08 Lesson 5: Basic Drawing Tools

For this lesson we'll take a step back from photographs, and
learn how to use the gimp for drawing.

Let's start with a blank canvas: File->New. You can make it any
size you want, but it might be best to give yourself some space,
say 640x480 or larger.

A New Image window will open up filled with the current background
color. It's probably white, if you haven't changed it, and that's
a good canvas color for practicing drawing, though you can use any
color you like.


The two main drawing tools are the Pencil (draws hard-edged lines)
and the Paintbrush (draws fuzzy-edged lines). For both of these
tools, you can change the width of the stroke by changing the
"brush". The current brush is shown at the bottom right of the
toolbox, just to the right of the foreground/background color
swatches. It's probably a small black circle by default.
Click on it, and the brushes dialog comes up (you can also get
the dialog through the menus, File->Dialogs->Brushes).
In gimp2, you can also change the brush through a dropdown menu
in the Tool Options part of the toolbox.

Some of the brushes are silly, like the pepper. But play around
with what's there and get an idea what they all do. Go ahead and
scribble! Try changing color, brush, and tool.


What if you want to draw a straight line?

That's easy: shift-click. Click once (without the shift key) where
you want the line to start, move to the other end of the line, and
hold down the shift key. Gimp will show you where the line will be:
and when you click (still holding shift), it will draw a straight
line, using the current tool, color, and brush.

This might be a good time to mention guides. If you ever need to
position something accurately -- a selection, a line you're drawing,
or a layer -- if you click on the ruler to the left of the image,
and drag right, out into the image, you'll see a line follows you.
That's a guide. When you release the mouse button, the guide will
stay where you put it (and if you need it at a specific location,
just watch the coordinates in the lower left corner of the image
window until the coordinates are what you want). Similarly, you
can drag from the top ruler, down, to get a horizontal guide.
You can make as many guides as you want. They're not part of the
image: they're just hints to help you position things accurately.
If you make a selection and drag near a guide, the selection will
"snap to" the guide. This is especially helpful for positioning
elliptical selections.


A few other line drawing tools:

Airbrush draws fuzzy lines that get bigger if you stay in one place.
Ink Pen draws with an asymmetric brush -- it's good for calligraphy.
Both these tools also respond to pressure if you have special hardware
like a drawing tablet.
Eraser: erases to the background color (or to transparent, if the
layer you're drawing on has transparency).

Finally, you can clear (erase) an area by selecting it, using any
selection tool, then doing Edit->Clear. This is bound to Ctrl-K
(like "clear to end of line" in the shell, emacs or most other
linux programs) and I find I use it often enough that I usually
use the key binding rather than the menus.

Drawing, like most things in gimp, is undoable. If you've been
scribbling away trying out some of these things, try undoing now:
hit ctrl-Z repeatedly and watch your lines and squiggles disappear
one by one, until you hit the limit of Gimp's Undo buffer. (This
is configurable: in File->Preferences there's a setting for the size
of the undo stack. Larger means more room for correcting oopses, but
gimp will take up more memory.)


Most of the time, the Bucket Fill tool is the one to use when you want
a filled shape, like a circle or rectangle.

First make a selection where you want the shape to be, using the
rectangle or ellipse selection tool from lesson 4. You might even
want to try the free select tool -- also known as the "Lasso tool" for
its icon in the toolbox. This lets you make a selection of any shape,
as long as you can draw it in one go without releasing the mouse
button. You can even use free select to cut out shapes or people from
an image -- but there are easier ways of doing that, as we'll discuss
in a later lesson.

Then select Bucket Fill -- it looks like it's pouring paint from a
paint can -- and click inside the selection. It should fill with the
foreground color.

Bucket Fill has some interesting options, though. First, you can
"fill whole selection" or "fill similar colors". "Whole selection"
is obvious, and is most often what you want. "Similar colors" is a
bit trickier: you can click on a pixel in a photograph, and bucket
fill will try to fill nearby colors that are "similar enough" to the
place where you clicked. You can adjust how similar they need to be
with the Threshold slider. This can do strange things to your image;
try it, if you have a photo loaded in gimp, but don't be surprised
if you have to Undo.

In addition, you can also bucket fill with a pattern. Try it:
click Pattern Fill in the tool options dialog, select an area in the
image, then click inside it.

The currently chosen pattern is shown in a little square in the
toolbox, just to the right of the active brush. Clicking on it
brings up the Patterns dialog, where you can choose from a wide
selection. Try some of them! Click on a pattern in the Patterns
dialog (notice that the active pattern shown in the toolbox changes),
then go back to the image and click on your selection again.


