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Files and Preferences

The File Menu

In Gimp, you can get to the File menu in two different ways: via the Toolbox, and viathe right mouse buttonin an image window. The menus are slightly different in the two places.

In the Toolbox File menu, you will find the following menu items:

• New
• Open
• About
• Preferences
• Tip of the day
• Dialogs
• Quit

And in the Image File menu you will find:

• New
• Open
• Save
• Save as
• Preferences
• Close
• Quit
• Mail
• Print

In the Xtns menu (in the Toolbox), you will find:

• DB Browser
• Gimptcl Consolio
• Guash
• Screen Shot
• PDB Help
• Waterselect
• Script-Fu
• Web Browser

We will discuss all of these menu items, except for Dialogs and Script-Fu, in this chapter.

Creating Images

Let's start by creating our first image. Choosethe File menu in the Toolbox, and select New. This will bring up the dialog box shown to the left:

Here you must decide the size of your image in pixels, whether your image should be grayscale or RGB, and whether it should have a solid background or be transparent.

As you can see, there are two types of solid background available: Background and White. White will produce a white background, whereas Background will produce a colored background based the background color in the Toolbox (more about that in chapter 7). Transparent results in a checkerboard-like background that signifies transparency. This is a nice feature if you are creating transparent GIFs.

For now, let's stick to the default values; just press OK. Now you have a new image that you can start working with. Let's close the image by choosing Close in the <Image> Filemenu. This will close your image, as opposed to Quit, which will both close your image and quit Gimp.

You may wonder why you can't create an indexed image (that is, an image with a small, fixed number of colors) at once, for the nice GIF for the Web that you're trying to make. The reason is that it's impossible for Gimp to guess which colors you will want to use in your image. Also, it's usually a very bad idea to start out with an indexed image. You can of course still create GIFs by converting the image from RGB image to indexed color (see chapter 12). The rule of thumb is: Always work with RGB, and don't convert it until you're finished with it. The same goes for every other indexed file format.

Guash

One of the best things about Gimp is Guash. If you have worked on a Unix system before, you have probably used XV and its Visual Schnauzer, which enables you to load images via a graphical interface, that shows thumbnail representations of your images. If you are a former Mac and Photoshop user, and are used to the small thumbnails in an image directory, then you're going to love Guash. Guash lets you browse your home directory and see all of your images as small thumbnails.

To start up Guash, select it via Xtns/Guash. When you first start up Guash, it will scan your home directory for all of the images that Gimp can read. When it comes across a PostScript file, a dialog box will appear in which you may press Load to load the image, or select Cancel to skip that file, since loading PostScript files can take some time. Because Postscript files are sometimes many pages long, they also have the potential to take up a great deal of space in the gimpswap file. In other words: load PostScript files only if you need to, and only load the first page in any case.

The scanning procedure can take anywhere up to five minutes depending on the number of images in the directory being scanned. To load an image into Gimp, simply double-click on it (one click will select it, the second will open it), and it will open in a regular Gimp window. As you can see, Guash only displays N directories or images at a time. To alter Guash's behavior you must edit the gimprc file in your .gimp directory:

• (guash-ncol "5") changes the number of columns (valid range is 4 to 10);
• (guash-nrow "3") changes the number of rows (valid range is 2 to 10); and
• (guash-keybindings "emacs") enables Emacs key-bindings.

If you click on a thumbnail, it will be selected and highlighted with a red frame. If you click once more on the highlighted image, it will be loaded into Gimp. To select or deselect further images hold down SHIFT and click on their thumbnails. If there are no selected images in Guash, pressing the right mouse button will bring up a root menu. If any images are selected, a select menu will pop up allowing you to perform various operations on the selected images. All of the items on the menus are easy to use and learn. To get the root menu when images are selected, hold down Shift and press the right mouse button.

In Guash, you can do all sorts of things like moving, copying and deleting images, and creating directories. You can even apply Unix commands, and more importantly, Script-Fu "commands" to your images. This is all possible from either menu. The Jump menu item brings up a quick way to change directory. In the Jump menu, you have short cuts to directories you've already visited. You can also bring up a file dialog, which makes it simple to move quickly to another directory. We recommend using the Jump menu because moving around within Guash is quite slow, since Guash has to scan every directory for images.

