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author | Guido van Rossum <guido@python.org> | 1994-01-02 01:22:07 (GMT) |
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committer | Guido van Rossum <guido@python.org> | 1994-01-02 01:22:07 (GMT) |
commit | 5fdeeeae2a12b9956cc84d62eae82f72cabc8664 (patch) | |
tree | ac0053479e10099850c8e0d06e31cb3afbf632bb /Doc/libstdwin.tex | |
parent | 0b0719866e8a32d0a787e73bca9e79df1d1a74f8 (diff) | |
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Restructured library documentation
Diffstat (limited to 'Doc/libstdwin.tex')
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diff --git a/Doc/libstdwin.tex b/Doc/libstdwin.tex new file mode 100644 index 0000000..12771c9 --- /dev/null +++ b/Doc/libstdwin.tex @@ -0,0 +1,893 @@ +\chapter{STDWIN ONLY} + +\section{Built-in Module \sectcode{stdwin}} +\bimodindex{stdwin} + +This module defines several new object types and functions that +provide access to the functionality of the Standard Window System +Interface, STDWIN [CWI report CR-R8817]. +It is available on systems to which STDWIN has been ported (which is +most systems). +It is only available if the \code{DISPLAY} environment variable is set +or an explicit \samp{-display \var{displayname}} argument is passed to +the interpreter. + +Functions have names that usually resemble their C STDWIN counterparts +with the initial `w' dropped. +Points are represented by pairs of integers; rectangles +by pairs of points. +For a complete description of STDWIN please refer to the documentation +of STDWIN for C programmers (aforementioned CWI report). + +\subsection{Functions Defined in Module \sectcode{stdwin}} + +The following functions are defined in the \code{stdwin} module: + +\renewcommand{\indexsubitem}{(in module stdwin)} +\begin{funcdesc}{open}{title} +Open a new window whose initial title is given by the string argument. +Return a window object; window object methods are described below.% +\footnote{The Python version of STDWIN does not support draw procedures; all + drawing requests are reported as draw events.} +\end{funcdesc} + +\begin{funcdesc}{getevent}{} +Wait for and return the next event. +An event is returned as a triple: the first element is the event +type, a small integer; the second element is the window object to which +the event applies, or +\code{None} +if it applies to no window in particular; +the third element is type-dependent. +Names for event types and command codes are defined in the standard +module +\code{stdwinevent}. +\end{funcdesc} + +\begin{funcdesc}{pollevent}{} +Return the next event, if one is immediately available. +If no event is available, return \code{()}. +\end{funcdesc} + +\begin{funcdesc}{getactive}{} +Return the window that is currently active, or \code{None} if no +window is currently active. (This can be emulated by monitoring +WE_ACTIVATE and WE_DEACTIVATE events.) +\end{funcdesc} + +\begin{funcdesc}{listfontnames}{pattern} +Return the list of font names in the system that match the pattern (a +string). The pattern should normally be \code{'*'}; returns all +available fonts. If the underlying window system is X11, other +patterns follow the standard X11 font selection syntax (as used e.g. +in resource definitions), i.e. the wildcard character \code{'*'} +matches any sequence of characters (including none) and \code{'?'} +matches any single character. +\end{funcdesc} + +\begin{funcdesc}{setdefscrollbars}{hflag\, vflag} +Set the flags controlling whether subsequently opened windows will +have horizontal and/or vertical scroll bars. +\end{funcdesc} + +\begin{funcdesc}{setdefwinpos}{h\, v} +Set the default window position for windows opened subsequently. +\end{funcdesc} + +\begin{funcdesc}{setdefwinsize}{width\, height} +Set the default window size for windows opened subsequently. +\end{funcdesc} + +\begin{funcdesc}{getdefscrollbars}{} +Return the flags controlling whether subsequently opened windows will +have horizontal and/or