+\subsection{Programming with wxRichTextCtrl}
+
+\subsubsection{Starting to use wxRichTextCtrl}
+
+You need to include {\tt <wx/richtext/richtextctrl.h>} in your source, and link
+with the appropriate wxWidgets library with {\tt richtext} suffix. Put the rich text
+library first in your link line to avoid unresolved symbols.
+
+Then you can create a wxRichTextCtrl, with the wxWANT\_CHARS style if you want tabs to
+be processed by the control rather than being used for navigation between controls.
+
+\subsubsection{wxRichTextCtrl and styles}
+
+Styling attributes are represented by \helpref{wxTextAttr}{wxtextattr}.
+
+When setting a style, the flags of the attribute object determine which
+attributes are applied. When querying a style, the passed flags are ignored
+except (optionally) to determine whether attributes should be retrieved from
+character content or from the paragraph object.
+
+wxRichTextCtrl takes a layered approach to styles, so that different parts of
+the content may be responsible for contributing different attributes to the final
+style you see on the screen.
+
+There are four main notions of style within a control:
+
+\begin{enumerate}\itemsep=0pt
+\item {\bf Basic style:} the fundamental style of a control, onto which any other
+styles are layered. It provides default attributes, and changing the basic style
+may immediately change the look of the content depending on what other styles
+the content uses. Calling wxRichTextCtrl::SetFont changes the font for the basic style.
+The basic style is set with \helpref{wxRichTextCtrl::SetBasicStyle}{wxrichtextctrlsetbasicstyle}.
+\item {\bf Paragraph style:} each paragraph has attributes that are set independently
+from other paragraphs and independently from the content within the paragraph.
+Normally, these attributes are paragraph-related, such as alignment and indentation,
+but it is possible to set character attributes too.
+The paragraph style can be set independently of its content by passing wxRICHTEXT\_SETSTYLE\_PARAGRAPHS\_ONLY
+to \helpref{wxRichTextCtrl::SetStyleEx}{wxrichtextctrlsetstyleex}.
+\item {\bf Character style:} characters within each paragraph can have attributes.
+A single character, or a run of characters, can have a particular set of attributes.
+The character style can be with \helpref{wxRichTextCtrl::SetStyle}{wxrichtextctrlsetstyle} or
+\helpref{wxRichTextCtrl::SetStyleEx}{wxrichtextctrlsetstyleex}.
+\item {\bf Default style:} this is the `current' style that determines the
+style of content that is subsequently typed, pasted or programmatically inserted.
+The default style is set with \helpref{wxRichTextCtrl::SetDefaultStyle}{wxrichtextctrlsetdefaultstyle}.
+\end{enumerate}
+
+What you see on the screen is the dynamically {\it combined} style, found by merging
+the first three of the above style types (the fourth is only a guide for future content
+insertion and therefore does not affect the currently displayed content).
+
+To make all this more concrete, here are examples of where you might set these different
+styles:
+
+\begin{enumerate}\itemsep=0pt
+\item You might set the {\bf basic style} to have a Times Roman font in 12 point,
+left-aligned, with two millimetres of spacing after each paragraph.
+\item You might set the {\bf paragraph style} (for one particular paragraph) to
+be centred.
+\item You might set the {\bf character style} of one particular word to bold.
+\item You might set the {\bf default style} to be underlined, for subsequent
+inserted text.
+\end{enumerate}
+
+Naturally you can do any of these things either using your own UI, or programmatically.
+
+The basic wxTextCtrl doesn't make the same distinctions as wxRichTextCtrl regarding
+attribute storage. So we need finer control when setting and retrieving
+attributes. \helpref{wxRichTextCtrl::SetStyleEx}{wxrichtextctrlsetstyleex} takes a {\it flags} parameter:
+
+\begin{itemize}\itemsep=0pt
+\item wxRICHTEXT\_SETSTYLE\_OPTIMIZE specifies that the style should be changed only if
+the combined attributes are different from the attributes for the current object. This is important when
+applying styling that has been edited by the user, because he has just edited the {\it combined} (visible)
+style, and wxRichTextCtrl wants to leave unchanged attributes associated with their original objects
+instead of applying them to both paragraph and content objects.
+\item wxRICHTEXT\_SETSTYLE\_PARAGRAPHS\_ONLY specifies that only paragraph objects within the given range
+should take on the attributes.
+\item wxRICHTEXT\_SETSTYLE\_CHARACTERS\_ONLY specifies that only content objects (text or images) within the given range
+should take on the attributes.
+\item wxRICHTEXT\_SETSTYLE\_WITH\_UNDO specifies that the operation should be undoable.
+\end{itemize}
+
+It's great to be able to change arbitrary attributes in a wxRichTextCtrl, but
+it can be unwieldy for the user or programmer to set attributes separately. Word processors have collections
+of styles that you can tailor or use as-is, and this means that you can set a heading with one click
+instead of marking text in bold, specifying a large font size, and applying a certain
+paragraph spacing and alignment for every such heading. Similarly,
+wxWidgets provides a class called \helpref{wxRichTextStyleSheet}{wxrichtextstylesheet} which manages style definitions
+(\helpref{wxRichTextParagraphStyleDefinition}{wxrichtextparagraphstyledefinition}, \helpref{wxRichTextListStyleDefinition}{wxrichtextliststyledefinition} and \helpref{wxRichTextCharacterStyleDefinition}{wxrichtextcharacterstyledefinition}).
