[Newbies] Coloring images with transparant parts

[Bert Freudenberg]

Off the top of my head, this should make a nice rainbow palette:

	anArray := (1 to: 256) collect:
		[:i | Color h: i*360/256 s: 1 v: 1].
	someColorForm colors: anArray.

So basically the color map is simply an array of Colors.

- Bert -

On 22.11.2008, at 13:07, Matthias Korn wrote:

> Hi Bert,
>
> I have quite a hard time understanding how to use color maps. And I
> really did not find any helpful documentation on them for Squeak.
>
> One example I found in the image is in BitBlt class>>exampleColorMap.
> But I don't know how to use it with a Form/BitBlt, well, and what the
> heck they are actually doing there...
> In most occasions they used the Bitmap class instead of ColorMap and I
> couldn't find anything to convert.
>
> Could you provide a simple code example on how to modify the color
> map of a Form? Or any other pointers....
>
> Thanks a lot,
> Matthias
>
>
> Am Sat, 22 Nov 2008 01:58:33 +0100
> schrieb Bert Freudenberg <bert at freudenbergs.de>:
>
>> On 22.11.2008, at 01:15, Matthias Korn wrote:
>>
>>> Hi,
>>>
>>> thanks for your hints. I also found ColorForm>>replaceColor:with:
>>> which
>>> does what you describe. But it is unfortunately not what I was
>>> looking for. I wasn't very clear in my original post:
>>>
>>> I (now) have a gray-scale image which I want to colorize, that is I
>>> want to change the hue of the image and not just replace a color
>>> with another (or floodfill for that matter).
>>>
>>> Hope you guys have some ideas. I tried searching with the Method
>>> Finder,
>>> but my poor english didn't take me very far.
>>
>>
>> Use a color map. Your grayscale image could be 8 bits, so with a 256
>> entries palette you can map that to any color(s) you want. Color
>> maps are used in ColorForm, or directly with BitBlt.
>>
>> - Bert -
>>
>>
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>
>
> -- 
> Matthias Korn
> Institut für Wirtschaftsinformatik
> Fachbereich 5
> Universität Siegen
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