Palette Cleanup - Revision history

Doofus-01 at 00:49, 24 August 2025

2025-08-24T00:49:36Z

← Older revision		Revision as of 00:49, 24 August 2025
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	==Purpose==		==Purpose==
	Unit sprites are supposed to be pixel art, but sometimes this breaks down. Maybe someone accidentally edited an image with an anti-aliasing tool (e.g. cut-paste lasso, paintbrush) or maybe the original contribution just had too many similar colors. Starting in 1.17, an effort was made to enforce a set palette: https://github.com/wesnoth/wesnoth/issues/6417		Unit sprites are supposed to be pixel art, but sometimes this breaks down. Maybe someone accidentally edited an image with an anti-aliasing tool (e.g. cut-paste lasso, paintbrush) or maybe the original contribution just had too many similar colors. Starting in 1.17, an effort was made to enforce a set palette: https://github.com/wesnoth/wesnoth/issues/6417

			This page does not address image metadata, that is covered elsewhere.<sup>*</sup>

	==Background==		==Background==
	====Why do sprites need to be pixel art?====		====Why do sprites need to be pixel art?====
	The game works just fine with non-pixel art images, but there are ~~few~~ reasons for the pixel art sprite convention:		The game works just fine with non-pixel art images<sup>*</sup>, but there are some reasons for the pixel art sprite convention:
	* Simplifies color swapping - having a set palette makes it simpler to map the original colors to new colors. The most obvious example of this is the team coloring magenta/pink conversion to red for player 1.		* Simplifies color swapping - having a set palette makes it simpler to map the original colors to new colors. The most obvious example of this is the team coloring magenta/pink conversion to red for player 1.
	* Distinction from terrain/scenery - The terrain and scenery images are not pixel art. With the current conventions, the sprites or "game pieces" should have a clear distinction from the background or "game board"		* Distinction from terrain/scenery - The terrain and scenery images are not pixel art. With the current conventions, the sprites or "game pieces" should have a clear distinction from the background or "game board"
	* Stylistic decision - pixel art is an art form, not simply a limitation, even if it may have had its origins in graphics limitations.		* Stylistic decision - pixel art is an art form, not simply a limitation, even if it may have had its origins in graphics limitations of the 1970s and earlier.

	====Enforcing a palette means restricting colors... Don't cramp my artistic expression!====		====Enforcing a palette means restricting colors... Don't cramp my artistic expression!====
	It might sound restrictive, but no one said the palette needed to be 8-bit. If you need to add a color to the palette, that is fine, just do it deliberately.		It might sound restrictive, but no one said the palette needed to be 8-bit. If you need to add a color to the palette, that is fine, just do it deliberately (see below).

	==Palette Cleanup (with an Example)==		==Palette Cleanup (with an Example)==
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	https://github.com/wesnoth/wesnoth/blob/master/data/core/images/units/human-loyalists/HumanLoyalist_ColorMap.png?raw=true&type=.png		https://github.com/wesnoth/wesnoth/blob/master/data/core/images/units/human-loyalists/HumanLoyalist_ColorMap.png?raw=true&type=.png

	is included in mainline unit image directories, but you could use your own. With the ImageMagick bash script shown above, the ColorMap needs three things:		is included in mainline unit image directories, but you could use your own if the image is not intended for mainline contribution. With the ImageMagick bash script shown above, the ColorMap needs three things:
	# the colors needed for the palette		# the colors needed for the palette
	# at least one fully transparent pixel		# at least one fully transparent pixel
	# at least one 60% opacity shadow pixel (''srgba(23,0,53,0.6)'')<sup>*</sup>		# at least one 60% opacity shadow pixel (''srgba(23,0,53,0.6)'')<sup>**</sup>

	You'll see in the output reports that there are still colors with only 1-3 pixels, so this isn't optimized. But the palette is still fairly small and, most importantly, every color is tracked and the same across the animation frames, so simple color-swapping is now (reliably) possible and broken team coloring is less likely. The restrictions on the alpha channel, where only the shadow can be semitransparent, help to clean up any almost invisible cruft floating around the sprite.		You'll see in the output reports that there are still colors with only 1-3 pixels, so this isn't optimized. But the palette is still fairly small and, most importantly, every color is tracked and the same across the animation frames, so simple color-swapping is now (reliably) possible and broken team coloring is less likely. The restrictions on the alpha channel, where only the shadow can be semitransparent, help to clean up any almost invisible cruft floating around the sprite.

			If you do intend to contribute a sprite image to mainline, and the relevant ColorMap image does not have the colors you need, simply add the needed colors as squares to the ColorMap. The image can be as large as it needs to be, so add another column or row if needed (be sure to leave at least one empty square).

			----
			----
			<small>
			==Notes==
			<sup>*</sup>CI currently enforces attribution and copyright, it doesn't enforce color palettes, that is still a manual process. Neither of these things are required for UMC, however the copyrights of UMC content do still matter if hosted on the add-ons server.

			<sup>**</sup>It looks like there has already been some slight drift since [[Creating_Shadows_Under_Units]] was written, which makes the palette restriction more relevant
			</small>

Doofus-01: /* Example */

2025-08-23T23:55:05Z

Example

← Older revision		Revision as of 23:55, 23 August 2025
Line 14:		Line 14:
	It might sound restrictive, but no one said the palette needed to be 8-bit. If you need to add a color to the palette, that is fine, just do it deliberately.		It might sound restrictive, but no one said the palette needed to be 8-bit. If you need to add a color to the palette, that is fine, just do it deliberately.

