+++ /dev/null
-=====================
- The wxPython Manual
-=====================
-
---------------------------------------------
- A guide to wxPython for Python programmers
---------------------------------------------
-
-:Author: Patrick K. O'Brien
-:Contact: pobrien@orbtech.com
-:Organization: Orbtech_
-:Date: $Date$
-:Revision: $Revision$
-:License: wxWindows Free Documentation Licence, Version 3
-
-.. _Orbtech: http://www.orbtech.com/
-
-.. contents::
-
-
-Introduction
-============
-
-This is a guide to the wxPython GUI toolkit, written **by** a Python
-programmer **for** his fellow Python programmers. It began as a
-simple translation of the wxWidgets documentation (which is written
-for C++ programmers), and evolved from there. And while there's
-nothing wrong with C++...
-
-Okay, you got me there. I hate C++. That's why I use Python. If you
-like C++, go read the wxWidgets documentation. If you'd rather read a
-guide that's written with Python programmers in mind, keep reading
-this one. If you like it, feel free to send me freshly roasted coffee
-beans, dark chocolate, and large denomination currency. Better yet,
-buy huge quantities of my wxPython book (written with Robin Dunn) and
-send one to each of your friends, relatives, and coworkers.
-
-
-What is wxPython?
-=================
-
-wxPython is a GUI toolkit for the Python programming language. It
-allows Python programmers to create programs with a robust, highly
-functional graphical user interface, simply and easily. It is
-implemented as a Python extension module (native code) that wraps the
-popular wxWidgets cross platform GUI library, which is written in C++.
-
-Like Python and wxWidgets, wxPython is Open Source, which means that
-it is free for anyone to use and the source code is available for
-anyone to look at and modify. And anyone can contribute fixes or
-enhnacments to the project.
-
-wxPython is a cross-platform toolkit. This means that the same
-program will run on multiple platforms without modification.
-Currently supported platforms are 32-bit Microsoft Windows, most Unix
-or unix-like systems, and Macintosh OS X.
-
-Since the language is Python, wxPython programs are simple, easy to
-write and easy to understand.
-
-
-wxPython requirements
-=====================
-
-To make use of wxPython, you currently need one of the following
-setups.
-
-MS-Windows
-----------
-
-* A 486 or higher PC running MS Windows.
-* At least ?? MB of disk space.
-
-Linux or Unix
--------------
-
-* Almost any C++ compiler, including GNU C++ (EGCS 1.1.1 or above).
-* Almost any Unix workstation, and one of: GTK+ 1.2, GTK+ 2.0, Motif
- 1.2 or higher, Lesstif.
-* At least ?? MB of disk space.
-
-Mac OS X
---------
-
-* A PowerPC Mac running Mac OS X 10.x.
-* At least ?? MB of disk space.
-
-
-What is wxWidgets?
-==================
-
-wxWidgets is a C++ framework providing GUI (Graphical User Interface)
-and other facilities on more than one platform. Version 2 currently
-supports all desktop versions of MS Windows, Unix with GTK+, Unix with
-Motif, and MacOS. An OS/2 port is in progress.
-
-wxWidgets was originally developed at the Artificial Intelligence
-Applications Institute, University of Edinburgh, for internal use, and
-was first made publicly available in 1992. Version 2 is a vastly
-improved version written and maintained by Julian Smart, Robert
-Roebling, Vadim Zeitlin, Vaclav Slavik and many others.
-
-Please note that in the following, "MS Windows" often refers to all
-platforms related to Microsoft Windows, including 16-bit and 32-bit
-variants, unless otherwise stated. All trademarks are acknowledged.
-
-
-Why another cross-platform development tool?
-============================================
-
-wxWidgets was developed to provide a cheap and flexible way to
-maximize investment in GUI application development. While a number of
-commercial class libraries already existed for cross-platform
-development, none met all of the following criteria:
-
-* low price
-* source availability
-* simplicity of programming
-* support for a wide range of compilers
-
-Since wxWidgets was started, several other free or almost-free GUI
-frameworks have emerged. However, none has the range of features,
-flexibility, documentation and the well-established development team
-that wxWidgets has.
-
-As open source software, wxWidgets has benefited from comments, ideas,
-bug fixes, enhancements and the sheer enthusiasm of users. This gives
-wxWidgets a certain advantage over its commercial competitors (and
-over free libraries without an independent development team), plus a
-robustness against the transience of one individual or company. This
-openness and availability of source code is especially important when
-the future of thousands of lines of application code may depend upon
-the longevity of the underlying class library.