vertical scroll bars. +\end{funcdesc} + +\begin{funcdesc}{getdefwinpos}{} +Return the default window position for windows opened subsequently. +\end{funcdesc} + +\begin{funcdesc}{getdefwinsize}{} +Return the default window size for windows opened subsequently. +\end{funcdesc} + +\begin{funcdesc}{getscrsize}{} +Return the screen size in pixels. +\end{funcdesc} + +\begin{funcdesc}{getscrmm}{} +Return the screen size in millimeters. +\end{funcdesc} + +\begin{funcdesc}{fetchcolor}{colorname} +Return the pixel value corresponding to the given color name. +Return the default foreground color for unknown color names. +Hint: the following code tests wheter you are on a machine that +supports more than two colors: +\bcode\begin{verbatim} +if stdwin.fetchcolor('black') <> \ + stdwin.fetchcolor('red') <> \ + stdwin.fetchcolor('white'): + print 'color machine' +else: + print 'monochrome machine' +\end{verbatim}\ecode +\end{funcdesc} + +\begin{funcdesc}{setfgcolor}{pixel} +Set the default foreground color. +This will become the default foreground color of windows opened +subsequently, including dialogs. +\end{funcdesc} + +\begin{funcdesc}{setbgcolor}{pixel} +Set the default background color. +This will become the default background color of windows opened +subsequently, including dialogs. +\end{funcdesc} + +\begin{funcdesc}{getfgcolor}{} +Return the pixel value of the current default foreground color. +\end{funcdesc} + +\begin{funcdesc}{getbgcolor}{} +Return the pixel value of the current default background color. +\end{funcdesc} + +\begin{funcdesc}{setfont}{fontname} +Set the current default font. +This will become the default font for windows opened subsequently, +and is also used by the text measuring functions \code{textwidth}, +\code{textbreak}, \code{lineheight} and \code{baseline} below. +This accepts two more optional parameters, size and style: +Size is the font size (in `points'). +Style is a single character specifying the style, as follows: +\code{'b'} = bold, +\code{'i'} = italic, +\code{'o'} = bold + italic, +\code{'u'} = underline; +default style is roman. +Size and style are ignored under X11 but used on the Macintosh. +(Sorry for all this complexity --- a more uniform interface is being designed.) +\end{funcdesc} + +\begin{funcdesc}{menucreate}{title} +Create a menu object referring to a global menu (a menu that appears in +all windows). +Methods of menu objects are described below. +Note: normally, menus are created locally; see the window method +\code{menucreate} below. +\strong{Warning:} the menu only appears in a window as long as the object +returned by this call exists. +\end{funcdesc} + +\begin{funcdesc}{newbitmap}{width\, height} +Create a new bitmap object of the given dimensions. +Methods of bitmap objects are described below. +\end{funcdesc} + +\begin{funcdesc}{fleep}{} +Cause a beep or bell (or perhaps a `visual bell' or flash, hence the +name). +\end{funcdesc} + +\begin{funcdesc}{message}{string} +Display a dialog box containing the string. +The user must click OK before the function returns. +\end{funcdesc} + +\begin{funcdesc}{askync}{prompt\, default} +Display a dialog that prompts the user to answer a question with yes or +no. +Return 0 for no, 1 for yes. +If the user hits the Return key, the default (which must be 0 or 1) is +returned. +If the user cancels the dialog, the +\code{KeyboardInterrupt} +exception is raised. +\end{funcdesc} + +\begin{funcdesc}{askstr}{prompt\, default} +Display a dialog that prompts the user for a string. +If the user hits the Return key, the default string is returned. +If the user cancels the dialog, the +\code{KeyboardInterrupt} +exception is raised. +\end{funcdesc} + +\begin{funcdesc}{askfile}{prompt\, default\, new} +Ask the user to specify a filename. +If +\var{new} +is zero it must be an existing file; otherwise, it must be a new file. +If the user cancels the dialog, the +\code{KeyboardInterrupt} +exception is raised. +\end{funcdesc} + +\begin{funcdesc}{setcutbuffer}{i\, string} +Store the string in the system's cut buffer number +\var{i}, +where it can be found (for pasting) by other applications. +On X11, there are 8 cut buffers (numbered 0..7). +Cut buffer number 0 is the `clipboard' on the Macintosh. +\end{funcdesc} + +\begin{funcdesc}{getcutbuffer}{i} +Return the contents of the system's cut buffer number +\var{i}. +\end{funcdesc} + +\begin{funcdesc}{rotatecutbuffers}{n} +On X11, rotate the 8 cut buffers by +\var{n}. +Ignored on the Macintosh. +\end{funcdesc} + +\begin{funcdesc}{getselection}{i} +Return X11 selection number +\var{i.