1 | <!-- ******************************************************** --> |
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2 | <!-- --> |
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3 | <!-- [History] --> |
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4 | <!-- Converted to DocBook: Katsuya Amako, Aug-2006 --> |
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5 | <!-- --> |
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6 | <!-- ******************************************************** --> |
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7 | |
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8 | |
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9 | <!-- ******************* Section (Level#1) ****************** --> |
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10 | <sect1 id="sect.VisPlylMrkTxt"> |
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11 | <title> |
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12 | Polylines, Markers and Text |
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13 | </title> |
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14 | |
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15 | <para> |
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16 | Polylines, markers and text are defined in the |
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17 | <literal>graphics_reps</literal> category, and are used only for |
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18 | visualization. Here we explain their definitions and usages. |
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19 | </para> |
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20 | |
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21 | |
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22 | <!-- ******************* Section (Level#2) ****************** --> |
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23 | <sect2 id="sect.VisPlylMrkTxt.Plyl"> |
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24 | <title> |
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25 | Polylines |
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26 | </title> |
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27 | |
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28 | <para> |
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29 | A polyline is a set of successive line segments. It is defined with |
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30 | a class <emphasis>G4Polyline</emphasis> defined in the |
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31 | <literal>graphics_reps</literal> category. |
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32 | A polyline is used to visualize tracking steps, particle |
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33 | trajectories, coordinate axes, and any other user-defined objects |
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34 | made of line segments. |
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35 | </para> |
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36 | |
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37 | <para> |
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38 | <emphasis>G4Polyline</emphasis> is defined as a list of |
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39 | <emphasis>G4Point3D</emphasis> objects, i.e., vertex positions. |
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40 | The vertex positions are set to a <emphasis>G4Polyline</emphasis> |
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41 | object with the <literal>push_back()</literal> method. |
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42 | </para> |
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43 | |
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44 | <para> |
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45 | For example, an x-axis with length 5 cm and with red color is |
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46 | defined in <xref linkend="programlist_VisPlylMrkTxt_1" />. |
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47 | |
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48 | <example id="programlist_VisPlylMrkTxt_1"> |
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49 | <title> |
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50 | Defining an x-axis with length 5 cm and with colour red. |
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51 | </title> |
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52 | |
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53 | <programlisting> |
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54 | //----- C++ source codes: An example of defining a line segment |
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55 | // Instantiate an emply polyline object |
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56 | G4Polyline x_axis; |
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57 | |
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58 | // Set red line colour |
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59 | G4Colour red(1.0, 0.0, 0.0); |
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60 | G4VisAttributes att(red); |
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61 | x_axis.SetVisAttributes(&att); |
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62 | |
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63 | // Set vertex positions |
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64 | x_axis.push_back( G4Point3D(0., 0., 0.) ); |
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65 | x_axis.push_back( G4Point3D(5.*cm, 0., 0.) ); |
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66 | |
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67 | //----- end of C++ source codes |
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68 | </programlisting> |
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69 | </example> |
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70 | </para> |
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71 | |
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72 | </sect2> |
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73 | |
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74 | |
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75 | <!-- ******************* Section (Level#2) ****************** --> |
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76 | <sect2 id="sect.VisPlylMrkTxt.Mrk"> |
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77 | <title> |
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78 | Markers |
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79 | </title> |
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80 | |
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81 | <para> |
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82 | Here we explain how to use 3D markers in Geant4 Visualization. |
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83 | </para> |
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84 | |
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85 | <!-- ******* Bridgehead ******* --> |
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86 | <bridgehead renderas='sect4'> |
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87 | What are Markers? |
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88 | </bridgehead> |
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89 | |
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90 | <para> |
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91 | Markers set marks at arbitrary positions in the 3D space. They |
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92 | are often used to visualize hits of particles at detector |
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93 | components. A marker is a 2-dimensional primitive with shape |
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94 | (square, circle, etc), color, and special properties (a) of always |
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95 | facing the camera and (b) of having the possibility of a size |
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96 | defined in screen units (pixels). Here "size" means "overall size", |
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97 | e.g., diameter of circle and side of square (but diameter and |
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98 | radius access functions are defined to avoid ambiguity). |
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99 | </para> |
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100 | |
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101 | <para> |
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102 | So the user who constructs a marker should decide whether or not |
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103 | it should be visualized to a given size in world coordinates by |
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104 | setting the world size. Alternatively, the user can set the screen |
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105 | size and the marker is visualized to its screen size. Finally, the |
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106 | user may decide not to set any size; in that case, it is drawn |
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107 | according to the sizes specified in the default marker specified in |
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108 | the class <emphasis>G4ViewParameters</emphasis>. |
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109 | </para> |
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110 | |
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111 | <para> |
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112 | By default, "square" and "circle" are supported in Geant4 |
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113 | Visualization. The former is described with class <emphasis>G4Square</emphasis>, |
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114 | and the latter with class <emphasis>G4Circle</emphasis>: |
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115 | |
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116 | <informaltable> |
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117 | <tgroup cols="2"> |
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118 | <tbody> |