-
-Version 2 goes much further than previous versions in terms of
-generality and features, allowing applications to be produced that are
-often indistinguishable from those produced using single-platform
-toolkits such as Motif, GTK+ and MFC.
-
-The importance of using a platform-independent class library cannot be
-overstated, since GUI application development is very time-consuming,
-and sustained popularity of particular GUIs cannot be guaranteed.
-Code can very quickly become obsolete if it addresses the wrong
-platform or audience. wxWidgets helps to insulate the programmer from
-these winds of change. Although wxWidgets may not be suitable for
-every application (such as an OLE-intensive program), it provides
-access to most of the functionality a GUI program normally requires,
-plus many extras such as network programming, PostScript output, and
-HTML rendering; and it can of course be extended as needs dictate. As
-a bonus, it provides a far cleaner and easier programming interface
-than the native APIs. Programmers may find it worthwhile to use
-wxWidgets even if they are developing on only one platform.
-
-It is impossible to sum up the functionality of wxWidgets in a few
-paragraphs, but here are some of the benefits:
-
-* Low cost (free, in fact!)
-* You get the source.
-* Available on a variety of popular platforms.
-* Works with almost all popular C++ compilers and Python.
-* Over 50 example programs.
-* Over 1000 pages of printable and on-line documentation.
-* Includes Tex2RTF, to allow you to produce your own documentation in
- Windows Help, HTML and Word RTF formats.
-* Simple-to-use, object-oriented API.
-* Flexible event system.
-* Graphics calls include lines, rounded rectangles, splines,
- polylines, etc.
-* Constraint-based and sizer-based layouts.
-* Print/preview and document/view architectures.
-* Toolbar, notebook, tree control, advanced list control classes.
-* PostScript generation under Unix, normal MS Windows printing on the
- PC.
-* MDI (Multiple Document Interface) support.
-* Can be used to create DLLs under Windows, dynamic libraries on Unix.
-* Common dialogs for file browsing, printing, colour selection, etc.
-* Under MS Windows, support for creating metafiles and copying them to
- the clipboard.
-* An API for invoking help from applications.
-* Ready-to-use HTML window (supporting a subset of HTML).
-* Dialog Editor for building dialogs.
-* Network support via a family of socket and protocol classes.
-* Support for platform independent image processing.
-* Built-in support for many file formats (BMP, PNG, JPEG, GIF, XPM,
- PNM, PCX).
-
-
-wxPython Overview
-=================
-
-To set a wxPython application going, you will need to derive an App
-class and override App.OnInit.
-
-An application must have a top-level Frame or Dialog window. Each
-frame may contain one or more instances of classes such as Panel,
-SplitterWindow or other windows and controls.
-
-A frame can have a MenuBar, a ToolBar, a status line, and an Icon for
-when the frame is iconized.
-
-A Panel is used to place controls (classes derived from Control) which
-are used for user interaction. Examples of controls are Button,
-CheckBox, Choice, ListBox, RadioBox, Slider.
-
-Instances of Dialog can also be used for controls, and they have the
-advantage of not requiring a separate frame.
-
-Instead of creating a dialog box and populating it with items, it is
-possible to choose one of the convenient common dialog classes, such
-as MessageDialog and FileDialog.
-
-You never draw directly onto a window. Instead, you use a device
-context (DC). DC is the base for ClientDC, PaintDC, MemoryDC,
-PostScriptDC, MemoryDC, MetafileDC and PrinterDC. If your drawing
-functions have DC as a parameter, you can pass any of these DCs to the
-function, and thus use the same code to draw to several different
-devices. You can draw using the member functions of DC, such as
-DC.DrawLine and DC.DrawText. Control colour on a window (Colour) with
-brushes (Brush) and pens (Pen).
-
-.. To intercept events, you add a DECLARE_EVENT_TABLE macro to the
- window class declaration, and put a BEGIN_EVENT_TABLE
- ... END_EVENT_TABLE block in the implementation file. Between these
- macros, you add event macros which map the event (such as a mouse
- click) to a member function. These might override predefined event
- handlers such as for KeyEvent and MouseEvent.
-
-Most modern applications will have an on-line, hypertext help system;
-for this, you need Help and the HelpController class to control
-Help.
-
-GUI applications aren't all graphical wizardry. You'll also need
-lists and hash tables. But since you're working with Python, you
-should use the ones Python provides (list, tuple, dict), rather than
-the wxWidgets versions. Same goes for the database related classes.
-The basic rule of thumb is this: If you can do it directly in Python,
-you probably should. If there is a reason not to use a Python data
-type, wxPython will provide a wrapper for the wxWidgets class.
