viewport.c

Intro/: Directory containing introductory examples. HelloWorld.c A simple program that draws a bo

#include <phigs.h>			/* get HP-PHIGS definitions for C */
#include <stdio.h>			/* get standard I/O definitions */
#define  FALSE			0	/* boolean false is integer 0 */
#define	 TRUE			1	/* boolean true is integer 1 */

main()					/* file "Viewport.c" */
{
    Pint	WorkstnID = 1;		/* workstation identifier */
    Pint	ConnID;			/* connection identifier */
    Pint	WorkstnType = POIDDX;	/* out/in, direct, dbl bfr, Xwindow */
    Pint	TheCurve = 1;		/* structure ID (chosen by user) */
    Ppoint	LinePts[100];		/* points for the polyline */
    Ppoint_list	LineData;		/* data for the polyline */
    FILE	*datafile;		/* file pointer */
    int		I = 0;			/* loop control variable */

    /*=== read data file into the structure array ==========================*/
    datafile = fopen("data", "r");	/* open data file (2 numbers/line) */
    while (fscanf(datafile, "%f%f", &LinePts[I].x, &LinePts[I].y) != EOF)
	I++;
    fclose(datafile);
    LineData.num_points = I;
    LineData.points = LinePts;
    /*=== set up HP-PHIGS to plot data =====================================*/
    popen_phigs((char *) stderr, 0);	/* errors go to "stderr" */
    pescape_u4("/dev/screen/phigs_window", &ConnID);
    popen_ws(WorkstnID, (void *) ConnID, WorkstnType);
    DefineView(WorkstnID, 1,		/* mapping for view index 1: */
      0.0,  1.0,  0.0,  1.0,		/*   window: 0-1, 0-1 */
      0.12, 0.98, 0.10, 0.88,		/*   viewport: in a subset */
      FALSE);				/*   don't clip at view window */
    popen_struct(TheCurve);
    pset_view_ind(1);
    DefineRectangle(0.0, 1.0, 0.0, 1.0);
    ppolyline(&LineData);
    pclose_struct();
    /*=== post the image and close up shop =================================*/
    ppost_struct(WorkstnID, TheCurve, 1.0);
    pupd_ws(WorkstnID, PFLAG_PERFORM);	/* (regeneration flag) */
    pclose_ws(WorkstnID);
    pclose_phigs();
}
/****************************************************************************/
DefineView(WorkstnID, ViewIndex, Wxmin, Wxmax, Wymin, Wymax,
  Vxmin, Vxmax, Vymin, Vymax, ClipAtWindow)
int	WorkstnID;			/* workstation identifier */
int	ViewIndex;			/* the view being defined */
float	Wxmin, Wxmax, Wymin, Wymax;	/* view window limits */
float	Vxmin, Vxmax, Vymin, Vymax;	/* projection viewport limits */
int	ClipAtWindow;			/* window (or display surface?) */
{
    Pview_map	Mapping;		/* window-onto-viewport mapping */
    Pint	ErrorReturn;		/* error return variable */
    Pview_rep	ViewRep;		/* complete description of view */
    int		I, J;			/* loop control variables */

    /*--- define the view orientation matrix as identity -------------------*/
    for (I = 0; I < 3; I++)
	for (J = 0; J < 3; J++)
	    ViewRep.ori_matrix[I][J] = (I == J);
    /*--- define view mapping matrix ---------------------------------------*/
    Mapping.win.x_min = Wxmin;			/* \			    */
    Mapping.win.x_max = Wxmax;			/*  \ put individual values */
    Mapping.win.y_min = Wymin;			/*  / into the structure    */
    Mapping.win.y_max = Wymax;			/* /			    */
    Mapping.proj_vp.x_min = Vxmin;		/* \			    */
    Mapping.proj_vp.x_max = Vxmax;		/*  \ put individual values */
    Mapping.proj_vp.y_min = Vymin;		/*  / into the structure    */
    Mapping.proj_vp.y_max = Vymax;		/* /			    */
    peval_view_map_matrix(&Mapping, &ErrorReturn, ViewRep.map_matrix);
    if (ErrorReturn != 0) {			/* did we get an error? */
        printf("%s %d %s %s\n", "Error", ErrorReturn, "occurred during",
          "call to Evaluate View Mapping Matrix.");
        exit(1);
    }
    /*--- define the clip limits -------------------------------------------*/
    if (ClipAtWindow)
	ViewRep.clip_limit = Mapping.proj_vp;	/* clip at viewport */
    else {
	ViewRep.clip_limit.x_min = 0.0;		/* \		       */
	ViewRep.clip_limit.x_max = 1.0;		/*  \ clip at edges of */
	ViewRep.clip_limit.y_min = 0.0;		/*  / display surface  */
	ViewRep.clip_limit.y_max = 1.0;		/* /		       */
    }
    /*--- define clip indicator --------------------------------------------*/
    ViewRep.xy_clip = PIND_CLIP;
    /*--- set the view representation --------------------------------------*/
    pset_view_rep(WorkstnID, ViewIndex, &ViewRep);
}
/****************************************************************************/
DefineRectangle(Xmin, Xmax, Ymin, Ymax)
float	Xmin, Xmax, Ymin, Ymax;			/* rectangle's limits */
{
    Ppoint_list	Rectangle;
    Ppoint	Corners[5];
      
    Rectangle.num_points = 5;
    Corners[0].x = Xmin, Corners[0].y = Ymin;	/* lower left corner */
    Corners[1].x = Xmax, Corners[1].y = Ymin;	/* lower right corner */
    Corners[2].x = Xmax, Corners[2].y = Ymax;	/* upper right corner */
    Corners[3].x = Xmin, Corners[3].y = Ymax;	/* upper left corner */
    Corners[4].x = Xmin, Corners[4].y = Ymin;	/* lower left corner */
    Rectangle.points = Corners;
    ppolyline(&Rectangle);
}