} +Selections are not cut buffers. +Selection numbers are defined in module +\code{stdwinevents}. +Selection \code{WS_PRIMARY} is the +\dfn{primary} +selection (used by +xterm, +for instance); +selection \code{WS_SECONDARY} is the +\dfn{secondary} +selection; selection \code{WS_CLIPBOARD} is the +\dfn{clipboard} +selection (used by +xclipboard). +On the Macintosh, this always returns an empty string. +\end{funcdesc} + +\begin{funcdesc}{resetselection}{i} +Reset selection number +\var{i}, +if this process owns it. +(See window method +\code{setselection()}). +\end{funcdesc} + +\begin{funcdesc}{baseline}{} +Return the baseline of the current font (defined by STDWIN as the +vertical distance between the baseline and the top of the +characters). +\end{funcdesc} + +\begin{funcdesc}{lineheight}{} +Return the total line height of the current font. +\end{funcdesc} + +\begin{funcdesc}{textbreak}{str\, width} +Return the number of characters of the string that fit into a space of +\var{width} +bits wide when drawn in the curent font. +\end{funcdesc} + +\begin{funcdesc}{textwidth}{str} +Return the width in bits of the string when drawn in the current font. +\end{funcdesc} + +\begin{funcdesc}{connectionnumber}{} +\funcline{fileno}{} +(X11 under \UNIX{} only) Return the ``connection number'' used by the +underlying X11 implementation. (This is normally the file number of +the socket.) Both functions return the same value; +\code{connectionnumber()} is named after the corresponding function in +X11 and STDWIN, while \code{fileno()} makes it possible to use the +\code{stdwin} module as a ``file'' object parameter to +\code{select.select()}. Note that if \code{select()} implies that +input is possible on \code{stdwin}, this does not guarantee that an +event is ready --- it may be some internal communication going on +between the X server and the client library. Thus, you should call +\code{stdwin.pollevent()} until it returns \code{None} to check for +events if you don't want your program to block. Because of internal +buffering in X11, it is also possible that \code{stdwin.pollevent()} +returns an event while \code{select()} does not find \code{stdwin} to +be ready, so you should read any pending events with +\code{stdwin.pollevent()} until it returns \code{None} before entering +a blocking \code{select()} call. +\ttindex{select} +\end{funcdesc} + +\subsection{Window Object Methods} + +Window objects are created by \code{stdwin.open()}. They are closed +by their \code{close()} method or when they are garbage-collected. +Window objects have the following methods: + +\renewcommand{\indexsubitem}{(window method)} + +\begin{funcdesc}{begindrawing}{} +Return a drawing object, whose methods (described below) allow drawing +in the window. +\end{funcdesc} + +\begin{funcdesc}{change}{rect} +Invalidate the given rectangle; this may cause a draw event. +\end{funcdesc} + +\begin{funcdesc}{gettitle}{} +Returns the window's title string. +\end{funcdesc} + +\begin{funcdesc}{getdocsize}{} +\begin{sloppypar} +Return a pair of integers giving the size of the document as set by +\code{setdocsize()}. +\end{sloppypar} +\end{funcdesc} + +\begin{funcdesc}{getorigin}{} +Return a pair of integers giving the origin of the window with respect +to the document. +\end{funcdesc} + +\begin{funcdesc}{gettitle}{} +Return the window's title string. +\end{funcdesc} + +\begin{funcdesc}{getwinsize}{} +Return