-
-You will undoubtedly need some platform-independent file functions,
-and you may find it handy to maintain and search a list of paths using
-PathList. There's a miscellany of operating system and other
-functions.
-
-See also Classes by Category for a list of classes.
-
-
-Utilities and libraries supplied with wxPython
-==============================================
-
-In addition to the core wxWidgets library, a number of further
-libraries and utilities are supplied with each distribution.
-
-[Need to list these.]
-
-
-Creating and deleting wxPython objects
-======================================
-
-[This section needs to be reviewed.]
-
-.. In general, classes derived from wxWindow must dynamically
- allocated with new and deleted with delete. If you delete a window,
- all of its children and descendants will be automatically deleted,
- so you don't need to delete these descendants explicitly.
-
-.. When deleting a frame or dialog, use Destroy rather than delete so
- that the wxWidgets delayed deletion can take effect. This waits
- until idle time (when all messages have been processed) to actually
- delete the window, to avoid problems associated with the GUI
- sending events to deleted windows.
-
-.. If you decide to allocate a C++ array of objects (such as wxBitmap)
- that may be cleaned up by wxWidgets, make sure you delete the array
- explicitly before wxWidgets has a chance to do so on exit, since
- calling delete on array members will cause memory problems.
-
-.. wxColour can be created statically: it is not automatically cleaned
- up and is unlikely to be shared between other objects; it is
- lightweight enough for copies to be made.
-
-.. Beware of deleting objects such as a wxPen or wxBitmap if they are
- still in use. Windows is particularly sensitive to this: so make
- sure you make calls like wxDC::SetPen(wxNullPen) or
- wxDC::SelectObject(wxNullBitmap) before deleting a drawing object
- that may be in use. Code that doesn't do this will probably work
- fine on some platforms, and then fail under Windows.
-
-
-App overview
-============
-
-Classes: wx.App
-
-Application initialization
---------------------------
-
-The OnInit method defined for a class derived from wx.App will usually
-create a top window as a bare minimum.
-
-OnInit must return a boolean value to indicate whether processing
-should continue (True) or not (False). You call App.SetTopWindow to
-let wxPython know about the top window.
-
-An application closes by destroying all windows. Because all frames
-must be destroyed for the application to exit, it is advisable to use
-parent frames wherever possible when creating new frames, so that
-deleting the top level frame will automatically delete child frames.
-The alternative is to explicitly delete child frames in the top-level
-frame's CloseEvent handler.
-
-In emergencies the wx.Exit() function can be called to kill the
-application, however, normally the application shuts down
-automatically, see below.
-
-An example of defining an application follows::
-
- import wx
-
- from frame import Frame
-
- class App(wx.App):
- """Application class."""
-
- def OnInit(self):
- self.frame = Frame()
- self.frame.Show()
- self.SetTopWindow(self.frame)
- return True
-
- def main():
- app = App()
- app.MainLoop()
-
- if __name__ == '__main__':
- main()
-
-
-Application shutdown
---------------------
-
-The application normally shuts down when the last of its top level
-windows is closed. This is normally the expected behaviour and means
-that it is enough to call Close() in response to the "Exit" menu
-command if your program has a single top level window. If this
-behaviour is not desirable, App.SetExitOnFrameDelete can be called to
-change it. Note that such logic doesn't apply for the windows shown
-before the program enters the main loop: in other words, you can
-safely show a dialog from App.OnInit and not be afraid that your
-application terminates when this dialog -- which is the last top level
-window for the moment -- is closed.
-
-Another aspect of the application shutdown is the OnExit which is
-called when the application exits but before wxPython cleans up its
-internal structures. You should delete all wxPython objects that you
-created by the time OnExit finishes.
-
-For example, this code may crash:
-
-[Need examples of objects needing cleanup to keep app from crashing.]
-
-
-Sizer overview
-==============
-
-Classes: wx.Sizer, wx.GridSizer, wx.FlexGridSizer, wx.BoxSizer,
-wx.StaticBoxSizer, wx.NotebookSizer, wx.CreateButtonSizer
-
-============== ======================================================
-
-Sizer Abstract base class.
-
-GridSizer A sizer for laying out windows in a grid with all
- fields having the same size.
-
-FlexGridSizer A sizer for laying out windows in a flexible grid.
-
-BoxSizer A sizer for laying out windows in a row or column.
-
-StaticBoxSizer Same as BoxSizer, but with a surrounding static box.
-
-NotebookSizer Sizer to use with the Notebook control.
