select Tools->Add Remove Toolbox Items from the menu. Click Browse and then select Leadtools.WinForms.DLL from "C:\Program Files\LEAD Technologies\LEADTOOLS 15\Bin\DotNet\Win32" and then click Open and then click OK.
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Change the following properties:
Property Value Dock Fill -
Switch to Form1 code view (right-click Form1 in
the solution explorer then select View Code ) and add the
following lines at the beginning of the file:
[Visual Basic]
Imports System.Drawing.Drawing2D Imports Leadtools Imports Leadtools.Codecs Imports Leadtools.WinForms
[C#]
using System.Drawing.Drawing2D; using Leadtools; using Leadtools.Codecs; using Leadtools.WinForms;
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Add an event handler to the Form1 Load event and add the following code:
[Visual Basic]
' what shape we are drawing Private Enum ShapeType Line Rectangle Ellipse End Enum ' shape we are currently drawing Private shape As ShapeType ' start and end point for the line Private startCoords As Point Private endCoords As Point ' coordinate for the rectangle and the ellipse Private rectangleCoords As Rectangle ' are we currently drawing or not Private drawing As Boolean Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load ' Initialize the private varibles shape = ShapeType.Line drawing = False RasterCodecs.Startup() ' Load an image into the viewer Dim codecs As New RasterCodecs() rasterImageViewer1.Image = codecs.Load("C:\Program Files\LEAD Technologies\LEADTOOLS 15\Images\Image1.cmp") RasterCodecs.Shutdown() End Sub
[C#]
// what shape we are drawing private enum ShapeType { Line, Rectangle, Ellipse } // shape we are currently drawing ShapeType shape; // start and end point for the line private Point startCoords; private Point endCoords; // coordinate for the rectangle and the ellipse private Rectangle rectangleCoords; // are we currently drawing or not private bool drawing; private void Form1_Load(object sender, System.EventArgs e) { // Initialize the private varibles shape = ShapeType.Line; drawing = false; RasterCodecs.Startup(); // Load an image into the viewer RasterCodecs codecs = new RasterCodecs(); rasterImageViewer1.Image = codecs.Load(@"C:\Program Files\LEAD Technologies\LEADTOOLS 15\Images\Image1.cmp"); RasterCodecs.Shutdown(); }
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Add the following code to the Raster Image Viewer MouseDown event:
[Visual Basic]
Private Sub RasterImageViewer1_MouseDown(ByVal sender As Object, ByVal e As System.Windows.Forms.MouseEventArgs) Handles RasterImageViewer1.MouseDown ' check if we are already drawing, if so cancel it If (drawing) Then ' erase the shape DrawShape() drawing = False Else ' based on shape, initialize the coordinates Select Case (shape) Case ShapeType.Line ' drawing a line startCoords = New Point(e.X, e.Y) endCoords = startCoords Case ShapeType.Rectangle Case ShapeType.Ellipse ' drawing a rectangle or an ellipse rectangleCoords = New Rectangle(e.X, e.Y, 0, 0) End Select ' draw the shape drawing = True DrawShape() End If End Sub
[C#]
private void rasterImageViewer1_MouseDown(object sender, System.Windows.Forms.MouseEventArgs e) { // check if we are already drawing, if so cancel it if(drawing) { // erase the shape DrawShape(); drawing = false; } else { // based on shape, initialize the coordinates switch(shape) { case ShapeType.Line: // drawing a line startCoords = new Point(e.X, e.Y); endCoords = startCoords; break; case ShapeType.Rectangle: case ShapeType.Ellipse: // drawing a rectangle or an ellipse rectangleCoords = new Rectangle(e.X, e.Y, 0, 0); break; } // draw the shape drawing = true; DrawShape(); } }
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Add the following code to the Raster Image Viewer MouseMove event:
[Visual Basic]
Private Sub RasterImageViewer1_MouseMove(ByVal sender As Object, ByVal e As System.Windows.Forms.MouseEventArgs) Handles RasterImageViewer1.MouseMove If (drawing) Then ' first, erase the shape DrawShape() ' get new coords for the shape Select Case (shape) Case ShapeType.Line endCoords = New Point(e.X, e.Y) Case ShapeType.Rectangle, ShapeType.Ellipse rectangleCoords = Rectangle.FromLTRB(rectangleCoords.Left, rectangleCoords.Top, e.X, e.Y) End Select ' draw the shape again DrawShape() End If End Sub
