GRASS GIS 7 Programmer's Manual  7.5.svn(2017)-r71785
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plot.c File Reference

GIS Library - Plotting functions. More...

#include <stdlib.h>
#include <math.h>
#include <grass/gis.h>
Include dependency graph for plot.c:

Go to the source code of this file.

Macros

#define POINT   struct point
 
#define OK   0
 
#define TOO_FEW_EDGES   2
 
#define NO_MEMORY   1
 
#define OUT_OF_SYNC   -1
 
#define X(e)   (st->left + st->xconv * ((e) - st->window.west))
 
#define Y(n)   (st->top + st->yconv * (st->window.north - (n)))
 
#define EAST(x)   (st->window.west + ((x)-st->left)/st->xconv)
 
#define NORTH(y)   (st->window.north - ((y)-st->top)/st->yconv)
 

Functions

void G_setup_plot (double t, double b, double l, double r, int(*Move)(int, int), int(*Cont)(int, int))
 Initialize plotting routines. More...
 
void G_setup_fill (int gap)
 Set row_fill routine to row_solid_fill or row_dotted_fill. More...
 
void G_plot_where_xy (double east, double north, int *x, int *y)
 Converts east,north to x,y. More...
 
void G_plot_where_en (int x, int y, double *east, double *north)
 Converts x,y to east,north. More...
 
void G_plot_point (double east, double north)
 Plot point. More...
 
void G_plot_line (double east1, double north1, double east2, double north2)
 Plot line between latlon coordinates (fastline) More...
 
void G_plot_line2 (double east1, double north1, double east2, double north2)
 Plot line between latlon coordinates (slowline) More...
 
int G_plot_polygon (const double *x, const double *y, int n)
 Plot filled polygon with n vertices. More...
 
int G_plot_area (double *const *xs, double *const *ys, int *rpnts, int rings)
 Plot multiple polygons. More...
 
void G_plot_fx (double(*f)(double), double east1, double east2)
 Plot f(east1) to f(east2) More...
 

Detailed Description

GIS Library - Plotting functions.

Plot lines and filled polygons. Input space is current window. Output space and output functions are user defined. Converts input east,north lines and polygons to output x,y and calls user supplied line drawing routines to do the plotting.

Handles global wrap-around for lat-lon locations.

Does not perform window clipping. Clipping must be done by the line draw routines supplied by the user.

Note: Hopefully, cartographic style projection plotting will be added later.

(C) 2001-2008, 2013 by the GRASS Development Team

This program is free software under the GNU General Public License (>=v2). Read the file COPYING that comes with GRASS for details.

Author
Original author CERL

Definition in file plot.c.

Macro Definition Documentation

#define EAST (   x)    (st->window.west + ((x)-st->left)/st->xconv)

Definition at line 143 of file plot.c.

Referenced by G_plot_where_en().

#define NO_MEMORY   1

Definition at line 70 of file plot.c.

Referenced by G_plot_area(), and G_plot_polygon().

#define NORTH (   y)    (st->window.north - ((y)-st->top)/st->yconv)

Definition at line 144 of file plot.c.

Referenced by G_plot_where_en().

#define OK   0

Definition at line 68 of file plot.c.

Referenced by G_plot_area(), and G_plot_polygon().

#define OUT_OF_SYNC   -1

Definition at line 71 of file plot.c.

Referenced by G_plot_area(), and G_plot_polygon().

#define POINT   struct point

Definition at line 48 of file plot.c.

Referenced by G_plot_area(), and G_plot_polygon().

#define TOO_FEW_EDGES   2

Definition at line 69 of file plot.c.

Referenced by G_plot_area(), and G_plot_polygon().

#define X (   e)    (st->left + st->xconv * ((e) - st->window.west))

Definition at line 140 of file plot.c.

Referenced by G_plot_area(), G_plot_polygon(), and G_plot_where_xy().

#define Y (   n)    (st->top + st->yconv * (st->window.north - (n)))

Definition at line 141 of file plot.c.

Referenced by G_plot_area(), G_plot_polygon(), and G_plot_where_xy().

Function Documentation

int G_plot_area ( double *const *  xs,
double *const *  ys,
int rpnts,
int  rings 
)

Plot multiple polygons.

Like G_plot_polygon(), except it takes a set of polygons, each with npts[i] vertices, where the number of polygons is specified with the rings argument. It is especially useful for plotting vector areas with interior islands.