Opening Files

Now we'll open an image using File/Open. This will pop up a file selector dialog box that allows you to browse filenames in order to select the image you want. In the Determine file type menu you can choose what kind of file you want to open, or let Gimp do it automatically. It's a good idea to let Gimp figure out what kind of file it is. It's only when Gimp has a hard time determining what kind of image you are loading that it's advisable to use the non-automatic options.

Familiarize yourself with the interface by opening some images in the usual formats like GIF, JPEG and TIFF. Later in this chapter we'll discuss what kind of formats Gimp can read and write.

Tip: Gimp expands your file name so that you only have to type the beginning of the name and then press Tab to get the rest, just as you would in bash or tsch.

The Open dialog box also allows you to delete and rename files. To do this, simply select the file that you want to delete or rename and press the corresponding button. This will bring up a confirmation dialog box. In order to create a directory, press the Create Dir button, and a dialog box will prompt you for the name of the directory.

Just remember to double-click on the "./" current directory symbol to update the dialog, otherwise you will not see the new directory (this goes for files too: If you can't see the file, double-click "./" and the directory will be updated). The possibility to create directories in the Open or Save As dialogs is quite handy, since you often want to save an image in a new directory where you put all new images with a certain theme.

Opening Postscript and PDF Files

The Open dialog box for Postscript and PDF files is shown to the left. Our advice is to notchange any values here if you're going to print it at home or in the office - the default values are fine when displaying the paper formats that are normally used for PostScript files.

If you lower the resolution you'll also have to reduce the width and height of the image canvas (and vice versa for increasing the resolution). If you don't change the width and height when you increase resolution, only part of your PostScript file will be displayed. If the width or height exceeds the size of your PostScript file, the display will automatically be adjusted.

If you uncheck the Try BoundingBox checkbox, the pages will be stacked over each other, otherwise, they will be displayed side by side. The Pages entry allows you to specify what page, or page interval to display; for example "1-99" specifies page 1 to 99, and "75" specifies page 75. (If your PostScript file has fewer pages than the numbers you specify, they will be adjusted automatically).

Selecting B/W will produce a black and white image from a color PostScript file, Grayscale or Color will produce a grayscale respectively a colored image. Automatic will produce whatever type of image the Postscript file was created as. You can of course never obtain a colored image from a B/W PostScript file, even if you select Color.

You can also specify how fine the antialiasing will be for text and graphics. If you only want a quick look, then select None or Weak, if you want to edit the file and produce high-quality result then select Strong. Naturally, there are exceptions to this rule; if you only want to alter a few minor details in the PostScript file without altering the whole thing, then it's wise to open with None; otherwise it will change the entire file when you save it.

Saving Images

Gimp naturally lets you save the images you have created. Isn't it wonderful? A free program with save abilities!It's not like when you get Photoshop for free in demo mode, where "save and print are disabled, this is a demo copy".

You may access the Save dialog box via the right-mouse-button menu in the window that contains the image you want to save. The Save dialog is exactly the same as the Open dialog box, except that the Determine file type menu is a bit different: the default in this context is By extension. This means that the format of the resulting image depends upon the image filename's extension. For example, if you name your imagehello.gif it will automatically be saved in GIF format. You can of course choose to save hello.gif in TIFF format, by selecting TIFF in the Determine File type menu, but this is highly discouraged. If you want to save a file without an extension, then you must choose the file type from the menu. Remember to flatten the layers in your image before you save it, unless you are using the XCF format ( Gimp's native file format) or creating a GIF animation.

Gimp supports many different file formats; how many depends on which plug-ins you have installed. Yes, as with many things in Gimp, file format support is implemented via plug-ins. Examples of plug-ins are the mail and print plug-ins, and of course all the filters. We will discuss plug-ins in general later on in this manual; but for now, we will concentrate on the file format plug-ins that are included in the base Gimp distribution.

Su pported File Formats

The list below lists the file formats that Gimp supports for reading and/or writing..

TABLE 1.  File Formats

• XCF is the native Gimp format. It supports layers and other Gimp-specific information. If you save your image in a different file format, all Gimp specific information will be lost, and you won't be able to open and edit your layers anymore (GIF supports layers in that each layer becomes a frame in a GIF-animation). Note that only the active layer gets saved when you save an image in formats other than XCF and GIF. So, for example, if you want to save a layered image in TIFF format, make sure you flatten it before you save it.