[C#]
private void rasterImageViewer1_MouseMove(object sender, System.Windows.Forms.MouseEventArgs e) { if(drawing) { // first, erase the shape DrawShape(); // get new coords for the shape switch(shape) { case ShapeType.Line: endCoords = new Point(e.X, e.Y); break; case ShapeType.Rectangle: case ShapeType.Ellipse: rectangleCoords = Rectangle.FromLTRB(rectangleCoords.Left, rectangleCoords.Top, e.X, e.Y); break; } // draw the shape again DrawShape(); } }
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Add the following code to the Raster Image Viewer MouseUp event:
[Visual Basic]
Private Sub RasterImageViewer1_MouseUp(ByVal sender As Object, ByVal e As System.Windows.Forms.MouseEventArgs) Handles RasterImageViewer1.MouseUp If (drawing) Then ' erase the shape DrawShape() drawing = False ' draw the shape on the image Select Case (shape) Case ShapeType.Line If (startCoords.X <> endCoords.X OrElse startCoords.Y <> endCoords.Y) Then ' convert the points to image coordinates Dim t As New Transformer(RasterImageViewer1.Transform) startCoords = Point.Round(t.PointToLogical(New PointF(startCoords.X, startCoords.Y))) endCoords = Point.Round(t.PointToLogical(New PointF(endCoords.X, endCoords.Y))) startCoords = RasterImageViewer1.Image.PointToImage(RasterViewPerspective.TopLeft, startCoords) endCoords = RasterImageViewer1.Image.PointToImage(RasterViewPerspective.TopLeft, endCoords) ' create the graphics container for the image and draw the line Dim container As RasterImageGdiPlusGraphicsContainer = RasterImageViewer1.Image.CreateGdiPlusGraphics() Try Dim pen As New Pen(Color.Yellow, 2) Try ' use anti-alias lines container.Graphics.SmoothingMode = SmoothingMode.AntiAlias container.Graphics.DrawLine(pen, startCoords, endCoords) ' draw a rectangle next shape = ShapeType.Rectangle Finally pen.Dispose() End Try Finally container.Dispose() End Try RasterImageViewer1.Invalidate() End If case ShapeType.Rectangle, ShapeType.Ellipse: ' "fix" the rectangle so it does not have a negative width or height rectangleCoords = FixRectangle(rectangleCoords) If (Not rectangleCoords.IsEmpty) Then ' convert the rectangle to image coordinates Dim t As New Transformer(RasterImageViewer1.Transform) rectangleCoords = Rectangle.Round(t.RectangleToLogical(New RectangleF(rectangleCoords.Left, rectangleCoords.Top, rectangleCoords.Width, rectangleCoords.Height))) rectangleCoords = RasterImageViewer1.Image.RectangleToImage(RasterViewPerspective.TopLeft, rectangleCoords) ' create the graphics container for the image and draw the rectangle or ellipse Dim container As RasterImageGdiPlusGraphicsContainer = RasterImageViewer1.Image.CreateGdiPlusGraphics() Try Dim pen As New Pen(Color.Yellow, 2) Try ' use anti-alias lines container.Graphics.SmoothingMode = SmoothingMode.AntiAlias If (shape = ShapeType.Rectangle) Then container.Graphics.DrawRectangle(pen, rectangleCoords) ' draw an ellipse next shape = ShapeType.Ellipse Else container.Graphics.DrawEllipse(pen, rectangleCoords) ' draw a line next shape = ShapeType.Line End If Finally pen.Dispose() End Try Finally container.Dispose() End Try RasterImageViewer1.Invalidate() End If End Select End If End Sub
[C#]
private void rasterImageViewer1_MouseUp(object sender, System.Windows.Forms.MouseEventArgs e) { if(drawing) { // erase the shape DrawShape(); drawing = false; // draw the shape on the image switch(shape) { case ShapeType.Line: if(startCoords.X != endCoords.X || startCoords.Y != endCoords.Y) { // convert the points to image coordinates Transformer t = new Transformer(rasterImageViewer1.Transform); startCoords = Point.Round(t.PointToLogical(startCoords)); endCoords = Point.Round(t.PointToLogical(endCoords)); startCoords = rasterImageViewer1.Image.PointToImage(RasterViewPerspective.TopLeft, startCoords); endCoords = rasterImageViewer1.Image.PointToImage(RasterViewPerspective.TopLeft, endCoords); // create