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119 | <row> |
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120 | <entry> |
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121 | <emphasis role="bold">Marker Type</emphasis> |
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122 | </entry> |
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123 | <entry> |
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124 | <emphasis role="bold">Class Name</emphasis> |
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125 | </entry> |
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126 | </row> |
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127 | <row> |
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128 | <entry> |
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129 | circle |
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130 | </entry> |
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131 | <entry> |
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132 | <emphasis>G4Circle</emphasis> |
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133 | </entry> |
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134 | </row> |
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135 | <row> |
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136 | <entry> |
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137 | right square |
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138 | </entry> |
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139 | <entry> |
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140 | <emphasis>G4Square</emphasis> |
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141 | </entry> |
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142 | </row> |
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143 | </tbody> |
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144 | </tgroup> |
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145 | </informaltable> |
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146 | </para> |
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147 | |
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148 | <para> |
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149 | These classes are inherited from class <emphasis>G4VMarker</emphasis>. |
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150 | They have constructors as follows: |
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151 | |
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152 | <informalexample> |
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153 | <programlisting> |
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154 | //----- Constructors of G4Circle and G4Square |
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155 | G4Circle::G4Circle (const G4Point3D& pos ); |
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156 | G4Square::G4Square (const G4Point3D& pos); |
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157 | </programlisting> |
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158 | </informalexample> |
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159 | </para> |
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160 | |
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161 | <para> |
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162 | Access functions of class <emphasis>G4VMarker</emphasis> are summarized below. |
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163 | </para> |
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164 | |
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165 | <!-- ******* Bridgehead ******* --> |
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166 | <bridgehead renderas='sect4'> |
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167 | Access functions of markers |
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168 | </bridgehead> |
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169 | |
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170 | <para> |
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171 | <xref linkend="programlist_VisPlylMrkTxt_2" /> shows the access functions |
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172 | inherited from the base class <emphasis>G4VMarker</emphasis>. |
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173 | |
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174 | <example id="programlist_VisPlylMrkTxt_2"> |
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175 | <title> |
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176 | The access functions inherited from the base class |
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177 | <emphasis>G4VMarker</emphasis>. |
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178 | </title> |
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179 | |
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180 | <programlisting> |
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181 | //----- Set functions of G4VMarker |
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182 | void G4VMarker::SetPosition( const G4Point3D& ); |
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183 | void G4VMarker::SetWorldSize( G4double ); |
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184 | void G4VMarker::SetWorldDiameter( G4double ); |
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185 | void G4VMarker::SetWorldRadius( G4double ); |
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186 | void G4VMarker::SetScreenSize( G4double ); |
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187 | void G4VMarker::SetScreenDiameter( G4double ); |
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188 | void G4VMarker::SetScreenRadius( G4double ); |
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189 | void G4VMarker::SetFillStyle( FillStyle ); |
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190 | // Note: enum G4VMarker::FillStyle {noFill, hashed, filled}; |
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191 | |
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192 | //----- Get functions of G4VMarker |
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193 | G4Point3D G4VMarker::GetPosition () const; |
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194 | G4double G4VMarker::GetWorldSize () const; |
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195 | G4double G4VMarker::GetWorldDiameter () const; |
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196 | G4double G4VMarker::GetWorldRadius () const; |
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197 | G4double G4VMarker::GetScreenSize () const; |
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198 | G4double G4VMarker::GetScreenDiameter () const; |
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199 | G4double G4VMarker::GetScreenRadius () const; |
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200 | FillStyle G4VMarker::GetFillStyle () const; |
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201 | // Note: enum G4VMarker::FillStyle {noFill, hashed, filled}; |
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202 | </programlisting> |
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203 | </example> |
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204 | </para> |
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205 | |
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206 | <para> |
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207 | <xref linkend="programlist_VisPlylMrkTxt_3" /> shows sample C++ source |
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208 | code to define a very small red circle, i.e., a dot with diameter 1.0 pixel. |
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209 | Such a dot is often used to visualize a hit. |
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210 | |
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211 | <example id="programlist_VisPlylMrkTxt_3"> |
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212 | <title> |
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213 | Sample C++ source code to define a very small red circle. |
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214 | </title> |
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215 | |
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216 | <programlisting> |
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217 | //----- C++ source codes: An example of defining a red small maker |
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218 | G4Circle circle(position); // Instantiate a circle with its 3D |
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219 | // position. The argument "position" |
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220 | // is defined as G4Point3D instance |
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221 | circle.SetScreenDiameter (1.0); // Should be circle.SetScreenDiameter |
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222 | // (1.0 * pixels) - to be implemented |
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223 | circle.SetFillStyle (G4Circle::filled); // Make it a filled circle |
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224 | G4Colour colour(1.,0.,0.); // Define red color |
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225 | G4VisAttributes attribs(colour); // Define a red visualization attribute |
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226 | circle.SetVisAttributes(attribs); // Assign the red attribute to the circle |
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227 | //----- end of C++ source codes |
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228 | </programlisting> |
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229 | </example> |
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230 | </para> |
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231 | |
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232 | </sect2> |
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233 | |
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234 | |
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235 | <!-- ******************* Section (Level#2) ****************** --> |
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236 | <sect2 id="sect.VisPlylMrkTxt.Txt"> |
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237 | <title> |
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238 | Text |