The following is a brief description of the different file formats. For more information on file formats, see appendix E about graphics books and links.

• BMP: This is an uncompressed bitmap format used by Microsoft Windows for displaying graphics. Color depth is typically 1, 4 or 8 bits, although the format does support more.
• Bzip: Lets you open and save bzip'ed images. The name of the file must be <name>.<well-known suffix like tiff>.bz.This format is ideal for saving large, multi-layered XCF images. Bzip compression is a little bit better than gzip.
• CEL: This is the file format used by KISS programs.
• FaxG3: This is the format used by faxes. It's very useful if you have a fax connected to your Unix workstation.
• FITS: (Flexible Image Transport System) is mainly used in astronomy. For example, it's used by NASA in their space program.
• FLI/FLC: This file format is used by many animation programs. Gimp reads both FLI and FLC file formats. The main difference between these two is that FLI only supports 64 colors at a resolution of 320x320 pixels, whereas FLC supports 256 colors at a resolution of 64Kx64K pixels.
• GBR: This is Gimp's native brush format. You will learn how to make brushes in chapter 11.
• GIcon: This is Gimp's native icon format, used for the icons in the Toolbox. This format only supports grayscale images.
• GIF: (Graphics Interchange Format) trademarked by CompuServe, with LZW compression patented by Unisys. GIF images are in 8-bit indexed color and supports transparency (but not semi-transparency). They can also be loaded in interlaced form by some programs. The GIF format also supports animations and comments. Use GIF for transparent Web graphics and GIF animations.
• Gzip: Lets you open and save gzip'ed images. The name of the file must be <name>.<well-known suffix like tiff>.gz. This format is ideal for saving large, multi-layered XCF images.
• Header: This format is a C programming language header file. This format is for programmers who want to include their image in a C program.
• HRZ: This format is always 256x240 pixels and it is, or rather was, used in amateur slow-scan TV broadcasts. The format does not support compression, it's just raw RGB data.
• JPEG: (Joint Photographic Experts Group) This format supports compression and works at all color depths. The image compression is adjustable, but beware: too high a compression could severely damage your image, since JPEG compression is lossy. Use JPEG to create TrueColor Web graphics, or if you don't want your image to take up a lot of space
• MPEG: (Motion Picture Experts Group) A well known animation format. With this plug-in you can load an MPEG movie into Gimp and play it with the Animation Player plug-in. What's nice about this is that you can open an MPEG movie and save it as a GIF animation (but make sure that you remove all unnecessary frames beforehand). You can't (yet) save an animation created in Gimp as MPEG.
• PAT: This is Gimp's native pattern format.
• PCX: This is the Zsoft file format, mainly used by the Windows Paintbrush program and other PC paint programs.
• PIX: This is a format is used by the Alias/Wavefront program on SGI workstations. It supports only 24-bit color and 8-bit grayscale images.
• PNG: (Portable Network Graphics) This is the format that is supposed to replace the GIF format and solve all the related trademark/patent issues. Indexed color, grayscale, and truecolor images are supported, plus an optional alpha channel. PNG also uses compression, but unlike JPEG it doesn't lose image information. We recommend not using this format until all major Web browsers support it, or until your Web page can recognize what kind of browser is reading your page, and based on that information choose the right image to display.
• PNM: (Portable aNyMap) PNM supports indexed color, grayscale, and truecolor images. PNM images can be converted to many other formats with the programs that come with the netpbm or pbmplus distributions. Use this format when you know that you will want to change the image later with a PBM program
• PSD: This is the format used by Adobe Photoshop. Great if you are a former Photoshop user and have lots of images in PSD format. (Note that Gimp will preserve your PSD layers now.)
• Po stScript & EPS: PostScript was created by Adobe. It is a page description language, that is mainly used by printers and other output devices. It's also an excellent way to distribute documents. This plug-in can also read PDF (Acrobat) files. (Read the installation chapter on how to make this work.) This is the format to use when you want to print your image at a professional printing works.
• SGI: This is the original file format used by SGI graphic applications.
• SNP: This format is used by MicroEyes for their animations. You can load this format and then save the resulting image as a GIF to obtain a GIF animation.
• SunRas: (Sun rasterfile) This format is used mostly by different Sun applications. It supports grayscale, indexed color and TrueColor.
• Targa: The Targa file format supports compression, as well as 8, 16, 24, 32 bits per pixel.
• TIFF: (Tagged Image File Format) This format was designed to be a standard. There are many variations of TIFF, considering that TIFF supports six different encoding routines, and three different image modes: black and white, grayscale and color. Uncompressed TIFF images may be 1, 4, 8, 24 bits per pixel. TIFF images compressed using the LZW algorithm may be 4, 8, 24 bits per pixel. This is a high quality file format that is perfect for images you want to import to other programs like FrameMaker or Corel Draw.
• XCF: This is the native Gimp format. Use this format to store all your Gimp images (if you have enough disk space).
• XWD: (X Window Dump) This is the format used by the screendump utility shipped with X.
• XPM: (X PixMap) This is the file format used by color icons in X. Gimp's XPM plug-in supports 8-bit, 16-bit, and 24-bit images.
• URL: (Uniform Resource Locator). With this plug-in you can download a picture off the Internet directly into Gimp. The format of the "filename" (i.e URL) that you must enter into the open dialog is ftp://<address>/<file> or http://<address>/<file>For more info see the installation chapter.

