doc/ctsim-appendix.tex

   1 \chapter{Appendix}\label{appendix}\index{Appendix}%
   2 \setheader{{\it CHAPTER \thechapter}}{}{}{}{}{{\it CHAPTER \thechapter}}%
   3 \setfooter{\thepage}{}{}{}{}{\thepage}%
   4
   5 \section{Simple Graphics Package}\index{Simple Graphics Package}%
   6
   7 \subsection{Overview}%
   8 Simple Graphics Package was created in 1980 by Kevin Rosenberg and
   9 is modelled after the graphics library in Foley and van
  10 Dam\cite{FOLEY82}.
  11
  12 \begin{verbatim}
  13                        +------------------------+
  14                        | World Coordinate level |
  15                        +-----------+------------+
  16                                    |
  17                      +-------------+-------------+
  18                      | Clipping against Window() |
  19                      +-------------+-------------+
  20                                    |
  21                       +------------+-------------+
  22                       | Convert to Normalized    |
  23                       | device coordinates (NDC) |
  24                       +------------+-------------+
  25                                    |
  26                      +-------------+-------------+
  27                      | Clipping against Viewport |
  28                      +-------------+-------------+
  29                                    |
  30                       +------------+-------------+
  31                       | Convert to Physical      |
  32                       | device coordinates (PDC) |
  33                       +--------------------------+
  34 \end{verbatim}
  35
  36 \subsection{Functions}%
  37
  38 \subsubsection{World Coordinate Level}
  39 \begin{twocollist}
  40 \twocolitem{initgrf2}{Initialize 2 dimensional graphics}
  41 \twocolitem{termgrf2}{Terminate 2 dimensional graphics}
  42 \twocolitem{setColor(color)}{Set current drawing color}
  43 \twocolitem{setLinestyle (style)}{Set current line style}
  44 \twocolitem{setLinewidth (width)}{Set current line width}
  45 \twocolitem{setTextColor (foreground, background)}{If back=-1,
  46 then transparent} \twocolitem{setMarker (type, color)}{Set marker
  47 attibutes}
  48 \end{twocollist}
  49
  50 \subsubsection{State Commands}
  51 \begin{twocollist}
  52 \twocolitem{Window(xmin, ymin, xmax, ymax)}{Set window for world
  53 coordinates} \twocolitem{MoveAbs(x, y)}{Move graphics cursor}
  54 \twocolitem{MoveRel(dx, dy)}{} \twocolitem{PointAbs (x, y)}{Plot
  55 point at current position} \twocolitem{PointRel (dx, dy)}{}
  56 \twocolitem{LineAbs2 (x, y)}{Draw line from current point to
  57 point} \twocolitem{LineRel2 (dx, dy)}{} \twocolitem{MarkerAbs2 (x,
  58 y)}{Draw marker at current position} \twocolitem{MarkerRel2 (dx,
  59 dy)}{} \twocolitem{PolylineAbs (x[], y[], n)}{Draw a set of lines}
  60 \twocolitem{PolylineRel (dx[], dy[], n)}{}
  61 \twocolitem{wc\_to\_ndc(xwc, ywc, xndc, yndc)}{Convert from world
  62 coord to NDC} \twocolitem{ndc\_to\_wc(xndc, yndc, xwc,
  63 ywc)}{Convert from NDC to world coord} \twocolitem{DrawText
  64 (str)}{Draw text string at current positon}
  65 \end{twocollist}
  66
  67
  68 \subsubsection{Normalized Coordinate level}%
  69 \begin{twocollist}
  70 \twocolitem{Viewport (xmin, ymin, xmax, ymax)}{Viewport for window
  71 in NDC} \twocolitem{stylus (x, y, beam)}{Draw a line from current
  72 position} \twocolitem{markerNDC(xndc, yndc)}{Draw marker at NDC
  73 position}
  74 \end{twocollist}
  75
  76
  77 \subsection{Coordinate Mapping}
  78
  79 \subsubsection{Mapping from world coordinates to physical device coordinates}%
  80
  81 Window (World Coordinates):  $X_{wmin}, X_{wmax}, Y_{wmin}, Y_{wmax}$ \\
  82 Viewport (Normalized Device Coordinates): $X_{vmin}, X_{vmax}, Y_{vmin}, Y_{vmax}$\\
  83 Physical (Physicial Device Coordinates): $X_{pmax}, Y_{pmax}$\\
  84
  85 To convert from WC to NDC:\\
  86 \begin{equation}
  87      X_{ndc} = X_{vmin} + (X_{vmax} - X_{vmin})  (X_{wc} - X_{wmin}) / (X_{wmax} - X_{wmin})
  88 \end{equation}
  89 \begin{equation}
  90      Y_{ndc} = Y_{vmin} + (Y_{vmax} - Y_{vmin}) (Y_{wc} - Y_{wmin}) / (Y_{wmax} - Y_{wmin})
  91 \end{equation}
  92
  93 To convert from NDC to PDC:
  94 \begin{equation}
  95      X_{pdc} = X_{ndc} X_{pmax}
  96 \end{equation}
  97 \begin{equation}
  98      Y_{pdc} = X_{ndc} Y_{pmax}
  99 \end{equation}