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+#Copyright ReportLab Europe Ltd. 2000-2004
+#see license.txt for license details
+#history http://www.reportlab.co.uk/cgi-bin/viewcvs.cgi/public/reportlab/trunk/reportlab/docs/userguide/ch2_graphics.py
+from reportlab.tools.docco.rl_doc_utils import *
+from reportlab.lib.codecharts import SingleByteEncodingChart
+
+heading1("Graphics and Text with $pdfgen$")
+
+heading2("Basic Concepts")
+disc("""
+The $pdfgen$ package is the lowest level interface for
+generating PDF documents.  A $pdfgen$ program is essentially
+a sequence of instructions for "painting" a document onto
+a sequence of pages.  The interface object which provides the
+painting operations is the $pdfgen canvas$.
+""")
+
+disc("""
+The canvas should be thought of as a sheet of white paper
+with points on the sheet identified using Cartesian ^(X,Y)^ coordinates
+which by default have the ^(0,0)^ origin point at the lower
+left corner of the page.  Furthermore the first coordinate ^x^
+goes to the right and the second coordinate ^y^ goes up, by
+default.""")
+
+disc("""
+A simple example
+program that uses a canvas follows.
+""")
+
+eg("""
+    from reportlab.pdfgen import canvas
+    def hello(c):
+        c.drawString(100,100,"Hello World")
+    c = canvas.Canvas("hello.pdf")
+    hello(c)
+    c.showPage()
+    c.save()
+""")
+
+disc("""
+The above code creates a $canvas$ object which will generate
+a PDF file named $hello.pdf$ in the current working directory.
+It then calls the $hello$ function passing the $canvas$ as an argument.
+Finally the $showPage$ method saves the current page of the canvas
+and the $save$ method stores the file and closes the canvas.""")
+
+disc("""
+The $showPage$ method causes the $canvas$ to stop drawing on the
+current page and any further operations will draw on a subsequent
+page (if there are any further operations -- if not no
+new page is created).  The $save$ method must be called after the
+construction of the document is complete -- it generates the PDF
+document, which is the whole purpose of the $canvas$ object.
+""")
+
+heading2("More about the Canvas")
+disc("""
+Before describing the drawing operations, we will digress to cover
+some of the things which can be done to configure a canvas.  There
+are many different settings available.  If you are new to Python
+or can't wait to produce some output, you can skip ahead, but
+come back later and read this!""")
+
+disc("""First of all, we will look at the constructor
+arguments for the canvas:""")
+eg("""    def __init__(self,filename,
+                 pagesize=(595.27,841.89),
+                 bottomup = 1,
+                 pageCompression=0,
+                 encoding=rl_config.defaultEncoding,
+                 verbosity=0):
+                 """)
+
+disc("""The $filename$ argument controls the
+name of the final PDF file.  You
+may also pass in any open file object (such as $sys.stdout$, the python process standard output)
+and the PDF document will be written to that.  Since PDF
+is a binary format, you should take care when writing other
+stuff before or after it; you can't deliver PDF documents
+inline in the middle of an HTML page!""")
+
+disc("""The $pagesize$ argument is a tuple of two numbers
+in points (1/72 of an inch). The canvas defaults to $A4$ (an international standard
+page size which differs from the American standard page size of $letter$),
+but it is better to explicitly specify it.  Most common page
+sizes are found in the library module $reportlab.lib.pagesizes$,
+so you can use expressions like""")
+
+eg("""from reportlab.lib.pagesizes import letter, A4
+myCanvas = Canvas('myfile.pdf', pagesize=letter)
+width, height = letter  #keep for later
+""")
+
+pencilnote()
+
+disc("""If you have problems printing your document make sure you
+are using the right page size (usually either $A4$ or $letter$).
+Some printers do not work well with pages that are too large or too small.""")
+
+disc("""Very often, you will want to calculate things based on
+the page size.  In the example above we extracted the width and
+height.  Later in the program we may use the $width$ variable to
+define a right margin as $width - inch$ rather than using
+a constant.  By using variables the margin will still make sense even
+if the page size changes.""")
+
+disc("""The $bottomup$ argument
+switches coordinate systems.  Some graphics systems (like PDF
+and PostScript) place (0,0) at the bottom left of the page
+others (like many graphical user interfaces [GUI's]) place the origen at the top left.  The
+$bottomup$ argument is deprecated and may be dropped in future""")
+
+todo("""Need to see if it really works for all tasks, and if not
+     then get rid of it""")
+
+disc("""The $pageCompression$ option determines whether the stream
+of PDF operations for each page is compressed.  By default
+page streams are not compressed, because the compression slows the file generation process.
+If output size is important set $pageCompression=1$, but remember that, compressed documents will
+be smaller, but slower to generate.  Note that images are <i>always</i> compressed, and this option
+will only save space if you have a very large amount of text and vector graphics
+on each page.""")
+
+disc("""The $encoding$ argument is largely obsolete in version 2.0 and can
+probably be omitted by 99% of users.  Its default value is fine unless you
+very specifically need to use one of the 25 or so characters which are present
+in MacRoman and not in Winansi.  A useful reference to these is here:
+<font color="blue"><u><a href="http://www.alanwood.net/demos/charsetdiffs.html">http://www.alanwood.net/demos/charsetdiffs.html</a></u></font>.