a pair of integers giving the size of the window. +\end{funcdesc} + +\begin{funcdesc}{getwinpos}{} +Return a pair of integers giving the position of the window's upper +left corner (relative to the upper left corner of the screen). +\end{funcdesc} + +\begin{funcdesc}{menucreate}{title} +Create a menu object referring to a local menu (a menu that appears +only in this window). +Methods of menu objects are described below. +{\bf Warning:} the menu only appears as long as the object +returned by this call exists. +\end{funcdesc} + +\begin{funcdesc}{scroll}{rect\, point} +Scroll the given rectangle by the vector given by the point. +\end{funcdesc} + +\begin{funcdesc}{setdocsize}{point} +Set the size of the drawing document. +\end{funcdesc} + +\begin{funcdesc}{setorigin}{point} +Move the origin of the window (its upper left corner) +to the given point in the document. +\end{funcdesc} + +\begin{funcdesc}{setselection}{i\, str} +Attempt to set X11 selection number +\var{i} +to the string +\var{str}. +(See stdwin method +\code{getselection()} +for the meaning of +\var{i}.) +Return true if it succeeds. +If succeeds, the window ``owns'' the selection until +(a) another applications takes ownership of the selection; or +(b) the window is deleted; or +(c) the application clears ownership by calling +\code{stdwin.resetselection(\var{i})}. +When another application takes ownership of the selection, a +\code{WE_LOST_SEL} +event is received for no particular window and with the selection number +as detail. +Ignored on the Macintosh. +\end{funcdesc} + +\begin{funcdesc}{settimer}{dsecs} +Schedule a timer event for the window in +\code{\var{dsecs}/10} +seconds. +\end{funcdesc} + +\begin{funcdesc}{settitle}{title} +Set the window's title string. +\end{funcdesc} + +\begin{funcdesc}{setwincursor}{name} +\begin{sloppypar} +Set the window cursor to a cursor of the given name. +It raises the +\code{RuntimeError} +exception if no cursor of the given name exists. +Suitable names include +\code{'ibeam'}, +\code{'arrow'}, +\code{'cross'}, +\code{'watch'} +and +\code{'plus'}. +On X11, there are many more (see +\file{<X11/cursorfont.h>}). +\end{sloppypar} +\end{funcdesc} + +\begin{funcdesc}{setwinpos}{h\, v} +Set the the position of the window's upper left corner (relative to +the upper left corner of the screen). +\end{funcdesc} + +\begin{funcdesc}{setwinsize}{width\, height} +Set the window's size. +\end{funcdesc} + +\begin{funcdesc}{show}{rect} +Try to ensure that the given rectangle of the document is visible in +the window. +\end{funcdesc} + +\begin{funcdesc}{textcreate}{rect} +Create a text-edit object in the document at the given rectangle. +Methods of text-edit objects are described below. +\end{funcdesc} + +\begin{funcdesc}{setactive}{} +Attempt to make this window the active window. If successful, this +will generate a WE_ACTIVATE event (and a WE_DEACTIVATE event in case +another window in this application became inactive). +\end{funcdesc} + +\begin{funcdesc}{close}{} +Discard the window object. It should not be used again. +\end{funcdesc} + +\subsection{Drawing Object Methods} + +Drawing objects are created exclusively by the window method +\code{begindrawing()}. +Only one drawing object can exist at any given time; the drawing object +must be deleted to finish drawing. +No drawing object may exist when +\code{stdwin.getevent()} +is called. +Drawing objects have the following methods: + +\renewcommand{\indexsubitem}{(drawing method)} + +\begin{funcdesc}{box}{rect} +Draw a box just inside a rectangle. +\end{funcdesc} + +\begin{funcdesc}{circle}{center\, radius} +Draw a circle with given center point and radius. +\end{funcdesc} + +\begin{funcdesc}{elarc}{center\, \(rh\, rv\)\, \(a1\, a2\)} +Draw an elliptical arc with given center point. +\code{(\var{rh}, \var{rv})} +gives the half sizes of the horizontal and vertical radii. +\code{(\var{a1}, \var{a2})} +gives the angles (in degrees) of the begin and end