+Once you have added definitions to a style sheet and associated it with a wxRichTextCtrl,
+you can apply a named definition to a range of text. The classes \helpref{wxRichTextStyleComboCtrl}{wxrichtextstylecomboctrl}\rtfsp
+and \helpref{wxRichTextStyleListBox}{wxrichtextstylelistbox} can be used to present the user with a list
+of styles in a sheet, and apply them to the selected text.
+
+You can reapply a style sheet to the contents of the control, by calling \helpref{wxRichTextCtrl::ApplyStyleSheet}{wxrichtextctrlapplystylesheet}.
+This is useful if the style definitions have changed, and you want the content to reflect this.
+It relies on the fact that when you apply a named style, the style definition name is recorded in the
+content. So ApplyStyleSheet works by finding the paragraph attributes with style names and re-applying the definition's
+attributes to the paragraph. Currently, this works with paragraph and list style definitions only.
+
+\subsection{wxRichTextCtrl dialogs}\label{wxrichtextctrldialogs}
+
+wxRichTextCtrl comes with standard dialogs to make it easier to implement
+text editing functionality.
+
+\helpref{wxRichTextFormattingDialog}{wxrichtextformattingdialog} can be used
+for character or paragraph formatting, or a combination of both. It's a wxPropertySheetDialog
+with the following available tabs: Font, Indents \& Spacing, Tabs, Bullets, Style, and List Style.
+You can select which pages will be shown by supplying flags to the dialog constructor.
+In a character formatting dialog, typically only the Font page will be shown.
+In a paragraph formatting dialog, you'll show the Indents \& Spacing, Tabs and Bullets
+pages. The Style tab is useful when editing a style definition.
+
+You can customize this dialog by providing your own wxRichTextFormattingDialogFactory
+object, which tells the formatting dialog how many pages are supported, what their identifiers
+are, and how to creates the pages.
+
+\helpref{wxRichTextStyleOrganiserDialog}{wxrichtextstyleorganiserdialog} is a multi-purpose dialog
+that can be used for managing style definitions, browsing styles and applying them, or selecting list styles with
+a renumber option. See the sample for usage - it is used for the "Manage Styles" and "Bullets and Numbering"
+menu commands.
+
+\helpref{wxSymbolPickerDialog}{wxsymbolpickerdialog} lets the user insert a symbol from
+a specified font. It has no wxRichTextCtrl dependencies besides being included in
+the rich text library.
+
+\subsection{How wxRichTextCtrl is implemented}
+
+Data representation is handled by wxRichTextBuffer, and a wxRichTextCtrl
+always has one such buffer.
+
+The content is represented by a hierarchy of objects, all derived from
+wxRichTextObject. An object might be an image, a fragment of text, a paragraph,
+or a whole buffer. Objects store a wxTextAttr containing style information;
+a paragraph object can contain both paragraph and character information, but
+content objects such as text can only store character information. The final
+style displayed in the control or in a printout is a combination of base
+style, paragraph style and content (character) style.
+
+The top of the hierarchy is the buffer, a kind of wxRichTextParagraphLayoutBox.
+containing further wxRichTextParagraph objects, each of which can include text,
+images and potentially other types of object.
+
+Each object maintains a range (start and end position) measured
+from the start of the main parent object.
+
+When Layout is called on an object, it is given a size which the object
+must limit itself to, or one or more flexible directions (vertical
+or horizontal). So, for example, a centred paragraph is given the page
+width to play with (minus any margins), but can extend indefinitely
+in the vertical direction. The implementation of Layout caches the calculated
+size and position.
+
+When the buffer is modified, a range is invalidated (marked as requiring
+layout), so that only the minimum amount of layout is performed.
+
+A paragraph of pure text with the same style contains just one further
+object, a wxRichTextPlainText object. When styling is applied to part of
+this object, the object is decomposed into separate objects, one object
+for each different character style. So each object within a paragraph always has
+just one wxTextAttr object to denote its character style. Of course, this can
+lead to fragmentation after a lot of edit operations, potentially leading
+to several objects with the same style where just one would do. So
+a Defragment function is called when updating the control's display, to ensure that
+the minimum number of objects is used.
+
+\subsection{wxRichTextCtrl roadmap}
+
+\wxheading{Bugs}
+
+This is an incomplete list of bugs.
+
+\begin{itemize}\itemsep=0pt
+\item Moving the caret up at the beginning of a line sometimes incorrectly positions the
+caret.
+\item As the selection is expanded, the text jumps slightly due to kerning differences between
+drawing a single text string versus drawing several fragments separately. This could
+be improved by using wxDC::GetPartialTextExtents to calculate exactly where the separate fragments
+should be drawn. Note that this problem also applies to separation of text fragments due to difference in their attributes.
+\end{itemize}
+
+\wxheading{Features}
+
+This is a list of some of the features that have yet to be implemented. Help with them will be appreciated.
projects / wxWidgets.git / blobdiff