Believe it or not, monitors are one of the more difficult things you’ll have do deal with when you’re using Director to write programs.
This is because there are hundreds of different possible configurations for monitors. Some are capable of showing relatively few colors, and a relatively small image area, while others can handle more colors than the human eye is actually capable of seeing, and display them over a very large desktop space.
The absolute rock-bottom configuration for a monitor you’ll likely ever need to consider will be capable of showing only 256 colors in a 640 x 480 pixel area. That’s pretty confined, and for the most part such configurations are pretty rare. Modern desktop systems can do much better than that.
However, portable PCs can still be pretty severely limited. Most can show about 65 thousand colors over an 800 x 600 pixel area, which sounds a bit like an improvement, but 800 x 600 pixels is not a lot of space. Sure, the number of colors has improved, but an 800 x 600 pixel window is not a whole lot of real estate.
When we speak of the amount of image data that can be shown on a monitor, we are talking of its screen resolution. This is not a description of how large a monitor is; rather, it is a description of how much data can be displayed on it at once.
A monitor that can display 800 x 600 pixels is capable of showing 35 percent more data than is a monitor that maxes out at 640 x 480. This does not mean the monitor is 35 percent larger, but that it can squeeze just that much more information into its image area.
And actually, we shouldn’t speak of monitors here at all, but video cardsthe devices inside the computer to which the monitors are attached. It’s the video card that really determines how much information can be sent to the screen at once.
Some cards are capable of displaying multiple resolutions. Often these cards are capable of at least 640 x 480, 800 x 600, and 1024 x 768 pixel images. Naturally, the higher the numbers go, the smaller things appear to be on the monitor. This is of course because if you want to display more information on a screen of fixed size, the only way to do it is proportionally shrink the information you’re attempting to display.
If you are writing software for a client, you’ll want to have discussions about minimum system requirements anyway; just make sure display resolution is one thing you discuss at length. Macromedia publishes minimum specification information in the documentation that came with your copy of Director, so make sure that your client’s systems are going to at least be on a par with the description listed under "playback requirements."
You can get away with running your Director movies on systems that have less power, but you have to reduce the number of colors you use, limit the amount of animation you do, and try to keep things like video or Flash to a minimum. The programs we’ve written so far in this book will work fine on machines that fall well below the minimum specifications stipulated by Macromedia, but that’s because we’re not really doing anything taxing with any of them.
This really becomes a factor when you start creating programs that might end up anywhere, such as Shockwave files. You have no way of predicting what the end user’s configuration is going to be, so you don’t know if you’re going to overload his or her system by trying to display too many graphics, animations, and so on at one time. You also have no way of knowing what the maximum resolution of the display will be, so you could end up writing a program that can’t be entirely seen on some monitors.
There are some ways around that last concern, the simplest being to create a "safe" area in your program where you’ll put all the controls. If you’re assuming most users will be running at 800 x 600, you can set up your Stage to be that size, and you can certainly fill that space with graphics. However, you should put all the controls and critical information a user will need to run your program into the center of that space, so that when the program loads, even if the user’s display is set to 640 x 480, all the important parts of your program will be visible. (Unless you simply want to insist on a minimum resolution of 800 x 600; however, that will significantly reduce the number of public schools that can run your programs, if that’s an issue, as many schools can’t afford to upgrade their video cards to the point they can handle anything past 640 x 480.)
Additionally, if you’re really unsure what kind of system your software will be loaded onto, try to keep the graphics down to 8-bit (256 shade) color, and avoid using huge images, since a rule of thumb is that if a display’s color depth can’t go past 8 bits, it’s probably running in a slow system with very little memory or speed to spare.
Next in this module, we’ll be discussing testing and ways you can help ensure your program will function more or less as expected on a wide range of systems.