/* The GIMP -- an image manipulation program
 * Copyright (C) 1995 Spencer Kimball and Peter Mattis
 *
 * gimp_brush_generated module Copyright 1998 Jay Cox <jaycox@earthlink.net>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
 */

#include "appenv.h"
#include "gimpbrushgenerated.h"
#include "gimpbrushlist.h"
#include "paint_core.h"
#include <math.h>

#define OVERSAMPLING 5

static GimpObjectClass* parent_class;

static void
gimp_brush_generated_destroy(GimpBrushGenerated *object)
{
  GTK_OBJECT_CLASS(parent_class)->destroy (object);
}

static void
gimp_brush_generated_class_init (GimpBrushGeneratedClass *klass)
{
  GtkObjectClass *object_class;
  
  object_class = GTK_OBJECT_CLASS(klass);

  parent_class = gtk_type_class (GIMP_TYPE_BRUSH);
  object_class->destroy =  gimp_brush_generated_destroy;
}


void
gimp_brush_generated_init(GimpBrushGenerated *brush)
{
  brush->radius        = 5.0;
  brush->hardness      = 0.0;
  brush->angle         = 0.0;
  brush->aspect_ratio  = 1.0;
}

guint gimp_brush_generated_get_type(void)
{
  static GtkType type;
  if(!type){
    GtkTypeInfo info={
      "GimpBrushGenerated",
      sizeof(GimpBrushGenerated),
      sizeof(GimpBrushGeneratedClass),
      (GtkClassInitFunc)gimp_brush_generated_class_init,
      (GtkObjectInitFunc)gimp_brush_generated_init,
      NULL,
      NULL };
    type=gtk_type_unique(GIMP_TYPE_BRUSH, &info);
  }
  return type;
}

GimpBrushGenerated *gimp_brush_generated_new(float radius, float hardness,
				    float angle, float aspect_ratio)
{
  GimpBrushGenerated *brush;

/* set up normal brush data */
  brush = GIMP_BRUSH_GENERATED(gimp_type_new(gimp_brush_generated_get_type ()));

  GIMP_BRUSH(brush)->name = g_strdup ("AAAGenerated");
  GIMP_BRUSH(brush)->spacing = 20;

/* set up gimp_brush_generated data */
  brush->radius = radius;
  brush->hardness = hardness;
  brush->angle = angle;
  brush->aspect_ratio = aspect_ratio;

 /* render brush mask */
  gimp_brush_generated_generate(brush);

/* add brush to brush list */
/* FIXME: Get rid of this */
  gimp_brush_list_add(brush_list, GIMP_BRUSH(brush));
  select_brush(GIMP_BRUSH(brush));

  return brush;
}

void
gimp_brush_generated_generate(GimpBrushGenerated *brush)
{
  register GimpBrush *gbrush = NULL;
  register int x, y;
  register guchar *centerp;
  register double d;
  register double exponent;
  register guchar a;
  register int length;
  register char *lookup;
  double buffer[OVERSAMPLING];
  register double sum, c, s, tx, ty;
  int width, height;
  if (!GIMP_IS_BRUSH_GENERATED(brush))
  {
    g_message("call to gimp_brush_generated_generate on non generated brush");
    return;
  }
  gbrush = GIMP_BRUSH(brush);
  if (gbrush->mask)
  {
    temp_buf_free(gbrush->mask);
  }
#define D_TO_R M_PI/180
  /* compute the range of the brush, should do a better job than this */
  s = sin(brush->angle*M_PI/180);
  c = cos(brush->angle*M_PI/180);
  tx = MAXIMUM(fabs(c*ceil(brush->radius) - s*ceil(brush->radius)
		    /brush->aspect_ratio), 
	       fabs(c*ceil(brush->radius) + s*ceil(brush->radius)
		    /brush->aspect_ratio));
  ty = MAXIMUM(fabs(s*ceil(brush->radius) + c*ceil(brush->radius)
		    /brush->aspect_ratio),
	       fabs(s*ceil(brush->radius) - c*ceil(brush->radius)
		    /brush->aspect_ratio));
  if (brush->radius > tx)
    width = ceil(tx);
  else
    width = ceil(brush->radius+1);
  if (brush->radius > ty)
    height = ceil(ty);
  else
    height = ceil(brush->radius);