+
+The parameter determines which font encoding is used for the
+standard Type 1 fonts; this should correspond to the encoding on your system.
+Note that this is the encoding used <i>internally by the font</i>; text you
+pass to the ReportLab toolkit for rendering should always either be a Python
+unicode string object or a UTF-8 encoded byte string (see the next chapter)!
+The font encoding has two values at present: $'WinAnsiEncoding'$ or
+$'MacRomanEncoding'$.  The variable $rl_config.defaultEncoding$ above points
+to the former, which is standard on Windows, Mac OS X and many Unices
+(including Linux). If you are Mac user and don't have OS X, you may want to
+make a global change: modify the line at the top of
+<i>reportlab/pdfbase/pdfdoc.py</i> to switch it over.  Otherwise, you can
+probably just ignore this argument completely and never pass it.  For all TTF
+and the commonly-used CID fonts, the encoding you pass in here is ignored,
+since the reportlab library itself knows the right encodings in those
+cases.""")
+
+disc("""The demo script $reportlab/demos/stdfonts.py$
+will print out two test documents showing all code points
+in all fonts, so you can look up characters.  Special
+characters can be inserted into string commands with
+the usual Python escape sequences; for example \\101 = 'A'.""")
+
+disc("""The $verbosity$ argument determines how much log
+information is printed.  By default, it is zero to assist
+applications which want to capture PDF from standard output.
+With a value of 1, you will get a confirmation message
+each time a document is generated.  Higher numbers may
+give more output in future.""")
+
+todo("to do - all the info functions and other non-drawing stuff")
+
+
+
+
+
+todo("""Cover all constructor arguments, and setAuthor etc.""")
+
+heading2("Drawing Operations")
+disc("""
+Suppose the $hello$ function referenced above is implemented as
+follows (we will not explain each of the operations in detail
+yet).
+""")
+
+eg(examples.testhello)
+
+disc("""
+Examining this code notice that there are essentially two types
+of operations performed using a canvas.  The first type draws something
+on the page such as a text string or a rectangle or a line.  The second
+type changes the state of the canvas such as
+changing the current fill or stroke color or changing the current font
+type and size.
+""")
+
+disc("""
+If we imagine the program as a painter working on
+the canvas the "draw" operations apply paint to the canvas using
+the current set of tools (colors, line styles, fonts, etcetera)
+and the "state change" operations change one of the current tools
+(changing the fill color from whatever it was to blue, or changing
+the current font to $Times-Roman$ in 15 points, for example).
+""")
+
+disc("""
+The document generated by the "hello world" program listed above would contain
+the following graphics.
+""")
+
+illust(examples.hello, '"Hello World" in pdfgen')
+
+heading3("About the demos in this document")
+
+disc("""
+This document contains demonstrations of the code discussed like the one shown
+in the rectangle above.  These demos are drawn on a "tiny page" embedded
+within the real pages of the guide.  The tiny pages are %s inches wide
+and %s inches tall. The demo displays show the actual output of the demo code.
+For convenience the size of the output has been reduced slightly.
+""" % (examplefunctionxinches, examplefunctionyinches))
+
+heading2('The tools: the "draw" operations')
+
+disc("""
+This section briefly lists the tools available to the program
+for painting information onto a page using the canvas interface.
+These will be discussed in detail in later sections.  They are listed
+here for easy reference and for summary purposes.
+""")
+
+heading3("Line methods")
+
+eg("""canvas.line(x1,y1,x2,y2)""")
+eg("""canvas.lines(linelist)""")
+
+disc("""
+The line methods draw straight line segments on the canvas.
+""")
+
+heading3("Shape methods")
+
+eg("""canvas.grid(xlist, ylist) """)
+eg("""canvas.bezier(x1, y1, x2, y2, x3, y3, x4, y4)""")
+eg("""canvas.arc(x1,y1,x2,y2) """)
+eg("""canvas.rect(x, y, width, height, stroke=1, fill=0) """)
+eg("""canvas.ellipse(x1,y1, x2,y2, stroke=1, fill=0)""")
+eg("""canvas.wedge(x1,y1, x2,y2, startAng, extent, stroke=1, fill=0) """)
+eg("""canvas.circle(x_cen, y_cen, r, stroke=1, fill=0)""")
+eg("""canvas.roundRect(x, y, width, height, radius, stroke=1, fill=0) """)
+
+disc("""
+The shape methods draw common complex shapes on the canvas.
+""")
+
+heading3("String drawing methods")
+
+eg("""canvas.drawString(x, y, text):""")
+eg("""canvas.drawRightString(x, y, text) """)
+eg("""canvas.drawCentredString(x, y, text)""")
+
+disc("""
+The draw string methods draw single lines of text on the canvas.
+""")
+
+heading3("The text object methods")
+eg("""textobject = canvas.beginText(x, y) """)
+eg("""canvas.drawText(textobject) """)
+
+disc("""
+Text objects are used to format text in ways that
+are not supported directly by the $canvas$ interface.
+A program creates a text object from the $canvas$ using $beginText$
+and then formats text by invoking $textobject$ methods.
+Finally the $textobject$ is drawn onto the canvas using
+$drawText$.
