[Tuxpaint-users] How to make a Starter coloring book image

[Bill K. <nb...@so...>]

Hi everyone!  Someone emailed me privately today, asking for help getting
some JPEG images put into Tux Paint to use for coloring.  I replied with
some instructions, and ended up focusing on preparing an image using
The Gimp (since it's also Open Source and runs on Windows, Mac and Linux),
and was planning on creating some "official documentation" based on my
emailed instructions.

I thought I'd post the instructions here, first, to get feedbac from other
Tux Paint users.  (Do the instructions make sense?  Easy to read?  Etc.)

Thanks in advance for any comments/suggestions/improvements! ;^)

-bill!


What you need to do is find the "starters" folder in Tux Paint's folder
on your system.  (If you're using Windows, it should be under
"C:\Program Files\TuxPaint\starters", assuming you installed Tux Paint in
the default location, using the installer version, and not the ZIP-file
version of Tux Paint.)

Inside you should find the four Starters that came with Tux Paint 0.9.14.
Two are coloring-book-outline style: a chicken and an airplane.
The other two are photographics: a coral reef and a skyline.

You should see these same pictures when you hit the "Open" button from
within Tux Paint.  (In the future, we might move these into a new dialog
that will appear when you hit "New", but we haven't worked on that yet.)

If you load either of the coloring book images in a more professional
graphics program, like Photoshop, Paint Shop Pro or The Gimp
(the latter of which is free, Open Source software, like Tux Paint),
you'll notice that it is actually a black outline on top of transparency
(no color).

So if you're interested in making coloring-book images with the current
version of Tux Paint, you'll need to load them -- you said they were JPEG --
into something like The Gimp, and then remove the white background.
Then save it in PNG format, which is what Tux Paint prefers.  (You CANNOT
use JPEG, since it doesn't have a concept of "transparent", which is
currently a requirement in Tux Paint.)

The "PNG" documentation in Tux Paint explains a little more about this:

  http://www.newbreedsoftware.com/tuxpaint/docs/PNG.txt


What you'll need to do is tell the professional paint program
"turn white into transparent", and then simply save the image as a PNG
inside Tux Paint's "starters" folder.

In The Gimp, you can do this using the "Select Regions by color" tool.
(It looks like a little hand with a finger pointing at a box of color.)
Once you pick that tool, simply click any white pixel in your image
and it should select ALL of the white in the image.

Of course, if the image was scanned, or was stored as a JPEG, not all
white pixels will be exactly the same color white.  You can tell Gimp to
be a little more sloppy when by increasing the tool's "Threshold".
Double-click the "Select Regions..." icon in Gimp's toolbox and a
"Tool Options" dialog should appear.

Once you have all of the white selected, you need to turn it transparent,
so that Tux Paint will let the kids draw on the transparent bits.
First, make sure you CAN.  In the image window's menubar, select the
"Layers" menu and find the "Transparency" sub-menu.  Click the
"Add Alpha Channel" item.

Finally, hit Ctrl+K (or use the "Edit->Clear" menu item) and all of the
white in the image should turn into a kind of checkerboard pattern.
It's not transparent!

Do "File->Save As..." and save the image with a ".png" extension
inside Tux Paint's "starters" folder, and then, from within Tux Paint,
click the 'Open' button.  You should see your picture towards the top
of the thumbnail listing.

Open it, and you should be able to draw 'behind' the outlines.
(Everywhere that appears as white inside Tux Paint.)


From a technical standpoint, all Tux Paint is doing is re-drawing the
starter image _on top_ of the canvas, every time you draw or stamp in
Tux Paint.  The result is that the opaque parts of starter image are
immutable.


-- 
-bill!
bi...@ne...
http://www.newbreedsoftware.com/