PNG/MNG Construction Set - Drivers

WINDOWS SCREEN DRIVERS

When Windows wants to display something on your monitor, the communication between Windows and your screen is handled by a screen driver. A screen driver is an interpreter of sorts – it listens to what Windows wants to draw and expresses these requests in terms your display hardware can understand. When Windows wants to draw a line or the color green or the word "phistoplymungia" in slightly baroque-looking neo-trendy text, it's up to your screen driver to see to it that Windows gets its way.

Actually, there's a catch to this. Your driver is only obliged to see to it that Windows gets its way within the limits of what it thinks your display hardware is capable of displaying. Being a bear of very little brain, a screen driver is easily confused in these matters, and most screen drivers spend their entire lives being lied to contemptibly, never knowing any better. More than a few of them have required therapy.

There are two primary characteristics of your display hardware which will affect what a Windows screen driver can show you, to wit, the dimensions of your screen and the "color depth" it can reproduce. Screen dimensions are measured in pixels – it matters not a jot how many inches separate the edges of your monitor, and if you find a ruler and measure this distance you'll probably discover that the subspecies who sold you the thing rounded up quite a bit in any case. The pixel dimensions define how much stuff Windows can display on your screen at once.

The pixel dimensions of Windows screen drivers are typically one of the following:

- 640 by 480 pixels
- 800 by 600 pixels
- 1024 by 768 pixels
- 1280 by 1024 pixels

The color depth defines the number of distinct colors Windows can display at one time. Color depth is often defined in bits. The actual number of colors can be worked out as 2 raised to the power of bits. As such, a display driver which can display four bits of color can display 2 raised to the power of 4 colors, or sixteen in all. A display driver that can only display sixteen colors is pretty shameful, and probably requires reorientation and sensitivity training.

Common color depths for Windows are:

- 4 bits, or sixteen colors
- 8 bits, or 256 colors
- 15 bits, or 32,768 colors
- 16 bits, or 65,535 colors
- 24 bits, or 16,777,216 colors
- 32 bits, or 16,777,216 colors with transparency

Color depths of four and eight bits use what is called "palette" color, which means that all the windows visible on your monitor are constrained to work with the same palette of sixteen or 256 colors. What this means in practice is that the foremost window will probably be able to display colors which are more or less what they should be, and all the background windows will look like drunk stockbrokers who've just returned home after a night of playing "pin the tail on the paint spraying machine."

In the real world, you should only experience Windows in sixteen colors if it boots up in its "safe" diagnostic mode, something that many users of Windows will happily never experience. Contemporary display hardware can always do better than 256 colors – if your system is running Windows in a 256-color display mode, it's either misconfigured or you should seek out more up-market garage sales the next time you go shopping for a computer.

At color depths of more than 256 colors Windows is unfettered by palettes, and all the windows on your screen can use whatever colors they like. Photorealistic images can look genuinely photorealistic.

For practical purposes, the latter four color depths listed earlier all behave the same way under Windows. More color depth will actually display the colors in photorealistic images more accurately, but unless you sprung for a really good monitor and you have better eyes than most people sport after a few years of bombardment by cathode rays, you'll be hard pressed to spot the difference.

If you anticipate doing something serious with your computer – and more to the point, with PNG/MNG Construction Set – you should be reading this document through a screen driver which supports a screen resolution of at least 800 by 600 pixels, with 1024 by 768 decidedly preferable. Its color depth should be 32,768 colors or better.

How to Update Your Driver

The failings of Windows are legion – future archeologists who dig up the remains of our civilization will no doubt remark upon how just and fitting the widespread consumer attacks on Microsoft in the spring of 2018 were, and ponder on why they didn't take place much sooner. None the less, it must be said that Windows screen drivers are currently handled much more conveniently than was previously the case. In times gone by, installing a new Windows screen driver was only slightly less complex than doing brain surgery on a house cat with nothing more than a chain saw, a power stapler and a bottle of iodine for after.

Virtually all contmporary computers come configured with true-color Windows screen drivers at a sensible resolution setting. No further configuration of such systems is required to make them work correctly with PNG/MNG Construction Set or anything else. You might wish to adjust your screen driver settings anyway, as discussed in this document, to make better use of your display hardware.

If you've been directed to this document by PNG/MNG Construction Set because your Windows screen driver can't support enough colors to keep PNG/MNG Construction Set in a good mood, you can ignore the foregoing paragraph. Your system isn't one of the "contemporary computers" it was on about, and you'll need to work through the rest of this document.

