Geografic-Information-System/display/d.barscale/draw_scale.c

/*
 * draw_scale places a scale in the upper left hand corner of a map image
 */

#include <stdio.h>
#include <string.h>
#include <grass/gis.h>
#include <grass/display.h>
#include "options.h"

#define NUMSCALES	16

/* declare variables */
static const struct scale
{
    char *name;
    double size;
    double limit;
    int seg;
} all_scales[2][NUMSCALES] = {
    {
	/* meters */
	{"", 0., 2., 10},
	{"1 meter", 1., 7., 10},
	{"5 meters", 5., 20., 5},
	{"10 meters", 10., 70., 10},
	{"50 meters", 50., 200., 5},
	{"100 meters", 100., 700., 10},
	{"500 meters", 500., 2000., 5},
	{"1 km", 1000., 7000., 10},
	{"5 km", 5000., 20000., 5},
	{"10 km", 10000., 70000., 10},
	{"50 km", 50000., 200000., 5},
	{"100 km", 100000., 700000., 10},
	{"500 km", 500000., 2000000., 5},
	{"1000 km", 1000000., 7000000., 10},
	{"5000 km", 5000000., 20000000., 5},
	{"10000 km", 10000000., 70000000., 10}
    },
    {/* feet/miles */
	{"", 0.000, 1., 10},
	{"1 foot", 0.305, 2., 10},
	{"5 feet", 1.524, 10., 5},
	{"10 feet", 3.048, 20., 10},
	{"50 feet", 15.240, 100., 5},
	{"100 feet", 30.480, 200., 10},
	{"500 feet", 152.400, 1000., 5},
	{"1000 feet", 304.800, 2000., 10},
	{"1 mile", 1609.344, 10000., 5},
	{"5 miles", 8046.720, 20000., 5},
	{"10 miles", 16093.440, 100000., 10},
	{"50 miles", 80467.200, 200000., 5},
	{"100 miles", 160934.400, 1000000., 10},
	{"500 miles", 804672.000, 2000000., 5},
	{"1000 miles", 1609344.000, 10000000., 10},
	{"5000 miles", 8046720.000, 20000000., 5},
    }
};

int draw_scale(int toptext, int size)
{
    double meters;
    double line_len;
    int incr;
    int x_pos, y_pos;
    double t, b, l, r;
    int pt, pb, pl, pr;
    int i;
    double xarr[5], yarr[5];
    double seg_len;
    const struct scale *scales = all_scales[use_feet];

    /* Establish text size */
    D_text_size(size, size);

    D_setup_unity(0);
    D_get_src(&t, &b, &l, &r);

    x_pos = (int)(east * (r - l) / 100.);
    y_pos = (int)((100. - north) * (b - t) / 100.);

    if (draw == 1) {
	int w, h;

	w = 30;
	h = 17 + 2 * w;

	pl = x_pos;
	pt = y_pos;
	pr = x_pos + w + 2;	/* 1 pixel margin for both sides */
	pb = y_pos + h + 2;	/* 1 pixel margin for both sides */

	if (do_background) {
	    D_use_color(color1);
	    D_box_abs(pl, pt, pr, pb);
	}
	/* Draw legend */
	D_use_color(color2);

	D_begin();

	D_move_abs(pl + w / 2 + 1, pt + 17 + 1);
	D_cont_rel(-0.5 * w,  2.0 * w);
	D_cont_rel( 0.5 * w, -0.5 * w);
	D_close();

	D_move_abs(pl + w / 2 + 1, pt + 17 + 1);
	D_cont_rel( 0.5 * w,  2.0 * w);
	D_cont_rel(-0.5 * w, -0.5 * w);
	D_close();

	D_end();
	D_stroke();

	/* actual text width is 81% of size? from d.legend */
	D_pos_abs(pl + w / 2 - 7 * .81, pt + 14);
	D_text("N");

	return 0;
    }

    D_setup(0);

    meters = D_get_u_east() - D_get_u_west();
    meters *= G_database_units_to_meters_factor();

