doc/parts/dynamic/graphic.sxml

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  16 <!-- Copyright 2008, 2010 Henrik Tidefelt                                   -->
  17
  18 <section id="dynamic/graphic">
  19 <title>Graphics</title>
  20 <top>
  21         <p>The bindings in this section are closely related to the <em>graphics state parameters</em> in <str-PDF />.</p>
  22         <p>Many of these dynamic variables can be set to a <named-type name="Void" /> value, which means that painted objects do not specify the property for themselves, but inherit the property from the context where they appear.  This feature is a low-level <str-PDF /> trick, and the effects may be (or at least seem) unpredictable.</p>
  23 </top>
  24
  25 <dynamic-variable name="width">
  26         <type><union-type><named-type name="Length" /> <named-type name="Void" /></union-type></type>
  27         <default><physical><scalar>1</scalar><unit>bp</unit></physical></default>
  28         <constraint><self /> ≥ <physical><scalar>0</scalar><unit>bp</unit></physical></constraint>
  29         <description>
  30                 <p>Intended to be used as the width when paths are stroked.  A value of <physical><scalar>0</scalar><unit>bp</unit></physical> has a special meaning in <str-PDF />, being that the stroke shall be as thin as possible without dissappearing on the rendering device.  On high resolution printers, this may result in a line which is very hard to read, while such a line shall allways be clearly visible on a computer screen.</p>
  31                 <p>Note that if the width is inherited from the context, it will not be possible to compute a correct bounding box of a stroked object.</p>
  32         </description>
  33 </dynamic-variable>
  34
  35 <dynamic-variable name="stroking">
  36         <type><union-type><named-type name="Color" /> <named-type name="Void" /></union-type></type>
  37         <default><value name="GRAY_BLACK" /></default>
  38         <description>
  39                 <p>Color used when paths are stroked.</p>
  40         </description>
  41         <see-also>
  42                 <dynamic name="strokingalpha" />
  43         </see-also>
  44 </dynamic-variable>
  45
  46 <dynamic-variable name="nonstroking">
  47         <type><union-type><named-type name="Color" /> <named-type name="Void" /></union-type></type>
  48         <default><value name="GRAY_BLACK" /></default>
  49         <description>
  50                 <p>Color used when paths are filled (or, more generally, anything but stroked).  (The name is inherited from <str-PDF />.)</p>
  51         </description>
  52         <see-also>
  53                 <dynamic name="nonstrokingalpha" />
  54         </see-also>
  55 </dynamic-variable>
  56
  57 <dynamic-variable name="cap">
  58         <type><union-type><named-type name="CapStyle" /> <named-type name="Void" /></union-type></type>
  59         <default><value name="CAP_BUTT" /></default>
  60         <description>
  61                 <p>Line cap style.</p>
  62         </description>
  63 </dynamic-variable>
  64
  65 <dynamic-variable name="join">
  66         <type><union-type><named-type name="JoinStyle" /> <named-type name="Void" /></union-type></type>
  67         <default><value name="JOIN_MITER" /></default>
  68         <description>
  69                 <p>Line join style.</p>
  70         </description>
  71         <see-also>
  72                 <dynamic name="miterlimit" />
  73         </see-also>
  74 </dynamic-variable>
  75
  76 <dynamic-variable name="miterlimit">
  77         <type><union-type><named-type name="Float" /> <named-type name="Void" /></union-type></type>
  78         <default><eq>10</eq></default>
  79         <constraint><self /> ≥ <eq>1</eq></constraint>
  80         <description>
  81                 <p>Miter limit value to use when <dynamic name="join" /> is <value name="JOIN_MITER" />.</p>
  82         </description>
  83 </dynamic-variable>
  84
  85 <dynamic-variable name="dash">
  86         <type><union-type><named-type name="Dash" /> <named-type name="Void" /></union-type></type>
  87         <default><inline>[dashpattern]</inline></default>
  88         <description>
  89                 <p>Dash pattern to use for strokes.  (The default value gives solid lines.)</p>
  90         </description>
  91         <see-also>
  92                 <value name="dashpattern" />
  93         </see-also>
  94 </dynamic-variable>
  95
  96 <dynamic-variable name="strokingalpha">
  97         <type><union-type><named-type name="Alpha" /> <named-type name="Void" /></union-type></type>
  98         <default><inline>[shape 1]</inline></default>
  99         <description>
 100                 <p>Alpha settings for stroking operations.</p>
 101         </description>
 102         <see-also>
 103                 <value name="alphashape" /> <value name="alphaopacity" /> <dynamic name="stroking" />
 104         </see-also>
 105 </dynamic-variable>
 106
 107 <dynamic-variable name="nonstrokingalpha">
 108         <type><union-type><named-type name="Alpha" /> <named-type name="Void" /></union-type></type>
 109         <default><inline>[shape 1]</inline></default>
 110         <description>
 111                 <p>Alpha settings for nonstroking operations.</p>
 112         </description>
 113         <see-also>
 114                 <value name="alphashape" /> <value name="alphaopacity" /> <dynamic name="nonstroking" />
 115         </see-also>
 116 </dynamic-variable>
 117
 118 <dynamic-variable name="blend">
 119         <type><union-type><named-type name="BlendMode" /> <named-type name="Void" /></union-type></type>
 120         <default><value name="BLEND_NORMAL" /></default>
 121         <description>
 122                 <p>Blend mode.</p>
 123         </description>
 124 </dynamic-variable>
 125
 126 <dynamic-variable name="blendspace">
 127         <type><named-type name="ColorSpace" /></type>
 128         <default><em>(inherited)</em></default>
 129         <description>
 130                 <p>Color space for blending.</p>
 131         </description>
 132 </dynamic-variable>
 133
 134 <dynamic-variable name="spot">
 135         <type><named-type name="Drawable" /></type>
 136         <default><inline>dynamic [spot (0m,0m)]</inline></default>
 137         <constraint><em>Cannot be changed!</em></constraint>
 138         <description>
 139                 <p>A function call with fixed arguments (or no arguments at all) is like a dynamic variable, and then a dynamic variable is generally preferred over the function call since using a dynamic variable emphasizes the dynamic nature of the expression.  Since the need for a spot at the origin (which can then be transformed to any desired position) is so frequent, this dynamic variable is simply an alternative to calling <value name="spot" /> with the origin as argument.</p>
 140                 <p>The value of this dynamic variable will depend on other dynamic variables, compare <value name="spot" />.</p>
 141         </description>
 142 </dynamic-variable>
 143
 144 </section>