-
-============== ======================================================
-
-Sizers, as represented by the wx.Sizer class and its descendants in
-the wxPython class hierarchy, have become the method of choice to
-define the layout of controls in dialogs in wxPython because of their
-ability to create visually appealing dialogs independent of the
-platform, taking into account the differences in size and style of the
-individual controls. Editors such as wxDesigner, wxrcedit, XRCed and
-wxWorkshop create dialogs based exclusively on sizers, practically
-forcing the user to create platform independent layouts without
-compromises.
-
-
-The idea behind sizers
-----------------------
-
-The layout algorithm used by sizers in wxPython is closely related to
-layout systems in other GUI toolkits, such as Java's AWT, the GTK
-toolkit or the Qt toolkit. It is based upon the idea of individual
-subwindows reporting their minimal required size and their ability to
-get stretched if the size of the parent window has changed. This will
-most often mean that the programmer does not set the start-up size of
-a dialog, the dialog will rather be assigned a sizer and this sizer
-will be queried about the recommended size. This sizer in turn will
-query its children (which can be normal windows, empty space or other
-sizers) so that a hierarchy of sizers can be constructed. Note that
-wx.Sizer does not derive from wx.Window and thus does not interfere
-with tab ordering and requires very few resources compared to a real
-window on screen.
-
-What makes sizers so well fitted for use in wxPython is the fact that
-every control reports its own minimal size and the algorithm can
-handle differences in font sizes or different window (dialog item)
-sizes on different platforms without problems. For example, if the
-standard font as well as the overall design of Linux/GTK widgets
-requires more space than on Windows, the initial dialog size will
-automatically be bigger on Linux/GTK than on Windows.
-
-There are currently five different kinds of sizers available in
-wxPython. Each represents either a certain way to lay out dialog items
-in a dialog or it fulfils a special task such as wrapping a static box
-around a dialog item (or another sizer). These sizers will be
-discussed one by one in the text below.
-
-
-Common features
----------------
-
-All sizers are containers, that is, they are used to lay out one
-dialog item (or several dialog items), which they contain. Such items
-are sometimes referred to as the children of the sizer. Independent
-of how the individual sizers lay out their children, all children have
-certain features in common:
-
-
-A minimal size
-~~~~~~~~~~~~~~
-
-This minimal size is usually identical to the initial size of the
-controls and may either be set explicitly in the size field of the
-control constructor or may be calculated by wxPython, typically by
-setting the height and/or the width of the item to -1. Note that only
-some controls can calculate their size (such as a checkbox) whereas
-others (such as a listbox) don't have any natural width or height and
-thus require an explicit size. Some controls can calculate their
-height, but not their width (e.g. a single line text control):
-
-[Need graphics]
-
-
-A border
-~~~~~~~~
-
-The border is just empty space and is used to separate dialog items in
-a dialog. This border can either be all around, or at any combination
-of sides such as only above and below the control. The thickness of
-this border must be set explicitly, typically 5 points. The following
-samples show dialogs with only one dialog item (a button) and a border
-of 0, 5, and 10 pixels around the button:
-
-[Need graphics]
-
-
-An alignment
-~~~~~~~~~~~~
-
-Often, a dialog item is given more space than its minimal size plus
-its border. Depending on what flags are used for the respective dialog
-item, the dialog item can be made to fill out the available space
-entirely, i.e. it will grow to a size larger than the minimal size, or
-it will be moved to either the centre of the available space or to
-either side of the space. The following sample shows a listbox and
-three buttons in a horizontal box sizer; one button is centred, one is
-aligned at the top, one is aligned at the bottom:
-
-[Need graphics]
-
-
-A stretch factor
-~~~~~~~~~~~~~~~~
-
-If a sizer contains more than one child and it is offered more space
-than its children and their borders need, the question arises how to
-distribute the surplus space among the children. For this purpose, a
-stretch factor may be assigned to each child, where the default value
-of 0 indicates that the child will not get more space than its
-requested minimum size. A value of more than zero is interpreted in
-relation to the sum of all stretch factors in the children of the
-respective sizer, i.e. if two children get a stretch factor of 1, they
-will get half the extra space each independent of whether one control
-has a minimal sizer inferior to the other or not. The following
-sample shows a dialog with three buttons, the first one has a stretch
-factor of 1 and thus gets stretched, whereas the other two buttons
-have a stretch factor of zero and keep their initial width:
-
-[Need graphics]
-
-Within wxDesigner, this stretch factor gets set from the Option menu.
