Int To Object

[_PJ_]

(Technically this is NG issue, but I am assuming it is the same in "vanilla" BMax)

So I was wanting to automate the process of building a palette library for a bunch of sprite images (so I can later simplify the images and also do some code-based palette swapping etc)

but I ran into some issues with trying to make a list of the pixel values, as the TList commands refer to Object arguments.

Usually, Strings and whatever can simply recast as "Object" but not Integers it seems:::

Here's a simplified example:

Code Select Expand

Global Palette:TList

Local Image:TPixmap=LoadPixmap("Test.png")

For Local Y:Int= 0 Until Image.height
	For Local X:Int= 0 Until Image.width
		Local Pixel:Int=ReadPixel(Image,X,Y)
		If ( Not (ExistInPalette(Pixel))) Then AddToPalette(Pixel)
	Next
Next

DebugLog("Found "+Palette.Count()+" colours")


Function ExistInPalette:Byte(Pixel:Int)
	If (Palette=Null) Then Return False
	Return Palette.Contains(Pixel)
End Function

Function AddToPalette(Pixel:Int)
	If (Palette=Null) Then Palette=New TList
	Palette.AddLast(Pixel)
End Function

Working with an array may be easier, iterating through each array item, but I don't know how big the array may need to be in advance...

[Sledge]

You might be better off with an IntMap rather than a List:

https://blitzmax.org/docs/en/api/brl/brl.map/tintmap/

You could use the Int pixel values as keys (the actual value the key returns wouldn't really matter -- a string representation of the key would be my choice). You can check for a key before adding via Contains(), then at the end of the process get a collection of all the keys with Keys(), which would be your entire palette.

It's a bit of a weird case for a Map because the keys themselves are the values that you care about, but hey ho!

[Midimaster]

Code Select Expand

Local Image:TPixmap=LoadPixmap("Test.png")

For Local Y:Int= 0 Until Image.height
	For Local X:Int= 0 Until Image.width
		Local Pixel:Int=ReadPixel(Image,X,Y)
		TPalette.Add Pixel
	Next
Next

Type TPalette
	Global List:TList= New TList
	Field Pixel:Int

	Function Add(Pixel:Int)
		If Contains(Pixel)=True Then Return
		Item:TPalette = New TPalette
		Item.Pixel = Pixel
		List.AddLast Item
	End Function 

	Function Contains:Int(Pixel)
		For Local Item:TPalette = EachIn List
			If Item.Pixel=Pixel then Return True
		Next 
		Return False
	End Function 
End Type

[_PJ_]

Awesome!
Thanks so much for the qwuick replies

@Sledge I am not very familiar with the "Map" types and so was a little intimidated to try and risk overcomplicating and making things a lot worse - but thanks for the explanation - it would certainly be a neater approach!


@Midimaster - Thanks. I guess having the Pixel explicit cast as integer within the type scope and then using a custom iteration "contains" helps the compiler to interpret the Object?

What's funny as I originally wrote a function with similar iteration and equivalence check, but then changed it when I remembered the "contains" method

[Midimaster]

...using a custom iteration "contains" helps the compiler to interpret the Object?...

No it is the Local x:Type EachIn, that picks only the searched type in a list.

If your list contains objects of different types then the code line...

For Local Item:TPalette = EachIn List

... already casts and limits the iteration to only one type.

[_PJ_]

Got it!

Thanks, Midimaster