Now that we've had some fun and created some true art, it's time to find out what all those icons in the GIMP toolbox do. Before we do this, however, we should look at those two boxes at the bottom of the toolbox because what they offer affects what the icons do.
The block on the right is the color menu (Figure 16-19). It gives you quick and easy access to foreground and background colors. The black and white squares on the left can be changed to other colors by double-clicking on one or the other. If you click on the arrow between the two, you switch between foreground and background colors.
The box to the right is a quick dialog menu and really consists of three different tools: a brush selector, a pattern selector, and a gradient selector. Click on any of them to bring up the list of choices each provides (Figure 16-20).
If you select a different gradient, pattern, or brush from the resulting menus, you'll see them change on the dialog menu at the bottom of the GIMP toolbox, as well. This gives you a quick visual feedback on what brush, pattern, or gradient is active at the moment.
Start by moving your mouse over the various icons, pausing over each one. Tooltips will appear, telling you what tool each of the icons represents (I'll go over these in a moment). If you double-click on any of these icons, a new window will appear, providing you with that tool's options (Figure 16-21).
So what are all those icons for? An excellent question. Let's look at them again, one row at a time, starting with?you guessed it?the first row (Figure 16-22).
The first icon, represented by a dotted rectangle, lets you select a rectangular area. Just hold down the left mouse button at whatever point you choose for a starting corner, and drag it across your image. A dotted line will indicate the area you've selected. If you hold down the <Shift> key at the same time as the left mouse button, your selections will always be perfect squares.
To undo changes, press <Ctrl+Z>.
The dotted circle icon next to it is much the same except that it selects circular or elliptical area. Similar to the rectangular select, you can hold down the <Shift> key along with the left mouse button to select only perfect circles.
Next, we have the lasso tool. This is another selection tool, but this one lets you select irregular or hand-drawn regions. Hold down the left mouse button and draw your selection around the object.
When you have selected an area on an image, you can right-click, move your mouse cursor over the Edit menu, and select Cut or Copy. You can then Paste your selection back to another part of the image.
Then comes the magic wand. This is a strange tool to get used to. It selects an area by analyzing the colored pixels wherever you click. Holding down the <Shift> key lets you select multiple areas. This is a very useful tool but also a little tricky. Double-click on the icon to change the sensitivity.
Finally, we wrap up the first row with the Bezier tool, which to be honest takes some getting used to. Once you get used to it, however, you'll be impressed with the flexibility it affords you in selecting both straight and curved areas. Click a point outside the area you want to select, and it creates an anchor point. Click again a little further along your outline, and you get new anchor points with a straight line connecting to the original. Click and drag an existing anchor point, and a bar will appear with control boxes on either end. You can then grab those control points and drag or rotate them to modify the straight line between the points. Once you have joined the final point, click inside the outlined region, and this completes your selection (you'll see an animated dotted line, as with the other selection tools).
That wraps it up for the first row of tools. It's time to look at the next set (Figure 16-23).
We've still got one last selection tool to look at, the so-called intelligent-scissors. These will remind you somewhat of the Bezier tool, in that you select an area by clicking around it. What this tool does that the other does not is follow curved lines around an object. It does so by concentrating on areas of similar contrast or color. Simply click around the perimeter of the area you wish to select and watch the lines magically draw themselves. When you join the last dot, click inside the area to select it.
The second icon on the second row looks like a cross with arrows pointing in all directions. This is the move tool. It is really quite simple. Click the tool, then grab the selected area on the screen and move it to where you want. If you haven't selected an area, you can move the entire image in the window.
The magnifying glass does exactly what you expect it to. Click an area of the screen to zoom in. Double-click the icon to reverse the zoom. This doesn't actually scale the image, it just changes your view of things. Zoom is usually used to make it easier to work on a small area of the image.
On to the knife icon?the crop tool. I use the crop tool all the time when I am trying to get a small part of a larger image. It is what I used to separate the rows of icons from the GIMP toolbox image I captured. Click on a part of the screen, drag it to encompass the area you want to keep, and click Crop when asked to confirm. You can also fine-tune the settings (X and Y position, etc.) at this time.
The final item on this row is the transform tool, and it is really quite interesting. By default, this is a rotation tool. Click on an image (or a selection), and a grid will appear over your image or the selection. Grab a point on the grid, drag the mouse, and the grid rotates. When you have it in a position you like, click Rotate on the pop-up window that appears. The image will lock into place. But that's not all: Double-click on the transform tool icon, and three additional capabilities appear?scaling , shearing, and perspective.
On to row three (and Figure 16-24).
The first box is the flip tool. By default, it flips the image horizontally. Double-click the icon to bring up the menu, and you can change it to flip vertically.
The next icon is the text tool. That's what the big T signifies. Click on your image, and the font selection box you used for your logo will appear. Select a font, type in your text in the Preview section, and click OK. Where the text appears on the screen, the move tool will be activated, allowing you to place the text accurately. The color of the text will be your current foreground color.
The third icon looks like an eyedropper. This is the color picker. Choosing an exact color can be difficult (if you need to get the tone just right), but if the color you want is on your existing image, click on that spot, and you've got it (your default active color will change).
Closely related to this is the fourth button on the third row, the paint can. This is the fill tool. It can fill a selected area not only with a chosen color but with a pattern, as well. To choose between color and pattern fill, double-click on the icon to bring up its menu.
The last item on this line is the gradient fill tool. Start by selecting an area on your image, then switch to this tool. Now click on a spot inside your selected area and drag with the tool. The current gradient style will fill that area. This is one of those things you almost need to try in order to understand what I mean.
And now . . . row 4 (Figure 16-25)!