points. +0 degrees is at 3 o'clock, 90 degrees is at 12 o'clock. +\end{funcdesc} + +\begin{funcdesc}{erase}{rect} +Erase a rectangle. +\end{funcdesc} + +\begin{funcdesc}{fillcircle}{center\, radius} +Draw a filled circle with given center point and radius. +\end{funcdesc} + +\begin{funcdesc}{fillelarc}{center\, \(rh\, rv\)\, \(a1\, a2\)} +Draw a filled elliptical arc; arguments as for \code{elarc}. +\end{funcdesc} + +\begin{funcdesc}{fillpoly}{points} +Draw a filled polygon given by a list (or tuple) of points. +\end{funcdesc} + +\begin{funcdesc}{invert}{rect} +Invert a rectangle. +\end{funcdesc} + +\begin{funcdesc}{line}{p1\, p2} +Draw a line from point +\var{p1} +to +\var{p2}. +\end{funcdesc} + +\begin{funcdesc}{paint}{rect} +Fill a rectangle. +\end{funcdesc} + +\begin{funcdesc}{poly}{points} +Draw the lines connecting the given list (or tuple) of points. +\end{funcdesc} + +\begin{funcdesc}{shade}{rect\, percent} +Fill a rectangle with a shading pattern that is about +\var{percent} +percent filled. +\end{funcdesc} + +\begin{funcdesc}{text}{p\, str} +Draw a string starting at point p (the point specifies the +top left coordinate of the string). +\end{funcdesc} + +\begin{funcdesc}{xorcircle}{center\, radius} +\funcline{xorelarc}{center\, \(rh\, rv\)\, \(a1\, a2\)} +\funcline{xorline}{p1\, p2} +\funcline{xorpoly}{points} +Draw a circle, an elliptical arc, a line or a polygon, respectively, +in XOR mode. +\end{funcdesc} + +\begin{funcdesc}{setfgcolor}{} +\funcline{setbgcolor}{} +\funcline{getfgcolor}{} +\funcline{getbgcolor}{} +These functions are similar to the corresponding functions described +above for the +\code{stdwin} +module, but affect or return the colors currently used for drawing +instead of the global default colors. +When a drawing object is created, its colors are set to the window's +default colors, which are in turn initialized from the global default +colors when the window is created. +\end{funcdesc} + +\begin{funcdesc}{setfont}{} +\funcline{baseline}{} +\funcline{lineheight}{} +\funcline{textbreak}{} +\funcline{textwidth}{} +These functions are similar to the corresponding functions described +above for the +\code{stdwin} +module, but affect or use the current drawing font instead of +the global default font. +When a drawing object is created, its font is set to the window's +default font, which is in turn initialized from the global default +font when the window is created. +\end{funcdesc} + +\begin{funcdesc}{bitmap}{point\, bitmap\, mask} +Draw the \var{bitmap} with its top left corner at \var{point}. +If the optional \var{mask} argument is present, it should be either +the same object as \var{bitmap}, to draw only those bits that are set +in the bitmap, in the foreground color, or \code{None}, to draw all +bits (ones are drawn in the foreground color, zeros in the background +color). +\end{funcdesc} + +\begin{funcdesc}{cliprect}{rect} +Set the ``clipping region'' to a rectangle. +The clipping region limits the effect of all drawing operations, until +it is changed again or until the drawing object is closed. When a +drawing object is created the clipping region is set to the entire +window. When an object to be drawn falls partly outside the clipping +region, the set of pixels drawn is the intersection of the clipping +region and the set of pixels that would be drawn by the same operation +in the absence of a clipping region. +clipping region +\end{funcdesc} + +\begin{funcdesc}{noclip}{} +Reset the clipping region to the entire window. +\end{funcdesc} + +\begin{funcdesc}{close}{} +\funcline{enddrawing}{} +Discard the drawing object. It should not be used again. +\end{funcdesc} + +\subsection{Menu Object Methods} + +A menu object represents a menu. +The menu is destroyed when the menu object is deleted. +The following methods are defined: + +\renewcommand{\indexsubitem}{(menu method)} + +\begin{funcdesc}{additem}{text\, shortcut} +Add a menu item with given text. +The shortcut must be a string of