-
-
-BoxSizer
---------
-
-BoxSizer can lay out its children either vertically or horizontally,
-depending on what flag is being used in its constructor. When using a
-vertical sizer, each child can be centered, aligned to the right or
-aligned to the left. Correspondingly, when using a horizontal sizer,
-each child can be centered, aligned at the bottom or aligned at the
-top. The stretch factor described in the last paragraph is used for
-the main orientation, i.e. when using a horizontal box sizer, the
-stretch factor determines how much the child can be stretched
-horizontally. The following sample shows the same dialog as in the
-last sample, only the box sizer is a vertical box sizer now:
-
-[Need graphics]
-
-
-StaticBoxSizer
---------------
-
-StaticBoxSixer is the same as a BoxSizer, but surrounded by a static
-box. Here is a sample:
-
-[Need graphics]
-
-
-GridSizer
----------
-
-GridSizer is a two-dimensional sizer. All children are given the same
-size, which is the minimal size required by the biggest child, in this
-case the text control in the left bottom border. Either the number of
-columns or the number or rows is fixed and the grid sizer will grow in
-the respectively other orientation if new children are added:
-
-[Need graphics]
-
-
-FlexGridSizer
--------------
-
-Another two-dimensional sizer derived from GridSizer. The width of
-each column and the height of each row are calculated individually
-according the minimal requirements from the respectively biggest
-child. Additionally, columns and rows can be declared to be
-stretchable if the sizer is assigned a size different from that which
-it requested. The following sample shows the same dialog as the one
-above, but using a flex grid sizer:
-
-[Need graphics]
-
-
-NotebookSizer
--------------
-
-NotebookSizer can be used with notebooks. It calculates the size of
-each notebook page and sets the size of the notebook to the size of
-the biggest page plus some extra space required for the notebook tabs
-and decorations.
-
-[Need graphics]
-
-
-Programming with BoxSizer
--------------------------
-
-The basic idea behind a BoxSizer is that windows will most often be
-laid out in rather simple basic geometry, typically in a row or a
-column or several hierarchies of either.
-
-As an example, we will construct a dialog that will contain a text
-field at the top and two buttons at the bottom. This can be seen as a
-top-hierarchy column with the text at the top and buttons at the
-bottom and a low-hierarchy row with an OK button to the left and a
-Cancel button to the right. In many cases (particularly dialogs under
-Unix and normal frames) the main window will be resizable by the user
-and this change of size will have to get propagated to its children.
-In our case, we want the text area to grow with the dialog, whereas
-the button shall have a fixed size. In addition, there will be a thin
-border around all controls to make the dialog look nice and - to make
-matter worse - the buttons shall be centred as the width of the dialog
-changes.
-
-It is the unique feature of a box sizer, that it can grow in both
-directions (height and width) but can distribute its growth in the
-main direction (horizontal for a row) unevenly among its children. In
-our example case, the vertical sizer is supposed to propagate all its
-height changes to only the text area, not to the button area. This is
-determined by the proportion parameter when adding a window (or
-another sizer) to a sizer. It is interpreted as a weight factor,
-i.e. it can be zero, indicating that the window may not be resized at
-all, or above zero. If several windows have a value above zero, the
-value is interpreted relative to the sum of all weight factors of the
-sizer, so when adding two windows with a value of 1, they will both
-get resized equally much and each half as much as the sizer owning
-them.
-
-Then what do we do when a column sizer changes its width? This
-behaviour is controlled by flags (the second parameter of the Add()
-function): zero or no flag indicates that the window will preserve it
-is original size, wx.GROW flag (same as wx.EXPAND) forces the window
-to grow with the sizer, and wx.SHAPED flag tells the window to change
-it is size proportionally, preserving original aspect ratio. When
-wx.GROW flag is not used, the item can be aligned within available
-space. wx.ALIGN_LEFT, wx.ALIGN_TOP, wx.ALIGN_RIGHT, wx.ALIGN_BOTTOM,
-wx.ALIGN_CENTER_HORIZONTAL and wx.ALIGN_CENTER_VERTICAL do what they
-say. wx.ALIGN_CENTRE (same as wx.ALIGN_CENTER) is defined as
-(``wx.ALIGN_CENTER_HORIZONTAL | wx.ALIGN_CENTER_VERTICAL``). Default
-alignment is ``wx.ALIGN_LEFT | wx.ALIGN_TOP``.
-
-As mentioned above, any window belonging to a sizer may have border,
-and it can be specified which of the four sides may have this border,
-using the wx.TOP, wx.LEFT, wx.RIGHT and wx.BOTTOM constants or wx.ALL
-for all directions (and you may also use wx.NORTH, wx.WEST etc
-instead). These flags can be used in combination with the alignment
-flags above as the second parameter of the Add() method using the
-binary or operator (``|``). The sizer of the border also must be made
-known, and it is the third parameter in the Add() method. This means,
-that the entire behaviour of a sizer and its children can be
-controlled by the three parameters of the Add() method.
