Simple Bitmap Color Swapper

[Boonzeet]

Simple C++ Library to swap colours of an input RPG Maker Bitmap.

Takes two input CSV-formatted color palettes to swap, one for the other.

This allows you to create simple greyscale or other images which can then be dynamically colorized, for example to create a character or item customisation option.

To use:
Download Release/PaletteSwap.dll from the GitHub repository. Place this in the root folder of your project.

Next, place this script above Main:

module PaletteSwap
  VERSION = 1.0
  DLL_NAME = 'PaletteSwap' # Optionally change this to store the DLL elsewhere

  module Error
    def self.raise_error(err, obj, msg)
      klass = obj.class.to_s
      stack = caller.slice(1..15)
      stack.each do |i|
        script = i.scan(/\d+/)[0]
        i.sub!(/{\d+}/, $RGSS_SCRIPTS.at(script.to_i)[1]) if script
      end
      raise err, msg % klass << "\n\n#{stack.join("\n")}"
    end
    def self.raise_bitmap(bitmap)
      raise_error(RGSSError, bitmap, "%s is a disposed or invalid bitmap!")
    end
  end
end

#==============================================================================
# ** Bitmap
#==============================================================================

class Bitmap
  @@colorize = Win32API.new(PaletteSwap::DLL_NAME, 'Colorize', ['l', 'p', 'p'], 'l').freeze

  # Colorize call
  def colorize!(og_palette, new_palette)
    PaletteSwap::Error::raise_bitmap(self) if self.disposed?
    @@colorize.call(object_id, og_palette, new_palette)
  end
end

Then call like so (example from Essentials):

bmp = BitmapCache.load_bitmap("example.png")
bmp.colorize!("75,75,75\n105,105,105\n135,135,135", "50,65,98\n65,96,159\n57,119,198")

The palette sizes should be the same length. Please ensure these strings are properly formatted with the RGB values separated by commas and each separate color separated by "\n".

This will swap each color in the first list, e.g. rgb(105,105,105), with the corresponding item in the second list, i.e. rgb(65,96,159).

I'm using this for a clothing generator, but I thought this could potentially have more uses to a wider audience.

Credit to Copern for the error handling in the RGSS script, which is based on his version.

 

[Zeak6464]

where is the "GitHub repository" ?

 

[ArchyTheArc]

where is the "GitHub repository" ?

simple mishap their side, its on the RC page but here :https://github.com/boonzeet/rpgmaker-palette-swap
im sure they'll add it when they realise though

 

[Boonzeet]

where is the "GitHub repository" ?

simple mishap their side, its on the RC page but here :https://github.com/boonzeet/rpgmaker-palette-swap
im sure they'll add it when they realise though

Yep, my bad! I've updated the post with the link. Thanks for providing it!

 

[pansygum]

Hello, and thank you for sharing your resource!

By my understanding, this allows you to edit the displayed colors that essentials uses when showing an image. So you could change all of the red pixels on trback000.png to blue whenever it is displayed, or something like that. Is that correct?

Also, when you say to call it - does that mean you'd call it from within an event in RMXP (using the Script command), or you'd call it from within a script that you'd need to write?

Again, thanks for sharing.

Edit: I've been tinkering around trying to figure this one out. I have the .dll in the root folder. I've added the script above main, and am calling it from within an event using the Script command. I've checked and double checked that my filepath to the .png is correct, and that the string that contains the RGB color combos is correctly formatted, and am using the RGB numbers from Photoshop when I select the color. When I interact with the event, I don't get any errors, but also none of the colors change on the event's graphics. I figure there must be something simple that I'm missing here!

 

[Boonzeet]

Hello, and thank you for sharing your resource!

By my understanding, this allows you to edit the displayed colors that essentials uses when showing an image. So you could change all of the red pixels on trback000.png to blue whenever it is displayed, or something like that. Is that correct?

...

Yes, if you input red and blue on the respective palettes all red pixels would be colored blue.

This library only works with a passed-in Bitmap, and it doesn't store or save it anywhere. You'll need to write a command to save it to file, or explore if event graphics can be set to Bitmaps (I've not tried this).

filepath = "file-example.png"
bmp = BitmapCache.load_bitmap(filepath)
bmp.colorize!("255,0,0", "0,0,255")
bmp.saveToPng("Graphics/Characters/example.png")

Here's a bit of mock code how that could work