length 1, or omitted (to specify no +shortcut). +\end{funcdesc} + +\begin{funcdesc}{setitem}{i\, text} +Set the text of item number +\var{i}. +\end{funcdesc} + +\begin{funcdesc}{enable}{i\, flag} +Enable or disables item +\var{i}. +\end{funcdesc} + +\begin{funcdesc}{check}{i\, flag} +Set or clear the +\dfn{check mark} +for item +\var{i}. +\end{funcdesc} + +\begin{funcdesc}{close}{} +Discard the menu object. It should not be used again. +\end{funcdesc} + +\subsection{Bitmap Object Methods} + +A bitmap represents a rectangular array of bits. +The top left bit has coordinate (0, 0). +A bitmap can be drawn with the \code{bitmap} method of a drawing object. +The following methods are defined: + +\renewcommand{\indexsubitem}{(bitmap method)} + +\begin{funcdesc}{getsize}{} +Return a tuple representing the width and height of the bitmap. +(This returns the values that have been passed to the \code{newbitmap} +function.) +\end{funcdesc} + +\begin{funcdesc}{setbit}{point\, bit} +Set the value of the bit indicated by \var{point} to \var{bit}. +\end{funcdesc} + +\begin{funcdesc}{getbit}{point} +Return the value of the bit indicated by \var{point}. +\end{funcdesc} + +\begin{funcdesc}{close}{} +Discard the bitmap object. It should not be used again. +\end{funcdesc} + +\subsection{Text-edit Object Methods} + +A text-edit object represents a text-edit block. +For semantics, see the STDWIN documentation for C programmers. +The following methods exist: + +\renewcommand{\indexsubitem}{(text-edit method)} + +\begin{funcdesc}{arrow}{code} +Pass an arrow event to the text-edit block. +The +\var{code} +must be one of +\code{WC_LEFT}, +\code{WC_RIGHT}, +\code{WC_UP} +or +\code{WC_DOWN} +(see module +\code{stdwinevents}). +\end{funcdesc} + +\begin{funcdesc}{draw}{rect} +Pass a draw event to the text-edit block. +The rectangle specifies the redraw area. +\end{funcdesc} + +\begin{funcdesc}{event}{type\, window\, detail} +Pass an event gotten from +\code{stdwin.getevent()} +to the text-edit block. +Return true if the event was handled. +\end{funcdesc} + +\begin{funcdesc}{getfocus}{} +Return 2 integers representing the start and end positions of the +focus, usable as slice indices on the string returned by +\code{gettext()}. +\end{funcdesc} + +\begin{funcdesc}{getfocustext}{} +Return the text in the focus. +\end{funcdesc} + +\begin{funcdesc}{getrect}{} +Return a rectangle giving the actual position of the text-edit block. +(The bottom coordinate may differ from the initial position because +the block automatically shrinks or grows to fit.) +\end{funcdesc} + +\begin{funcdesc}{gettext}{} +Return the entire text buffer. +\end{funcdesc} + +\begin{funcdesc}{move}{rect} +Specify a new position for the text-edit block in the document. +\end{funcdesc} + +\begin{funcdesc}{replace}{str} +Replace the text in the focus by the given string. +The new focus is an insert point at the end of the string. +\end{funcdesc} + +\begin{funcdesc}{setfocus}{i\, j} +Specify the new focus. +Out-of-bounds values are silently clipped. +\end{funcdesc} + +\begin{funcdesc}{settext}{str} +Replace the entire text buffer by the given string and set the focus +to \code{(0, 0)}. +\end{funcdesc} + +\begin{funcdesc}{setview}{rect} +Set the view rectangle to \var{rect}. If \var{rect} is \code{None}, +viewing mode is reset. In viewing mode, all output from the text-edit +object is clipped to the viewing rectangle. This may be useful to +implement your own scrolling text subwindow. +\end{funcdesc} + +\begin{funcdesc}{close}{} +Discard the text-edit object. It should not be used again. +\end{funcdesc} + +\subsection{Example} +\nodename{Stdwin Example} + +Here is a minimal example of using STDWIN in Python. +It creates a window and draws the string ``Hello world'' in the top +left corner of the window. +The window will be correctly redrawn when covered and re-exposed. +The program quits when the close icon or menu item is requested. + +\bcode\begin{verbatim} +import stdwin +from stdwinevents