-
-[Show code and graphic here.]
-
-
-Programming with GridSizer
---------------------------
-
-GridSizer is a sizer which lays out its children in a two-dimensional
-table with all table fields having the same size, i.e. the width of
-each field is the width of the widest child, the height of each field
-is the height of the tallest child.
-
-[Show code and graphic here.]
-
-
-Programming with FlexGridSizer
-------------------------------
-
-FlexGridSizer is a sizer which lays out its children in a
-two-dimensional table with all table fields in one row having the same
-height and all fields in one column having the same width, but all
-rows or all columns are not necessarily the same height or width as in
-the GridSizer.
-
-[Show code and graphic here.]
-
-
-Programming with NotebookSizer
-------------------------------
-
-NotebookSizer is a specialized sizer to make sizers work in connection
-with using notebooks. This sizer is different from any other sizer as
-you must not add any children to it - instead, it queries the notebook
-class itself. The only thing this sizer does is to determine the size
-of the biggest page of the notebook and report an adjusted minimal
-size to a more toplevel sizer.
-
-In order to query the size of notebook page, this page needs to have
-its own sizer, otherwise the NotebookSizer will ignore it. Notebook
-pages get their sizer by assigning one to them using SetSizer() and
-setting the auto-layout option to True using SetAutoLayout(). Here is
-one example showing how to add a notebook page that the notebook sizer
-is aware of:
-
-[Show code and graphic here.]
-
-
-Programming with StaticBoxSizer
--------------------------------
-
-StaticBoxSizer is a sizer derived from BoxSizer but adds a static box
-around the sizer. Note that this static box has to be created
-separately.
-
-[Show code and graphic here.]
-
-
-Dialog.CreateButtonSizer
-------------------------
-
-As a convenience, the Dialog class has a CreateButtonSizer(flags)
-method that can be used to create a standard button sizer in which
-standard buttons are displayed. The following flags can be passed to
-this method:
-
-============= =======================================================
-wx.YES_NO add Yes/No subpanel
-wx.YES return wx.ID_YES
-wx.NO return wx.ID_NO
-wx.NO_DEFAULT make the wx.NO button the default, otherwise wx.YES or
- wx.OK button will be default
-wx.OK return wx.ID_OK
-wx.CANCEL return wx.ID_CANCEL
-wx.HELP return wx.ID_HELP
-wx.FORWARD return wx.ID_FORWARD
-wx.BACKWARD return wx.ID_BACKWARD
-wx.SETUP return wx.ID_SETUP
-wx.MORE return wx.ID_MORE
-============= =======================================================
-
-
-Date and time classes overview
-==============================
-
-wxPython provides a set of powerful classes to work with dates and
-times. Some of the supported features of the DateTime class are:
-
-============= =======================================================
-
-Wide range The range of supported dates goes from about 4714 B.C. to
- some 480 million years in the future.
-
-Precision Not using floating point calculations anywhere ensures that
- the date calculations don't suffer from rounding
- errors.
-
-Many features Not only all usual calculations with dates are
- supported, but also more exotic week and year day
- calculations, work day testing, standard astronomical
- functions, conversion to and from strings in either
- strict or free format.
-
-
-Efficiency Objects of DateTime are small (8 bytes) and working
- with them is fast
-
-============= =======================================================
-
-
-All date/time classes at a glance
----------------------------------
-
-There are 3 main classes: except DateTime itself which represents an
-absolute moment in time, there are also two classes - TimeSpan and
-DateSpan which represent the intervals of time.
-
-There are also helper classes which are used together with DateTime:
-DateTimeHolidayAuthority which is used to determine whether a given
-date is a holiday or not and DateTimeWorkDays which is a derivation of
-this class for which (only) Saturdays and Sundays are the holidays.
-See more about these classes in the discussion of the holidays.
-
-
-DateTime characteristics
-------------------------
-
-DateTime stores the time as a signed number of milliseconds since the
-Epoch which is fixed, by convention, to Jan 1, 1970 - however this is
-not visible to the class users (in particular, dates prior to the
-Epoch are handled just as well (or as bad) as the dates after it).
-But it does mean that the best resolution which can be achieved with
-this class is 1 millisecond.