+""")
+
+heading3("The path object methods")
+
+eg("""path = canvas.beginPath() """)
+eg("""canvas.drawPath(path, stroke=1, fill=0) """)
+eg("""canvas.clipPath(path, stroke=1, fill=0) """)
+
+disc("""
+Path objects are similar to text objects: they provide dedicated control
+for performing complex graphical drawing not directly provided by the
+canvas interface.  A program creates a path object using $beginPath$
+populates the path with graphics using the methods of the path object
+and then draws the path on the canvas using $drawPath$.""")
+
+disc("""It is also possible
+to use a path as a "clipping region" using the $clipPath$ method -- for example a circular path
+can be used to clip away the outer parts of a rectangular image leaving
+only a circular part of the image visible on the page.
+""")
+
+heading3("Image methods")
+pencilnote()
+disc("""
+You need the Python Imaging Library (PIL) to use images with the ReportLab package.
+Examnples of the techniques below can be found by running the script $test_pdfgen_general.py$
+in our $test$ subdirectory and looking at page 7 of the output.
+""")
+
+disc("""
+There are two similar-sounding ways to draw images.  The preferred one is
+the $drawImage$ method.  This implements a caching system so you can
+define an image once and draw it many times; it will only be
+stored once in the PDF file.  $drawImage$ also exposes one advanced parameter,
+a transparency mask, and will expose more in future.  The older technique,
+$drawInlineImage$, stores bitmaps within the page stream and is thus very
+inefficient if you use the same image more than once in a document; but can result
+in PDFs which render faster if the images are very small and not repeated. We'll
+discuss the oldest one first:
+""")
+
+eg("""canvas.drawInlineImage(self, image, x,y, width=None,height=None) """)
+
+disc("""
+The $drawInlineImage$ method places an image on the canvas.  The $image$
+parameter may be either a PIL Image object or an image filename.  Many common
+file formats are accepted including GIF and JPEG.  It returns the size of the actual
+image in pixels as a (width, height) tuple.
+""")
+
+eg("""canvas.drawImage(self, image, x,y, width=None,height=None,mask=None) """)
+disc("""
+The arguments and return value work as for $drawInlineImage$.  However, we use a caching
+system; a given image will only be stored the first time it is used, and just referenced
+on subsequent use.  If you supply a filename, it assumes that the same filename
+means the same image.  If you supply a PIL image, it tests if the content
+has actually changed before re-embedding.""")
+
+disc("""
+The $mask$ parameter lets you create transparent images.  It takes 6 numbers
+and defines the range of RGB values which will be masked out or treated as
+transparent. For example with [0,2,40,42,136,139], it will mask out any pixels
+with a Red value from 0 or 1, Green from 40 or 41 and Blue of  136, 137 or 138
+(on a scale of 0-255). It's currently your job to know which color is the
+'transparent' or background one.""")
+
+disc("""PDF allows for many image features and we will expose more of the over
+time, probably with extra keyword arguments to $drawImage$.""")
+
+heading3("Ending a page")
+
+eg("""canvas.showPage()""")
+
+disc("""The $showPage$ method finishes the current page.  All additional drawing will
+be done on another page.""")
+
+pencilnote()
+
+disc("""Warning!  All state changes (font changes, color settings, geometry transforms, etcetera)
+are FORGOTTEN when you advance to a new page in $pdfgen$.  Any state settings you wish to preserve
+must be set up again before the program proceeds with drawing!""")
+
+heading2('The toolbox: the "state change" operations')
+
+disc("""
+This section briefly lists the ways to switch the tools used by the
+program
+for painting information onto a page using the $canvas$ interface.
+These too will be discussed in detail in later sections.
+""")
+
+heading3("Changing Colors")
+eg("""canvas.setFillColorCMYK(c, m, y, k) """)
+eg("""canvas.setStrikeColorCMYK(c, m, y, k) """)
+eg("""canvas.setFillColorRGB(r, g, b) """)
+eg("""canvas.setStrokeColorRGB(r, g, b) """)
+eg("""canvas.setFillColor(acolor) """)
+eg("""canvas.setStrokeColor(acolor) """)
+eg("""canvas.setFillGray(gray) """)
+eg("""canvas.setStrokeGray(gray) """)
+
+disc("""
+PDF supports three different color models: gray level, additive (red/green/blue or RGB), and
+subtractive with darkness parameter (cyan/magenta/yellow/darkness or CMYK).
+The ReportLab packages also provide named colors such as $lawngreen$.  There are two
+basic color parameters in the graphics state: the $Fill$ color for the interior of graphic
+figures and the $Stroke$ color for the boundary of graphic figures.  The above methods
+support setting the fill or stroke color using any of the four color specifications.
+""")
+
+heading3("Changing Fonts")
+eg("""canvas.setFont(psfontname, size, leading = None) """)
+
+disc("""
+The $setFont$ method changes the current text font to a given type and size.
+The $leading$ parameter specifies the distance down to move when advancing from
+one text line to the next.
+""")
+
+heading3("Changing Graphical Line Styles")
+
+eg("""canvas.setLineWidth(width) """)
+eg("""canvas.setLineCap(mode) """)
+eg("""canvas.setLineJoin(mode) """)
+eg("""canvas.setMiterLimit(limit) """)
+eg("""canvas.setDash(self, array=[], phase=0) """)
+
+disc("""
+Lines drawn in PDF can be presented in a number of graphical styles.