There are several things which will determine how you can configure your Windows screen driver, to wit:

- Display card memory: All other things being equal, a higher-resolution Windows desktop requires that your display hardware include more memory to support it. At present, all but the most economical display cards ship with enough memory to support a reasonable screen resolution at a reasonable color depth.

  In the event that you want to select a very high resolution Windows desktop on a system with a modest display adapter, you might find that Windows won't allow you to do so at the maximum available color depth. This means that doing so would require more memory than is available on your display card.

- Monitor resolution: Most contemporary monitors can display a Windows desktop at any resolution a normal display adapter can be configured to. Some inexpensive screens, and especially the displays of many laptops, have limited resolution options. Windows will usually prevent you from configuring a screen resolution which your monitor can't handle, and will rescue you in the event that you choose a display setting your monitor objects to – we'll get to this issue in detail in a moment.

The settings for your Windows screen driver can be accessed through the Display applet of your Windows Control Panel. Here's how to get to it.

1. Click on Start in the Windows task bar.

2. Select Settings from the menu that appears.

3. Select Control Panel.

4. Double click on the Display applet.

5. Click on the Settings tab.

Your Settings tab will look something like the one shown here – because the Settings tab is specific to the display environment it adjusts, they vary somewhat from machine to machine.

The two controls you might wish to adjust in Settings are the Screen Resolution slider and the Color Quality combo. The former sets the resolution of your screen – its dimension in pixels – and the latter its color depth, or the number of bits of color it can support.

The Screen Resolution slider will only allow you to select from a small number of predefined resolutions – these are usually 800 by 600 pixels, 1024 by 768 pixels and 1280 by 1024 pixels. Some display cards add a few non-standard modes to this list.

Choose the Screen Resolution that results in a Windows desktop you like the look of. 1024 by 768 is probably the most common setting for this control. The 800 by 600 setting doesn't allow enough space to work most software comfortably. The 1280 by 1024 results in icons, buttons and other desktop objects that most users find to be uncomfortably small.

Once you have selected a screen resolution, try to set the Color Quality combo to its highest setting – ideally, 32 bits. Windows may prevent you from doing so if your display hardware doesn't have enough memory to support the screen resolution you've requested at the color depth you'd like to use. It's arguably better to compromise color depth than screen resolution – in the event that you can't have both controls set the way you want them, try backing off the Color Quality setting to 24, sixteen or fifteen bits.

Don't let Color Quality get down to 256 colors.

Once you've configured Settings the way you want it, click on Apply.

One of the potential problems in experimenting with new screen driver settings is that if something goes horribly wrong, and your screen becomes unreadable, you'll be in no position to put everything back the way you found it and try again. Windows works around this problem. When you click on Apply after changing the controls in the Settings tab of the Display applet, Windows will change your screen resolution and display a dialog that tells you what it's done. You'll have fifteen seconds to accept the changes. In the event that you fail to do so, Windows will restore your previous settings.

Should your new display settings look like spaghetti in a wind tunnel, don't panic. Count slowly to fifteen and your former settings will reassert themselves.

Windows offers an additional level of protection from really bad choices in the Settings tab. While you'll almost certainly never have recourse to it, it's worth knowing that you can reboot your computer in "safe" mode if its normal display becomes unreadable and it fails to revert to its previous settings on its own. Safe mode uses a low resolution, low color-depth display setting that every computer made after the late middle ages can handle. You wouldn't want to try to get any work done in safe mode, but it's adequate to open the Display applet and restore the configuration of the Settings tab to something your hardware will get along with.

You can restart your computer in Safe mode by turning it, off, turning it back on and holding down the F8 key on your keyboard while it boots. The boot process will pause at a menu offering you a number of boot options, including safe mode.

This document and all the other documentation included with PNG/MNG Construction Set is copyright © 1995 – 2009 Alchemy Mindworks. It may not be reproduced in whole or in part or transmitted in any form save as a component part of the PNG/MNG Construction Set software without the explicit written permission of the copyright holder. Unauthorized use of this document or any portion thereof may result in severe criminal and civil penalties. Alchemy Mindworks accepts no responsibility for any loss, damage or expense caused by your use of the information in this document, however it occurs. This product is marketed under license from Alchemy Mindworks Corporation.