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239 | </title> |
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240 | |
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241 | <para> |
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242 | Text, i.e., a character string, is used to visualize various kinds |
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243 | of description, particle name, energy, coordinate names etc. Text |
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244 | is described by the class <emphasis>G4Text</emphasis> . The following |
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245 | constructors are supported: |
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246 | |
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247 | <informalexample> |
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248 | <programlisting> |
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249 | //----- Constructors of G4Text |
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250 | G4Text (const G4String& text); |
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251 | G4Text (const G4String& text, const G4Point3D& pos); |
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252 | </programlisting> |
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253 | </informalexample> |
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254 | |
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255 | where the argument <literal>text</literal> is the text (string) to be |
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256 | visualized, and <literal>pos</literal> is the 3D position at which the text |
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257 | is visualized. |
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258 | </para> |
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259 | |
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260 | <para> |
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261 | Note that class <emphasis>G4Text</emphasis> also inherits <emphasis>G4VMarker</emphasis>. |
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262 | Size of text is recognized as "font size", i.e., height of the |
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263 | text. All the access functions defined for class <emphasis>G4VMarker</emphasis> |
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264 | mentioned above are available. In addition, the following access |
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265 | functions are available, too: |
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266 | |
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267 | <informalexample> |
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268 | <programlisting> |
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269 | //----- Set functions of G4Text |
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270 | void G4Text::SetText ( const G4String& text ) ; |
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271 | void G4Text::SetOffset ( double dx, double dy ) ; |
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272 | |
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273 | //----- Get functions of G4Text |
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274 | G4String G4Text::GetText () const; |
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275 | G4double G4Text::GetXOffset () const; |
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276 | G4double G4Text::GetYOffset () const; |
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277 | </programlisting> |
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278 | </informalexample> |
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279 | </para> |
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280 | |
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281 | <para> |
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282 | Method <literal>SetText()</literal> defines text to be visualized, and |
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283 | <literal>GetText()</literal> returns the defined text. Method |
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284 | <literal>SetOffset()</literal> defines x (horizontal) and y (vertical) |
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285 | offsets in the screen coordinates. By default, both offsets are |
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286 | zero, and the text starts from the 3D position given to the |
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287 | constructor or to the method <literal>G4VMarker:SetPosition()</literal>. |
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288 | Offsets should be given with the same units as the one adopted for |
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289 | the size, i.e., world-size or screen-size units. |
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290 | </para> |
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291 | |
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292 | <para> |
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293 | <xref linkend="programlist_VisPlylMrkTxt_4" /> shows sample C++ source code |
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294 | to define text with the following properties: |
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295 | |
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296 | <itemizedlist spacing="compact"> |
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297 | <listitem><para> |
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298 | Text: "Welcome to Geant4 Visualization" |
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299 | </para></listitem> |
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300 | <listitem><para> |
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301 | Position: (0.,0.,0.) in the world coordinates |
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302 | </para></listitem> |
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303 | <listitem><para> |
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304 | Horizontal offset: 10 pixels |
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305 | </para></listitem> |
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306 | <listitem><para> |
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307 | Vertical offset: -20 pixels |
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308 | </para></listitem> |
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309 | <listitem><para> |
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310 | Colour: blue (default) |
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311 | </para></listitem> |
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312 | </itemizedlist> |
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313 | </para> |
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314 | |
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315 | <para> |
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316 | <example id="programlist_VisPlylMrkTxt_4"> |
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317 | <title> |
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318 | An example of defining text. |
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319 | </title> |
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320 | |
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321 | <programlisting> |
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322 | //----- C++ source codes: An example of defining a visualizable text |
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323 | |
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324 | //----- Instantiation |
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325 | G4Text text ; |
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326 | text.SetText ( "Welcome to Geant4 Visualization"); |
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327 | text.SetPosition ( G4Point3D(0.,0.,0.) ); |
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328 | // These three lines are equivalent to: |
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329 | // G4Text text ( "Welcome to Geant4 Visualization", |
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330 | // G4Point3D(0.,0.,0.) ); |
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331 | |
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332 | //----- Size (font size in units of pixels) |
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333 | G4double fontsize = 24.; // Should be 24. * pixels - to be implemented. |
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334 | text.SetScreenSize ( fontsize ); |
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335 | |
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336 | //----- Offsets |
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337 | G4double x_offset = 10.; // Should be 10. * pixels - to be implemented. |
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338 | G4double y_offset = -20.; // Should be -20. * pixels - to be implemented. |
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339 | text.SetOffset( x_offset, y_offset ); |
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340 | |
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341 | //----- Color (Blue is the default setting, and so the codes below are omissible) |
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342 | G4Colour blue( 0., 0., 1. ); |
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343 | G4VisAttributes att ( blue ); |
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344 | text.SetVisAttributes ( att ); |
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345 | |
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346 | //----- end of C++ source codes |
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347 | </programlisting> |
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348 | </example> |
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349 | </para> |
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350 | |
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351 | |
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352 | </sect2> |
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353 | </sect1> |
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354 | |
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