+Lines can have different widths, they can end in differing cap styles,
+they can meet in different join styles, and they can be continuous or
+they can be dotted or dashed.  The above methods adjust these various parameters.""")
+
+heading3("Changing Geometry")
+
+eg("""canvas.setPageSize(pair) """)
+eg("""canvas.transform(a,b,c,d,e,f): """)
+eg("""canvas.translate(dx, dy) """)
+eg("""canvas.scale(x, y) """)
+eg("""canvas.rotate(theta) """)
+eg("""canvas.skew(alpha, beta) """)
+
+disc("""
+All PDF drawings fit into a specified page size.  Elements drawn outside of the specified
+page size are not visible.  Furthermore all drawn elements are passed through an affine
+transformation which may adjust their location and/or distort their appearence.  The
+$setPageSize$ method adjusts the current page size.  The $transform$, $translate$, $scale$,
+$rotate$, and $skew$ methods add additional transformations to the current transformation.
+It is important to remember that these transformations are <i>incremental</i> -- a new
+transform modifies the current transform (but does not replace it).
+""")
+
+heading3("State control")
+
+eg("""canvas.saveState() """)
+eg("""canvas.restoreState() """)
+
+disc("""
+Very often it is important to save the current font, graphics transform, line styles and
+other graphics state in order to restore them later. The $saveState$ method marks the
+current graphics state for later restoration by a matching $restoreState$.  Note that
+the save and restore method invokation must match -- a restore call restores the state to
+the most recently saved state which hasn't been restored yet.
+You cannot save the state on one page and restore
+it on the next, however -- no state is preserved between pages.""")
+
+heading2("Other $canvas$ methods.")
+
+disc("""
+Not all methods of the $canvas$ object fit into the "tool" or "toolbox"
+categories.  Below are some of the misfits, included here for completeness.
+""")
+
+eg("""
+ canvas.setAuthor()
+ canvas.addOutlineEntry(title, key, level=0, closed=None)
+ canvas.setTitle(title)
+ canvas.setSubject(subj)
+ canvas.pageHasData()
+ canvas.showOutline()
+ canvas.bookmarkPage(name)
+ canvas.bookmarkHorizontalAbsolute(name, yhorizontal)
+ canvas.doForm()
+ canvas.beginForm(name, lowerx=0, lowery=0, upperx=None, uppery=None)
+ canvas.endForm()
+ canvas.linkAbsolute(contents, destinationname, Rect=None, addtopage=1, name=None, **kw)
+ canvas.getPageNumber()
+ canvas.addLiteral()
+ canvas.getAvailableFonts()
+ canvas.stringWidth(self, text, fontName, fontSize, encoding=None)
+ canvas.setPageCompression(onoff=1)
+ canvas.setPageTransition(self, effectname=None, duration=1,
+                        direction=0,dimension='H',motion='I')
+""")
+
+
+heading2('Coordinates (default user space)')
+
+disc("""
+By default locations on a page are identified by a pair of numbers.
+For example the pair $(4.5*inch, 1*inch)$ identifies the location
+found on the page by starting at the lower left corner and moving to
+the right 4.5 inches and up one inch.
+""")
+
+disc("""For example, the following function draws
+a number of elements on a $canvas$.""")
+
+eg(examples.testcoords)
+
+disc("""In the default user space the "origin" ^(0,0)^ point is at the lower
+left corner.  Executing the $coords$ function in the default user space
+(for the "demo minipage") we obtain the following.""")
+
+illust(examples.coords, 'The Coordinate System')
+
+heading3("Moving the origin: the $translate$ method")
+
+disc("""Often it is useful to "move the origin" to a new point off
+the lower left corner.  The $canvas.translate(^x,y^)$ method moves the origin
+for the current page to the point currently identified by ^(x,y)^.""")
+
+disc("""For example the following translate function first moves
+the origin before drawing the same objects as shown above.""")
+
+eg(examples.testtranslate)
+
+disc("""This produces the following.""")
+
+illust(examples.translate, "Moving the origin: the $translate$ method")
+
+
+#illust(NOP) # execute some code
+
+pencilnote()
+
+
+disc("""
+<i>Note:</i> As illustrated in the example it is perfectly possible to draw objects
+or parts of objects "off the page".
+In particular a common confusing bug is a translation operation that translates the
+entire drawing off the visible area of the page.  If a program produces a blank page
+it is possible that all the drawn objects are off the page.
+""")
+
+heading3("Shrinking and growing: the scale operation")
+
+disc("""Another important operation is scaling.  The scaling operation $canvas.scale(^dx,dy^)$
+stretches or shrinks the ^x^ and ^y^ dimensions by the ^dx^, ^dy^ factors respectively.  Often
+^dx^ and ^dy^ are the same -- for example to reduce a drawing by half in all dimensions use
+$dx = dy = 0.5$.  However for the purposes of illustration we show an example where
+$dx$ and $dy$ are different.
+""")
+
+eg(examples.testscale)
+
+disc("""This produces a "short and fat" reduced version of the previously displayed operations.""")
