Scrolling Credits Control

• Download source files VS 2005 Beta 2 - 25.3 Kb
• Download source files VS 2003 - 13.6 Kb

Introduction

This is my first submission to CodeProject as I've been keeping all my good controls to myself for years. I've had a change of heart recently and thought I should share my code.

I recently saw a Scrolling Box control on CodeProject and I thought I could improve on its performance, so here's my rendition of it.

Using the code

You can set the alignment of the scrolling text / images to Near/Center/Far. Padding can be applied on the left and right of the control (top and bottom not used).

Adding text or images is via the Items property by creating a new ScrollingBoxText or ScrollingBoxImage which inherits from the ScrollingBoxItem.

scrollingBox1.Alignment = StringAlignment.Center;
scrollingBox1.Padding = new Padding(10, 10, 0, 0);

scrollingBox1.Items.Add(new 
  ScrollingBox.ScrollingBoxText("Hello this is a test"));
scrollingBox1.Items.Add(new 
  ScrollingBox.ScrollingBoxText("Hello this also is a test"));
scrollingBox1.Items.Add(new 
  ScrollingBox.ScrollingBoxImage(Image.FromFile("C:\\image.gif")));
scrollingBox1.Items.Add(new 
  ScrollingBox.ScrollingBoxText("Try having a long string to test wrapping"));
scrollingBox1.Items.Add(new 
  ScrollingBox.ScrollingBoxText("You can use new line switch\nHello"));

The added extra on this control is the ability to scroll backwards or push forward with the mouse, although slightly clumsy in use.

You can also change the font, background color or even have a background image.

Points of Interest

First off, I have written this in Visual Studio 2005 Beta 2, and I guess I'm gonna get a low ranking and a serious flaming because of this. Well, downgrading to a lower version is pretty simple, so if you need an earlier version, post a comment and I'll have to convert it.

Because this control will be constantly updating on the interface we have to reduce flicker to a minimum. I do this in three ways.

1. Ensure I set the correct styles for the control.

   SetStyle(ControlStyles.UserPaint
       | ControlStyles.OptimizedDoubleBuffer
       | ControlStyles.AllPaintingInWmPaint, true);
       //ControlStyles.DoubleBuffer if not using .NET v2.0

2. Only update the area of the control that needs to be updated, by using clipping (I've not actually done this in this control) and checking where the control needs to be updated.

   if (clipRectF.IntersectsWith(item.rectF))

3. Write the bare minimum amount of code in the OnPaint function that is needed to complete the job, ensuring that all calculations are done else where.

Known Issues

• The mouse is not really in control of the up and down movements, I just call the function that calculates the text / images when the mouse moves.
• No design support for adding text or images.

History

• Uploaded as Visual Studio 2005 Beta 2 solution - 15 June 2005.
• Uploaded as Visual Studio 2003 solution - 21 June 2005.