About rich text editing in Common Graphics

This document contains the following sections:

1.0 The Rich Text Interactive Interface

Getting Started

Invoke the File | New Form menu command and select rich-edit-dialog from the list of choices. This will make a rich-edit-dialog form and will automatically add a rich-edit control and an associated rich-edit-ruler just above it to the form, and also add auxiliary widgets in a toolbar for use with the rich-edit control.

This dialog will act as a complete WordPad-like application. If you would like to add additional controls to the form or toolbar, you can do so. The rich-edit controls appear at the right end of the component toolbar. Note that if multiple rich-edit controls are added to a single form, the single set of rich-edit helper controls works for all of the rich-edit controls on the same parent window, reflecting the rich-edit that most recently had the keyboard focus.

Try running the initial rich-edit form (with that form selected, click on Run | Run Form), then clicking the Open button in the toolbar and selecting the file cg\rich-edit-sample.rtf (in the cg subdirectory of the main Allegro directory). This should show some sample rich text.

Building Rich Edit Forms from Scratch

To test making your own rich edit dialog from scratch, invoke the File | New Form command, and select dialog from the list of window classes that you can create. Double click the interior of the new form to inspect it.

If you would like to start the menu-bar off with the special rich-edit commands, then go to the menu property of the form in the inspector and enter #.(rich-edit-menubar) in the inspector line for the menu property. (The #. reader macro is a trick to evaluate the expression typed directly into a line of the inspector.) This should add the standard rich-edit menu-bar to the form, and you can further edit this menu as you like.

Back on the inspector, toggle the toolbar property on to give the form a toolbar. Also toggle the status-bar property to give the form a status-bar for messages. Next, click on the Rich-Edit button of the Component Toolbar (the one with a big green "R"), and then click in the main interior of your form to create a rich-edit control. You may want to size the rich-edit control larger, since the default size is rather small. Now click on each of the next three rich-edit "helper" controls on the Component Toolbar and instantiate those widgets from left to right on the toolbar of your new form. (The helper controls consist of the rich-edit-multipic, the font-face-combo-box, and the font-size-combo-box. Finally, click on the Ruler button on the Component Toolbar, position it just above the rich-edit control, and then drag it or stretch it partly over the rich-edit as needed to make it snap into place along the top.

Having done this, you now have a dialog that is functionally similar to the one created by using the rich-edit-dialog class. You can customize either however you like by adding additional controls and editing the initial rich-edit menubar. Note that only a rich-edit-dialog has the built-in feature of prompting the user to save any unsaved rich-edit controls when a closing gesture is made.

Special Features

While the rich edit functionality basically allows for custom WordPad-like applications, there are a couple of features that are somewhat unique:

Multiple editor panes. The rich-edit helper controls will automatically keep track of which rich-edit control most recently had the keyboard focus, and apply any editing commands to that rich-edit. Also, as the focus moves from one rich-edit to another, the rich edit helper controls will update themselves to reflect the current rich-edit, just as they update to reflect the currently selected text within a single rich-edit.

Copying formatting. The Edit menu (on the rich-edit-dialog) has a couple of items called Copy Format and Paste Format that allow you to easily copy character formatting rather than text. Just select some text (or position the text cursor), invoke Edit | Copy Format, then select some other text, and invoke Edit | Paste Format (again, these commands are on the Edit menu on the rich-edit-dialog, not on the Allegro CL Edit menu) The second text range will now have the character formatting of the first text range.

2.0 The Rich Text Programmatic Interface

Package of symbols

All symbols documented here are exported from the common-graphics (cg) package, since this is an extension to common graphics.

Widgets (controls) versus windows

Most of these commands work on a window (the new rich-edit-pane and/or the older text-edit-pane) rather than on a widget. If you are using a widget instead (the new rich-edit control or the older multi-line-editable-text control), then you first need to call the function window on the control to retrieve the window of the control, and then pass that to the function that expects a window.

Rich-edit-specific classes versus plain-text classes

Much of this functionality works using the pre-existing text-edit-pane windows and multi-line-editable-text controls. The corresponding newer classes, rich-edit-pane and the rich-edit control, are provided mostly for automatically linking up with text-formatting controls, for determining which type of text is pasted into a given control, and other potential circumstances in which the controls will need to default either to rich or plain text. Thus, anything that's documented here to work on a text-edit-pane will also work on a rich-edit-pane, and anything that works on a multi-line-editable-text will also work on a rich-edit. But note that the converse is not true.

