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Screen Enhancements

Posted by walker7, 15 November 2017 · 181 views

assembly computer 8-bit 16-bit screen enhancement color picture video

When assembling, there are several different screen enhancements that could use to make the experience more enjoyable.  One way is to change the background and foreground colors.
This is the shot from the previous installment:
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By pressing a certain key (or key combo) on the keyboard, it will bring up a screen saying what color you want to use.  That screen might look something like this:
Posted Image
As indicated on the screen, press 0-9 or A-F to choose the appropriate color.  When you press one of these buttons, the color beside the "current" heading changes to the selected color.  For example, if you press "3," while in the palette shown above, you will choose purple.
You can also toggle between foreground/background color choice by pressing the "/" key.
To change palettes, press up/down.  There are seven different palettes, plus one palette you can customize. The chart below shows the seven fixed palettes:
Posted Image
Each row is one palette, and each palette has a different theme.  They are based on palettes from older gaming and computer systems.

  • Palette 0 - Apple ][
  • Palette 1 - Commodore 64
  • Palette 2 - Mattel Aquarius
  • Palette 3 - Commodore VIC-20
  • Palette 4 - MSX
  • Palette 5 - CGA
  • Palette 6 - ZX Spectrum
Palette 7 can be defined using your own colors.  Each color in every palette is stored as a 24-bit RGB value.  I will get to palette 7 editing in another post.
Using the Apple ][ palette, let's say you decide to change the background to dark blue and the foreground to aquamarine.  This is the result:
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If you don't want to change the colors, hit the ESC key.  This causes any changes to be cancelled, leaving the background/foreground colors as they are.
Another thing you could do is have some picture to look at while programming.  To change the background to a picture, press a certain key combination.  Pictures can be uploaded from flash drives.  If you have a flash drive installed, it will list all the picture files on it.  The screen would look like this:
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Press the appropriate button (0-9 or A-Z, depending on the number of pictures)  to choose the picture.  If there are too many picture files to fit on one page, press left or right to move to another page.
For example, let's say you want to use the following image.  It's the back of an old McCormick food coloring box from 1975.  This picture was taken from Etsy:
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When pictures are loaded into memory, they are stored as 24-bit RGB values for simplicity of decoding.  The picture is also scaled to a size of 480*360 so it can fit on the screen.
The picture replaces the background color.  Here's how the screenshot at the top of the page would look with this picture as the background:
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You can change the picture by going back to the picture menu.  Plus, you can choose to go back to a solid color background by going to the background color change menu.  The foreground color change menu works the same.
In addition to pictures, you could also use a video for the background.  The video loops forever.  Like with pictures, you could upload videos from a flash drive.  They can be in any format, but each frame is converted to 24-bit RGB format before being displayed.  Frames are buffered.
You could also choose to play two or more videos in a continuous loop.  After one video ends, the next one starts.  After the last video, it wraps back to the first one and the cycle repeats forever.
Next, I'll mention code-as-you-go, one of the most important aspects of this type of computer.

March 2018

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