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diff --git a/Master/texmf-dist/doc/generic/pgf/version-for-tex4ht/en/pgfmanualse18.html b/Master/texmf-dist/doc/generic/pgf/version-for-tex4ht/en/pgfmanualse18.html new file mode 100644 index 00000000000..fe0a36ad211 --- /dev/null +++ b/Master/texmf-dist/doc/generic/pgf/version-for-tex4ht/en/pgfmanualse18.html @@ -0,0 +1,285 @@ +<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" + "http://www.w3.org/TR/html4/loose.dtd"> +<html > +<head><title>18 Design Principles</title> +<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1"> +<meta name="generator" content="TeX4ht (http://www.cis.ohio-state.edu/~gurari/TeX4ht/mn.html)"> +<meta name="originator" content="TeX4ht (http://www.cis.ohio-state.edu/~gurari/TeX4ht/mn.html)"> +<!-- html --> +<meta name="src" content="pgfmanual.tex"> +<meta name="date" content="2005-10-23 18:34:00"> +<link rel="stylesheet" type="text/css" href="pgfmanual.css"> +</head><body +> + <div class="crosslinks"><p class="noindent">[<a +href="pgfmanualse19.html" >next</a>] [<a +href="#tailpgfmanualse18.html">tail</a>] [<a +href="pgfmanual.html#pgfmanualse18.html" >up</a>] </p></div> + <h3 class="sectionHead"><span class="titlemark">18 </span> <a + id="x19-18700018"></a>Design Principles</h3> +<!--l. 10--><p class="noindent">This section describes the basic layer of <span +class="cmcsc-10"><small +class="small-caps">P</small><small +class="small-caps">G</small><small +class="small-caps">F</small></span>. This layer is build on top of the system layer. Whereas the system +layer just provides the absolute minimum for drawing graphics, the basic layer provides numerous commands that +make it possible to create sophisticated graphics easily and also quickly. +<!--l. 16--><p class="indent"> The basic layer does not provide a convenient syntax for describing graphics, which is left to frontends like Ti<span +class="cmti-10">k</span>Z. +For this reason, the basic layer is typically used only by “other programs.” For example, the <span +class="cmcsc-10"><small +class="small-caps">B</small><small +class="small-caps">E</small><small +class="small-caps">A</small><small +class="small-caps">M</small><small +class="small-caps">E</small><small +class="small-caps">R</small> </span>package uses +the basic layer extensively, but does not need a convenient input syntax. Rather, speed and flexibility are needed +when <span +class="cmcsc-10"><small +class="small-caps">B</small><small +class="small-caps">E</small><small +class="small-caps">A</small><small +class="small-caps">M</small><small +class="small-caps">E</small><small +class="small-caps">R</small> </span>creates graphics. +<!--l. 23--><p class="indent"> The following basic design principles underlie the basic layer: + <ol type="1" class="enumerate1" > + <li class="enumerate" value="1" +><a + id="x19-187002x1"></a>Structuring into a core and several optional packages. + </li> + <li class="enumerate" value="2" +><a + id="x19-187004x2"></a>Consistently named <span class="TEX">T<span +class="E">E</span>X</span> macros for all graphics commands. + </li> + <li class="enumerate" value="3" +><a + id="x19-187006x3"></a>Path-centered description of graphics. + </li> + <li class="enumerate" value="4" +><a + id="x19-187008x4"></a>Coordinate transformation system.</li></ol> +<!--l. 33--><p class="noindent"> + <h4 class="subsectionHead"><span class="titlemark">18.1 </span> <a + id="x19-18800018.1"></a>Core and Optional Packages</h4> +<!--l. 35--><p class="noindent">The basic layer consists of a <span +class="cmti-10">core package</span>, called <span class="obeylines-h"><span class="verb"><span +class="cmtt-10">pgfcore</span></span></span>, which provides the most basic commands, and several +optional package like <span class="obeylines-h"><span class="verb"><span +class="cmtt-10">pgfbaseshade</span></span></span> that offer more special-purpose commands. +<!