  gbrush->mask = temp_buf_new(width*2 + 1,
			     height*2 + 1,
			     1, width, height, 0);
  centerp = &gbrush->mask->data[height*gbrush->mask->width + width];
  if ((1.0 - brush->hardness) < 0.000001)
    exponent = 1000000; 
  else
    exponent = 1/(1.0 - brush->hardness);
/* set up lookup table */
  length = ceil(sqrt(2*ceil(brush->radius+1)*ceil(brush->radius+1))+1) * OVERSAMPLING;
  lookup = g_malloc(length);
  sum = 0.0;
  for (x = 0; x < OVERSAMPLING; x++)
  {
    d = fabs((x+.5)/OVERSAMPLING - .5);
    if (d > brush->radius)
      buffer[x] = 0.0;
    else
      buffer[x] =  (1.0 - pow(d/brush->radius, exponent));
    sum += buffer[x];
  }
  for (x = 0; d < brush->radius || sum > .00001; d += 1.0/OVERSAMPLING)
  {
    sum -= buffer[x%OVERSAMPLING];
    if (d > brush->radius)
      buffer[x%OVERSAMPLING] = 0.0;
    else
      buffer[x%OVERSAMPLING] =  (1.0 - pow(d/brush->radius, exponent));
    sum += buffer[x%OVERSAMPLING];
    lookup[x++] =  rint(sum*(255.0/OVERSAMPLING));
  }
  while (x < length)
  {
    lookup[x++] = 0;
  }
 /* compute one half and mirror it */
  for (y = 0; y <= height; y++)
  {
    for (x = -width; x <= width; x++)
    {
      tx = c*x - s*y;
      ty = c*y + s*x;
      ty *= brush->aspect_ratio;
      d = sqrt(tx*tx + ty*ty);
      if (d < brush->radius+1)
	a = lookup[(int)rint(d*OVERSAMPLING)];
      else
	a = 0;
      centerp[   y*gbrush->mask->width + x] = a;
      centerp[-1*y*gbrush->mask->width - x] = a;
/*      centerp[-1*y*brush->mask->width + x] = a;
      centerp[-1*y*brush->mask->width - x] = a;
      centerp[   x*brush->mask->width + y] = a;
      centerp[   x*brush->mask->width - y] = a;
      centerp[-1*x*brush->mask->width + y] = a;
      centerp[-1*x*brush->mask->width - y] = a;*/
    }
  }
  g_free (lookup);
/*  gtk_signal_emit_by_name(brush, "dirty"); */
  brush_changed_notify(GIMP_BRUSH(brush));
}

float
gimp_brush_generated_set_radius (GimpBrushGenerated* brush, float radius)
{
  g_return_val_if_fail (GIMP_IS_BRUSH_GENERATED(brush), -1.0);
  if (radius < 0.0)
    radius = 0.0;
  else if(radius > 32767.0)
    radius = 32767.0;
  brush->radius = radius;
  return brush->radius;
}

float
gimp_brush_generated_set_hardness (GimpBrushGenerated* brush, float hardness)
{
  g_return_val_if_fail (GIMP_IS_BRUSH_GENERATED(brush), -1.0);
  if (hardness < 0.0)
    hardness = 0.0;
  else if(hardness > 1.0)
    hardness = 1.0;
  brush->hardness = hardness;
  return brush->hardness;
}

float
gimp_brush_generated_set_angle (GimpBrushGenerated* brush, float angle)
{
  g_return_val_if_fail (GIMP_IS_BRUSH_GENERATED(brush), -1.0);
  if (angle < 0.0)
    angle = -1.0 * fmod(angle, 180.0);
  else if(angle > 180.0)
    angle = fmod(angle, 180.0);
  brush->angle = angle;
  return brush->angle;
}

float
gimp_brush_generated_set_aspect_ratio (GimpBrushGenerated* brush, float ratio)
{
  g_return_val_if_fail (GIMP_IS_BRUSH_GENERATED(brush), -1.0);
  if (ratio < 1.0)
    ratio = 1.0;
  else if(ratio > 1000)
    ratio = 1000;
  brush->aspect_ratio = ratio;
  return brush->aspect_ratio;
}

float 
gimp_brush_generated_get_radius (GimpBrushGenerated* brush)
{
  g_return_val_if_fail (GIMP_IS_BRUSH_GENERATED(brush), -1.0);
  return brush->radius;
}

float
gimp_brush_generated_get_hardness (GimpBrushGenerated* brush)
{
  g_return_val_if_fail (GIMP_IS_BRUSH_GENERATED(brush), -1.0);
  return brush->hardness;
}

float
gimp_brush_generated_get_angle (GimpBrushGenerated* brush)
{
  g_return_val_if_fail (GIMP_IS_BRUSH_GENERATED(brush), -1.0);
  return brush->angle;
}

float
gimp_brush_generated_get_aspect_ratio (GimpBrushGenerated* brush)
{
  g_return_val_if_fail (GIMP_IS_BRUSH_GENERATED(brush), -1.0);
  return brush->aspect_ratio;
}