From 4f88b483b5bb9482c87a0ddf94c531d638fa3052 Mon Sep 17 00:00:00 2001 From: Julian Smart Date: Thu, 12 Oct 2006 04:27:35 +0000 Subject: [PATCH] Some additions to the wxRichTextCtrl overview. git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@41963 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775 --- docs/latex/wx/richtextoverview.tex | 148 +++++++++++++++++++++++++---- docs/latex/wx/tapp.tex | 1 + 2 files changed, 131 insertions(+), 18 deletions(-) diff --git a/docs/latex/wx/richtextoverview.tex b/docs/latex/wx/richtextoverview.tex index 498f115cd7..97c7254a9c 100644 --- a/docs/latex/wx/richtextoverview.tex +++ b/docs/latex/wx/richtextoverview.tex @@ -191,6 +191,8 @@ The following code is taken from the sample, and adds text and styles to a rich \subsection{Programming with wxRichTextCtrl} +\subsubsection{Starting to use wxRichTextCtrl} + You need to include {\tt } 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. @@ -198,19 +200,123 @@ 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. -It's helpful to have a model of how styling works. Any piece of text can have its -style changed, but there also two global notions of style. The control's {\it basic} style -is the fundamental style for the whole control, to which other character and paragraph styles are -applied. For example, you can change the control's overall font by either calling SetBasicStyle with -the appropriate font style, or by calling SetFont. - -The {\it default} style, on the other hand, is applied to subsequently inserted -content. You might click on a Bold formatting tool, which sets bold as one of the default -attributes, and typing will appear in bold. Then when you select Italic, both -bold and italic attributes are applied as you type. The default attribute -is set with \helpref{SetDefaultStyle}{wxrichtextctrlsetdefaultstyle}. +\subsubsection{wxRichTextCtrl and styles} + +Styling attributes are represented by one of three classes: \helpref{wxTextAttr}{wxtextattr}, \helpref{wxTextAttrEx}{wxtextattrex} and \helpref{wxRichTextAttr}{wxrichtextattr}. +wxTextAttr is shared across all controls that are derived from wxTextCtrl and +can store basic character and paragraph attributes. wxTextAttrEx derives +from wxTextAttr and adds some further attributes that are only supported +by wxRichTextCtrl. Finally, wxRichTextAttr is a more efficient version +of wxTextAttrEx that doesn't use a wxFont object and can be used to +query styles more quickly. wxTextAttrEx and wxRichTextAttr are largely +interchangeable and have suitable conversion operators between them. + +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} -(To be finished.) +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} 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 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, and 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{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} @@ -225,8 +331,8 @@ paragraph style information is ignored by children of a paragraph (only character style is relevant to these objects). The top of the hierarchy is the buffer, a kind of wxRichTextParagraphLayoutBox. -containing further wxRichTextParagraph objects, each of which can include text and -images. +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 box. @@ -251,24 +357,30 @@ 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. -(To be finished.) - \subsection{wxRichTextCtrl roadmap} \wxheading{Bugs} This is an incomplete list of bugs. -\begin{itemize} +\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. +Alternatively, it might be possible to use the difference between the width of text from +a to b+1, versus the width of the text from a to b added to the width of b to b+1. +Note that this problem also applies to separation of text fragments due to difference in their attributes. +\item Selection doesn't work properly for text that contains tabs. \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. -\begin{itemize} +\begin{itemize}\itemsep=0pt \item Printing \item RTF input and output \item Floating images, with content wrapping around them diff --git a/docs/latex/wx/tapp.tex b/docs/latex/wx/tapp.tex index 9af797b27d..f87e1a4c8f 100644 --- a/docs/latex/wx/tapp.tex +++ b/docs/latex/wx/tapp.tex @@ -116,3 +116,4 @@ int MyApp::OnExit() return 0; } \end{verbatim} + -- 2.45.2