.NET news » Graphics

How to create a panel with a transparent drop shadow in C# using GDI+

Windows has long had the ability to specify a region or transparency key allowing you to define an arbitrary Window border. This is often used with a background image to define an image outline as a Window frame. However, this border is composited with the desktop as a one bit mask giving you a pixelated boundary. It is especially unattractive with curvilinear borders which really need antialiasing and per pixel compositing. Aside from the unsightliness, it's not easy to define the region and/or transparency key to achieve a complex image based Window frame.

This is a Windows Forms control that works with Win32 APIs and without WPF. The control allows you to layout a 32 bit image with an alpha channel in the Forms designer and arrange additional controls within user specified areas of the image. At runtime, the control will generate a per pixel alpha composited Form with the desktop. The Form's Region property defines areas of the Form to host other controls, and it's calculated on the fly from the image's alpha channel. This control also supports runtime changing of the image. Before we discuss some of the code specifics, let's run through how you use it.

Take a snapshot of the main Window of any UI application

I am developing a 4X Space Opera game called Star Odyssey, in the tradition of the Master of Orion series. Every game needs a User Interface and mine is no exception. The DirectX SDK provides a sample UI that looks very cool, but it is very difficult to extrapolate from the project and it relies on textured GUI elements. Since I am not very good at drawing GUI elements, it would have taken ages for me to go that way. Instead, I took the ''programmer art'' way: to create controls and other GUI elements in a dynamic way, trying my best to make it look cool at the same time. The result is presented here.

This article demonstrates a complex analog-style thermometer control in C#. The control is in pure managed code. Most visual elements can be adjusted through the control's properties.

Visual Basic .NET class implements image filter which can change hue, saturation and/or lightness of the image.

The fact is, in .net, there are only two color formats that can be used : the RGB color model and the HSB color model. Those two are encapsulated in the Color structure of the System.Drawing namespace. It is largely sufficient for simple uses, like changing the background color of a component, but insufficient if we want to develop graphic tools (or something which implies conversion between color formats).

I've started looking for other formats, like CMYK, when I was learning how to add cool design-time support to my custom controls.

I worked on a project in which I needed a graph control. Later on, I was also required to use a chart control. So I thought, hey, let's just combine them both into one nice and simple control..

You can find text scrollers in many programs, especially in their "About" dialogs. In most cases, it's a simple colored text which 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 (like 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 seems 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+..

jThermometer is a class for creating thermometer charts of the type used generally to show progress toward a fund raising goal. The chart uses GDI+ to compose an image and stream it out to the browser.