+
+illust(examples.scale, "Scaling the coordinate system")
+
+
+#illust(NOP) # execute some code
+
+pencilnote()
+
+
+disc("""<i>Note:</i> scaling may also move objects or parts of objects off the page,
+or may cause objects to "shrink to nothing." """)
+
+disc("""Scaling and translation can be combined, but the order of the
+operations are important.""")
+
+eg(examples.testscaletranslate)
+
+disc("""This example function first saves the current $canvas$ state
+and then does a $scale$ followed by a $translate$.  Afterward the function
+restores the state (effectively removing the effects of the scaling and
+translation) and then does the <i>same</i> operations in a different order.
+Observe the effect below.""")
+
+illust(examples.scaletranslate, "Scaling and Translating")
+
+
+#illust(NOP) # execute some code
+
+pencilnote()
+
+
+disc("""<em>Note:</em> scaling shrinks or grows everything including line widths
+so using the canvas.scale method to render a microscopic drawing in
+scaled microscopic units
+may produce a blob (because all line widths will get expanded a huge amount).
+Also rendering an aircraft wing in meters scaled to centimeters may cause the lines
+to shrink to the point where they disappear.  For engineering or scientific purposes
+such as these scale and translate
+the units externally before rendering them using the canvas.""")
+
+heading3("Saving and restoring the $canvas$ state: $saveState$ and $restoreState$")
+
+disc("""
+The $scaletranslate$ function used an important feature of the $canvas$ object:
+the ability to save and restore the current parameters of the $canvas$.
+By enclosing a sequence of operations in a matching pair of $canvas.saveState()$
+an $canvas.restoreState()$ operations all changes of font, color, line style,
+scaling, translation, or other aspects of the $canvas$ graphics state can be
+restored to the state at the point of the $saveState()$.  Remember that the save/restore
+calls must match: a stray save or restore operation may cause unexpected
+and undesirable behavior.  Also, remember that <i>no</i> $canvas$ state is
+preserved across page breaks, and the save/restore mechanism does not work
+across page breaks.
+""")
+
+heading3("Mirror image")
+
+disc("""
+It is interesting although perhaps not terribly useful to note that
+scale factors can be negative.  For example the following function
+""")
+
+eg(examples.testmirror)
+
+disc("""
+creates a mirror image of the elements drawn by the $coord$ function.
+""")
+
+illust(examples.mirror, "Mirror Images")
+
+disc("""
+Notice that the text strings are painted backwards.
+""")
+
+heading2("Colors")
+
+disc("""
+There are four ways to specify colors in $pdfgen$: by name (using the $color$
+module, by red/green/blue (additive, $RGB$) value,
+by cyan/magenta/yellow/darkness (subtractive, $CMYK$), or by gray level.
+The $colors$ function below exercises each of the four methods.
+""")
+
+eg(examples.testcolors)
+
+disc("""
+The $RGB$ or additive color specification follows the way a computer
+screen adds different levels of the red, green, or blue light to make
+any color, where white is formed by turning all three lights on full
+$(1,1,1)$.""")
+
+disc("""The $CMYK$ or subtractive method follows the way a printer
+mixes three pigments (cyan, magenta, and yellow) to form colors.
+Because mixing chemicals is more difficult than combining light there
+is a fourth parameter for darkness.  For example a chemical
+combination of the $CMY$ pigments generally never makes a perfect
+black -- instead producing a muddy color -- so, to get black printers
+don't use the $CMY$ pigments but use a direct black ink.  Because
+$CMYK$ maps more directly to the way printer hardware works it may
+be the case that colors specified in $CMYK$ will provide better fidelity
+and better control when printed.
+""")
+
+illust(examples.colors, "Color Models")
+
+heading2('Painting back to front')
+
+disc("""
+Objects may be painted over other objects to good effect in $pdfgen$.  As
+in painting with oils the object painted last will show up on top.  For
+example, the $spumoni$ function below paints up a base of colors and then
+paints a white text over the base.
+""")
+
+eg(examples.testspumoni)
+
+disc("""
+The word "SPUMONI" is painted in white over the colored rectangles,
+with the apparent effect of "removing" the color inside the body of
+the word.
+""")
+
+illust(examples.spumoni, "Painting over colors")
+
+disc("""
+The last letters of the word are not visible because the default $canvas$
+background is white and painting white letters over a white background
+leaves no visible effect.
+""")
+
+disc("""
+This method of building up complex paintings in layers can be done
+in very many layers in $pdfgen$ -- there are fewer physical limitations
+than there are when dealing with physical paints.
+""")
+
+eg(examples.testspumoni2)
+
+disc("""
+The $spumoni2$ function layers an ice cream cone over the
+$spumoni$ drawing.  Note that different parts of the cone
+and scoops layer over eachother as well.
+""")
+illust(examples.spumoni2, "building up a drawing in layers")
+
+
+heading2('Standard fonts and text objects')
+
+disc("""
+Text may be drawn in many different colors, fonts, and sizes in $pdfgen$.
+The $textsize$ function demonstrates how to change the color and font and
+size of text and how to place text on the page.
+""")
+
+eg(examples.testtextsize)
+
+disc("""
+The $textsize$ function generates the following page.