Two final tools left to mention. One is the eraser (located near the
paintbrush), which does the obvious. The other is that whenever you
have something selected, you can Edit->Cut or Edit->Clear to erase the
whole selection. (The difference is that Cut copies it so that you
can paste it later, whereas Clear just erases it.)

Here's the image I have left after scribbling around while writing this
lesson. It looks like something a five-year-old made with Tux Paint. :-)


For this lesson, we started with a blank canvas. But you can draw
on top of a photo, too! For instance, how about cartoon thought
bubbles, like Poppy's cat had in Lesson 4?

I'll start with a photo of my last manager's dog, Polarbear, who used
to brighten up our group meetings. Here he is at a meeting:

Now I need some text. I can't make the thought bubble until I know
how big the text is going to be. The text is in its own layer.

Now I'll make a new layer to hold my thought bubble. I very strongly
recommend that you make a new layer for any drawing you do on top of
an existing image. Any drawing you do in this layer will be optional:
if you erase, you'll erase your drawing, not the original image, and
if you decide you don't like your drawing, you can throw it all away
and the image underneath will be fine.

Go to the Layers dialog, and click the New Layer button. The new
layer needs to be transparent (which should be the default). In the
"Create a New Layer" dialog, I'll change the layer name to be "thought
bubble" so it will be easy to remember which layer is which. You
don't have to name your layer, but it will make things easier later
when you make image with lots of layers. I click OK, and the new
layer is created.

But here's a tricky part: I need the thought bubble to be underneath
the text, not on top of it. The bubble layer needs to be in between
the Background and the text layer. Right now, the thought bubble is
on top, and if I draw a white area on it, that white area will hide
the text behind it.

I solve this by clicking the down arrow button in the Layers dialog to
move the "thought bubble" layer down. The down and up arrows always
move the currently selected layer.

I'm finally ready to draw! I'll make my bubble oval: I use the
elliptical selection tool until I have an oval just the right size.
Then switch to the bucket fill tool, set the color to white (or pick
"BG color fill" if the background color is already white), and click
inside the oval but not on top of the text. Voila! A white thought
bubble layer under the text. Now it looks like this:

Notice that the text isn't really centered on the bubble? It's fairly
difficult to control exactly where an elliptical selection will end
up, but that's okay: all I have to do is switch to the move tool, and
drag the bubble layer around until I'm happy with its placement.
(Notice that you can still see the selection outline, and it's no
longer lined up with the bubble. I use Select->None to get rid of
the selection once I no longer need it.)

I'm not quite done yet, though. I still need some dots
to link the thought bubble to the coot doing the thinking.
I can either make another new layer for that, or draw it on the
thought bubble layer. I'm going to make a new layer for it.
Why? (1) it means I can change to a different shaped thought
bubble layer, and (2) it means I can change my mind later about
which bird is doing the thinking, and replace just that part.

It isn't critical whether this new layer is above or below the thought
bubble layer or text layer, because it won't overlap with either one
of them. It's only when layers overlap that you need to worry about
which one is on top.

On this new layer (I called it "bubbles") I'll make several small
circular selections and fill them each with white:

But there's still something missing. The small bubbles are hard to
see against that busy background. Okay, class, what do we do when we
want to make something stand out? You, there in the second row.
That's right! A drop shadow! I make a drop shadow on the thought
bubble layer, and another one on the bubbles layer.

Here's the final image:

Since I made the thought bubble layer separate from the bubbles layer,
I can even go back and try a different shape of thought bubble.
If I toggle visibility off (remember, click on the "eye" icon in the
layers dialog) on the thought bubble and its drop shadow, then use
the lasso select tool to draw a puffy-cloud shape, fill it with
bucket fill, then add a drop shadow, here's what I get:

Don't forget to save your image as .xcf as well as a .jpg! That way
you can go back and make changes to any of these layers at any time.
Mine is here (and you can see where I tried another set of bubbles,
but decided they didn't work as well so I didn't use them):

If you look at the xcf in gimp, you may notice that I've renamed
all the various drop shadow layers. I was getting confused keeping
track of which shadow layer went with which bubble, so I doubleclicked
on each shadow layer and edited the name that way.

Here's what my layers dialog looks like now (GIMP can take a screen shot
of any window, with File->Aquire->Screen Shot, then click on the window):

Homework: either a drawing on a blank canvas, or something drawn
on top of an existing image. Be silly! Be creative! Have fun!

Next lesson: Removing unwanted objects from photos.