#ifndef hexpaint_H
#define hexpaint_H

/* Routines to paint figures on a hexagonal grid. */
/* Last edited on 2005-02-04 07:11:15 by stolfi */

#include <i2.h>
#include <r2.h>
#include <interval.h>
#include <cpkbasic.h>
#include <pswr.h>
#include <stdio.h>
#include <stdlib.h>

typedef struct hxp_color_t { float R, G, B; } hxp_color_t;

typedef unsigned char hxp_pixel_t;

typedef struct hxp_canvas_t 
  { hxp_pixel_t *pix; /* The pixels. */
    r2_t org;         /* Position of lower left grid point. */
    r2_t step;        /* Grid steps. */
    i2_t size;          /* Number of grid points along each axis. */    
  } hxp_canvas_t;
  /* A {hxp_canvas_t} is  an array of byte "pixels", 
    associated with points of an hexagonal grid. 
    The bottom left point of the grid is {org}; points are spaced 
    {step[0]} along each horizontal row, and each
    row is spaced {step[1]} vertically from the previous
    one. Both steps are positive. Odd rows are displaced 
    by {0.5*step[0]} in the positive direction. Each row has
    {size[0]} points, and there are {size[1]} rows. */
    
hxp_canvas_t hxp_canvas_new(r2_t org, r2_t step, i2_t size, hxp_pixel_t v);
  /* Allocates a new canvas with the specified parameters,
    fills it with value {v}. */

r2_t hxp_pixel_pos(hxp_canvas_t *s, i2_t p);
  /* Returns the nominal coordinates of the point number {p.c[0]} on
    row {p.c[1]} of the grid of canvas {s}. */

void hxp_paint_polygon
  ( r2_vec_t p,      /* Vertices of polygon, ccw around interior. */
    hxp_canvas_t *s, /* Where to paint. */
    hxp_pixel_t val  /* Value to paint. */
  );
  /* Assigns {val} to all canvas pixels that lie inside the 
    polygon {p}. */
  
void hxp_paint_circle
  ( r2_t ctr,        /* Center of circle. */
    double rad,      /* Radius of circle. */
    hxp_canvas_t *s, /* Where to paint. */
    hxp_pixel_t val  /* Value to paint. */
  );
  /* Assigns {val} to all canvas pixels that lie inside the 
  circle with center {ctr} and radius {rad}. */
  
void hxp_paint_stroke
  ( r2_t a,          /* Beginning of stroke axis. */
    r2_t b,          /* End of stroke axis. */
    double r,        /* Half-width of stroke. */
    hxp_canvas_t *s, /* Where to paint. */
    hxp_pixel_t val  /* Value to paint. */
  );
  /* Assigns {val} to all canvas pixels that lie inside the 
    rectangle whose axis is the segment {a,b} and whose
    extent perpendicular to that axis is {r} in 
    each direction. */

i2_vec_t hxp_list_pixels (hxp_canvas_t *s, hxp_pixel_t v);
  /* Returns a list of the indices of all pixels 
    in {s} that have value equal to {v}. */

void hxp_plot_canvas
  ( PSStream *ps,     /* Where to plot. */
    hxp_canvas_t *s,  /* The canvas to plot. */
    double rad(hxp_pixel_t v)  /* Radius function. */
  );
  /* Plots the pixels of the canvas {s} the Postscript file {f}. A
    pixel with value {v} is plotted as a circle with radius {rad(v)}.
    If the X and Y ranges in {o} are not empty, clips the map to those
    ranges. */

#endif