+""")
+
+illust(examples.textsize, "text in different fonts and sizes")
+
+disc("""
+A number of different fonts are always available in $pdfgen$.
+""")
+
+eg(examples.testfonts)
+
+disc("""
+The $fonts$ function lists the fonts that are always available.
+These don't need to be stored in a PDF document, since they
+are guaranteed to be present in Acrobat Reader.
+""")
+
+illust(examples.fonts, "the 14 standard fonts")
+
+disc("""
+For information on how to use arbitrary fonts, see the next chapter.
+""")
+
+
+heading2("Text object methods")
+
+disc("""
+For the dedicated presentation of text in a PDF document, use a text object.
+The text object interface provides detailed control of text layout parameters
+not available directly at the $canvas$ level.  In addition, it results in smaller
+PDF that will render faster than many separate calls to the $drawString$ methods.
+""")
+
+eg("""textobject.setTextOrigin(x,y)""")
+eg("""textobject.setTextTransform(a,b,c,d,e,f)""")
+eg("""textobject.moveCursor(dx, dy) # from start of current LINE""")
+eg("""(x,y) = textobject.getCursor()""")
+eg("""x = textobject.getX(); y = textobject.getY()""")
+eg("""textobject.setFont(psfontname, size, leading = None)""")
+eg("""textobject.textOut(text)""")
+eg("""textobject.textLine(text='')""")
+eg("""textobject.textLines(stuff, trim=1)""")
+
+disc("""
+The text object methods shown above relate to basic text geometry.
+""")
+
+disc("""
+A text object maintains a text cursor which moves about the page when
+text is drawn.  For example the $setTextOrigin$ places the cursor
+in a known position and the $textLine$ and $textLines$ methods move
+the text cursor down past the lines that have been missing.
+""")
+
+eg(examples.testcursormoves1)
+
+disc("""
+The $cursormoves$ function relies on the automatic
+movement of the text cursor for placing text after the origin
+has been set.
+""")
+
+illust(examples.cursormoves1, "How the text cursor moves")
+
+disc("""
+It is also possible to control the movement of the cursor
+more explicitly by using the $moveCursor$ method (which moves
+the cursor as an offset from the start of the current <i>line</i>
+NOT the current cursor, and which also has positive ^y^ offsets
+move <i>down</i> (in contrast to the normal geometry where
+positive ^y^ usually moves up.
+""")
+
+eg(examples.testcursormoves2)
+
+disc("""
+Here the $textOut$ does not move the down a line in contrast
+to the $textLine$ function which does move down.
+""")
+
+illust(examples.cursormoves2, "How the text cursor moves again")
+
+heading3("Character Spacing")
+
+eg("""textobject.setCharSpace(charSpace)""")
+
+disc("""The $setCharSpace$ method adjusts one of the parameters of text -- the inter-character
+spacing.""")
+
+eg(examples.testcharspace)
+
+disc("""The
+$charspace$ function exercises various spacing settings.
+It produces the following page.""")
+
+illust(examples.charspace, "Adjusting inter-character spacing")
+
+heading3("Word Spacing")
+
+eg("""textobject.setWordSpace(wordSpace)""")
+
+disc("The $setWordSpace$ method adjusts the space between words.")
+
+eg(examples.testwordspace)
+
+disc("""The $wordspace$ function shows what various word space settings
+look like below.""")
+
+illust(examples.wordspace, "Adjusting word spacing")
+
+heading3("Horizontal Scaling")
+
+eg("""textobject.setHorizScale(horizScale)""")
+
+disc("""Lines of text can be stretched or shrunken horizontally by the
+$setHorizScale$ method.""")
+
+eg(examples.testhorizontalscale)
+
+disc("""The horizontal scaling parameter ^horizScale^
+is given in percentages (with 100 as the default), so the 80 setting
+shown below looks skinny.
+""")
+illust(examples.horizontalscale, "adjusting horizontal text scaling")
+
+heading3("Interline spacing (Leading)")
+
+eg("""textobject.setLeading(leading)""")
+
+disc("""The vertical offset between the point at which one
+line starts and where the next starts is called the leading
+offset.  The $setLeading$ method adjusts the leading offset.
+""")
+
+eg(examples.testleading)
+
+disc("""As shown below if the leading offset is set too small
+characters of one line my write over the bottom parts of characters
+in the previous line.""")
+
+illust(examples.leading, "adjusting the leading")
+
+heading3("Other text object methods")
+
+eg("""textobject.setTextRenderMode(mode)""")
+
+disc("""The $setTextRenderMode$ method allows text to be used
+as a forground for clipping background drawings, for example.""")
+
+eg("""textobject.setRise(rise)""")
+
+disc("""
+The $setRise$ method <super>raises</super> or <sub>lowers</sub> text on the line
+(for creating superscripts or subscripts, for example).
+""")
+
+eg("""textobject.setFillColor(aColor);
+textobject.setStrokeColor(self, aColor)
+# and similar""")
+
+disc("""
+These color change operations change the <font color=darkviolet>color</font> of the text and are otherwise
+similar to the color methods for the $canvas$ object.""")
