Chapter 7. Resolution Independence

Table of Contents

Resolution and Images
tk scaling
Vector Graphics
An Vector Graphic Primeur
Vector Signature
Drawing window
Position: x and y
Vector Size

In the beginning was the »CRT«.

A cathode-ray tube is limited by manufacturing constraints. The luminance decreases when the »pitches« shrink, resulting in physical constraints for the possible resolution of a CRT. For a very long time we were burdened with displays of about 72ppi to 85ppi max.

Computing power was also limited during the heyday of CRTs. Today, computing power exists in abundance, and TFT-LCD Monitors are commonplace.

LCDs have constrains too, others than CRTs have. LCDs ain’t good at displaying Motion. This is due to the mass of the liquid crystals. Smaller pitches means less mass and improves the responsiveness of LCDs.

High-Definition video is a driving force toward monitors with high resolution. And HD has already left its mark on nowadays computing. May it be as a traveling device for watching movies or as a video editing machine. In consequence the smallest resolution for a single monitor will be High-Definition (HD) –1920x1440 or 1920x1080 pixels–regardless of the monitor’s physical dimension.

These transition is under way now. Standard laptops can be ordered with HD resolution. A 15.4 inch monitor thus features a resolution around 150ppi. Twice the resolution CRTs once had!

Normal mobile phones do already have resolution higher then 290ppi. Software techniques such as anti-aliasing, to simulate a higher resolution, has no effect with these displays anymore.

The convergence between mobile phones, computer and video makes it reasonable certain, that HD-Video will be played on such devices with full resolution.

There is no technical reason to stop at 290ppi. Monitors should feature resolution beyond 600ppi. Finally rivaling the resolution of printed books and replacing them.

Anti-aliasing –added to Tk 8.5— becomes obsolete with high resolution displays. In essence anti-aliasing mimics a higher resolution by blurring pixels. These effect is only visible on displays with low resolution. A HD-laptop (150ppi) won’t profit much from using anti-aliasing.

Higher resolution has an immanent impact on Graphical User Interface design. While the obsolete CRTs will remain with us for a period of time, new high resolution displays have already entered the market. And even higher resolution have to be expected. Only one conclusion can be drawn for developing Software today: Graphical User Interfaces must be resolution independent!

Well, resolution independence isn’t exactly cheap to get. A battery of old working habits have to be abandoned!