Editing with different fonts

Arjen Markus (3 october 2009) At the conference somebody raised the question if and how the text widget could be used to provide a "rich text" editor - that is: allow the user to type in text in different fonts and colours and what not. I apologise for not remembering who it was, but the program below illustrates how this could be done.

It allows the user to select bold, italic, bold and italic or normal font. Storing what you typed in does not work yet - I just wanted to show that you can get this information from the text widget.

As it is, it is not useful yet. But you could extend it to save the text in some convenient form and add the various menu items that one normally expects of a true text editor.

SEH -- Thanks Arjen!

# wordp.tcl --
#     A very basic word processor
#

# mainWindow --
#     Set up the window with some buttons
#
# Arguments:
#     None
#
# Returns:
#     Nothing
#
# Side effects:
#     Creates a text widget and some formatting buttons
#
proc mainWindow {} {

    global bold
    global italic
    global texttag

    #
    # Create the toolbar
    #
    set t [frame .toolbar]


    ttk::button      $t.store  -text Store -style Toolbutton -command {storeText}
    ttk::checkbutton $t.bold   -text B     -style Toolbutton -variable bold \
        -command {toggleFont}
    ttk::checkbutton $t.italic -text I     -style Toolbutton -variable italic \
        -command {toggleFont}

    ttk::separator .sep

    text   .text

    grid   $t.store $t.bold $t.italic -padx 2 -sticky ns

    grid   $t    -sticky w
    grid   .sep  -sticky we
    grid   .text

    #
    # Tags for the various fonts
    #
    .text tag configure bolditalic -font "Times 12 bold italic"
    .text tag configure bold       -font "Times 12 bold"
    .text tag configure italic     -font "Times 12 italic"
    .text tag configure normal     -font "Times 12"
    .text tag add normal insert

    bind .text <KeyPress> {+insertChar %K}

    set texttag normal
    set italic  0
    set bold    0
}

# insertChar --
#     Insert the typed character with the right tag
#
# Arguments:
#     char        Character to be typed
#
# Returns:
#     Nothing
#
proc insertChar {char} {

    if { [string length $char] == 1 } {
        .text insert insert $char $::texttag
        return -code break
    }
}

# toggleFont --
#     Make the text appear in bold or italic font or normal
#
# Arguments:
#     None
#
# Returns:
#     Nothing
#
# Side effects:
#     Next letters typed in the text widget have the selected font
#
proc toggleFont {} {
    global bold
    global italic
    global texttag

    if { $italic } {
        if { $bold } {
            set texttag bolditalic
        } else {
            set texttag italic
        }
    } else {
        if { $bold } {
            set texttag bold
        } else {
            set texttag normal
        }
    }
}

# toggleBold --
#     Make the text appear in bold font (or ordinary if it was bold)
#
# Arguments:
#     None
#
# Returns:
#     Nothing
#
# Side effects:
#     Next letters typed in the text widget are italic
#
proc toggleBold {} {
    global bold
    global texttag

    if { $bold } {
        set texttag bold
    } else {
        set texttag normal
    }
}

# storeText --
#     Dump the contents
#
# Arguments:
#     None
#
# Returns:
#     Nothing
#
# Side effects:
#     Prints the contents of the text widget in a console
#
proc storeText {} {
    console show
    puts [.text dump 1.0 end]
}

# main --
#     Test the thing
#
#
mainWindow

Category Word and Text Processing