The first icon looks a pencil. In fact, this and the next three buttons all work with a brush selection (the bottom right-hand box). This pencil, as with a real pencil, is used to draw lines with sharply defined edges. Try drawing on your image with the different types to get an idea of what each brush type offers.
Would you like a blank canvas right about now? Click File on the GIMP toolbox menu bar and select New.
The next icon is the paintbrush. The difference between it and the pencil is that the brush has softer, less starkly defined edges to the strokes. Double-click the icon to bring up the paintbrush's menu and try both the Fade Out and Gradient options for something different.
If the next icon looks like an eraser, that's no accident. The shape of the eraser is also controlled by the current brush type, size, and style. Here's something kind of fun to try. Double-click on the icon to bring up its menu, then change the Opacity to something like 50%. Then start erasing again.
Now it's on to the airbrush tool. Just like a real airbrush, you can change the pressure to achieve different results. Hold it down longer in one spot, and you'll get a darker application of color.
Finally, we have the clone tool (the icon looks a bit like a rubber stamp). Sheep? No problem! We can even clone humans. Okay, that's a bit over the top. Where the clone tool comes in handy is during touch-ups of photographs. Open an image, hold down the <Ctrl> key, and press the left mouse button over a portion of the image?the tool will change to a crosshair. Let go of both the mouse button and the <Ctrl> key. This is your starting area for cloning. Now move to another part of the screen, click, and start moving your mouse button (the shape of the area uncovered is controlled by the brush type). As you paint at this new location, you'll notice that you are re-creating that portion of the image where you indicated with the <Ctrl+mouse-click> combination. Start with someone's head or body, and you can have twins on the screen.
And now, the last row of icons (Figure 16-26)!
The droplet you see on the first item represents the convolver tool. It is used to blur or sharpen parts of an image. You switch between the two operations by double-clicking the icon and selecting the operation you want. Change the rate to make the effect more pronounced.
Next we arrive at another drawing tool, the pen, or ink tool. Double-clicking the icon brings up a menu that lets you select the tip style and shape, as well as the virtual tilt of the pen. The idea is to mimic the effect of writing with a fountain pen.
The dodge and burn tool looks like a stick-pin, but those who have worked in a darkroom might recognize it for something different?a stick with an opaque circle on the end of it. It is used to adjust the brightness or shade of various parts of an image (a photograph might have been partly overexposed).
On to the finger, or the smudge tool. Pretend that you are painting. You press your finger on the wet paint and move it around. The smudge tool has exactly the same effect on your virtual canvas.
Finally, we round up tools with the calipers, or measuring tool. This doesn't actually change anything on your image but reports. Click a starting point on the image, then drag the mouse pointer to another part of the image. Now look at the bottom of your image window. You'll see the distance in pixels from your starting location to where you let go of the mouse pointer. The angle of the line will also be displayed.
I've mentioned the idea of touching up photographs on a few occasions while I discussed the tools. The GIMP is a wonderful tool for this and more than just a little fun. One of the most common functions I use is changing the light levels on photographs, automagically and instantly. After all, light levels are rarely perfect unless you are a professional photographer and paying attention to every shot. Here's what I do.
Right-click on the image to bring up the GIMP menu. Now move to the Image submenu, move over to Colors, and select Levels. You should see a window like the one in Figure 16-27. Notice the Auto button? That's where the magic is. I've found that more often than not, you can get a nice, dependable reset of levels just by doing this simple operation.
We can also modify contrast, brightness, or color, but there are also the silly and just plain fun things we can do.
For instance, open an image in the GIMP, perhaps one you scanned in earlier. If you don't have something handy, grab an image from a Web site. This is just something to play with. Now right-click on the image and choose Filters by moving your mouse to that part of the menu. A submenu will open with even more options. You might want to detach this menu?you'll certainly want to play with what is there.
Try FlareFX under the Light Effects menu. If you've ever taken a flash picture through a window, you'll recognize this effect. Then try Emboss under the Distorts submenu. The effect is that of a metal-embossed picture (Figure 16-28).
Take some time to try the various filter options. When you are finished there, right-click on a fresh image and select the Script-Fu menu. There are other interesting effects available here, as well, such as Clothify under the Alchemy submenu. Your image will look as though it had been transferred to a piece of cloth.
Although it sounds like a strange form of martial arts, Script-Fu is in fact a scripting language that is part of the GIMP. With it, you can create scripts that automate a number of repetitive tasks to create desirable effects. When you created your logo, you might have noticed that a number of things were happening as it was being created. Try another logo and watch carefully what is happening. These steps are part of a Script-Fu script.
The GIMP comes with a number of Script-Fu scripts, and these are used for much more than just creating logos. Click Xtns on the GIMP toolbox, and scroll down to the Script-Fu menu. In addition to logos, you'll see options for creating buttons (for Web pages), custom brushes, patterns, and more. Play. Experiment. Don't be afraid.
Open an image. Then right-click on that image and scroll down to the Script-Fu part of the menu. Another menu drops down with selections such as Alchemy, Decore, Render, and so on. These are all pre-created effects that would ordinarily require many repetitious steps. Script-Fu is very much like a command script, where one command follows another. In this case, the commands just happen to be graphical transformations.
You can make some pretty cool images with the GIMP with just a little knowledge, but with time and further exploration, you can take that cool to the level of amazing. Make no mistake, the GIMP is a professional-grade tool, and covering it in detail would fill a book of its own.
Consider a visit to the GIMP home page at www.gimp.org for the latest developments, software, and links to other GIMP documents. Some great books specifically cover the GIMP. Visit your local computer bookstore, and have a look through the titles. I'm particularly fond of Michael J. Hammel's book, "Artist's Guide to the GIMP." Another title I've enjoyed is Joshua and Ramona Pruitt's "Teach Yourself GIMP in 24 Hours."