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Posted 6 Oct 2006


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Fuzzy DropShadows in GDI+

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4.53/5 (34 votes)
6 Oct 2006CPOL2 min read
Creating fuzzy drop shadows for GDI+ drawn objects.

Sample Image - FuzzyShadows.jpg


I develop a flow charting software for the company I work for and I am always looking for a way to spruce up the application. After getting the nitty gritty down in the application, I turned to the little stuff that users will look at or use and think, awe that's nice. So when it came down to the look of the flow charting object, I wanted a drop shadow to show some depth to the drawing canvas. I searched around and everything that I found on the internet was using an image and skewing or stretching it and drawing it under the object to give it a shadow. So I started drawing the shadow for the object with a transparent color, but there was the problem. It looked ok but the edges were way too sharp, that's when I came up with this solution. Hope you like it and use it - Larry


Here, I am going to show you a method that I found for making Drop Shadows for GDI+ drawn Shapes that have fuzzy edges. First, we need to set the distance that the shadow should be drawn from the shape. In this example I use a NumericUpDown control so that we can change this distance and see what distance looks best.

// set the shadow distance
// since we are going back and up minus the value from zero
// this will put the shadow down and to the right of the Shape
_ShadowDistance = 0f - (float)nmDistance.Value;
// force a redraw of the canvas

Now that we have setup the distance let's get to the drawing. Here, I will not go over what was done to draw the object, only the shadow. So at this point, we have a GraphicsPath() that has been created to draw our rounded rectangle. So now, we need to create the drop shadow and this is how it's done.

// this is where we create the shadow effect, so we will use a 
// pathgradientbursh and assign our GraphicsPath that we created of a 
// Rounded Rectangle
using(PathGradientBrush _Brush = new PathGradientBrush(_Path))
   // set the wrapmode so that the colors will layer themselves
   // from the outer edge in
   _Brush.WrapMode = WrapMode.Clamp;

   // Create a color blend to manage our colors and positions and
   // since we need 3 colors set the default length to 3
   ColorBlend _ColorBlend = new ColorBlend(3);

   // here is the important part of the shadow making process, remember
   // the clamp mode on the colorblend object layers the colors from
   // the outside to the center so we want our transparent color first
   // followed by the actual shadow color. Set the shadow color to a 
   // slightly transparent DimGray, I find that it works best.|
   _ColorBlend.Colors = new Color[]{Color.Transparent, 
   Color.FromArgb(180, Color.DimGray), 
   Color.FromArgb(180, Color.DimGray)};

   // our color blend will control the distance of each color layer
   // we want to set our transparent color to 0 indicating that the 
   // transparent color should be the outer most color drawn, then
   // our Dimgray color at about 10% of the distance from the edge
   _ColorBlend.Positions = new float[]{0f, .1f, 1f};

   // assign the color blend to the pathgradientbrush
   _Brush.InterpolationColors = _ColorBlend;

   // fill the shadow with our pathgradientbrush
   e.Graphics.FillPath(_Brush, _Path);

It's very simple to do but provides a much better presentation of a shadow then just drawing with a slightly transparent brush. I hope that this helps somebody out there.


This article, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)

Written By
Web Developer
United States United States
I am currently a software developer for Dearman Systems, Inc..

Comments and Discussions

GeneralMy vote of 5 Pin
alex_31221-Feb-12 18:33
Memberalex_31221-Feb-12 18:33 
GeneralMy vote of 5 Pin
Manoj Kumar Choubey18-Feb-12 3:21
professionalManoj Kumar Choubey18-Feb-12 3:21 
GeneralFaulty shadow if rectangle Pin
Johnny Hooyberghs31-Jan-07 23:57
MemberJohnny Hooyberghs31-Jan-07 23:57 
GeneralRe: Faulty shadow if rectangle Pin
Sautin.net1-Feb-07 4:27
MemberSautin.net1-Feb-07 4:27 
GeneralRe: Faulty shadow if rectangle Pin
Johnny Hooyberghs1-Feb-07 6:05
MemberJohnny Hooyberghs1-Feb-07 6:05 
GeneralRe: Faulty shadow if rectangle Pin
Edwin Evans19-May-08 9:46
MemberEdwin Evans19-May-08 9:46 
GeneralDon't vote adhoc Pin
eisernWolf9-Oct-06 21:30
MembereisernWolf9-Oct-06 21:30 
NewsDownload source link don't work Pin
FredyAlfredo7-Oct-06 12:37
MemberFredyAlfredo7-Oct-06 12:37 
GeneralRe: Download source link don't work Pin
Sautin.net9-Oct-06 7:42
MemberSautin.net9-Oct-06 7:42 
GeneralThey do now Pin
Chris Maunder9-Oct-06 11:57
cofounderChris Maunder9-Oct-06 11:57 
GeneralRe: They do now Pin
FredyAlfredo9-Oct-06 21:59
MemberFredyAlfredo9-Oct-06 21:59 

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