Save dialogs

When you save your newly created image, (for instance, test.jpeg) the Save or Save as command will bring up a dialog box asking you what kind of compression and other options you want to set for your image. We will now take look at the different dialog boxes, and discuss what impact these parameters have on the image.

GBR

This is the GBR save dialog. Spacing refers to the default spacing your brush will have as shown in the Brush dialog. (You will learn more about this in chapter 11.) Description refers to the name your brush will get in the brush dialog, e.g. "Olof's test brush"

GIcon

This is the GIcon save dialog. Here all you need to enter is the name of your icon. Note that this is not the file name, it's the internal name of the icon as Gimp sees it.

GIF

This is the GIF save dialog.
This dialog has many options. If you flattened your image, you can save it as an interlaced GIF image, which enables it to be downloaded incrementally by applications like Netscape. You have probably seen this on the Web, when the image is very rough at first but gradually becomes more recognizable.

You can also set the Comment stored in the GIF file to anything you want, like "Made by Karin with Gimp". To alter the default GIF comment, you will have to edit the GIF plug-in source code.

If you have layers in your image, you can create a GIF animation. If you only want the animation to display once, uncheck the Loop button, otherwise it will loop forever. The Delay input is the delay between frames in your animation. The checkboxes in the Default disposal where unspecified section do the following:

• Don't care and Make frame from cumulative layers are the same; they start the animation by showing you the first layer in the GIF image and then add the second layer on top of the existing ones. This mode is useful, for instance, when creating a logo that is going to be "written" one letter at a time.
• One frame per layer will use the first layer as the first frame, the second layer as second frame and so on, just like in a movie. This mode is useful when creating a spinning object, like a globe.

If your GIF image is transparent, the transparency will be retained when you save it. Transparency works in both flat and layered images. Note that GIF does not support semi-transparency; pixels are either 100% opaque or 100% transparent.

Transparent GIF images will sometimes be displayed incorrectly in some image programs that can't deal with transparency. In that case, a color shows instead of transparency. To forestall this, set the default background color in the toolbox to an appropriate color before saving the GIF.

jPEG

This is the JPEG save dialog. This dialog
lets you set the quality and smoothing of the image. There is also an option to optimize the image.

JPEG uses lossy compression that takes advantage of the fact that the human brain cannot easily distinguish small differences in the Hue part of an image (see chapter 12). In other words, the smaller the number of colors in your image, the lower you can set the quality. A Quality setting of 0.75 is generally fine for a full-color image, but it's often as low as you can go without losing too much information in the image. If the resulting image is too inaccurate, go back to the original image and increase the quality. But never go above 0.95 - the file will only get bigger without any noticeable improvement in quality. If you aren't so concerned about the image quality, then you can go down to 0.50. If you just want low quality images, like snapshots of an image archive or some such thing, then you can go down to 0.10. or 0.20 (although personally I think XV or Guash is better suited for this kind of task).

Sometimes sharp, colorful edges can appear a bit jagged due to the nature of JPEG. If this happens, you can increase the smoothing value to more than 0.00. This will blur the edges so that they will become less jagged. But note that the image can get very blurry and that's not good.

The optimize check button will enable even further downsizing of the image file.

