gimp/app/tools/gimperasertool.c

/* The GIMP -- an image manipulation program
 * Copyright (C) 1995 Spencer Kimball and Peter Mattis
 *
 * 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 "config.h"

#include <gtk/gtk.h>
#include <gdk/gdkkeysyms.h>

#include "libgimpwidgets/gimpwidgets.h"

#include "tools-types.h"

#include "base/pixel-region.h"
#include "base/temp-buf.h"

#include "paint-funcs/paint-funcs.h"

#include "core/gimp.h"
#include "core/gimpcontext.h"
#include "core/gimpdrawable.h"
#include "core/gimpimage.h"

#include "gimperasertool.h"
#include "paint_options.h"
#include "tool_manager.h"

#include "libgimp/gimpintl.h"

#include "libgimpcolor/gimpcolor.h"
#include "libgimpcolor/gimprgb.h"


#define ERASER_DEFAULT_HARD        FALSE
#define ERASER_DEFAULT_INCREMENTAL FALSE
#define ERASER_DEFAULT_ANTI_ERASE  FALSE
#define ERASER_DEFAULT_COLOR_ERASE FALSE


typedef struct _EraserOptions EraserOptions;

struct _EraserOptions
{
  PaintOptions  paint_options;

  gboolean      hard;
  gboolean      hard_d;
  GtkWidget    *hard_w;

  gboolean	anti_erase;
  gboolean	anti_erase_d;
  GtkWidget    *anti_erase_w;

  gboolean	color_erase;
  gboolean	color_erase_d;
  GtkWidget    *color_erase_w;
};


static void   gimp_eraser_tool_class_init   (GimpEraserToolClass  *klass);
static void   gimp_eraser_tool_init         (GimpEraserTool       *eraser);

static void   gimp_eraser_tool_modifier_key (GimpTool             *tool,
                                             GdkModifierType       key,
                                             gboolean              press,
                                             GdkModifierType       state,
                                             GimpDisplay          *gdisp);

static void   gimp_eraser_tool_paint        (GimpPaintTool        *paint_tool,
                                             GimpDrawable         *drawable,
                                             PaintState            state);

static void   gimp_eraser_tool_motion       (GimpPaintTool        *paint_tool,
                                             GimpDrawable         *drawable,
                                             PaintPressureOptions *pressure_options,
                                             gboolean              hard,
                                             gboolean              incremental,
                                             gboolean              anti_erase,
                                             gboolean              color_erase);

static EraserOptions * gimp_eraser_tool_options_new   (void);
static void            gimp_eraser_tool_options_reset (GimpToolOptions *tool_options);
static void            gimp_eraser_tool_colortoalpha  (GimpRGB       *src,
                                                       const GimpRGB *color);


/*  local variables  */
static gboolean   non_gui_hard        = ERASER_DEFAULT_HARD;
static gboolean   non_gui_incremental = ERASER_DEFAULT_INCREMENTAL;
static gboolean	  non_gui_anti_erase  = ERASER_DEFAULT_ANTI_ERASE;
static gboolean	  non_gui_color_erase = ERASER_DEFAULT_COLOR_ERASE;

static EraserOptions *eraser_options = NULL;

static GimpPaintToolClass *parent_class = NULL;


/*  functions  */

void
gimp_eraser_tool_register (Gimp *gimp)
{
  tool_manager_register_tool (gimp,
			      GIMP_TYPE_ERASER_TOOL,
			      TRUE,
  			      "gimp:eraser_tool",
  			      _("Eraser"),
  			      _("Paint fuzzy brush strokes"),
      			      N_("/Tools/Paint Tools/Eraser"), "<shift>E",
  			      NULL, "tools/eraser.html",
			      GIMP_STOCK_TOOL_ERASER);
}

GType
gimp_eraser_tool_get_type (void)
{
  static GType tool_type = 0;

  if (! tool_type)
    {
      static const GTypeInfo tool_info =
      {
        sizeof (GimpEraserToolClass),
	(GBaseInitFunc) NULL,
	(GBaseFinalizeFunc) NULL,
	(GClassInitFunc) gimp_eraser_tool_class_init,
	NULL,           /* class_finalize */
	NULL,           /* class_data     */
	sizeof (GimpEraserTool),
	0,              /* n_preallocs    */
	(GInstanceInitFunc) gimp_eraser_tool_init,
      };

      tool_type = g_type_register_static (GIMP_TYPE_PAINT_TOOL,
					  "GimpEraserTool", 
                                          &tool_info, 0);
    }

  return tool_type;
}

static void
gimp_eraser_tool_class_init (GimpEraserToolClass *klass)
{
  GimpToolClass      *tool_class;
  GimpPaintToolClass *paint_tool_class;

  tool_class       = GIMP_TOOL_CLASS (klass);
  paint_tool_class = GIMP_PAINT_TOOL_CLASS (klass);

  parent_class = g_type_class_peek_parent (klass);

  tool_class->modifier_key = gimp_eraser_tool_modifier_key;

  paint_tool_class->paint  = gimp_eraser_tool_paint;
}

static void
gimp_eraser_tool_init (GimpEraserTool *eraser)
{
  GimpTool      *tool;
  GimpPaintTool *paint_tool;

  tool       = GIMP_TOOL (eraser);
  paint_tool = GIMP_PAINT_TOOL (eraser);

