Introduction

Low resolution would be 640x480 pixels (width × height). High resolution would be 1280x1024. The Dell 15" WUXGA has 1920x1200. Because the more dots you have, the smaller they are, you must compensate by using a larger monitor for high resolution, or the type will be too small to read.

If you double the resolution, there are four times as many dots. This means the video hardware has four times as much work to do each second to keep the screen refreshed. Further, the computer has four times as many dots to render each time the screen changes. For high resolutions, you thus need high performance video hardware.

Recent LCDs use a hardware resolution between 86dpi and 147dpi, only a few LCDs use a resolution around 204dpi (Toshiba, IBM).

Measuring Resolution

1. total number of pixels (dots), e.g. 1280x1024. Bigger is better.
2. diagonal size of the screen, e.g. 15" (LCD makers are more honest that CRT makers). Bigger is better. Take a ruler to the showroom with you to get he honest figure.
3. dpi, dots per inch, how densely the pixels are packed. Bigger is better. A 1280 × 1024 image on a 17" monitor is only about 100 dpi. A 1600 × 1200 image on a 19" monitor is about 111 dpi.
4. dot pitch, how wide the physical sub-pixels are. Smaller in better. A typical monitor spaces the red dots about 0.231 mm apart.
5. VU. Visual Units. This is my personal proposal. One VU is the vertical distance between two lines of type the user can comfortably read. It is the leading of the user’s preferred body font. What it corresponds to in cm or pixels depends on many factors including visual acuity, personal preference and screen resolution. My idea is you would design in visual units, and the user would configure the value of a visual unit in pixels using a system wide slider in the Control Panel. The definition would then by used by the OS and all apps. The user could adjust it an any time, causing a system wide revalidate. The GUI and layouts would still work in pixels at the low level, but for various higher level methods you could specify co-ordinates and sizes in terms of a VU grid, or perhaps in terms of integral MVUs, thousandths of a VU. The notion could be used both for designing screen layouts and printed output easily readable by the user.

Printed Resolution

• An old HP Laserjet printer is 300 dpi.
• Newsprint is about 500 dpi.
• A modern laser printer is usually 600 dpi.
• Modern ink-jet printers are about 4800 × 1200 dpi. They are limited mainly by ink smudging and the quality of the paper.
• Glossy magazines and photypesetters are about 1200 dpi.

The Scale Problem

The free and open source JGoodies Forms layout system addresses this issue; it support non-pixel sizes: pt, mm, cm, in and more important, it supports dialog units (dlu) that scale with the resolution and dialog font size. Here is how to find the size and resolution of the screen to use in adjusting your Font and Frame sizes.

import java.awt.Dimension;
import java.awt.Toolkit;

...

// Get screen size in pixels, width by height.
Dimension dim = Toolkit.getDefaultToolkit().getScreenSize();

// Get screen resolution in dots per inch.
// The Americans who develop Java have not noticed the world has gone metric.
int dpi = Toolkit.getDefaultToolkit().getScreenResolution();

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