Units of measurement

Most measurements here are in points. A point is approximately 1 / 72nd of an inch. This applies even to font sizes, which are usually measured in pixels in common graphics, but there does not appear to be a feasible way to convert character formatting measurements to pixels, and so this difference needs to be kept in mind. Therefore the functions font and (setf font) should not be used to change the font of a rich-edit-pane, instead the rich-edit functions that change individual font attributes should be used, such as (setf face) and set-character-format. Note that a list of available faces is returned by (font-faces (screen *system*)). See font-faces, screen, and *system*.

Text-Formatting Functions --- Multiple Format Parameters

• get-character-format returns as multiple values information about rich text. The scope keyword argument is either :default (return the default characteristics of text in the rich-text-pane) or :selection (return information about the selected text in a rich-edit-pane). The information is the font face, whether it is bold, italic, underlined, and its color, and point-size. (See face, bold, italic, underline, color, and point-size). When scope is :selection, the information is about the first character of selected text and additional returned values say whether the whole selection shares the characteristic with the first character.
• set-character-format sets the format of text.
• get-paragraph-format returns information about the formatting of paragraphs in rich text.
• set-paragraph-format sets the paragraph format of a rich-edit-pane.
• character-format returns a character-format instance representing the character format of the character just before the current text cursor position in a rich-edit-pane.
• (setf character-format) sets the character formatting of the currently selected text of a rich-edit-pane to reflect an argument character-format instance.
• copy-character-format sets the global variable *copied-character-format* to a character-format instance reflecting the character format of the character just before the current text cursor position in a window.
• paste-character-format sets the character format of the currently selected text in a window to reflect the character-format instance that is currently the value of the global variable *copied-character-format*.

Text-Formatting Functions --- Individual Format Parameters

• bold returns true if all of the selected range of a text-edit-pane is bold, nil if it is all non-bold, and :some if there is a mix. (setf bold) sets whether selected text is bold or not.
• italic returns true if all of the selected range of a text-edit-pane is italic, nil if it is all non-italic, and :some if there is a mix. (setf italic) sets whether selected text is italic or not.
• underline returns true if all of the selected range of a text-edit-pane is underlined, nil if it is all not underlined, and :some if there is a mix. (setf underline) sets whether selected text is underlined or not.
• color returns two values: (1) an rgb object for the color of the first character in the selected range of a text-edit-pane (or the character at the cursor), and (2) non-nil if and only if the whole selection is the same color. (setf color) sets the color of the selected range of a text-edit-pane to an rgb color object.
• face returns two values: (1) the font face of the first character of the selected range of text-edit-pane as a keyword, and (2) non-nil if and only if the entire selection is the same font face. (setf face) sets the font face of the selected range of text-edit-pane to a specified font face. (font-faces (screen *system*)) returns the available face names that may be passed to (setf face). See face, font-faces, screen, and *system*.
• point-size returns two values: (1) the font point size of the first character of the selected range of a text-edit-pane, and (2) non-nil if and only if the entire selection is the same point-size. (setf point-size) sets the font point size of the selected range of a text-edit-pane (the new value should be an integer).
• justification returns the paragraph justification of the selected text of a text-edit-pane. The value can be :left, :center, or :right. (setf justification) sets the paragraph justification of the selected text.
• numbering-style returns the paragraph numbering style of the selected text of a text-edit-pane. The value can be either :plain or :bullets. (setf numbering-style) sets the paragraph numbering style of the selected text of a text-edit-pane.
• top-left-indentation returns the left indentation of the first line of the first paragraph of the selected text of a text-edit-pane. The value is the distance rightward from the interior left edge of text-edit-pane (or the printed page), and is specified in points. (setf top-left-indentation) sets the left indentation of the first line of each paragraph of the selected text of a text-edit-pane.
• body-left-indentation the current indentation of the lefthand side of a paragraph of text in a text-edit-pane, or the indentation indicated by the corresponding lower-left slider of a rich-edit-ruler.
• right-indentation returns the right indentation of the first paragraph of the selected text of a text-edit-pane. The value is the distance leftward from the interior right edge of text-edit-pane (or the printed page), and is specified in points. (setf right-indentation) sets it.
• tabs returns a list of tabstop positions for a text-edit-pane or a rich-edit control, indicating to where text will move rightward wherever a tab character appears in the text. (setf tabs) sets tabstop positions.

Responding to Format Changes

on-format-change is an event handler for rich-edit controls. Its value should be a function that will be called when formatting changes are made.

