Xfwm4, Xfce4's native window manager uses a simple yet flexible pixmap based theme engine using images in .xpm format. Xfwm4 also uses a text file for other configuration options (see themerc section). Further to this you can also make a theme pick up gtk theme colours which will be covered in the gtk color pickup section of the document.

In Xfwm4 version 4.0, the themes are searched in the following directories:

• User's home dir /.themes/xfwm4/theme_name (e.g.: /home/joe/.themes/xfwm4/b5)
• System's shared data directory /xfwm4/theme_name (e.g.: /usr/share/xfwm4/themes/b5)

In Xfwm version 4.2, the theme location is in line with the standard, searched in the following directories:

• User's home dir /.themes/theme_name/xfwm4 (e.g.: “/home/joe/.themes/b5/xfwm4”)
• System's shared data directory /themes/theme_name/xfwm4 (e.g.: “/usr/share/themes/b5/xfwm4”)

As windows can be in either active ¹⁾ or inactive ²⁾ states for which xfwm4 use pixmaps named accordingly e.g. title-1-active.xpm and title-1-inactive.xpm.

For title bar decorations, xfwm4 uses 5 pixmaps named title-1-active.xpm to title-5-active.xpm with top-left-active.xpm and top-right-active.xpm making up the corners on each end as per figure 2 below.

Figure 2 - The pixmaps that compose the whole window

The same naming convention is true for unfocused windows with the word inactive substituted.e.g. title-1-inactive.xpm

Title text colour and shadow options, alignment etc are set in the themerc file (detailed in the themerc section).

Each side of a window is made up of two pixmaps. The pixmaps on the left side are named left-active.xpm and bottom-left-active.xpm. with the right side (of course) being made up of right-active.xpm and bottom-right-active.xpm.

The Window bottom grab bar is made up of bottom-active.xpm and bottom-inactive.xpm pixmaps which will be repeated to fit as the window is resized.

N.B These pixmaps also make up the mouse grab handles so keep that in mind when deciding how many pixels wide they should be (particularly the bottom-left and bottom right pixmaps which make up the main resize handles on the windows).

Xfwm4 can use up to six action buttons - stick (sticky windows), menu, shade, hide, maximize and close.

Buttons have active ³⁾, inactive ⁴⁾, prelight and pressed states. As per figures 3 below: AbiWord Image menu-active.gif AbiWord Image menu-inactive.gif AbiWord Image image_2.gif

Figure 3 - Xfwm4 button states

Xfwm4 can also used “toggled” buttons to indicated whether buttons are toggled on or off - figure 4. AbiWord Image stick-active.gif AbiWord Image stick-inactive.gif AbiWord Image stick-pressed.gif AbiWord Image stick-toggled-active.gif AbiWord Image image_3.gif AbiWord Image stick-toggled-pressed.gif

Figure 4 - Stick buttons with extra toggled buttons

Xfwm4 4.6 brings a new button effect of the active window called prelight. Hovering the mouse over the buttons, the picture becomes clearer. Can be used in the six active buttons.

To set features such as title text colors, “button_spacing” and “button_offset” etc. xfwm4 uses an text file called “themerc” kept in the theme folder that contains the pixmaps.

It is also possible to “fix” button layouts for themes that use a particular button layout. - though it should be mentioned that forcing a special button layout or a title alignment in the theme, and thus reducing user's options, should be avoided (unless the theme really requires that, such as b5 theme mentioned below)

# button_layout :
#    O = Option menu
#    T = Stick
#    H = hide
#    S = shade
#    M = maximize
#    C = close
#    | = title
button_layout=OTS|HMC

A working example of this is the “B5” theme which only uses the close button. i.e. the entry “button_layout=C|” in the themerc file.

Another setting that needs to be set from the “themerc” file is the “title_full_width” parameter. This boolean value determines how the pixmap are arranged in the title bar.

When set to “true”, the center pixmap is repeated so that it fills the entire window width :

When set to “false”, the center pixmap is repeated just enough so that the title fits :

A shadow can be added to the title text by setting the boolean value “title_shadow_active” for the focused window, and “title_shadow_inactive” for the other unfocused windows.

Possible values are “false”, “true”, and “frame”.

The title text position can be adjusted to fit the theme design by using the offset values. The horizontal and vertical values can be adjusted by using the following settings:

• title_horizontal_offset
• title_vertical_offset_active
• title_vertical_offset_inactive

Simlilarily, the buttons can be shifted horizontally by using the “button offset” setting. It's worth noting that the value is relative to the corresponding application window border, not the frame border.

The “button_spacing” value gives the number of pixels between each button.

The “maximized_offset” value places a space between the right edge (top-right-active) and the button (close, hide…) when maximized.

With show_app_icon option you can replace the menu button with application icon. The application icon will be limited by width of menu button. Stay tuned!

• show_app_icon=true #Shows the application icon
• show_app_icon=false #Shows the menu button

If you don't have a menu button, you can use a blank square. Or you cannot use this option.