+
+heading2('Paths and Lines')
+
+disc("""Just as textobjects are designed for the dedicated presentation
+of text, path objects are designed for the dedicated construction of
+graphical figures.  When path objects are drawn onto a $canvas$ they
+are drawn as one figure (like a rectangle) and the mode of drawing
+for the entire figure can be adjusted: the lines of the figure can
+be drawn (stroked) or not; the interior of the figure can be filled or
+not; and so forth.""")
+
+disc("""
+For example the $star$ function uses a path object
+to draw a star
+""")
+
+eg(examples.teststar)
+
+disc("""
+The $star$ function has been designed to be useful in illustrating
+various line style parameters supported by $pdfgen$.
+""")
+
+illust(examples.star, "line style parameters")
+
+heading3("Line join settings")
+
+disc("""
+The $setLineJoin$ method can adjust whether line segments meet in a point
+a square or a rounded vertex.
+""")
+
+eg(examples.testjoins)
+
+disc("""
+The line join setting is only really of interest for thick lines because
+it cannot be seen clearly for thin lines.
+""")
+
+illust(examples.joins, "different line join styles")
+
+heading3("Line cap settings")
+
+disc("""The line cap setting, adjusted using the $setLineCap$ method,
+determines whether a terminating line
+ends in a square exactly at the vertex, a square over the vertex
+or a half circle over the vertex.
+""")
+
+eg(examples.testcaps)
+
+disc("""The line cap setting, like the line join setting, is only clearly
+visible when the lines are thick.""")
+
+illust(examples.caps, "line cap settings")
+
+heading3("Dashes and broken lines")
+
+disc("""
+The $setDash$ method allows lines to be broken into dots or dashes.
+""")
+
+eg(examples.testdashes)
+
+disc("""
+The patterns for the dashes or dots can be in a simple on/off repeating pattern
+or they can be specified in a complex repeating pattern.
+""")
+
+illust(examples.dashes, "some dash patterns")
+
+heading3("Creating complex figures with path objects")
+
+disc("""
+Combinations of lines, curves, arcs and other figures
+can be combined into a single figure using path objects.
+For example the function shown below constructs two path
+objects using lines and curves.
+This function will be used later on as part of a
+pencil icon construction.
+""")
+
+eg(examples.testpenciltip)
+
+disc("""
+Note that the interior of the pencil tip is filled
+as one object even though it is constructed from
+several lines and curves.  The pencil lead is then
+drawn over it using a new path object.
+""")
+
+illust(examples.penciltip, "a pencil tip")
+
+heading2('Rectangles, circles, ellipses')
+
+disc("""
+The $pdfgen$ module supports a number of generally useful shapes
+such as rectangles, rounded rectangles, ellipses, and circles.
+Each of these figures can be used in path objects or can be drawn
+directly on a $canvas$.  For example the $pencil$ function below
+draws a pencil icon using rectangles and rounded rectangles with
+various fill colors and a few other annotations.
+""")
+
+eg(examples.testpencil)
+
+pencilnote()
+
+disc("""
+Note that this function is used to create the "margin pencil" to the left.
+Also note that the order in which the elements are drawn are important
+because, for example, the white rectangles "erase" parts of a black rectangle
+and the "tip" paints over part of the yellow rectangle.
+""")
+
+illust(examples.pencil, "a whole pencil")
+
+heading2('Bezier curves')
+
+disc("""
+Programs that wish to construct figures with curving borders
+generally use Bezier curves to form the borders.
+""")
+
+eg(examples.testbezier)
+
+disc("""
+A Bezier curve is specified by four control points
+$(x1,y1)$, $(x2,y2)$, $(x3,y3)$, $(x4,y4)$.
+The curve starts at $(x1,y1)$ and ends at $(x4,y4)$
+and the line segment from $(x1,y1)$ to $(x2,y2)$
+and the line segment from $(x3,y3)$ to $(x4,y4)$
+both form tangents to the curve.  Furthermore the
+curve is entirely contained in the convex figure with vertices
+at the control points.
+""")
+
+illust(examples.bezier, "basic bezier curves")
+
+disc("""
+The drawing above (the output of $testbezier$) shows
+a bezier curves, the tangent lines defined by the control points
+and the convex figure with vertices at the control points.
+""")
+
+heading3("Smoothly joining bezier curve sequences")
+
+disc("""
+It is often useful to join several bezier curves to form a
+single smooth curve.  To construct a larger smooth curve from
+several bezier curves make sure that the tangent lines to adjacent
+bezier curves that join at a control point lie on the same line.
+""")
+
+eg(examples.testbezier2)
+
+disc("""
+The figure created by $testbezier2$ describes a smooth
+complex curve because adjacent tangent lines "line up" as
+illustrated below.
+""")
+
+illust(examples.bezier2, "bezier curves")
+
+heading2("Path object methods")
+
+disc("""
+Path objects build complex graphical figures by setting
+the "pen" or "brush" at a start point on the canvas and drawing
+lines or curves to additional points on the canvas.  Most operations
+apply paint on the canvas starting at the end point of the last
+operation and leave the brush at a new end point.
+""")
+
+eg("""pathobject.moveTo(x,y)""")
+
+disc("""
+The $moveTo$ method lifts the brush (ending any current sequence
+of lines or curves if there is one) and replaces the brush at the
+new ^(x,y)^ location on the canvas to start a new path sequence.