A bit of advice: don't save a TIFF image of your precious mother-in-law as a low quality JPEG, and then delete the TIFF image, because then your good mother-in-law will be gone for ever. To put it simply, don't save important images in JPEG format.

PAT

This is the PAT save dialog.
This dialog lets you name the pattern. Note that this is name is the one that will appear in the Pattern dialog box. Needless to say, you should give it a meaningful name, like "rock" for a rocky texture.

PNG

This is the PNG save dialog
. This dialog lets you set the compression level and whether or not the image should be interlaced.

The Interlace checkbox behaves just like the one in the GIF dialog, which means that the image can be loaded and displayed incrementally.

PNG compression is handled by zlib. If you slide the compression to 0, no compression will take place. If you slide it to 9, the image will be compressed by the maximum possible amount. zlib compression is lossless.

PNM

This is the PNM save dialog;.
it's pretty self-explanatory. I have always saved in Raw format, because it's smaller (8 times smaller) and faster than the Ascii format.

PostScript & EPS

This is the Postscript save dialog. Note that when you save your image as PostScript it's significantly different from saving it as TIFF, GIF, JPEG, etc.

When you save an image as PostScript you must specify the image size. You can think of this as specifying the size of the paper that the image is going to be printed on. Then, as you might expect, an image that is 300x400 pixels won't look too good if it's going to be stretched out to 11.30x7.87 inches, which is the default. You have to alter the paper size depending on your image size. To do so, change the Width and Height. The offset is the margin of your imaginary paper. Turning on the Keep aspect ratio checkbox means the image size is automatically adjusted to be the same relative shape as your image, so that the image won't be stretched out.

Let's say you are going to save the 300x400-pixel image, and that you decide that the resolution is going to be 100 pixels per inch (suitable for printing to a 300 dpi laser printer). Then the image area will be 3x4 inches, plus 2x0.2 inches at top and bottom and 0.2 inches on each side, which gives you a total image size of 3.4 x4.4 inches with a margin of 0.2 inches. Let's set Width to 3, Height=4, X-offset to 0.20, Y-offset to 0.20, Unit to inches and Rotation to 0. This will produce a pleasing result.

If you want to rotate your image by 90o then you have to switch Width and Height, and the image will be saved in landscape mode. If you rotate your image by 180o you'll get an upside-down portrait mode, and if you rotate by 270o, you'll get an upside-down landscape mode. Read more about this in the prepress chapter.

Turning on the Encapsulated PostScript checkbox will create an Encapsulated PostScript (.eps) file instead of a plain PostScript (.ps) file. EPS is useful for importing an image into a page layout program or an illustration program. Encapsulated PostScript is also a commonly requested file format when you print at a professional print house. If you're going to import your EPS file into another program, it is wise to check the Preview button; if you don't, it's quite possible that the program won't be show what your image looks like on screen, (it will be either be displayed as a gray square, or in very low resolution) and it'll only appear when you print it out.

SunRas

This is the SunRas save dialog.
When you save a SunRas file, you'll get a dialog box asking if you want RLE compression or standard format (no compression). The RLE compression is lossless so it's generally a good idea to select this option, but the RLE format only supports only 4 or 8 bits per pixel.

TGA

This is the Targa save dialog
. When you save a Targa image, you get a dialog box asking if you want RLE compression or no compression. As with the SunRas compression, RLE is generally a good idea, as it will cut down on disk space. You may also choose whether you want to save your image with 24 bits per pixel or 32 bits per pixel, which includes an Alpha channel.

TIFF

This is the TIFF save dialog
. This dialog asks what kind of compression you want. Since TIFF compression is lossless there's no danger in using it. Use LZW with 4, 8, and 24 bit images and Pack Bits with 1 bit (bitmap) images like FaxG3 images.

The fill order determines how the bits in your image are filled. The first option is Least Significant Bit (LSB) to Most Significant Bit (MSB). This is the default order on little-endian machines with e.g Intel X86 processors, this is also called PC filling in e.g PhotoShop. The other option is the other way around; MSB to LSB. This is the default order on big-endian machines with e.g Motorola and Sparc processors. This is also known as Mac filling. If you want to import the image into Frame Maker or some other page setting program, set Compression to None and Fill Order to the right type, depending on the machine the program is running on. Then you are on the safe side.