--l. 39--><p class="indent"> You can include the core by saying <span class="obeylines-h"><span class="verb"><span +class="cmtt-10">\usepackage{pgfcore}</span></span></span> or, as a plain <span class="TEX">T<span +class="E">E</span>X</span> user, <span class="obeylines-h"><span class="verb"><span +class="cmtt-10">\input</span><span +class="cmtt-10"> pgfcore.tex</span></span></span>. +<!--l. 42--><p class="indent"> The following optional packages are provided by the basic layer: + <ul class="itemize1"> + <li class="itemize"><span class="obeylines-h"><span class="verb"><span +class="cmtt-10">pgfbaseplot</span></span></span> provides commands for plotting functions. + </li> + <li class="itemize"><span class="obeylines-h"><span class="verb"><span +class="cmtt-10">pgfbaseshapes</span></span></span> provides commands for drawing shapes and nodes. + </li> + <li class="itemize"><span class="obeylines-h"><span class="verb"><span +class="cmtt-10">pgfbaseimage</span></span></span> provides commands for including external images. The <span class="obeylines-h"><span class="verb"><span +class="cmtt-10">graphicx</span></span></span> package does a much + better job at this than the <span class="obeylines-h"><span class="verb"><span +class="cmtt-10">pgfbaseimage</span></span></span> package does, so you should normally use <span class="obeylines-h"><span class="verb"><span +class="cmtt-10">\includegraphics</span></span></span> + and not <span class="obeylines-h"><span class="verb"><span +class="cmtt-10">\pgfimage</span></span></span>. However, in some situations (like when masking is needed or when plain <span class="TEX">T<span +class="E">E</span>X</span> is + used) this package is needed. + </li> + <li class="itemize"><span class="obeylines-h"><span class="verb"><span +class="cmtt-10">pgfbaselayers</span></span></span> provides commands for creating layered graphics. Using layers you can later on say + that a certain path should be behind a path that was specified earlier. + </li> + <li class="itemize"><span class="obeylines-h"><span class="verb"><span +class="cmtt-10">pgfbasesnakes</span></span></span> provides commands for adding snaked lines to the path. Such lines are not straight + but rather wind in some specific fashion.</li></ul> +<!--l. 66--><p class="indent"> If you say <span class="obeylines-h"><span class="verb"><span +class="cmtt-10">\usepackage{pgf}</span></span></span> or <span class="obeylines-h"><span class="verb"><span +class="cmtt-10">\input</span><span +class="cmtt-10"> pgf.tex</span></span></span>, all of the optional packages are loaded (as well as the core +and the system layer). + + +<!--l. 70--><p class="noindent"> + <h4 class="subsectionHead"><span class="titlemark">18.2 </span> <a + id="x19-18900018.2"></a>Communicating with the Basic Layer via Macros</h4> +<!--l. 72--><p class="noindent">In order to “communicate” with the basic layer you use long sequences of commands that start with <span class="obeylines-h"><span class="verb"><span +class="cmtt-10">\pgf</span></span></span>. You are +only allowed to give these commands inside a <span class="obeylines-h"><span class="verb"><span +class="cmtt-10">{pgfpicture}</span></span></span> environment. (Note that <span class="obeylines-h"><span class="verb"><span +class="cmtt-10">{tikzpicture}</span></span></span> opens a +<span class="obeylines-h"><span class="verb"><span +class="cmtt-10">{pgfpicture}</span></span></span> internally, so you can freely mix <span +class="cmcsc-10"><small +class="small-caps">P</small><small +class="small-caps">G</small><small +class="small-caps">F</small></span> commands and Ti<span +class="cmti-10">k</span>Z commands inside a <span class="obeylines-h"><span class="verb"><span +class="cmtt-10">{tikzpicture}</span></span></span>.) It +is possible to “do other things” between the commands. For example, you might use one command +to move to a certain point, then have a complicated computation of the next point, and then move +there. +<!