-
-The size of DateTime object is 8 bytes because it is represented as a
-64 bit integer. The resulting range of supported dates is thus
-approximatively 580 million years, but due to the current limitations
-in the Gregorian calendar support, only dates from Nov 24, 4714BC are
-supported (this is subject to change if there is sufficient interest
-in doing it).
-
-Finally, the internal representation is time zone independent (always
-in GMT) and the time zones only come into play when a date is broken
-into year/month/day components. See more about timezones below.
-
-Currently, the only supported calendar is Gregorian one (which is used
-even for the dates prior to the historic introduction of this calendar
-which was first done on Oct 15, 1582 but is, generally speaking,
-country, and even region, dependent). Future versions will probably
-have Julian calendar support as well and support for other calendars
-(Maya, Hebrew, Chinese...) is not ruled out.
-
-
-Difference between DateSpan and TimeSpan
-----------------------------------------
-
-While there is only one logical way to represent an absolute moment in
-the time (and hence only one DateTime class), there are at least two
-methods to describe a time interval.
-
-First, there is the direct and self-explaining way implemented by
-TimeSpan: it is just a difference in milliseconds between two moments
-in time. Adding or subtracting such an interval to DateTime is always
-well-defined and is a fast operation.
-
-But in daily life other, calendar-dependent time interval
-specifications are used. For example, 'one month later' is commonly
-used. However, it is clear that this is not the same as TimeSpan of
-60*60*24*31 seconds because 'one month later' Feb 15 is Mar 15 and not
-Mar 17 or Mar 16 (depending on whether the year is leap or not).
-
-This is why there is another class for representing such intervals
-called DateSpan. It handles these sort of operations in the most
-natural way possible, but note that manipulating with intervals of
-this kind is not always well-defined. Consider, for example, Jan 31 +
-'1 month': this will give Feb 28 (or 29), i.e. the last day of
-February and not the non-existent Feb 31. Of course, this is what is
-usually wanted, but you still might be surprised to notice that now
-subtracting back the same interval from Feb 28 will result in Jan 28
-and not Jan 31 we started with!
-
-So, unless you plan to implement some kind of natural language parsing
-in the program, you should probably use TimeSpan instead of DateSpan
-(which is also more efficient). However, DateSpan may be very useful
-in situations when you do need to understand what 'in a month' means
-(of course, it is just DateTime.Now() + DateSpan.Month()).
-
-
-Date arithmetics
-----------------
-
-Many different operations may be performed with the dates, however not
-all of them make sense. For example, multiplying a date by a number
-is an invalid operation, even though multiplying either of the time
-span classes by a number is perfectly valid.
-
-Here is what can be done:
-
-============== ======================================================
-
-Addition a TimeSpan or DateSpan can be added to DateTime resulting in
- a new DateTime object and also 2 objects of the same
- span class can be added together giving another object
- of the same class.
-
-
-Subtraction the same types of operations as above are allowed and,
- additionally, a difference between two DateTime
- objects can be taken and this will yield TimeSpan.
-
-Multiplication a TimeSpan or DateSpan object can be multiplied by an
- integer number resulting in an object of the same
- type.
-
-
-Unary minus a TimeSpan or DateSpan object may finally be negated
- giving an interval of the same magnitude but of
- opposite time direction.
-
-============== ======================================================
-
-
-Time zone considerations
-------------------------
-
-Although the time is always stored internally in GMT, you will usually
-work in the local time zone. Because of this, all DateTime
-constructors and setters which take the broken down date assume that
-these values are for the local time zone. Thus, DateTime(1,
-DateTime.Jan, 1970) will not correspond to the DateTime Epoch unless
-you happen to live in the UK.
-
-All methods returning the date components (year, month, day, hour,
-minute, second...) will also return the correct values for the local
-time zone by default. So, generally, doing the natural things will
-lead to natural and correct results.
-
-If you only want to do this, you may safely skip the rest of this
-section. However, if you want to work with different time zones, you
-should read it to the end.
-
-In this (rare) case, you are still limited to the local time zone when
-constructing DateTime objects, i.e. there is no way to construct a
-DateTime corresponding to the given date in, say, Pacific Standard
-Time. To do it, you will need to call ToTimezone or MakeTimezone
-methods to adjust the date for the target time zone. There are also
-special versions of these functions ToGMT and MakeGMT for the most
-common case - when the date should be constructed in GMT.
-
-You also can just retrieve the value for some time zone without
-converting the object to it first. For this you may pass TimeZone
-argument to any of the methods which are affected by the time zone
-(all methods getting date components and the date formatting ones, for
-example). In particular, the Format() family of methods accepts a
-TimeZone parameter and this allows to simply print time in any time
-zone.