Xpm

This is the XPM save dialog
This dialog is lets you set the alpha threshold in order to reduce saving time. This will determine what alpha value to set as transparent and which to set as opaque, e.g threshold=0.5 means that all alpha values under 128 will be transparent and all over 128 will be opaque. According to the source code, 16-bit and 24-bit XPM images are supported on 16-bit displays, and 8-bit images are coded but not tested.

Mailing Images

Gimp can mail images. This is a handy feature, particularly if you work in more than one location. Then you can mail your image home or to work. You can also use it to send digital Christmas cards to your friends and family. Note, however that the mail administrator for your friend's network may not be very happy if you mail large images, so use it with care. Now, let's check out how to do it. In the <Image> File menu, select Mail image. This will pop up the mail dialog box. The To field is the e-mail address of your friend. Subject is the subject of your email. Comment is a comment for the image, like "Here's a nice picture of my new pet."
Filename is the filename of the image that you want to send; it should have the format <name>.<well-known suffix>. You also have to choose the coding type of the mail; either Unencoded or 64bit-Mime.

Printing Images

Before you start to print from Gimp, be warned that only the active layer of layered images is printed, so you must flatten your image before printing. In addition, we're not going to discuss UNIX printing systems, spool systems and so on, because it's beyond the scope of this manual. If you want more information on setting up printers and printing systems in Linux/UNIX, see appendix E for relevant links and books.

What kind of printer does Gimp support internally? To find out, open an image and select the Print menu item in the <Image> File menu, this will bring up the Print dialog box. As you can see in the Printer menu, Gimp supports the following printers:

Supported printers

• PostScript printers and PostScript level 2
• HP DeskJet 500, 500C, 520, 540C, 600C, 660C, 68xC, 69xC, 850C, 855C, 855Cse, 855Cxi, 870Cse, 870Cxi, 1200C, and 1600C printers.
• HP LaserJet II, III, IIIp, IIIsi, 4, 4L, 4P, 4V, 4Si, 5, 5FS, 5L, 5P, 5SE, 5Si, 6L, 6P printers, and
• EPSON Stylus Color, Color Pro, Color Pro XL, Color 400, Color 500, Color 600, Color 800, Color 1500, Color 1520 and Color 3000 printers.

Settings

Gimp supports the most common printers internally, so you don't have to have GhostScript installed. If you have GhostScript installed and use it as a printer filter for your printers, then you probably want to print with the PostScript Printer option. However, it is recommended that those of you with Ghostscript installed should create a raw printer device, and let Gimp print directly to it, at least for testing purposes, so you can follow the examples in this manual.

The Output type selects what type of printer you have. If you have a color printer, use Color mode, otherwise use B&W.

The Media Size is the size of paper you have in your printer. Gimp supports Letter, Legal, Tabloid, A4 and A3 paper sizes, although your printer may only support one of them.

The Orientation menu, lets you select whether you want to print in Landscape or Portrait mode, or let Gimp decide in Auto mode.

When you open the Print dialog box, Scaling is set to 100 and the image is stretched so that it will cover the entire page (with a margin of 6mm on each side, and 13mm on top and bottom). Note that as a result a small image will get so enlarged that it will look very ugly, because the resolution will be extremely low). There is a lot that could be discussed with regard to printing images, but for now let's stick to what we have to do to get our image to look reasonably good. The key factor is resolution. If you have a small image and you enlarge it, it will get a very low resolution. In order to get a nice printout, the image will have to be relatively large; and when you print it, you will have to scale it down to increase the resolution. Read more about this in the chapter about prepress. An image that is 300x400 pixels will look good with a scaling around 30 (on A4 paper and a 300 dpi printer). The procedure is the same as when we saved in PostScript format.

The Brightness is by default 100, which is fine for printing to lasers and black and white inkjets. Usually though, you will have to increase this value when printing to a color inkjet. The author of the plug-in says 125 to 150, but for us, that's too bright. We use 110 for our Deskjet 870Cxi. The bottom line is that you will have to experiment and find out for yourself what setting gives the best results for your particular printer.

The Print menu is where you set what printer you want to print to (not the type, but the name of the printer queue) or if you want to print to file. In the File/Command field the printer command or file name will appear depending on your settings in the print menu. If you want print to file, just use <directory>/<filename> for example /tmp/hello.ps. If you print to file, the raw data that otherwise would be sent to the printer is instead sent to a file. A warning is in place; if you print to a file that already exists; It will be overwritten without any warnings.

