Soundy

The Amiga Gradient Master (TAGM)

July 2022

Amiga Gradient Master (deadliners.net)

Why?

• Allow graphic artists to create & preview how a gradient will behave on Amiga using 12 bits colors, especially to avoid ugly banding effects

• Provide programmers with palettes, directly as assembler source code.

• Let the coders use their Windows or Linux machine, and the artists use their Mac. Hence the choice of a web tool (unfortunately, I suck at javascript).

New features since last version

• Undo / redo
• Automatic loading of the last gradient you worked on when launching the tool
• Key copy / paste

Layout

Modifiers zone

Hue, Saturation, Value. They affect only the preview, and the exported data. Keypoints are not impacted and will keep the value you assigned them

Buttons

• “New” Creates a new empty gradient
• “Refresh” makes sure the preview & export zones are refreshed
• “Import” is a specific case: If you already have a picture featuring the gradient you need, you can just click this button to load your image file and use the data (Amiga assembly code) in the export window. Importing an image will do things the dirty way: 1 keypoint is created per line, the color of the keypoint being the first pixel of each line in your image.
• “Undo / Redo” guess what these ones do…

Keys zone

For each key, you have the following items (from left to right):

• Color : just click on the colored rectangle to pick a new color
• Line index : the Y of the key (from 0 to Line Count)
• Interpolation : How colors are interpolated from this key to the next key. 3 possible values:

• linear : linear interpolation
• near → far : fake perspective (cosine interpolation) with current key being near and next key being far
• far → near : fake perspective (cosine interpolation) with current key being far and next key being near

• Dither mode : how colors are dithered between the current key and next key. 4 possible values:

• direct : no modification, pure value
• shuffle : lines are interleaved to give more “texture” to the gradient
• soft dither :  light dithering is applied to gradients
• Hard dither :  hard dithering is applied to gradients

• delete key (minus icon) : deletes the key
• duplicate key (plus icon) : duplicates the key (inserts a copy of the key below it)
• copy key : copies the key to an internal clipboard
• paste key : copies the internal clipboard to the key

Below the keys, 2 extra fields remain:

• Line Count : Number of lines you want your gradient to be (height). This should update the preview zone immediately
• Zoomed : By default - and to ease visualization - the preview window features twice the line count (just for visualization). Untick the “Zoomed” check box to see the actual size.

Export zone

Coders will know what to do with this data. Still, there are some important details:

• Values per line : Allows to format the assembly code dump (how many words per line in the “dc.w” part).

• grdmstr_data info that comes before the «palette:» label features the information to re-generate the data. Keep this piece of text somewhere if you want to save a copy of your settings and adjust your gradient later.

• To load a previously edited gradient, just paste the «grdmstr_data» text and hit the «Load From Text» button