1.1 Introducing the GIMP Windows and Dialogs

This section gives an overview of the the main features of the GIMP windows and dialogs. The GIMP windows fall into four main categories. They are the Toolbox window; the image window; the Layers, Channels, and Paths dialogs; and the dialogs for selecting colors, brushes, patterns, gradients, and palettes. Each of these is briefly introduced in the following sections.

1.1.1 The Toolbox

Figure 1.1(a)

  

Figure 1.1: The Toolbox Window

illustrates the Toolbox window.   This window is the first to appear when the GIMP is run. It consists of 27 Toolbox function icons; the File and Xtns pull-down menus; and the Active Foreground Color, Active Background Color, Default Colors, Swap Colors, Active Brush, Active Pattern, and Active Gradient icons. The function icons are each named in the figure shown on page , and their uses are discussed in various places in this book.

Almost all the tools in the Toolbox have options. Double-clicking on a tool brings up its Tool Options dialog . Once opened, the dialog remains open until it is explicitly closed, supplying the interface for the tool options in use at the moment. Changing tools automatically changes the Tool Options dialog, if its window is open. This dialog can also be invoked with Toolbox:File/Dialogs/Tool Options or by typing C-S-t in the Toolbox window. Figure 1.1(b) shows the Tool Options dialog for the Gradient tool.

      
1.1.2 The Image Window

The image window is the most important window in the GIMP. It is also the most feature-rich. Figure 1.2(a)

  

Figure 1.2: The Image Window

illustrates a typical image window. Note that the window title bar is marked

*image-window.xcf-16.0 (RGB) 200%

which gives quite a bit of information about this image. The string image-window.xcf is the name of the file on disk which contains the original version of this image, and the * indicates that the image in the window has been modified with respect to the version on the disk. Thus, to avoid losing the changes made to the image it must be saved (see Section 1.2). The string 16.0 gives the window number, 16, and the view number, 0. Every time a new image window is opened, the window number is incremented except when the new window is created using New View and, then, the view number is incremented (see Section 1.8.2 for more on view numbers). The string in parentheses, (RGB), gives the image type (see Section 1.4), which can be RGB, Grayscale, or Indexed. Finally, the string 200% indicates that the image is zoomed and is displayed in its window at twice its true size.

Additional information about the image can be had from the Window Info   dialog, which is shown in Figure 1.2(b), and which is found in the Image:View menu, or can be displayed by typing C-S-i in the image window. This dialog gives the image type, its dimensions in pixels, and its resolution in dots per inch. The units of the rulers at the left and upper sides of the image window correspond to the dimensions shown in the Window Info dialog. Moving the mouse cursor into the image window makes an arrow appear on each ruler, indicating the cursor's position. The cursor position is also precisely shown in the status bar.  In Figure 1.2(a), the status bar indicates that the mouse cursor is located at the position (99,150). Both the rulers and the status bar can be toggled off, which is done with Toggle Rulers  and Toggle Statusbar,  both found in the Image:View menu.

The most important feature of the image window is the Image menu,  shown in Figure 1.2(c). This menu is displayed by right-clicking in the image window and can also be displayed by clicking the arrow icon found in the upper-left corner of the window (see Figure 1.2(a)). The Image menu and its submenus stay open until one of its items has been selected by the mouse. However, these menus can be opened as separate windows    and, in so doing, be made to remain on the screen. This is done by clicking on the dashed line at the top of the menu. This is illustrated in Figure 1.2(d). The menu window can be eliminated from the screen by again clicking on the dashed line at the top of the menu.

When an image is larger than can be displayed by the image window, the scroll bars  seen in Figure 1.2(a) allow the image to be panned inside the window. However, there is also a special panner   window that can be displayed by clicking and holding the left mouse button on the four-way arrow icon found at the lower-right corner of the image window. The panner window is shown in Figure 1.2(e). Dragging the mouse in this window pans the image in the image window. Alternatively, the image can also be panned by middle-button-clicking and dragging with the mouse in the image window.

Finally, there are a pair of buttons found at the lower-left corner of the image window that are used for the Quick Mask  function. This function is covered in Section 4.5.2.

1.1.3 The Layers, Channels, and Paths Dialogs

The Layers, Channels, and Paths  dialogs are very important tools in the GIMP. These dialogs can be displayed by selecting Layers & Channels   from the Image:Dialogs menu or by typing C-l in the image window and selecting the appropriate tab. The three dialogs are shown in Figures 1.3(a), (b), and (c).

  

Figure 1.3: The Layers, Channels, and Paths Dialogs

The Layers dialog  is discussed in detail in Section 2.1.1, the Paths dialog in Section 3.4, and the Channels dialog in Section 4.1.1.

1.1.4 The Dialogs for Color, Brushes, Patterns, Gradients, and Palettes

Clicking on the Active Foreground Color or Active Background Color patches in the Toolbox window (see Figure 1.1(a)), brings up the Color Selection dialog shown in Figure 1.4(a).

  

Figure 1.4: The Color Selection Dialog

The rainbow-colored vertical bar is for choosing hue, and the large colored square is for choosing saturation and value. A color choice is made by clicking and dragging with the mouse to select the desired hue, saturation, and value. Numerical values can also be entered for R (red), G (green), B (blue), H (hue), S (saturation), and V (value) in the data entry boxes. More on these color space components is discussed in Chapter 5. Several other color-choosing dialogs can be used by clicking on the tabs located in the upper part of the window.

Choosing a color in the Color Selection dialog makes that color appear in the Active Foreground Color or Active Background Color patch (see Figure 1.1(a)), depending on which patch was clicked to invoke the Color Selection tool. Clicking the Swap Colors      icon (the two-headed arrow next to the active color patches) switches the foreground and background colors. This can also be accomplished by typing x in the image window. Clicking the Default Colors  icon (the small black and white rectangles below the color patches) reverts the foreground and background colors to their defaults of black and white. This can also be accomplished by typing d in the image window.

Figure 1.5(a)

  

Figure 1.5: The Brush Selection Dialog

shows the Brush Selection  dialog. This dialog can be displayed by clicking on the Active Brush icon in the Toolbox window. Clicking on a brush from the dialog makes it appear as the new active brush in the Toolbox window, as shown in Figure 1.5(b).

Figure 1.6(a)

  

Figure 1.6: The Pattern Selection Dialog

shows the Pattern Selection dialog . This dialog can be displayed by clicking on the Active Pattern icon in the Toolbox window. Clicking on a pattern from the dialog makes it appear as the new active pattern in the Toolbox window, as shown in Figure 1.6(b).

Figure 1.7(a)

  

Figure 1.7: The Gradients Dialog

shows the Gradients dialog.  This dialog can be displayed by clicking on the Active Gradient icon in the Toolbox window. Clicking on a gradient from the dialog makes it appear as the new active gradient in the Toolbox window, as shown in Figure 1.7(b). Furthermore, custom gradients can be created by clicking on the Gradients dialog's Edit button. This produces the Gradient Editor, shown in Figure 1.7(c).

Figure 1.8(a)

  

Figure 1.8: The Color Palette Dialog

shows the Color Palette dialog.   This dialog can be displayed from the Image:Dialogs menu or by typing C-p in the Toolbox window. The dialog consists of the Palette tab which displays the active palette. Clicking on the Select tab allows you to choose from a large number of predefined palettes, as shown in Figure 1.8(b). In addition, you can create custom palettes by clicking on the Edit button. This produces the Color Palette Edit  dialog, shown in Figure 1.8(c).

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