    /* find the right scale */
    for (incr = 0; incr < NUMSCALES; incr++) {
	if (meters <= scales[incr].limit)
	    break;
    }

    if (!incr)
	return (-1);

    line_len = D_get_u_to_d_xconv() * scales[incr].size
	/ G_database_units_to_meters_factor();
    seg_len = line_len / scales[incr].seg;
    /* work around round off */
    line_len = ((int)seg_len) * scales[incr].seg;

    D_setup_unity(0);

    /* Blank out area with background color */
    if (toptext) {
	pr = x_pos + 35 + (int)line_len;
	pt = y_pos - 15;
	if (pt < t)
	    pt = t;
    }
    else {
	pr = x_pos + 35 + (int)line_len + size * strlen(scales[incr].name);
	pt = y_pos + 0;
	if (pt < t)
	    pt = t;
    }
    pb = y_pos + 30;
    if (pb > b)
	pb = b;
    pl = x_pos + 0;
    if (pl < l)
	pl = l;
    pr = pr;
    if (pr > r)
	pr = r;

    if (do_background) {
	D_use_color(color1);
	D_box_abs(pl, pt, pr, pb);
    }

    /* Draw legend */
    D_use_color(color2);

    if (draw != 2) {
	D_begin();
	D_move_abs(x_pos + 5, y_pos + 20);
	D_cont_rel(0, -10);
	D_cont_rel(10, 10);
	D_cont_rel(0, -10);
	D_move_rel(-5, 14);
	D_cont_rel(0, -17);
	D_cont_rel(-2, -0);
	D_cont_rel(2, -2);
	D_cont_rel(2, 2);
	D_cont_rel(-2, -0);
	D_end();
	D_stroke();
    }

    if (draw == 2) {
	D_begin();
	D_move_abs(x_pos + 25 - draw * 10, y_pos + 17);
	/* actual width is line_len-1+1=line_len and height is 7+1=8 */
	D_cont_rel(line_len - 1, 0);
	D_cont_rel(0, -7);
	D_cont_rel(line_len * -1 + 1, 0);
	D_cont_rel(0, 7);
	D_end();
	D_stroke();

	D_pos_rel(0, 1 - 4);
	for (i = 1; i <= scales[incr].seg; i++) {
	    xarr[0] = 0;	    yarr[0] = 0;
	    xarr[1] = seg_len;	    yarr[1] = 0;
	    xarr[2] = 0;	    yarr[2] = (i % 2 ? -4 : 4);
	    xarr[3] = -seg_len;	    yarr[3] = 0;
	    xarr[4] = 0;	    yarr[4] = (i % 2 ? 4 : -4);
	    /* width is seg_len and height is 4 */
	    D_polygon_rel(xarr, yarr, 4);
	    D_pos_rel(seg_len, 0);
	}
    }
    else if (do_bar) {
	D_begin();
	D_move_abs(x_pos + 25, y_pos + 17);
	/* actual width is line_len-1+1=line_len and height is 4+1=5 */
	D_cont_rel((int)line_len - 1, 0);
	D_cont_rel(0, -4);
	D_cont_rel((int)(line_len * -1 + 1), 0);
	D_cont_rel(0, 4);
	D_end();
	D_stroke();

	D_pos_rel(0, 1);
	for (i = 1; i <= scales[incr].seg; i += 2) {
	    /* width is seg_len and height is 5 */
	    D_box_rel(seg_len, -5);
	    D_pos_rel(seg_len * 2, 0);
	}
    }
    else {			/* draw simple line scale */
	D_begin();
	D_move_abs(x_pos + 25, y_pos + 5);
	D_cont_abs(x_pos + 25, y_pos + 25);
	D_move_abs(x_pos + 25, y_pos + 15);
	D_cont_abs(x_pos + 25 + line_len, y_pos + 15);
	D_move_abs(x_pos + 25 + line_len, y_pos + 5);
	D_cont_abs(x_pos + 25 + line_len, y_pos + 25);
	D_end();
	D_stroke();
    }

    if (toptext) {
	D_pos_abs(x_pos + 25 - draw * 10 + line_len / 2.
		  - strlen(scales[incr].name) * size * 0.81 / 2,
		  y_pos);
	D_text(scales[incr].name);
    }
    else {
	D_pos_abs(x_pos + 35 - draw * 10 + line_len, y_pos + 20);
	D_text(scales[incr].name);
    }

    return (0);
}