/* LIBGIMP - The GIMP Library                                                   
 * Copyright (C) 1995-1997 Peter Mattis and Spencer Kimball                
 * Copyright (C) 1998 Andy Thomas                
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2 of the License, or (at your option) any later version.             
 *                                                                              
 * This library 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            
 * Library General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the
 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
 * Boston, MA 02111-1307, USA.
 */                                                                             
#include <stdio.h>
#include <string.h>

#include "gimp.h"
#include "gimpui.h"


/* Idea is to have a function to call that returns a widget that 
 * completely controls the selection of a gradient.
 * you get a widget returned that you can use in a table say.
 * In:- Initial gradient name. Null means use current selection.
 *      pointer to func to call when gradient changes (GRunGradientCallback).
 * Returned:- Pointer to a widget that you can use in UI.
 * 
 * Widget simply made up of a preview widget (20x40) containing the gradient
 * which can be clicked on to changed the gradient selection.
 */


#define GSEL_DATA_KEY "__gsel_data"
#define CELL_SIZE_HEIGHT 18
#define CELL_SIZE_WIDTH 84

#define GRAD_CHECK_SIZE_SM 4

#define GRAD_CHECK_DARK  (1.0 / 3.0)
#define GRAD_CHECK_LIGHT (2.0 / 3.0)


struct __gradients_sel {
  gchar * dname;
  GRunGradientCallback cback;
  GtkWidget *gradient_preview;
  GtkWidget *button;
  GtkWidget *gradient_popup_pnt;
  gint width;
  gchar *gradient_name; /* Local copy */
  gdouble *grad_data; /* local copy */
  gint sample_size;
  gpointer udata;
};

typedef struct __gradients_sel GSelect, * GSelectP;

static void
gradient_pre_update(GtkWidget *gradient_preview,
		    gint width_data,
		    gdouble *grad_data)
{
  gint x,y;
  gdouble *src;
  double  r, g, b, a;
  double  c0, c1;
  guchar *p0, *p1,*even,*odd;
  gint width = width_data/4;

  /*  Draw the gradient  */
  src = grad_data;
  p0    = even = g_malloc(width*3);
  p1    = odd = g_malloc(width*3);

  for (x = 0; x < width; x++) {
    r =  src[x*4+0];
    g = src[x*4+1];
    b = src[x*4+2];
    a = src[x*4+3];
    
    if ((x / GRAD_CHECK_SIZE_SM) & 1) {
      c0 = GRAD_CHECK_LIGHT;
      c1 = GRAD_CHECK_DARK;
    } else {
      c0 = GRAD_CHECK_DARK;
      c1 = GRAD_CHECK_LIGHT;
    } /* else */
    
    *p0++ = (c0 + (r - c0) * a) * 255.0;
    *p0++ = (c0 + (g - c0) * a) * 255.0;
    *p0++ = (c0 + (b - c0) * a) * 255.0;
    
    *p1++ = (c1 + (r - c1) * a) * 255.0;
    *p1++ = (c1 + (g - c1) * a) * 255.0;
    *p1++ = (c1 + (b - c1) * a) * 255.0;
    
  } /* for */
  
  for (y = 0; y < CELL_SIZE_HEIGHT; y++)
    {
      if ((y / GRAD_CHECK_SIZE_SM) & 1)
	{
      gtk_preview_draw_row (GTK_PREVIEW (gradient_preview), (guchar *)odd, 0, y, (width < CELL_SIZE_WIDTH)?width:CELL_SIZE_WIDTH);
	}
      else
	{
      gtk_preview_draw_row (GTK_PREVIEW (gradient_preview), (guchar *)even, 0, y, (width < CELL_SIZE_WIDTH)?width:CELL_SIZE_WIDTH);
	}
    }

  g_free(even);
  g_free(odd);

