From 55e93964e6a4f4ab72a1856353a28c6e7ed430b6 Mon Sep 17 00:00:00 2001 From: Fred Drake Date: Mon, 15 Nov 1999 17:03:41 +0000 Subject: Preliminary documentation for turtle module (Tk), by Moshe Zadka. Fixed up a few TeXisms and markup nits, but otherwise unchanged. Somewhat raw. --- Doc/lib/libturtle.tex | 160 ++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 160 insertions(+) create mode 100644 Doc/lib/libturtle.tex diff --git a/Doc/lib/libturtle.tex b/Doc/lib/libturtle.tex new file mode 100644 index 0000000..641b40d --- /dev/null +++ b/Doc/lib/libturtle.tex @@ -0,0 +1,160 @@ +\section{\module{turtle} --- + Turtle graphics for Tk} + +\declaremodule{standard}{turtle} + \platform{Tk} +\moduleauthor{Guido van Rossum}{guido@python.org} +\modulesynopsis{An environment for turtle graphics.} + +\sectionauthor{Moshe Zadka}{mzadka@geocities.com} + + +The \module{turtle} module provides turtle graphics primitives, in both an +object-oriented and procedure-oriented ways. Because it uses \module{Tkinter} +for the underlying graphics, it needs a version of python installed with +Tk support. + +The procedural interface uses a pen and a canvas which are automagically +created when any of the functions are called. + +The \module{turtle} module defines the following functions: + +\begin{funcdesc}{degrees}{} +Set angle measurement units to degrees. +\end{funcdesc} + +\begin{funcdesc}{radians}{} +Set angle measurement units to radians. +\end{funcdesc} + +\begin{funcdesc}{reset}{} +Clear the screen, re-center the pen, and set variables to the default +values. +\end{funcdesc} + +\begin{funcdesc}{clear}{} +Clear the screen. +\end{funcdesc} + +\begin{funcdesc}{tracer}{flag} +Set tracing on/off (according to whether flag is true or not). Tracing +means line are drawn more slowly, with an animation of an arrow along the +line. +\end{funcdesc} + +\begin{funcdesc}{forward}{distance} +Go forward \var{distance} steps. +\end{funcdesc} + +\begin{funcdesc}{backward}{distance} +Go backward \var{distance} steps. +\end{funcdesc} + +\begin{funcdesc}{left}{angle} +Turn left \var{angle} units. Units are by default degrees, but can be +set via the \function{degrees()} and \function{radians()} functions. +\end{funcdesc} + +\begin{funcdesc}{right}{angle} +Turn right \var{angle} units. Units are by default degrees, but can be +set via the \function{degrees()} and \function{radians()} functions. +\end{funcdesc} + +\begin{funcdesc}{up}{} +Move the pen up --- stop drawing. +\end{funcdesc} + +\begin{funcdesc}{down}{} +Move the pen up --- draw when moving. +\end{funcdesc} + +\begin{funcdesc}{width}{width} +Set the line width to \var{width}. +\end{funcdesc} + +\begin{funcdesc}{color}{s} +Set the color by giving a Tk color string. +\end{funcdesc} + +\begin{funcdesc}{color}{(r, g, b)} +Set the color by giving a RGB tuple, each between 0 and 1. +\end{funcdesc} + +\begin{funcdesc}{color}{r, g, b} +Set the color by giving the RGB components, each between 0 and 1. +\end{funcdesc} + +\begin{funcdesc}{write}{text\optional{, move}} +Write \var{text} at the current pen position. If \var{move} is true, +the pen is moved to the bottom-right corner of the text. By default, +\var{move} is false. +\end{funcdesc} + +\begin{funcdesc}{fill}{flag} +The complete specifications are rather complex, but the recommended +usage is: call \code{fill(1)} before drawing a path you want to fill, +and call \code{fill(0)} when you finish to draw the path. +\end{funcdesc} + +\begin{funcdesc}{circle}{radius\optional{, extent}} +Draw a circle with radius \var{radius} whose center-point is where the +pen would be if a \code{forward(\var{radius})} were +called. \var{extent} determines which part of a circle is drawn: if +not given it defaults to a full circle. + +If \var{extent} is not a full circle, one endpoint of the arc is the +current pen position. The arc is drawn in a counter clockwise +direction if \var{radius} is positive, otherwise in a clockwise +direction. +\end{funcdesc} + +\begin{funcdesc}{goto}{x, y} +Go to co-ordinates (\var{x}, \var{y}). +\end{funcdesc} + +\begin{funcdesc}{goto}{(x, y)} +Go to co-ordinates (\var{x}, \var{y}) (specified as a tuple instead of +individually). +\end{funcdesc} + +This module also does a documented \code{from math import *}, so see +the documentation for the \refmodule{math} module for additional +constants and functions useful for turtle graphics. +% XXX Should we mention this? If so, a \seealso is also in place... + +\begin{funcdesc}{demo}{} +Exercise the module a bit. +\end{funcdesc} + +\begin{excdesc}{Error} +Exception raised on any error caught by this module. +\end{excdesc} + +For examples, see the code of the \function{demo()} function. + +This module defines the following classes: + +\begin{classdesc}{Pen}{} +Define a pen. All above functions can be called as a methods on the given +pen. The constructor automatically creates a canvas do be drawn on. +\end{classdesc} + +\begin{classdesc}{RawPen}{canvas} +Define a pen which draws on a canvas \var{canvas}. This is useful if +you want to use the module to create graphics in a ``real'' program. +\end{classdesc} + +\subsection{Pen and RawPen Objects \label{pen-rawpen-objects}} + +\class{Pen} and \class{RawPen} objects have all the global functions +described above, except for \function{demo()} as methods, which +manipulate the given pen. + +The only method which is more powerful as a method is +\function{degrees()}. + +\begin{methoddesc}{degrees}{\optional{fullcircle}} +\var{fullcircle} is by default 360. This can cause the pen to have any +angular units whatever: give \var{fullcircle} 2*$\pi$ for radians, or +400 for gradians. +\end{methoddesc} -- cgit v0.12