--l. 82--><p class="noindent"><div class="obeylines-v"></div><!--tex4ht:inline--><div class="tabular"><table class="tabular" +cellspacing="0" cellpadding="0" +frame="void" id="TBL-396-" ><colgroup id="TBL-396-1g"><col +id="TBL-396-1"><col +id="TBL-396-2"></colgroup><tr + valign="baseline" id="TBL-396-1-"><td align="left" style="white-space:nowrap; text-align:left;" id="TBL-396-1-1" +class="td11"> <object data="pgfmanual-469.svg" width="28.85274pt" height="28.85274pt" type="image/svg+xml"><p>SVG-Viewer needed.</p></object> </td><td align="left" style="white-space:nowrap; text-align:left;" id="TBL-396-1-2" +class="td11"> <table class="minipage"><tr><td><div class="obeylines-v"> +<br><span +class="cmtt-8">\newdimen\myypos</span> +<br><span +class="cmtt-8">\begin{pgfpicture}</span> +<br><span +class="cmtt-8"> </span><span +class="cmtt-8"> \pgfpathmoveto{\pgfpoint{0cm}{\myypos}}</span> +<br><span +class="cmtt-8"> </span><span +class="cmtt-8"> \pgfpathlineto{\pgfpoint{1cm}{\myypos}}</span> +<br><span +class="cmtt-8"> </span><span +class="cmtt-8"> \advance</span><span +class="cmtt-8"> \myypos</span><span +class="cmtt-8"> by</span><span +class="cmtt-8"> 1cm</span> +<br><span +class="cmtt-8"> </span><span +class="cmtt-8"> \pgfpathlineto{\pgfpoint{1cm}{\myypos}}</span> +<br><span +class="cmtt-8"> </span><span +class="cmtt-8"> \pgfpathclose</span> +<br><span +class="cmtt-8"> </span><span +class="cmtt-8"> \pgfusepath{stroke}</span> +<br><span +class="cmtt-8">\end{pgfpicture}</span></div> </td></tr></table> </td> +</tr></table></div> +<!--l. 94--><p class="indent"> The following naming conventions are used in the basic layer: +<!--l. 96--><p class="indent"> + <ol type="1" class="enumerate1" > + <li class="enumerate" value="1" +><a + id="x19-189002x1"></a>All commands and environments start with <span class="obeylines-h"><span class="verb"><span +class="cmtt-10">pgf</span></span></span>. + </li> + <li class="enumerate" value="2" +><a + id="x19-189004x2"></a>All commands that specify a point (a coordinate) start with <span class="obeylines-h"><span class="verb"><span +class="cmtt-10">\pgfpoint</span></span></span>. + </li> + <li class="enumerate" value="3" +><a + id="x19-189006x3"></a>All commands that extend the current path start with <span class="obeylines-h"><span class="verb"><span +class="cmtt-10">\pgfpath</span></span></span>. + </li> + <li class="enumerate" value="4" +><a + id="x19-189008x4"></a>All commands that set/change a graphics parameter start with <span class="obeylines-h"><span class="verb"><span +class="cmtt-10">\pgfset</span></span></span>. + </li> + <li class="enumerate" value="5" +><a + id="x19-189010x5"></a>All commands that use a previously declared object (like a path, image or shading) start with <span class="obeylines-h"><span class="verb"><span +class="cmtt-10">\pgfuse</span></span></span>. + </li> + <li class="enumerate" value="6" +><a + id="x19-189012x6"></a>All commands having to do with coordinate transformations start with <span class="obeylines-h"><span class="verb"><span +class="cmtt-10">\pgftransform</span></span></span>. + </li> + <li class="enumerate" value="7" +><a + id="x19-189014x7"></a>All commands having to do with arrow tips start with <span class="obeylines-h"><span class="verb"><span +class="cmtt-10">\pgfarrows</span></span></span>. + </li> + <li class="enumerate" value="8" +><a + id="x19-189016x8"></a>All commands for “quickly” extending or drawing a path start with <span class="obeylines-h"><span class="verb"><span +class="cmtt-10">\pgfpathq</span></span></span> or <span class="obeylines-h"><span class="verb"><span +class="cmtt-10">\pgfusepathq</span></span></span>.</li></ol> +<!--l. 119--><p class="noindent"> + <h4 class="subsectionHead"><span class="titlemark">18.3 </span> <a + id="x19-19000018.3"></a>Path-Centered Approach</h4> +<!