	==Example==		==Palette Cleanup (with an Example)==
	Consider these two images:		Consider these two images:
	https://forums.wesnoth.org/download/file.php?id=101241&type=.png		https://forums.wesnoth.org/download/file.php?id=101241&type=.png
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	</syntaxhighlight>		</syntaxhighlight>

	The ColorMap image is included in mainline unit image directories, but you could use your own. You'll see in the output reports that there are still colors with only 1-3 pixels.		The ColorMap image

			https://github.com/wesnoth/wesnoth/blob/master/data/core/images/units/human-loyalists/HumanLoyalist_ColorMap.png?raw=true&type=.png

			is included in mainline unit image directories, but you could use your own. With the ImageMagick bash script shown above, the ColorMap needs three things:
			# the colors needed for the palette
			# at least one fully transparent pixel
			# at least one 60% opacity shadow pixel (''srgba(23,0,53,0.6)'')<sup>*</sup>

			You'll see in the output reports that there are still colors with only 1-3 pixels, so this isn't optimized. But the palette is still fairly small and, most importantly, every color is tracked and the same across the animation frames, so simple color-swapping is now (reliably) possible and broken team coloring is less likely. The restrictions on the alpha channel, where only the shadow can be semitransparent, help to clean up any almost invisible cruft floating around the sprite.

Doofus-01: /* Example */

2025-08-23T20:59:14Z

Example

← Older revision		Revision as of 20:59, 23 August 2025
Line 14:		Line 14:
	It might sound restrictive, but no one said the palette needed to be 8-bit. If you need to add a color to the palette, that is fine, just do it deliberately.		It might sound restrictive, but no one said the palette needed to be 8-bit. If you need to add a color to the palette, that is fine, just do it deliberately.

	===Example===		==Example==
	Consider these two images:		Consider these two images:
	https://forums.wesnoth.org/download/file.php?id=101241&type=.png		https://forums.wesnoth.org/download/file.php?id=101241&type=.png

Doofus-01: /* Background - Is this really needed? */

2025-08-23T20:54:44Z

Background - Is this really needed?

← Older revision		Revision as of 20:54, 23 August 2025
Line 4:		Line 4:
	Unit sprites are supposed to be pixel art, but sometimes this breaks down. Maybe someone accidentally edited an image with an anti-aliasing tool (e.g. cut-paste lasso, paintbrush) or maybe the original contribution just had too many similar colors. Starting in 1.17, an effort was made to enforce a set palette: https://github.com/wesnoth/wesnoth/issues/6417		Unit sprites are supposed to be pixel art, but sometimes this breaks down. Maybe someone accidentally edited an image with an anti-aliasing tool (e.g. cut-paste lasso, paintbrush) or maybe the original contribution just had too many similar colors. Starting in 1.17, an effort was made to enforce a set palette: https://github.com/wesnoth/wesnoth/issues/6417

	===Background ~~- Is this really needed?=~~==		==Background==
	====Why do sprites need to be pixel art?====		====Why do sprites need to be pixel art?====
	The game works just fine with non-pixel art images, but there are few reasons for the pixel art sprite convention:		The game works just fine with non-pixel art images, but there are few reasons for the pixel art sprite convention:

Doofus-01: First Draft

2025-08-23T20:51:33Z

First Draft

@@ Line 1: / Line 1: @@
-This is WIP
+This is WIP, should not be linked to yet.
 ==Purpose==
 Unit sprites are supposed to be pixel art, but sometimes this breaks down.  Maybe someone accidentally edited an image with an anti-aliasing tool (e.g. cut-paste lasso, paintbrush) or maybe the original contribution just had too many similar colors.  Starting in 1.17, an effort was made to enforce a set palette: https://github.com/wesnoth/wesnoth/issues/6417
-===Why do sprites need to be pixel art?===
+===Background - Is this really needed?===
 The game works just fine with non-pixel art images, but there are few reasons for the pixel art sprite convention:
 * Simplifies color swapping - having a set palette makes it simpler to map the original colors to new colors.  The most obvious example of this is the team coloring magenta/pink conversion to red for player 1.
 * Distinction from terrain/scenery - The terrain and scenery images are not pixel art.  With the current conventions, the sprites or "game pieces" should have a clear distinction from the background or "game board"
 * Stylistic decision - pixel art is an art form, not simply a limitation, even if it may have had its origins in graphics limitations.

Doofus-01: Created page with "This is WIP ==Purpose== Unit sprites are supposed to be pixel art, but sometimes this breaks down. Maybe someone accidentally edited an image with an anti-aliasing tool (e.g..."

2025-08-23T13:32:09Z

Created page with "This is WIP ==Purpose== Unit sprites are supposed to be pixel art, but sometimes this breaks down. Maybe someone accidentally edited an image with an anti-aliasing tool (e.g..."

New page

This is WIP

==Purpose==
Unit sprites are supposed to be pixel art, but sometimes this breaks down. Maybe someone accidentally edited an image with an anti-aliasing tool (e.g. cut-paste lasso, paintbrush) or maybe the original contribution just had too many similar colors. Starting in 1.17, an effort was made to enforce a set palette: https://github.com/wesnoth/wesnoth/issues/6417

===Why do sprites need to be pixel art?===
The game works just fine with non-pixel art images, but there are few reasons for the pixel art sprite convention:
* Simplifies color swapping - having a set palette makes it simpler to map the original colors to new colors. The most obvious example of this is the team coloring magenta/pink conversion to red for player 1.
* Distinction from terrain/scenery - The terrain and scenery images are not pixel art. With the current conventions, the sprites or "game pieces" should have a clear distinction from the background or "game board"
* Stylistic decision - pixel art is an art form, not simply a limitation, even if it may have had its origins in graphics limitations.