Star Wars style text scroller






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Text scroller control with 3D-look (like in the intro of the Star Wars movies)
Introduction
You can find text scrollers in many programs, especially in their About dialogs. In most cases, it's a simple colored text that moves up. In this article, I attempted to create something unusual. I decided to write an "outgoing" text component, which looks like a 3D effect such as in the intro to the Star Wars movies.
GDI+ provides many easy-to-use objects and functions. Using these functions, you can do something special without much trouble. Before writing this component with the help of GDI+, I tried to create it with GDI. This required much more time and resulted in ten times more code. It seemed to be a hard task, but later I recreated this same component in GDI+. That was easy. After that, I decided to write this article to demonstrate some features of GDI+.
How we can do this
We can create this "outgoing" effect by transforming all points of text from rectangular to trapezoidal shape:
To animate our transformed text, we'll use an offset variable and timer. On the timer tick, we'll change this variable and repaint the control.
The code
The most useful code is situated in the Paint
event handler. First of all, we need to enable anti-aliasing for better quality:
e.Graphics.SmoothingMode = SmoothingMode.AntiAlias;
After that, we erase background to clean the previous frame:
e.Graphics.FillRectangle(new SolidBrush(this.BackColor),
this.ClientRectangle);
Then we create a GraphicsPath
object and fill it with visible lines of text depending on the offset:
GraphicsPath path = new GraphicsPath();
for (int i = m_text.Length - 1; i >= 0; i--)
{
Point pt = new Point((int)
((this.Width - e.Graphics.MeasureString(m_text[i],
this.Font).Width) / 2), (int)(m_scrollingOffset +
this.Height - (m_text.Length - i) * this.Font.Size));
// Adds visible lines to path.
if ((pt.Y + this.Font.Size > 0) && (pt.Y < this.Height))
path.AddString(m_text[i], new FontFamily("Arial"),
(int)FontStyle.Bold, this.Font.Size,
pt, StringFormat.GenericDefault);
}
After that, we transform our GraphicsPath
from rectangle to trapezoid:
path.Warp(new PointF[4]
{
new PointF(this.Width / 3, 0),
new PointF(this.Width * 2 / 3, 0),
new PointF(0, this.Height),
new PointF(this.Width, this.Height)
},
new RectangleF(this.ClientRectangle.X,
this.ClientRectangle.Y, this.ClientRectangle.Width,
this.ClientRectangle.Height),
null, WarpMode.Perspective);
The text is now ready. Next, we need to draw it and dispose of the GraphicsPath
object:
// Draws wrapped path.
e.Graphics.FillPath(new SolidBrush(this.ForeColor), path);
path.Dispose();
To make control more realistic, we can draw some "fog" using LinearGradientBrush
with transparent color:
// Draws fog effect with help of gradient brush with alpha colors.
using (Brush br = new LinearGradientBrush(new Point(0, 0),
new Point(0, this.Height),
Color.FromArgb(255, this.BackColor), Color.FromArgb(0,
this.BackColor)))
{
e.Graphics.FillRectangle(br, this.ClientRectangle);
}
Using the code
The Scroller
class represents an easy-to-use component with customizable font, background color, text color and, of course, text content. You can simply copy the Scroller
class to your project to use it. Also, you can create a separate class library for the Scroller
class.
Properties of the Scroller control
This control has the following properties:
TextToScroll
– this text will be separated into lines at the\n
symbolBackColor
– color of backgroundForeColor
– color of textInterval
- delay in milliseconds between frames for controlled scrolling speedTextFont
- font that is used to draw; units must be set toGraphicsUnit.Pixel
TopPartSizePercent
- top part size of text in percent of control width
Methods of the Scroller control
Start()
– starts the animation from the beginningStop()
– stops the animation
Points of interest
When I was creating this control, I noticed that the GraphicsPath
class can help you in situations where you need some specific transformation of graphics objects, including point transformations.
Disclaimer
You can use this code in any type of project, free or commercial. If you do, please add a link to this article in your code comments or the About dialog box.
Thanks for reading and thanks to all who have helped me improve this article.
History
- 9 July, 2007 - First updated version posted
- Fixed bug with text offset:
Font Units
is now set toGraphicsUnit.Pixel
- Added cycle scrolling feature
- Added
Interval
property - Added
TextFont
property - Added
TopPartSizePercent
property
- Fixed bug with text offset:
- 16 May, 2007 - Original version posted