-
-To see how to do it, the last issue to address is how to construct a
-TimeZone object which must be passed to all these methods. First of
-all, you may construct it manually by specifying the time zone offset
-in seconds from GMT, but usually you will just use one of the symbolic
-time zone names and let the conversion constructor do the
-job. I.e. you would just write
-
-wxDateTime dt(...whatever...);
-printf("The time is %s in local time zone", dt.FormatTime().c_str());
-printf("The time is %s in GMT", dt.FormatTime(wxDateTime::GMT).c_str());
-
-
-Daylight saving time (DST)
---------------------------
-
-DST (a.k.a. 'summer time') handling is always a delicate task which is
-better left to the operating system which is supposed to be configured
-by the administrator to behave correctly. Unfortunately, when doing
-calculations with date outside of the range supported by the standard
-library, we are forced to deal with these issues ourselves.
-
-Several functions are provided to calculate the beginning and end of
-DST in the given year and to determine whether it is in effect at the
-given moment or not, but they should not be considered as absolutely
-correct because, first of all, they only work more or less correctly
-for only a handful of countries (any information about other ones
-appreciated!) and even for them the rules may perfectly well change in
-the future.
-
-The time zone handling methods use these functions too, so they are
-subject to the same limitations.
-
-
-DateTime and Holidays
----------------------
-
-[TODO]
-
-
-Classes by category
-===================
-
-Not done yet.
-
-
-ID constants
-============
-
-wxPython provides the following predefined ID constants:
-
-ID_ABORT
-ID_ABOUT
-ID_ANY
-ID_APPLY
-ID_BACKWARD
-ID_CANCEL
-ID_CLEAR
-ID_CLOSE
-ID_CLOSE_ALL
-ID_CONTEXT_HELP
-ID_COPY
-ID_CUT
-ID_DEFAULT
-ID_DUPLICATE
-ID_EXIT
-ID_FILE1
-ID_FILE2
-ID_FILE3
-ID_FILE4
-ID_FILE5
-ID_FILE6
-ID_FILE7
-ID_FILE8
-ID_FILE9
-ID_FILTERLISTCTRL
-ID_FIND
-ID_FORWARD
-ID_HELP
-ID_HELP_COMMANDS
-ID_HELP_CONTENTS
-ID_HELP_CONTEXT
-ID_HELP_PROCEDURES
-ID_IGNORE
-ID_MORE
-ID_NEW
-ID_NO
-ID_NOTOALL
-ID_OK
-ID_OPEN
-ID_PASTE
-ID_PREVIEW
-ID_PRINT
-ID_PRINT_SETUP
-ID_REDO
-ID_RESET
-ID_RETRY
-ID_REVERT
-ID_SAVE
-ID_SAVEAS
-ID_SELECTALL
-ID_SEPARATOR
-ID_SETUP
-ID_STATIC
-ID_TREECTRL
-ID_UNDO
-ID_YES
-ID_YESTOALL
-
-
-Source document
-===============
-
-The source document is named wxPythonManual.txt and can be found by
-clicking the link at the bottom of this page (assuming you are viewing
-the html file). It is written using a fantastic formatting convention
-called reStructuredText. The wxPythonManual.html file is created
-using the Docutils utilities, which can turn reStructuredText
-documents into html, xml, pdf, and even OpenOffice files.
-
-
-Submitting changes to the source document
-=========================================
-
-Some items in the source text file look like this::
-
- .. This is text from the wxWidgets documentation that needs to be
- translated into something appropriate for the wxPython version.
- The two dots followed by uniformly indented text turns this
- paragraph into a reStructuredText comment, so it doesn't appear
- in any output file, such as the html file.
-
-They have been commented out and are awaiting editorial review and a
-rewrite so that they make sense in the context of wxPython. Feel free
-to send me suggestions for rewording these, or any other parts of this
-document that you think need improving. I will be eternally grateful
-to you and will show my gratitude by adding your name to the list of
-contributors. (Contributors who also send me gifts of coffee,
-chocolate, or currency will have their names listed in bold.)
-
-
-Contributors
-============
-
-Individuals who contributed to this documentation (in order by last
-name):
-
-* Robin Dunn
-* Patrick K. O'Brien
-* Robert Roebling
-* Julian Smart
-* Vadim Zeitlin
-
-
-License
-=======
-
-This document began as a translation of the wxWidgets documentation.
-As such, it adheres to the same license, which is provided here:
-
-.. include:: ../licence/licendoc.txt
- :literal:
projects / wxWidgets.git / blobdiff