Rich Edit Classes

• rich-edit-pane is a text-edit-pane that will automatically link up with any rich-edit formatting controls that are either on the same parent or on a toolbar of the parent.
• rich-edit is the control built on rich-edit-pane.
• rich-edit-dialog is a dialog intended for use with rich-edit controls.
• rich-edit-menubar is a useful associated function. It returns a menubar suitable for use on a dialog that has one or more rich-edit controls.
• rich-edit-multipic is a multi-picture-button that will automatically link up with any rich-edit controls that are on the same dialog, in order to edit the character and paragraph formatting of the rich-edit control(s).
• font-face-combo-box is a combo-box that will automatically link up with any rich-edit controls that are on the same dialog, in order to edit the font face of the rich-edit control(s).
• font-size-combo-box is a combo-box that will automatically link up with any rich-edit controls that are on the same dialog, in order to edit the font size of the rich-edit control(s). The font-size-combo-box may optionally be on a toolbar.
• rich-edit-ruler is a widget that reflects and controls the indentation and tabstops of the selected paragraph(s) of its associated rich-edit control.
• character-format is an object that contains a set of character format parameters.

Accessing Rich Text Strings

• rich-edit-range returns a rich-text or plain string from a window. With setf it sets a string in a window. start and end arguments control what is read or set.
• rich-edit-selected-range is similar to rich-edit-range but works on the selected text of a window and does not have start and end arguments.

Functions for reading and Writing Rich Text Files

• rich-edit-new clears a rich-edit-pane for editing a new file.
• rich-edit-open reads a new file into a rich-edit-pane for editing.
• rich-edit-save saves the contents of a rich-edit-pane to its file.
• rich-edit-save-as saves the contents of a rich-edit-pane to a new file.
• save-text creates a file containing a specified string (either a plain-text or rich-text string).
• read-text returns a lisp string containing the contents of a file, which may be either a plain-text or rich-text file.
• rich-edit-print prints the contents of rich-edit-pane to a printer.
• print-rich-text prints all or part of the text of a rich-edit-pane to a printer-stream.

Clipboard-Related Functions

• available-clipboard-formats returns a list of the clipboard formats that are currently on the Windows clipboard.
• can-paste returns non-nil if pasting particular formats (specified by the second argument) is possible.
• clipboard-string gets or sets (with setf) a string from the Windows clipboard.
• default-clipboard-format returns the clipboard format that will be used by default when copying, cutting, and pasting in a window.

Support for Hypertext Links

• color-string-at-index returns two values unless the text just before the index is black, in which case a single nil is returned. The two values returned are (1) the string that surrounds the character at the argument index and which is in the color of the rich-edit-pane at that position (in other words, the color of the character just before the index position), and (2) the color of the string as an RGB color object.
• color-string-at-cursor calls color-string-at-index with the location of the cursor as the index.
• find-links finds all of the substrings of a certain color on a rich-edit-pane and returns a list indicating the starting and ending indices of each string.
• links returns the list of links that were found by find-links and cached as the value of this property of a rich-edit-pane.
• save-links returns (or sets with setf) whether a rich-edit-pane will currently save its links into a .lin links file whenever rich-edit-save or rich-edit-save-as is called on it.
• jump-to-links is a property of a rich-edit-pane that determines whether jumping to links is enabled.
• save-links-file saves the current links of a rich-edit-pane to a file.
• read-links-file reads the links that were saved to an argument file and establishes them as the current links of an argument rich-text-pane.
• link-color returns (or sets with setf) the color that will be used by default when find-links is called to find all of the link strings in a rich-edit-pane. The link-color defaults to blue.
• link-at-mouse-cursor returns the link under the mouse cursor in a rich-edit-pane, if any.
• link-at-position returns the link at a certain pixel position in the interior of a rich-edit-pane, if any.
• link-at-text-cursor returns the link at the current text cursor position of a rich-edit-pane, if any.
• link-at-index returns the link at a certain character index, if any.
• character-index-at-position returns the character index at a certain pixel position in the interior of a text-edit-pane.
• jump-to-link is called when the user clicks on a link that has earlier been found by find-links and cached as the links property of a rich-edit-pane.
• pathname-for-link takes a link-string that was clicked on in a rich-edit-pane, and should return the path of an .rtf file that should be opened for that link.

Miscellaneous Functionality

• concatenate-rich-text takes any number of rich-text-strings as arguments and returns a single rich-text-string which is a concatenation of them all. Note that concatenate will not work properly with rich-text-strings.
• find-rich-edit-pane can be used to find a rich-edit-pane that has or most recently had keyboard focus on a window, its parent, and so on until a top-level window is searched.
• rich-to-plain-text creates and returns a plain-text string that is equivalent to the argument rich-text-string except without any formatting.
• plain-to-rich-text creates and returns a rich-text string with the text of a specified plain-text string.
• get-selection returns two values indicating the start and end of the current selection of a text-edit-pane.
• set-selection sets the selection of a text-edit-pane.

Copyright (c) 1998-2022, Franz Inc. Lafayette, CA., USA. All rights reserved.
This page was not revised from the 10.0 page.
Created 2019.8.20.