320 x 352 pixels, produced using a Vic-20 computer.

This image is made up from 27 square tiles wide x 30 square tiles high. A 27 x 30 element array was filled with many similar sequences of levels and then rendered by a program to show the array as an image, using one of 19 levels of tone to correspond to the value in each element of the array. The 19 different levels of tone were shown using the halftone patterns shown in earlier pages.

I wanted to experiment with images made up from tiles of varying tones. I could use my “BigArt” graphics screen and machine code routines to display my experiments.

320 x 352 pixels, produced using a Vic-20 computer.

This image is made up from 13 square tiles wide x 15 square tiles high. A 13 x 15 element array was filled with random levels and then rendered by a program to show the array as an image, using one of 19 levels of tone to correspond to the value in each element of the array. Here, the 19 different levels of tone were shown using more even spreads of dots to those used for the halftone patterns used for the previous image.

320 x 352 pixels, produced using a Vic-20 computer.

This image is made up from 27 square tiles wide x 30 square tiles high. A 27 x 30 element array was filled with with random levels and then rendered by a program to show the array as an image, using one of 19 levels of tone to correspond to the value in each element of the array. The 19 different levels of tone were shown using the more even spreads of dots to those used for the halftone patterns, as per the previous image.

320 x 352 pixels, produced using a Vic-20 computer.

This image is made up from 27 square tiles wide x 30 square tiles high. A 27 x 30 pixel greyscale TGA (Targa) image file was loaded into a section of available RAM and read by a program for rendering the tone of each pixel to one of 19 levels of tone. The 19 different levels of tone were shown using the more even spreads of dots to those used for the halftone patterns.

The image was taken from a photograph of my wife, Marianne. I was keen to see whether I could display a file loaded into the Vic-20. I found that I could only load in a very small file - there simply wasn't much RAM space left for loading in a file, with the “BigArt” screen and machine code routines already taking up most of the available RAM. I used a greyscale TGA (Targa) format graphics file, as its structure was straightforward to work with (reading the values and assigning suitable tonal values).

320 x 352 pixels, produced using a Vic-20 computer.

This image is made up from 54 square tiles wide x 60 square tiles high. A 54 x 60 pixel greyscale TGA (Targa) image file was loaded into a section of available RAM and read by a program for rendering the tone of each pixel to one of 19 levels of tone. The 19 different levels of tone were shown using the more even spreads of dots to those used for the halftone patterns.

The image was taken from a photograph of my portrait of my wife, Marianne. I was keen to see whether I could display a file loaded into the Vic-20. I found that I could only load in a very small file - there simply wasn't much RAM space left for loading in a file, with the “BigArt” screen and machine code routines already taking up most of the available RAM. I calculated that I could just fit in an image of 54 x 60 pixels. I used a greyscale TGA (Targa) format graphics file, as its structure was straightforward to work with (reading the values and assigning suitable tonal values).

Compared with the previous version of TGA Image File, I can see that the higher resolution of the starting TGA file results in a clearer result overall.