Gimp Preferences

In the Preferences dialog box, you'll find a lot of Gimp-related settings. There are four tabbed folders named Display, Interface, Environment and Directories. To save your changes permanently, press the Save button. If you only press OK, your changes will not show up next time you start up Gimp, and if you press Cancel all your changes will be discarded. To enable your modifications you must first quit Gimp and then start it up again.

Display

In the Display folder you can set the default size for new images (in pixels), and the default image type (RGB or Grayscale). You can also set the preview size. If you have a small screen and low computer resources you'll generally want to keep the preview size as small as possible.As for interpolation; Gimp uses Linear interpolation by default. When you scale an image (make it bigger), linear is faster and also leaner on system resources, but it does not produce as high a level of detail in the output image as Cubic interpolation does. To get a nice-looking image with a lot of detail when you scale it, check the Cubic interpolation check box. If you are on a machine with low resources use linear interpolation by ensuring that the Cubic interpolation check box is not checked. Check size lets you choose the size of the checks on the transparency checkerboard representation, and Transparency Type lets you specify the grayscale tone of the checks. We use the default values here.

Interface

In the Interface folder you can set the Levels of Undo. A high number of levels of undo requires a lot of disk space, so use it with care if you are low on such resources.

Resize window on zoom is the same as the Allow Window Resizing in the Magnify Options dialog box. Our advice is to keep this option unchecked since you can easily enable and disable it in the Zoom Options dialog box. Read more about this in the chapter about Transform tools.

Auto save is a nice feature; Gimp will automatically save the image in its tmp dir, so that if it crashes, you may be able to recover the image by looking in that directory.

Disable cursor update: By default Gimp changes the cursor symbol; for example, if you use the Move tool, your cursor will be the Move symbol. However, this consumes system resources, so if you are extremely low on resources, check the Disable Cursor Update checkbox. Bear in mind that this can be unwise since you won't be able to see what "mode" you are in. You can also set the speed of the marching ants (the blinking dots that appear whenever you make a selection): the value in the input field is the amount of time between updates (in milliseconds), so a lower value makes the ants march faster.

Environment

In the Environment folder you will find the Conservative memory usage option. Gimp will usually trade memory consumption for speed improvement. Checking Conservative Memory Usage will make Gimp more concerned about memory, but it will also slow it down, so only use it when memory is scarce.

Tile cache size is the amount of memory (RAM) that Gimp consumes in order to ensure that it doesn't damage the tile memory when Gimp moves memory to and from disk swap. The memory value is measured in bytes. A higher value will make Gimp go faster and a lower value will make it go slower, but the difference will only be evident when you work with really large images. We stick to the default value and that may work well for you too, but if you have low resources it may be wise to lower the memory value (note that Gimp will work even if you set it to 0). If you're working on an 8-bit display (in other words, you can only display 256 colors at once) you'll definitely want to use the Install color map option; otherwise Gimp will be rather useless. Since most of the colors will have already been claimed by other applications like the window manager, Netscape etc., Gimp and the images that it displays will only be allowed to use the leftover colors (unless you install colormap), and the result will of course be horrible.

Colormap cycling affects the "marching ants" or selection border. If you check this option, the "ants" will be replaced with a smooth line. This line is dark as you drag the selection, and turns bright when you release the mouse button.

Directories

The most important directories in the Directories folder are Temp and Swap. The Temp directory is where Gimp stores all of its temporary data, like working palettes and images. The Swap directory is where Gimp keeps its swap file for the tile-based memory system.

Suggestions

Here are some suggestions on how to configure these directories for optimal performance. If you are on a system that mounts home directories from a server over NFS and/or you have only a fixed quota of disk space that you can use, you will probably want your Swap directories on a local temporary directory like /tmp. Otherwise you won't have any disk space left to save your images, since the swap file can get (read almost always gets) nasty big. Another reason to do this is that if you have to send image data to and from a swap file over the net, Gimp will be terribly slow because it has to wait for the net traffic to finish before it can proceed.