Parameters
xspointer to pointer for X's
yspointer to pointer for Y's
rpntsarray of ints w/ num points per ring
ringsnumber of rings
Returns
0 on success
2 n < 3
-1 weird internal error
1 no memory

Definition at line 502 of file plot.c.

References edge_order(), G_free(), G_warning(), NO_MEMORY, NULL, OK, OUT_OF_SYNC, POINT, PROJECTION_LL, TOO_FEW_EDGES, W, x, X, and Y.

void G_plot_fx ( double(*)(double)  f,
double  east1,
double  east2 
)

Plot f(east1) to f(east2)

The function f(east) is plotted from east1 to east2. The function f(east) must return the map northing coordinate associated with east.

Parameters
fplotting function
east1easting (first point)
east2easting (second point)

Definition at line 779 of file plot.c.

References G_plot_line().

void G_plot_line ( double  east1,
double  north1,
double  east2,
double  north2 
)

Plot line between latlon coordinates (fastline)

A line from east1,north1 to east2,north2 is plotted in output x,y coordinates (e.g. pixels for graphics.) This routine handles global wrap-around for latitude-longitude databases.

Parameters
east1,north1first point (start line node)
east2,north2second point (end line node)

Definition at line 207 of file plot.c.

Referenced by G_plot_fx().

void G_plot_line2 ( double  east1,
double  north1,
double  east2,
double  north2 
)

Plot line between latlon coordinates (slowline)

A line from east1,north1 to east2,north2 is plotted in output x,y coordinates (e.g. pixels for graphics.) This routine handles global wrap-around for latitude-longitude databases.

Parameters
east1,north1first point (start line node)
east2,north2second point (end line node)

Definition at line 222 of file plot.c.

void G_plot_point ( double  east,
double  north 
)

Plot point.

Parameters
easteasting
northnorthing

Definition at line 188 of file plot.c.

References G_plot_where_xy(), and x.

int G_plot_polygon ( const double *  x,
const double *  y,
int  n 
)

Plot filled polygon with n vertices.

The polygon, described by the n vertices east,north, is plotted in the output x,y space as a filled polygon.

Parameters
xcoordinates of vertices
ycoordinates of vertices
nnumber of vertices
Returns
0 on success
2 n < 3
-1 weird internal error
1 no memory

Definition at line 373 of file plot.c.

References edge_order(), G_warning(), NO_MEMORY, OK, OUT_OF_SYNC, POINT, PROJECTION_LL, TOO_FEW_EDGES, W, X, and Y.

void G_plot_where_en ( int  x,
int  y,
double *  east,
double *  north 
)

Converts x,y to east,north.

The pixel coordinates x,y are converted to map coordinates east,north.

Parameters
xx coordinate
yy coordinate
easteasting
northnorthing

Definition at line 176 of file plot.c.

References EAST, G_adjust_easting(), and NORTH.

void G_plot_where_xy ( double  east,
double  north,
int x,
int y 
)

Converts east,north to x,y.

The map coordinates east,north are converted to pixel coordinates x,y.

Parameters
easteasting
northnothing
xx coordinate
yy coordinate

Definition at line 158 of file plot.c.

References G_adjust_easting(), X, and Y.

Referenced by G_plot_point().

void G_setup_fill ( int  gap)

Set row_fill routine to row_solid_fill or row_dotted_fill.

After calling this function, G_plot_polygon() and G_plot_area() fill shapes with solid or dotted lines. If gap is greater than zero, this value will be used for row_dotted_fill. Otherwise, row_solid_fill is used.

Parameters
gap

Definition at line 130 of file plot.c.

void G_setup_plot ( double  t,
double  b,
double  l,
double  r,
int(*)(int, int Move,
int(*)(int, int Cont 
)

Initialize plotting routines.

Initializes the plotting capability. This routine must be called once before calling the G_plot_*() routines described below. The parameters t, b, l, r are the top, bottom, left, and right of the output x,y coordinate space. They are not integers, but doubles to allow for subpixel registration of the input and output coordinate spaces. The input coordinate space is assumed to be the current GRASS region, and the routines supports both planimetric and latitude-longitude coordinate systems.

Move and Cont are subroutines that will draw lines in x,y space. They will be called as follows:

  • Move(x, y) move to x,y (no draw)
  • Cont(x, y) draw from previous position to x,y. Cont(~) is responsible for clipping
Parameters
t,b,l,rtop, bottom, left, right
moveMove function
ContCont function

Definition at line 94 of file plot.c.

References b, G_get_set_window(), l, r, and t.