import * + +def main(): + mywin = stdwin.open('Hello') + # + while 1: + (type, win, detail) = stdwin.getevent() + if type == WE_DRAW: + draw = win.begindrawing() + draw.text((0, 0), 'Hello, world') + del draw + elif type == WE_CLOSE: + break + +main() +\end{verbatim}\ecode + +\section{Standard Module \sectcode{stdwinevents}} +\stmodindex{stdwinevents} + +This module defines constants used by STDWIN for event types +(\code{WE_ACTIVATE} etc.), command codes (\code{WC_LEFT} etc.) +and selection types (\code{WS_PRIMARY} etc.). +Read the file for details. +Suggested usage is + +\bcode\begin{verbatim} +>>> from stdwinevents import * +>>> +\end{verbatim}\ecode + +\section{Standard Module \sectcode{rect}} +\stmodindex{rect} + +This module contains useful operations on rectangles. +A rectangle is defined as in module +\code{stdwin}: +a pair of points, where a point is a pair of integers. +For example, the rectangle + +\bcode\begin{verbatim} +(10, 20), (90, 80) +\end{verbatim}\ecode + +is a rectangle whose left, top, right and bottom edges are 10, 20, 90 +and 80, respectively. +Note that the positive vertical axis points down (as in +\code{stdwin}). + +The module defines the following objects: + +\renewcommand{\indexsubitem}{(in module rect)} +\begin{excdesc}{error} +The exception raised by functions in this module when they detect an +error. +The exception argument is a string describing the problem in more +detail. +\end{excdesc} + +\begin{datadesc}{empty} +The rectangle returned when some operations return an empty result. +This makes it possible to quickly check whether a result is empty: + +\bcode\begin{verbatim} +>>> import rect +>>> r1 = (10, 20), (90, 80) +>>> r2 = (0, 0), (10, 20) +>>> r3 = rect.intersect([r1, r2]) +>>> if r3 is rect.empty: print 'Empty intersection' +Empty intersection +>>> +\end{verbatim}\ecode +\end{datadesc} + +\begin{funcdesc}{is_empty}{r} +Returns true if the given rectangle is empty. +A rectangle +\code{(\var{left}, \var{top}), (\var{right}, \var{bottom})} +is empty if +\iftexi +\code{\var{left} >= \var{right}} or \code{\var{top} => \var{bottom}}. +\else +$\var{left} \geq \var{right}$ or $\var{top} \geq \var{bottom}$. +%%JHXXX{\em left~$\geq$~right} or {\em top~$\leq$~bottom}. +\fi +\end{funcdesc} + +\begin{funcdesc}{intersect}{list} +Returns the intersection of all rectangles in the list argument. +It may also be called with a tuple argument. +Raises +\code{rect.error} +if the list is empty. +Returns +\code{rect.empty} +if the intersection of the rectangles is empty. +\end{funcdesc} + +\begin{funcdesc}{union}{list} +Returns the smallest rectangle that contains all non-empty rectangles in +the list argument. +It may also be called with a tuple argument or with two or more +rectangles as arguments. +Returns +\code{rect.empty} +if the list is empty or all its rectangles are empty. +\end{funcdesc} + +\begin{funcdesc}{pointinrect}{point\, rect} +Returns true if the point is inside the rectangle. +By definition, a point +\code{(\var{h}, \var{v})} +is inside a rectangle +\code{(\var{left}, \var{top}), (\var{right}, \var{bottom})} if +\iftexi +\code{\var{left} <= \var{h} < \var{right}} and +\code{\var{top} <= \var{v} < \var{bottom}}. +\else +$\var{left} \leq \var{h} < \var{right}$ and +$\var{top} \leq \var{v} < \var{bottom}$. +\fi +\end{funcdesc} + +\begin{funcdesc}{inset}{rect\, \(dh\, dv\)} +Returns a rectangle that lies inside the +\code{rect} +argument by +\var{dh} +pixels horizontally +and +\var{dv} +pixels +vertically. +If +\var{dh} +or +\var{dv} +is negative, the result lies outside +\var{rect}. +\end{funcdesc} + +\begin{funcdesc}{rect2geom}{rect} +Converts a rectangle to geometry representation: +\code{(\var{left}, \var{top}), (\var{width}, \var{height})}. +\end{funcdesc} + +\begin{funcdesc}{geom2rect}{geom} +Converts a rectangle given in geometry representation back to the +standard rectangle representation +\code{(\var{left}, \var{top}), (\var{right}, \var{bottom})}. +\end{funcdesc} |