Added wxRichTextCtrl

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@35949 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

samples/richtext/readme.txt

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+
+wxRichTextCtrl README
+=====================
+
+Welcome to wxRichTextCtrl. It includes the following functionality:
+
+* Text entry, paragraph wrapping
+
+* Scrolling, keyboard navigation
+
+* Application of character styles:
+
+  bold, italic, underlined, font face, text colour
+
+* Application of paragraph styles:
+
+  left/right indentation, sub-indentation (first-line indent),
+  paragraph spacing (before and after), line spacing,
+  left/centre/right alignment, numbered bullets
+
+* Insertion of images
+
+* Copy/paste
+
+* Undo/Redo with optional batching and undo history suppression
+
+* Named paragraph and character styles management and application
+
+* File handlers allow addition of file formats
+
+* Text saving and loading, XML saving and loading, HTML saving (unfinished)
+
+Sorry, this is a Windows-only demo for now but the code should
+compile on other platforms.
+
+Design
+======
+
+Data is represented by a hierarchy of objects, all derived from
+wxRichTextObject.
+
+The top of the hierarchy is the buffer, a kind of wxRichTextParagraphLayoutBox.
+These boxes will allow flexible placement of text boxes on a page, but
+for now there will be a single box representing the document,
+and this box will a wxRichTextParagraphLayoutBox which contains further
+wxRichTextParagraph objects, each of which can include text and images.
+
+Each object maintains a range (start and end position) measured
+from the start of the main parent box.
+A paragraph object knows its range, and a text fragment knows its range
+too. So, a character or image in a page has a position relative to the
+start of the document, and a character in an embedded text box has
+a position relative to that text box. For now, we will not be dealing with
+embedded objects but it's something to bear in mind for later.
+
+Before display, a changed buffer must have Layout() called on it,
+to do wrapping, alignment etc. Ranges representing wrapped lines are stored
+with each paragraph.
+
+Since wxRichTextBuffer is separate from wxRichTextCtrl, the storage
+and rendering facilities can be used by other controls.
+
+API
+===
+
+It's basically the wxTextCtrl with some additions. There is a new
+wxTextAttrEx class deriving from wxTextAttr, to accomodate new
+style attributes. This could be merged with wxTextAttr. There
+is also a wxRichTextAttr which is similar to wxTextAttrEx but
+doesn't store the font as a wxFont: this allows much more
+efficient operations, especially when querying styles in a
+UI update handler. We would not want to create several new wxFonts
+when querying for italics, bold, etc. every few milliseconds.
+
+See "Functionality specific to wxRichTextCtrl" section in richtextctrl.h.
+
+One addition is Set/GetBasicStyle, which is needed in addition to
+Set/GetDefaultStyle to get the overall style for the buffer
+from which content will inherit (after apply the default style).
+
+wxRichTextRange is a new class representing start and end positions.
+It's used in the implementation so that pieces of content
+know their range, and also in the API in preference to using
+two positions.
+
+What next?
+==========
+
+- Decision about where to put it: wxCode, wxWidgets
+- Makefiles/bakefiles
+- Refining the API
+- Documentation
+- Bug fixing/improvements
+
+
+See todo.txt for a list of bugs, improvements and features,
+and also TODO throughout the source.
+
+==
+Julian Smart, October 18th 2005