As you have no doubt noticed when using Xfwm4's default theme, the theme uses the colors of the current Gtk theme. Colors for an XFWM theme can be defined in the theme's themrc file. If they are not defined there, they are picked up from the current Gtk theme. The following colors are used:

The Gtk values “fg” and “bg” are defined in the gtkrc file of the current Gtk theme. Please notice that the values “dark”, “light” and “mid” can not be defined in the gtkrc but are computed (dark = 0.7 * bg, light = 1.3 * bg, mid = 0.5 * (dark + light)). The symbols get replaced by the actual color values at runtime so that the window border can inherit Gtk theme colors automatically, unless they are defined in the themerc.

To use the defined colors in the XFWM theme, the XPM files have to be edited. Since XPM files are plain text, they can be edited with your favorite text editor.

XPM (X PixMap) is an ASCII image format used by the X Window System. It was created in 1989 by Daniel Dardailler and Colas Nahaboo working in Inria Laboratories, France, and was later enhanced by Arnaud Le Hors. It is intended primarily for creating icons, and supports transparent color. It has a simple structure, deriving from the earlier XBM syntax. It can be created and manipulated using any text editor and can be included in a C language file.

Therefore, if you open an xpm file with your favorite text editor, you'll see something like this:

/* XPM */
static char * title_2_active_xpm[] = {
"5 21 10 1",
"       c None",
".      c #000000",
"+      c #FFFFFF s active_hilight_2",
"@      c #D5D6D5 s active_color_2",
"#      c #4B58A2 s active_shadow_1",
"$      c #525FAB s active_color_1",
"%      c #848FD6 s active_mid_1",
"&      c #B4BAB4 s active_mid_2",
"*      c #949594 s active_shadow_2",
"=      c #FFFFFF s active_hilight_1",
".....",
"++++#",
"@@@@#",
"@@@@#",
"@@@@#",
"@@@@#",
"@@@@#",
"@@@@#",
"@@@@#",
"@@@@#",
"@@@@#",
"@@@@#",
"@@@@#",
"@@@@#",
"@@@@#",
"@@@@#",
"@@@@#",
"@@@@#",
"@@@@#",
"@@@@@",
"@@@@@"};

Not going too deep into the details of the XPM format, an XPM image is made of different sections, the values that describe the format of the image, the colors that compose the image, the pixels (and there is also the extensions, but it's safe to ignore them for now)

A character is assigned to each color of the image (if the image has more colors than available charaters, then more than a single character can be assiged to a colors). If a color symbol is specified, the given color will be ignored and replaced by the corresponding color in the color symbol table.

To get the gtk colors applied to your theme, you need to edit the XPM files and add the proper color symbols to the color definition table.

"       c None",
".      c #000000",
"+      c #FFFFFF",
"@      c #D5D6D5",
"#      c #4B58A2",
"$      c #525FAB",
"%      c #848FD6",
"&      c #B4BAB4",
"*      c #949594",
"=      c #FFFFFF",

must be changed to

"       c None",
".      c #000000",
"+      c #FFFFFF s active_hilight_2",
"@      c #D5D6D5 s active_color_2",
"#      c #4B58A2 s active_shadow_1",
"$      c #525FAB s active_color_1",
"%      c #848FD6 s active_mid_1",
"&      c #B4BAB4 s active_mid_2",
"*      c #949594 s active_shadow_2",
"=      c #FFFFFF s active_hilight_1",

As a matter of fact, “thinking” of the gtk colors as early as drawing the theme can save a lot of time in this phase. If you use the exact same color across all the pixmaps, you can use the Search/Replace functionnality of the text editor to add the color symbols. You could even use a tool such as “sed” to perform mass changes in all the XPM files of the theme.

As simple as it is, the color symbol replacement table of the XPM format is not powerfull enough to achive the nice color gradients seen in most recent themes.

Xfwm 4.2 includes yet another functionality that gives real nice result while being still compatible with the previous theme format: It composes the final image from the XPM file and it colors replacement table, and another PNG file with transparency, if present.

The names of the PNG files are identical to the names of the corresponding XPM files, with the “.png” file extension (ie title-1-active.png, top-right-inactive.png, etc.). The PNG file is by no mean required, if it's not present, xfwm4 won't complain, but if there is a PNG image of the same name as the XPM image, and if that PNG has an alpha channel (ie, it has semi-transparent pixels) then the PNG image will be automatically layered on top of the XPM image to produce the final image.

This technique has several advantages:

• It's fairly simple from a theme designer point of view, most people are working with similar techniques when composing themes with tools such as The GIMP.
• It's backward compatible with xfwm4 from Xfce 4.0, the PNG files are just ignored by xfwm4 4.0.

I hope this small “how-to” for creating themes for xfwm4 will help you design your own themes. It would be great if you could share your themes with others on http://www.themedepot.org (which is the prefered site for xfce related themes) or from http://themes.freshmeat.net.

you can also find xfce theme at http://www.xfce-look.org

This is a list of all possible part names in a decoration, so you can easily copy and paste them. (Tip: if using Firefox hold Ctrl while dragging, to select cells instead of lines. )

This how-to has been started by Drewbian (drewbian at tsn dot cc) and later modifed by Olivier Fourdan (fourdan at xfce dot org) and Renato Santos (renatosan at gmail dot com).