Geografic-Information-System/lib/ogsf/gsd_label.c

/*!
   \file lib/ogsf/gsd_label.c

   \brief OGSF library - label management (lower level functions)

   GRASS OpenGL gsurf OGSF Library 

   (C) 1999-2008 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 Bill Brown USACERL (1991-1992)
   \author Doxygenized by Martin Landa <landa.martin gmail.com> (May 2008)
 */

#include <grass/gis.h>
#include <grass/glocale.h>
#include <grass/ogsf.h>

#include "rgbpack.h"

#define MAX_LIST 20

static int first = 0;
GLuint label_base;
GLuint label_id;

/*!
   \brief Put label

   \todo Allocate label dynamicaly

   \param fontbase fontbase settings
   \param size font size
   \param color font color
   \param pt 
 */
void gs_put_label(const char *text, GLuint fontbase, int size,
		  unsigned long color, int *pt)
{
    int txt_width;
    GLint tmp[4];
    float labpt[2];
    int t, l, b, r;

    if (!first) {
	/* initialize display list */
	label_base = glGenLists(MAX_LIST);
	glListBase(label_base);
	label_id = label_base;
	first = 1;
    }

    if (label_id > (label_base + MAX_LIST)) {
	G_warning(_("Max. number of labels reached!"));
	return;
    }

    glNewList(label_id, GL_COMPILE_AND_EXECUTE);
    txt_width = gsd_get_txtwidth(text, size);

    /* adjust to center text string */
    labpt[X] = (float)(pt[X] - txt_width / 2.);
    labpt[Y] = (float)pt[Y];

    glGetIntegerv(GL_VIEWPORT, tmp);
    l = tmp[0];
    r = tmp[0] + tmp[2];
    b = tmp[1];
    t = tmp[1] + tmp[3];

    gsd_bgn_legend_viewport(l, b, r, t);


    /* Set text color */
    gsd_color_func(color);

    do_label_display(fontbase, labpt, text);


    gsd_end_legend_viewport();

    glEndList();

    label_id++;

    return;
}


/*!
   \brief Remove current label 
 */
void gsd_remove_curr(void)
{
    if (label_id) {
	glDeleteLists(label_id - 1, 1);
	label_id--;
    }

    return;
}


/*!
   \brief Remove all labels from display list
 */
void gsd_remove_all(void)
{
    glDeleteLists(label_base, MAX_LIST);
    label_id = label_base;

    return;
}

/*!
   \brief Call display list and draw defined labels -- called from gsd_prim (gsd_call_lists)
 */
void gsd_call_label(void)
{
    int i;

    for (i = 0; i < MAX_LIST; i++) {
	glCallList(i + label_base);
	glFlush();
    }
    return;
}