How to Go About to Develop Screensavers?

By: Boger Gray

What is a screensaver?

A screensaver is a pop up simple program within operating systems that appearswhenever you leave the keyboard or mouse unattended for a couple of minutes. To find outwhether it can start the screensaver or not, Windows sends a message to the foregroundapplication. This command is asking the application, "Can I start the screensaver?" A non-Windows program will not understand the command, and therefore will not answer it. A CBTapplication will understand it, but will respond with a command that means "No, I'm providingtraining right now." All other applications should respond positively to the command.

The screensavers were originally designed to protect the computer monitor fromphosphor burn-in. The phosphors, used to make the pixels in the display, would glow at aconstant rate for such a long period of time that they would actually discolor the glass surfaceof the CRT. This discoloration would then be visible as a faint image overlaying whatever elsewas displayed on the monitor.

Now you can use screensavers for:? Entertainment - most people use screensavers for the fun of watching them.There are several screensaver categories like: natural environments (e.g.animated waterfalls, aquariums, fireplaces etc.), favorite actor/actressscreensavers, cars screensavers etc.? Advertisement - many companies have developed their own themedscreensavers (e.g. a black background with the name of the company scrollingup and down)? Security - this might be one of the most important uses .You can simply set apassword so when your computer exits the screensaver will actually require apassword to go back to its desktop. Many people use this option to preventothers from invading their privacy.

Screensaver Development

A screensaver is really just an executable file, with the extension changed from .exe to.scr. By putting a screensaver file into the Windows or System directory and giving it a .scrextension, Windows knows that it should treat this file as a screensaver and makes it availableas an option in the Display properties window.

The bulk of the screen saver is written in C++ and uses OpenGL for rendering. It is sharedbetween both Windows and Macintosh versions. The Windows version also is in C++ and talksdirectly to the Win32 API (no MSVC classes). The development environment is Microsoft VisualC++ 2005 Express, but a VC++ 6.0 project is also included. The Macintosh version is in a mix ofC++ and ObjectiveC, and is built with Xcode. The screensaver interfaces indirectly with theoperating system to cause the physical display screen to be overlayed with one or more graphic'scenes'. The screensaver typically terminates after receiving a message from the operatingsystem that the mouse has been moved or a key has been pressed.

The screensaver file can be programmed in several different ways. It can:? Simply present a black screen? Load and display a particular image or group of images? Display a particular line of text? Display an animation or series of animations? Display information from another program or a Web site

To suit the user needs companies designed several types of screensavers based on:? Shockwave Flash? Image slide shows? Play movies and music different formats (avi,mpg,asf/mp3,aac,midi,wav)? 3D rendering objects? Open GL support screensavers

Most screensavers offer some combination of these features. Except for the slideshowscreensavers that display a sequence of images, screensavers generally move animage, piece of text or animation around the screen. The screensavers that have acustom interface, and do not use the Display properties window at all, are less common.Usually, these screensavers do not have the .scr extension. They require that you installthem using a setup program in order to configure them properly.

There are several available software over the internet that lets you make your ownscreensavers based on Shockwave Flash, Image Slide Show (display your favoritephotos) and Movie .The software offers you the possibility to let your imagination getloose and use all kind of multimedia support like Background music support, transitioneffect support, masking effect support, customizable screensaver Dialog box etc.

Installing and removing screensavers under Microsoft Windows

There are two types of screensavers:? compressed self installing Screensaver setup files(.EXE)? stand-alone screensaver file(.SCR)

The easiest way to install a screensaver under MS Windows platform is to download itfrom the internet and simply follow the install w izard's further instructions. All you have to doduring the wizard is to: read and agree the terms and conditions choose the install destinationpath and choose either if you want or not to create a shortcut icon on the menu folder. Anothermethod is to copy the screensaver w ith his original '.scr' extension on W indow s's root directoryc:windows.

To remove a screensaver from your computer simply erase it from c:windows folderwhere you have initially copied it or access 'add/rem ove program s' within Control Panel,locate the screensaver from the installed program s list and hit the 'add/rem ove button'.

Configuring your screensaver

1. Click Start, then click Settings and go to Control Panel.2. When the Control Panel window opens, double-click on the Display icon. Thisbrings up the Display Properties window.3. Select the Screensaver tab, and select the screensaver you want to use from thedrop-down menu.4. Determine how many minutes you want the system to be idle before Windowslaunches the screensaver, and enter that amount of time in the box provided.5. You can click on Preview to see what it will look like in full-screen use. If you want tochange the settings, click Settings. Depending on the screensaver, this window canhave one or more options that you can modify.6. Once you have finished changing the settings, click OK. You can also use thescreensaver for security by checking the "Password protected" box. Click OK againand your screensaver is set to go!

? 2006 Mastermen Pty Ltd
You are welcome to post this document on your own website provided it is unchanged and allacknowledgements are retained

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