the graphics container for the image and draw the line using(RasterImageGdiPlusGraphicsContainer container = rasterImageViewer1.Image.CreateGdiPlusGraphics()) { using(Pen pen = new Pen(Color.Yellow, 2)) { // use anti-alias lines container.Graphics.SmoothingMode = SmoothingMode.AntiAlias; container.Graphics.DrawLine(pen, startCoords, endCoords); // draw a rectangle next shape = ShapeType.Rectangle; } } rasterImageViewer1.Invalidate(); } break; case ShapeType.Rectangle: case ShapeType.Ellipse: // "fix" the rectangle so it does not have a negative width or height rectangleCoords = FixRectangle(rectangleCoords); if(!rectangleCoords.IsEmpty) { // convert the rectangle to image coordinates Transformer t = new Transformer(rasterImageViewer1.Transform); rectangleCoords = Rectangle.Round(t.RectangleToLogical(rectangleCoords)); rectangleCoords = rasterImageViewer1.Image.RectangleToImage(RasterViewPerspective.TopLeft, rectangleCoords); // create the graphics container for the image and draw the rectangle or ellipse using(RasterImageGdiPlusGraphicsContainer container = rasterImageViewer1.Image.CreateGdiPlusGraphics()) { using(Pen pen = new Pen(Color.Yellow, 2)) { // use anti-alias lines container.Graphics.SmoothingMode = SmoothingMode.AntiAlias; if(shape == ShapeType.Rectangle) { container.Graphics.DrawRectangle(pen, rectangleCoords); // draw an ellipse next shape = ShapeType.Ellipse; } else { container.Graphics.DrawEllipse(pen, rectangleCoords); // draw a line next shape = ShapeType.Line; } } } rasterImageViewer1.Invalidate(); } break; } } }
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Add the following method to Form1 Class:
[Visual Basic]
Private Sub DrawShape() ' draw the shape on screen (reversible) Select Case (shape) Case ShapeType.Line ControlPaint.DrawReversibleLine(RasterImageViewer1.PointToScreen(startCoords), RasterImageViewer1.PointToScreen(endCoords), Color.Transparent) Case ShapeType.Rectangle, ShapeType.Ellipse ' "fix" the rectangle so it does not have a negative width or height Dim rc As Rectangle = FixRectangle(rectangleCoords) ControlPaint.DrawReversibleFrame(RasterImageViewer1.RectangleToScreen(rc), Color.Transparent, FrameStyle.Thick) End Select End Sub Shared Function FixRectangle(ByVal rc As Rectangle) As Rectangle If (rc.Left > rc.Right OrElse rc.Top > rc.Bottom) Then Return Rectangle.FromLTRB( _ Math.Min(rc.Left, rc.Right), _ Math.Min(rc.Top, rc.Bottom), _ Math.Max(rc.Left, rc.Right), _ Math.Max(rc.Top, rc.Bottom)) Else Return rc End If End Function
[C#]
private void DrawShape() { // draw the shape on screen (reversible) switch(shape) { case ShapeType.Line: ControlPaint.DrawReversibleLine(rasterImageViewer1.PointToScreen(startCoords), rasterImageViewer1.PointToScreen(endCoords), Color.Transparent); break; case ShapeType.Rectangle: case ShapeType.Ellipse: // "fix" the rectangle so it does not have a negative width or height Rectangle rc = FixRectangle(rectangleCoords); ControlPaint.DrawReversibleFrame(rasterImageViewer1.RectangleToScreen(rc), Color.Transparent, FrameStyle.Thick); break; } } static Rectangle FixRectangle(Rectangle rc) { if(rc.Left > rc.Right || rc.Top > rc.Bottom) return Rectangle.FromLTRB( Math.Min(rc.Left, rc.Right), Math.Min(rc.Top, rc.Bottom), Math.Max(rc.Left, rc.Right), Math.Max(rc.Top, rc.Bottom)); else return rc; }
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If you create a C# project you need to do the following:
- Select the form1.
- Click "Shift + F7", Or right-click and select "View Designer", Or click in the "View Designer" button in the top of the solution explorer window.
- Click in the "rasterImageViewer1" from the form.
- In the properties window click on the "Events" button.
- Click on the "Categorized" button to sort the events by category.
- Goto the mouse category. • Select the "rasterImageViewer1_MouseDown" to the "MouseDown" event.
- Select the "rasterImageViewer1_MouseMove" to the "MouseMove" event.
- Select the "rasterImageViewer1_MouseUp" to the "MouseUp" event.
- Build, and Run the program to test it.