  /*  Draw the brush preview  */
  gtk_widget_draw (gradient_preview, NULL);
}

static void
gradient_select_invoker(gchar    *name,
			gint     width,
			gdouble *  grad_data,
			gint     closing,
			gpointer udata)
{
  GSelectP gsel = (GSelectP)udata;
  if(gsel->grad_data != NULL)
    g_free(gsel->grad_data);
  gsel->width = width;
  if(gsel->gradient_name)
    g_free(gsel->gradient_name);
  gsel->gradient_name = g_strdup(name);
  /* one row only each row has four doubles r,g,b,a */
  gsel->grad_data = g_malloc(width*sizeof(gdouble));
  /*  printf("name = %s width = %d\n",name,width);*/
  g_memmove(gsel->grad_data,grad_data,width*sizeof(gdouble)); 
  gradient_pre_update(gsel->gradient_preview,gsel->width,gsel->grad_data);
  if(gsel->cback != NULL)
    (gsel->cback)(name,width,grad_data,closing,gsel->udata);

  if(closing)
    gtk_widget_set_sensitive(gsel->button,TRUE);
}


static void
gradient_preview_callback(GtkWidget *widget,
			  gpointer   data)
{
  GSelectP gsel = (GSelectP)data;
  gtk_widget_set_sensitive(gsel->button,FALSE);
  gsel->gradient_popup_pnt = 
    gimp_interactive_selection_gradient((gsel->dname)?gsel->dname:"Gradient Plugin Selection",
					gsel->gradient_name,
					gsel->sample_size,
					gradient_select_invoker,gsel);
  
}

GtkWidget * 
gimp_gradient_select_widget(gchar *dname,
			    gchar *igradient, 
			    GRunGradientCallback cback,
			    gpointer udata)
{
  GtkWidget * button;
  GtkWidget * hbox;
  GtkWidget * gradient;
  gint width;
  gdouble *grad_data;
  gchar *gradient_name;

  GSelectP gsel = g_new(GSelect, sizeof(GSelect));

  hbox = gtk_hbox_new (FALSE, 3);
  gtk_widget_show(hbox);

  button = gtk_button_new();

  gradient = gtk_preview_new (GTK_PREVIEW_COLOR);
  gtk_preview_size (GTK_PREVIEW (gradient), CELL_SIZE_WIDTH, CELL_SIZE_HEIGHT); 
  gtk_widget_show(gradient);
  gtk_container_add (GTK_CONTAINER (button), gradient); 

  gtk_signal_connect (GTK_OBJECT (button), "clicked",
		      (GtkSignalFunc) gradient_preview_callback,
		      (gpointer)gsel);

  gtk_widget_show(button);

  gsel->button = button;
  gsel->cback = cback;
  gsel->udata = udata;
  gsel->grad_data = NULL;
  gsel->gradient_preview = gradient;
  gsel->dname = dname;
  gsel->gradient_popup_pnt = NULL;
  gsel->sample_size = CELL_SIZE_WIDTH;

  /* Do initial gradient setup */
  gradient_name = gimp_gradient_get_gradient_data(igradient,&width, CELL_SIZE_WIDTH,&grad_data);
  if(gradient_name)
    {
      gradient_pre_update(gsel->gradient_preview,width,grad_data);
      gsel->grad_data = grad_data;
      gsel->gradient_name = gradient_name;
      gsel->width = width;
    }
  else
    {
      gsel->gradient_name = g_strdup(igradient);
    }

  gtk_box_pack_start (GTK_BOX (hbox), button, TRUE, TRUE, 0);

  gtk_object_set_data(GTK_OBJECT(hbox),GSEL_DATA_KEY,(gpointer)gsel);

  return hbox;
}


gint
gimp_gradient_select_widget_close_popup(GtkWidget *w)
{
  gint ret_val = FALSE;

  GSelectP gsel = (GSelectP)gtk_object_get_data(GTK_OBJECT(w),GSEL_DATA_KEY);
  if(gsel && gsel->gradient_popup_pnt)
    {
      ret_val = gimp_gradient_close_popup(gsel->gradient_popup_pnt);
      gsel->gradient_popup_pnt = NULL;
    }

  return ret_val;
}

gint 
gimp_gradient_select_widget_set_popup(GtkWidget *w,gchar *gname)
{
  gint ret_val = FALSE;
  gint width;
  gdouble *grad_data;
  gchar *gradient_name;

  GSelectP gsel = (GSelectP)gtk_object_get_data(GTK_OBJECT(w),GSEL_DATA_KEY);

  if(gsel)
    {
      gradient_name = gimp_gradient_get_gradient_data(gname,&width,gsel->sample_size,&grad_data);
  
      if(gradient_name)
	{
	  gradient_select_invoker(gname,width,grad_data,0,gsel);

	  if(gsel->gradient_popup_pnt)
	    {
	      if(gimp_gradient_set_popup(gsel->gradient_popup_pnt,gname))
		{
		  ret_val = TRUE;
		}
	    }
	}
    }
  return ret_val;
}