+""")
+
+eg("""pathobject.lineTo(x,y)""")
+
+disc("""
+The $lineTo$ method paints straight line segment from the current brush
+location to the new ^(x,y)^ location.
+""")
+
+eg("""pathobject.curveTo(x1, y1, x2, y2, x3, y3) """)
+
+disc("""
+The $curveTo$ method starts painting a Bezier curve beginning at
+the current brush location, using ^(x1,y1)^, ^(x2,y2)^, and ^(x3,y3)^
+as the other three control points, leaving the brush on ^(x3,y3)^.
+""")
+
+eg("""pathobject.arc(x1,y1, x2,y2, startAng=0, extent=90) """)
+
+eg("""pathobject.arcTo(x1,y1, x2,y2, startAng=0, extent=90) """)
+
+disc("""
+The $arc$ and $arcTo$ methods paint partial ellipses.  The $arc$ method first "lifts the brush"
+and starts a new shape sequence.  The $arcTo$ method joins the start of
+the partial ellipse to the current
+shape sequence by line segment before drawing the partial ellipse.  The points
+^(x1,y1)^ and ^(x2,y2)^ define opposite corner points of a rectangle enclosing
+the ellipse.  The $startAng$ is an angle (in degrees) specifying where to begin
+the partial ellipse where the 0 angle is the midpoint of the right border of the enclosing
+rectangle (when ^(x1,y1)^ is the lower left corner and ^(x2,y2)^ is the upper
+right corner).  The $extent$ is the angle in degrees to traverse on the ellipse.
+""")
+
+eg(examples.testarcs)
+
+disc("""The $arcs$ function above exercises the two partial ellipse methods.
+It produces the following drawing.""")
+
+illust(examples.arcs, "arcs in path objects")
+
+eg("""pathobject.rect(x, y, width, height) """)
+
+disc("""The $rect$ method draws a rectangle with lower left corner
+at ^(x,y)^ of the specified ^width^ and ^height^.""")
+
+eg("""pathobject.ellipse(x, y, width, height)""")
+
+disc("""The $ellipse$ method
+draws an ellipse enclosed in the rectange with lower left corner
+at ^(x,y)^ of the specified ^width^ and ^height^.
+""")
+
+eg("""pathobject.circle(x_cen, y_cen, r) """)
+
+disc("""The $circle$ method
+draws a circle centered at ^(x_cen, y_cen)^ with radius ^r^.
+""")
+
+eg(examples.testvariousshapes)
+
+disc("""
+The $variousshapes$ function above shows a rectangle, circle and ellipse
+placed in a frame of reference grid.
+""")
+
+illust(examples.variousshapes, "rectangles, circles, ellipses in path objects")
+
+eg("""pathobject.close() """)
+
+disc("""
+The $close$ method closes the current graphical figure
+by painting a line segment from the last point of the figure
+to the starting point of the figure (the the most
+recent point where the brush was placed on the paper by $moveTo$
+or $arc$ or other placement operations).
+""")
+
+eg(examples.testclosingfigures)
+
+disc("""
+The $closingfigures$ function illustrates the
+effect of closing or not closing figures including a line
+segment and a partial ellipse.
+""")
+
+illust(examples.closingfigures, "closing and not closing pathobject figures")
+
+disc("""
+Closing or not closing graphical figures effects only the stroked outline
+of a figure, not the filling of the figure as illustrated above.
+""")
+
+
+disc("""
+For a more extensive example of drawing using a path object
+examine the $hand$ function.
+""")
+
+eg(examples.testhand)
+
+disc("""
+In debug mode (the default) the $hand$ function shows the tangent line segments
+to the bezier curves used to compose the figure.  Note that where the segments
+line up the curves join smoothly, but where they do not line up the curves show
+a "sharp edge".
+""")
+
+illust(examples.hand, "an outline of a hand using bezier curves")
+
+disc("""
+Used in non-debug mode the $hand$ function only shows the
+Bezier curves.  With the $fill$ parameter set the figure is
+filled using the current fill color.
+""")
+
+eg(examples.testhand2)
+
+disc("""
+Note that the "stroking" of the border draws over the interior fill where
+they overlap.
+""")
+
+illust(examples.hand2, "the finished hand, filled")
+
+
+
+heading2("Further Reading: The ReportLab Graphics Library")
+
+disc("""
+So far the graphics we have seen was created on a fairly low level.
+It should be noted, though, that there is another way of creating
+much more sophisticated graphics using the emerging dedicated
+high-level <i>ReportLab Graphics Library</i>.
+""")
+
+disc("""
+It can be used to produce high-quality, platform-independant,
+reusable graphics for different output formats (vector and bitmap)
+like PDF, EPS and soon others like SVG.
+""")
+
+disc("""
+A thorough description of its philsophy and features is beyond the
+scope of this general user guide and the reader is recommended to
+continue with the <i>"ReportLab Graphics Guide"</i>.
+There she will find information about the existing components and
+how to create customized ones.
+""")
+
+disc("""
+Also, the graphics guide contains a presentation of an emerging
+charting package and its components (labels, axes, legends and
+different types of charts like bar, line and pie charts) that
+builds directly on the graphics library.
+""")
+
+
+##### FILL THEM IN