Temp is a bit different. Most of the files here will disappear when you exit Gimp, but some will remain (such as working palettes for example) so you will probably want a Temp directory that you don't share with other people, and that isn't cleared if you reboot your workstation. A good idea is to make a personal directory under /usr/tmp or /var/tmp e.g mkdir /usr/tmp/your_user_name and set this directory as your temp dir. The other directories for brushes, gradients, palettes, patterns and plug-ins may be left as they are, or modified to suit your special needs; but if you change them, remember to move your gimp add-ons to the right place, because if you don't, you may not have any plug-ins available the next time you start up Gimp.

Misc. features & extensions

Tip of the day

Tip of the day is a handy feature for new Gimp users. You can browse the tips by clicking Prev.Tip and Next.Tip. To turn off Tip of the day uncheck the Show tip next time checkbox. The file which contains all of the Tips of the Day is in the Gimp system-wide data directory and is called gimp_tips.txt, so if you are a system administrator you can edit this file and add new tips for the Gimp users on your system.

DB Browser

In the DB browser you can search for Gimp PDB calls and routines. This is mainly of use to people who deal with scripts and plug-ins. Even if you are not writing scripts or plug-ins, this can be a source of information about Gimp's internals. You can search the database for both PDB procedure names and information (blurb). If you call the DB Browser from the Script-Fu Console then you can also apply the PDB command to the console.

PDB Help

This is another interface to the Gimp PDB. With this extension you can run a specific PDB call on your image. To do this, simply press Run which will bring up a dialog asking for information. As with the DB Browser, this extension is mainly for developers.

Gimptcl Consolio

Gimp's main scripting language is Scheme; one of many scripting languages available for Unix. This consolio is for the scripting language Tcl. If you are familiar with Tcl you probably don't want to learn Scheme. This consolio is written in Tcl and you can use it when you create Tcl scripting for Gimp. As a user with no technical background, you may well ask yourself why you should bother learning some obscure Unix scripting language? Let us first state that there is no need to learn a scripting language to use Gimp for your designs. You can happily use Gimp forever without a thought of learning any such language. But if you find yourself performing some operation over and over again, wouldn't it be nice to automate it? Take the drop shadow Script Fu for example. You can make a drop shadow by hand in Gimp, but isn't it nice that you have a script to do it for you? This is when it becomes interesting for ordinary users to learn a scripting language. At the time of writing, Gimp supports Scheme, Tcl and Perl (although Perl is still in early development stages). There are several books about each of these languages, so you can choose any one of them. If you are totally new to computer languages and scripting, then we suggest that you learn Scheme, because it's Gimp's native scripting language.

Screen Shot

With this utility you can take screen dumps directly into Gimp. You have three alternatives; the active window that you select with or without the window decoration (the frame that e.g fvwm creates around your window). You can also take a dump of the whole screen. In order to take a dump of the active window, check the appropriate options and press OK. You will now see a cross symbol that you can use to select the window that you want to dump (i.e click in the window that you want to dump). When you want to take a dump of the entire screen, check the right alternatives and press OK. After a little while a new Gimp window with your screen dump will appear.

Waterselect

Waterselect is an alternative to the Color Select dialog, when you want to select a special color. This tool resembles the little water cup you use for blending colors when you're making a watercolor painting. The interface is simple and easy to use. At the top you'll find the last ten colors that you mixed. Just press one of these colors, and it will be activated. If you want to mix a color, just move the mouse over the color scale while pressing the left mouse button. If the color gets too dark, release the mouse button and press the right mouse button while moving the mouse. The color will now get lighter, just as if you had added more water. Press OK when you're satisfied, and the chosen color will appear in the active color swatch in the Toolbox.

Webbrowser

The webbrowser allows you to start up or open a web site from Gimp. You'll find a few short cuts to important locations like Gimp.org, Plugin registry, Gimp news, etc. You can also open the on-line version of the Gimp User Manual this way. To open a site that is not available in the short cut menu, select open url. This option pops up a dialog box asking you about the site. You can also choose whether you want to open the site in an existing Netscape session, or whether you want to open a new Netscape window.

Naturally, Netscape must be installed and in your PATH. If you want to change or add a short cut, you have to edit the script which controls the behavior of this extension. It's called web-browser.scm and is usually located in /usr/local/share/gimp/scripts/ Just copy it to your personal gimp script directory cp /usr/local/share/gimp/scripts/web-browser.scm /your/home/.gimp/scripts/ and edit it in a text editor.