--l. 121--><p class="noindent">In <span +class="cmcsc-10"><small +class="small-caps">P</small><small +class="small-caps">G</small><small +class="small-caps">F</small></span> the most important entity is the <span +class="cmti-10">path</span>. All graphics are composed of numerous paths that can be stroked, +filled, shaded, or clipped against. Paths can be closed or open, they can self-intersect and consist of unconnected +parts. +<!--l. 126--><p class="indent"> Paths are first <span +class="cmti-10">constructed </span>and then <span +class="cmti-10">used</span>. In order to construct a path, you can use commands +starting with <span class="obeylines-h"><span class="verb"><span +class="cmtt-10">\pgfpath</span></span></span>. Each time such a command is called, the current path is extended in some +way. +<!--l. 131--><p class="indent"> Once a path has been completely constructed, you can use it using the command <span class="obeylines-h"><span class="verb"><span +class="cmtt-10">\pgfusepath</span></span></span>. Depending on +the parameters given to this command, the path will be stroked (drawn) or filled or subsequent drawings will be +clipped against this path. + + +<!--l. 139--><p class="noindent"> + <h4 class="subsectionHead"><span class="titlemark">18.4 </span> <a + id="x19-19100018.4"></a>Coordinate Versus Canvas Transformations</h4> +<!--l. 143--><p class="noindent"><span +class="cmcsc-10"><small +class="small-caps">P</small><small +class="small-caps">G</small><small +class="small-caps">F</small></span> provides two transformation systems: <span +class="cmcsc-10"><small +class="small-caps">P</small><small +class="small-caps">G</small><small +class="small-caps">F</small></span>’s own <span +class="cmti-10">coordinate </span>transformation matrix and <span +class="cmcsc-10"><small +class="small-caps">P</small><small +class="small-caps">D</small><small +class="small-caps">F</small></span>’s or PostScript’s +<span +class="cmti-10">canvas </span>transformation matrix. These two systems are quite different. Whereas a scaling by a factor of, say, 2 of the +canvas causes <span +class="cmti-10">everything </span>to be scaled by this factor (including the thickness of lines and text), a scaling of +two in the coordinate system causes only the <span +class="cmti-10">coordinates </span>to be scaled, but not the line width nor +text. +<!--l. 152--><p class="indent"> By default, all transformations only apply to the coordinate transformation system. However, using the +command <span class="obeylines-h"><span class="verb"><span +class="cmtt-10">\pgflowlevel</span></span></span> it is possible to apply a transformation to the canvas. +<!--l. 156--><p class="indent"> Coordinate transformations are often preferable over canvas transformations. Text and lines that are transformed +using canvas transformations suffer from differing sizes and lines whose thickness differs depending on whether the +line is horizontal or vertical. To appreciate the difference, consider the following two “circles” both of which +have been scaled in the <span +class="cmmi-10">x</span>-direction by a factor of 3 and by a factor of 0<span +class="cmmi-10">.</span>5 in the <span +class="cmmi-10">y</span>-direction. The left +circle uses a canvas transformation, the right uses <span +class="cmcsc-10"><small +class="small-caps">P</small><small +class="small-caps">G</small><small +class="small-caps">F</small></span>’s coordinate transformation (some viewers will +render the left graphic incorrectly since they do no apply the low-level transformation the way they +should): +<!--l. 182--><p class="indent"> <object data="pgfmanual-470.svg" width="448.1307pt" height="56.90549pt" type="image/svg+xml"><p>SVG-Viewer needed.</p></object> + + + + + + + <div class="crosslinks"><p class="noindent">[<a +href="pgfmanualse19.html" >next</a>] [<a +href="pgfmanualse18.html" >front</a>] [<a +href="pgfmanual.html#pgfmanualse18.html" >up</a>] </p></div> +<!--l. 8--><p class="indent"> <a + id="tailpgfmanualse18.html"></a> +</body></html> |