|
|
|
|
|
Home
»
VB.NET
»
Viewing multiple Images in GDI+ and VB.NET
|
|
|
|
Author Rank :
|
|
|
Page Views :
|
29479
|
|
Downloads :
|
613
|
|
Rating :
|
Rate it
|
|
Level :
|
Beginner
|
|
|
|
|
Download
Files:
|
|
|
|
|
|
|
|
|
|
|
I'm writing this article in response to a question on discussion forums, How do I view multiple images on top of each other? Basically the guy has two images. One is a large image and second image is a small image and he wants to view small image on top of the large one. Even though I answered it on the forums and I knew that this is the answer, but I thought to test it by myself.
I also thought, It would be nice if I've some kind of counter so I can set the transparency of the small image to see through it. In case some body ask this question again.
Any way, this is what application looks like. As you can see from Figure 1, I've one track bar control, which sets the transparency of small image.
Figure 1.
I add a trackBar control to the form. Make sure its Maximum and minimum properties are 10 and 0 respectively. See Figure 2.
Now I write the trackBar control scroll event so when you scroll the track bar, it should manage the transparency of the image. I forgot to tell you that I defined a float type variable in the biggining of the project.
Dim tpVal As Single = 1.0F
Now I convert the value of trackbar control to a floating value so I can use in the ColorMatrix to set the color of the image. See Drawing Transparent Images and Shapes Using Alpha Blending for more on how to draw transparent graphics objects in GDI+.
Private Sub trackBar1_Scroll(ByVal sender As Object, ByVal e As System.EventArgs)
tpVal = CSng(trackBar1.Value) / 10
Me.Invalidate()
End Sub 'trackBar1_Scroll
In the end, I view both images on the form's paint event as you can see from the following code.
Private Sub Form1_Paint(ByVal sender As Object, ByVal e As System.Windows.Forms.PaintEventArgs)
Dim curImage As Image = Image.FromFile("roses.jpg")
e.Graphics.DrawImage(curImage, AutoScrollPosition.X, AutoScrollPosition.Y, curImage.Width, curImage.Height)
Dim ptsArray As Single()() = {New Single() {1, 0, 0, 0, 0}, New Single() {0, 1, 0, 0, 0}, New Single() {0, 0, 1, 0, 0}, New Single() {0, 0, 0, tpVal, 0}, New Single() {0, 0, 0, 0, 1}}
Dim clrMatrix As New ColorMatrix(ptsArray)
Dim imgAttributes As New ImageAttributes
imgAttributes.SetColorMatrix(clrMatrix, ColorMatrixFlag.Default, ColorAdjustType.Bitmap)
Dim smallImage As Image = Image.FromFile("smallRoses.gif")
e.Graphics.DrawImage(smallImage, New Rectangle(100, 100, 100, 100), 0, 0, smallImage.Width, smallImage.Height, GraphicsUnit.Pixel, imgAttributes)
End Sub 'Form1_Paint
Wonder where ColorMatrix, ImageAttributes and other code came from? See Drawing Transparent Images and Shapes Using Alpha Blending for the answer.
|
|
Comment Request!
Thank you for reading this post. Please post your feedback, question, or comments about this post
Here.
|
|
|
|
|
Login
to add your contents and source code to this article
|
|
|
|
|
|
|
|
|
|
|
|
Mahesh Chand
Mahesh is the founder of C# Corner and Mindcracker Network, an author of several .NET programming books and a Microsoft MVP for 6 consecutive years. In his day to day work, Mahesh is a Senior Software Consultant with over 14 years of IT industry experience building systems for Financial and Banking, Engineering & Architectural, Imaging, Construction, Biological & Pharmaceuticals, Healthcare and Education industries. His expertise is Windows Forms, ASP.NET, Silverlight, WPF, WCF, Visual Studio 2010, SQL Server, and Oracle. If you are looking for a Sharepoint, Windows Forms, ASP.NET, WPF, Silverlight, C#, VB.NET, Oracle, and SQL Server Consultant in Philadelphia area or remote location, drop me a line at MAHESH [AT] C-SHARPCORNER [DOT] COM.
|
|
|
|
|
|
|
|
|
C# Consulting is founded in 2002 by the founders of C# Corner. Unlike a traditional
consulting company, our consultants are well-known experts in .NET and many of them
are MVPs, authors, and trainers. We specialize in Microsoft .NET development and
utilize Agile Development and Extreme Programming practices to provide fast pace
quick turnaround results. Our software development model is a mix of Agile Development,
traditional SDLC, and Waterfall models.
|
|
Click here to learn more about C# Consulting. |
|
|
|
|
|
|
|
Introducing MaxV - one click. infinite control. Hyper-V Hosting from MaximumASP.
Finally – a virtual platform that delivers next-generation Windows Server 2008 Hyper-V virtualization technology from a managed hosting partner you can truly depend on. Visit www.maximumasp.com/max for a FREE 30 day trial. Hurry offer ends soon.
Climb aboard the MaxV platform and take advantage of High Availability, Intelligent Monitoring, Recurrent Backups, and Scalability – with no hassle or hidden fees.
As a managed hosting partner focused solely on Microsoft technologies since 2000, MaximumASP is uniquely qualified to provide the superior support that our business is built on. Unparalleled expertise with Microsoft technologies lead to working directly with Microsoft as first to offer IIS 7 and SQL 2008 betas in a hosted environment; partnering in the Go Live Program for Hyper-V; and product co-launches built on WS 2008 with Hyper-V technology.
|
Dynamic PDF
ceTE software specializes in components for dynamic PDF generation and manipulation. The DynamicPDF™ product line allows you to dynamically generate PDF documents, merge PDF documents and new content to existing PDF documents from within your applications.
|
Nevron Chart for .NET 2010.1 Now Available
The leading .NET charting control now features PDF, Flash and Silverlight export, visualization of large datasets and more. Deliver true charting functionality to your BI, Scorecard, Presentation or Scientific apps. Download evaluation now.
|
ASP.NET 4 Hosting
Get 2 Months Free of ASP.NET Hosting for Only $4.95/month! Receive FREE MS SQL and MySQL Databases Including ASP.NET 4/3.5, MVC 3.0, Silverlight 4, Windows 2008/IIS 7.0 Plus FREE IIS 7 Modules. Host UNLIMITED ASP.NET Web Sites – Click Here!
|
|
|
|
|
|
|
|
|
|
|
|
|