  if (! eraser_options)
    {
      eraser_options = gimp_eraser_tool_options_new ();

      tool_manager_register_tool_options (GIMP_TYPE_ERASER_TOOL,
                                          (GimpToolOptions *) eraser_options);
    }

  tool->tool_cursor = GIMP_ERASER_TOOL_CURSOR;

  paint_tool->flags |= TOOL_CAN_HANDLE_CHANGING_BRUSH;
}

static void
gimp_eraser_tool_modifier_key (GimpTool        *tool,
                               GdkModifierType  key,
                               gboolean         press,
                               GdkModifierType  state,
                               GimpDisplay     *gdisp)
{
  if ((key == GDK_CONTROL_MASK) &&
      ! (state & GDK_SHIFT_MASK)) /* leave stuff untouched in line draw mode */
    {
      gtk_toggle_button_set_active
        (GTK_TOGGLE_BUTTON (eraser_options->anti_erase_w),
         ! eraser_options->anti_erase);
    }

  tool->toggled = eraser_options->anti_erase;
}
  
static void
gimp_eraser_tool_paint (GimpPaintTool *paint_tool,
                        GimpDrawable  *drawable,
                        PaintState     state)
{
  PaintPressureOptions *pressure_options;
  gboolean              hard;
  gboolean              incremental;
  gboolean              anti_erase;
  gboolean              color_erase;

  if (eraser_options)
    {
      pressure_options = eraser_options->paint_options.pressure_options;
      hard             = eraser_options->hard;
      incremental      = eraser_options->paint_options.incremental;
      anti_erase       = eraser_options->anti_erase;
      color_erase      = eraser_options->color_erase;
    }
  else
    {
      pressure_options = &non_gui_pressure_options;
      hard             = non_gui_hard;
      incremental      = non_gui_incremental;
      anti_erase       = non_gui_anti_erase;
      color_erase      = non_gui_color_erase;
    }

  switch (state)
    {
    case INIT_PAINT:
      break;

    case MOTION_PAINT:
      gimp_eraser_tool_motion (paint_tool,
                               drawable,
                               pressure_options,
                               hard,
                               incremental,
                               anti_erase,
			       color_erase);
      break;

    case FINISH_PAINT:
      break;

    default:
      break;
    }
}

static void
gimp_eraser_tool_motion (GimpPaintTool        *paint_tool,
                         GimpDrawable         *drawable,
                         PaintPressureOptions *pressure_options,
                         gboolean              hard,
                         gboolean              incremental,
                         gboolean              anti_erase,
                         gboolean              color_erase)
{
  GimpImage   *gimage;
  GimpContext *context;
  gint         opacity;
  TempBuf     *area;
  guchar       col[MAX_CHANNELS];
  gdouble      scale;
  TempBuf     *orig;
  gint         x, y, x1, y1, x2, y2;
  PixelRegion  srcPR, destPR;
  gpointer     pr;
  GimpRGB      bgcolor, color;
  guchar      *s, *d;


  if (! (gimage = gimp_drawable_gimage (drawable)))
    return;

  gimp_image_get_background (gimage, drawable, col);

  context = gimp_get_current_context (gimage->gimp);

  if (pressure_options->size)
    scale = paint_tool->cur_coords.pressure;
  else
    scale = 1.0;

  /*  Get a region which can be used to paint to  */
  if (! (area = gimp_paint_tool_get_paint_area (paint_tool, drawable, scale)))
    return;

  if (anti_erase || !color_erase)
    {
      /*  set the alpha channel  */
      col[area->bytes - 1] = OPAQUE_OPACITY;

      /*  color the pixels  */
      color_pixels (temp_buf_data (area), col,
                    area->width * area->height, area->bytes);

      opacity = 255 * gimp_context_get_opacity (context);

      if (pressure_options->opacity)
        opacity = opacity * 2.0 * paint_tool->cur_coords.pressure;

      /* paste the newly painted canvas to the gimage which is being
       * worked on  */
      gimp_paint_tool_paste_canvas (paint_tool, drawable, 
                                    MIN (opacity, 255),
                                    gimp_context_get_opacity (context) * 255,
                                    anti_erase ? (color_erase ? BEHIND_MODE : ANTI_ERASE_MODE ) : ERASE_MODE,
                                    hard ? HARD : (pressure_options->pressure ? PRESSURE : SOFT),
                                    scale,
                                    incremental ? INCREMENTAL : CONSTANT);
    }
  else
    {
      /* This is Simons evil Eraser Hack. Code is borrowed from the
       * colortoalpha plugin by Seth Burgess. Algorithm has been
       * described on IRC by clahey.
       */
  
      gimp_rgb_set_uchar (&bgcolor, col[0], col[1], col[2]);
      
      if (!gimp_drawable_has_alpha (drawable))
        return;

      /* is this necessary? */
      x1 = CLAMP (area->x, 0, gimp_drawable_width (drawable));
      y1 = CLAMP (area->y, 0, gimp_drawable_height (drawable));
      x2 = CLAMP (area->x + area->width,
                  0, gimp_drawable_width (drawable));
      y2 = CLAMP (area->y + area->height,
                  0, gimp_drawable_height (drawable));

      if (!(x2 - x1) || !(y2 - y1))
        return;

      /*  get the original image  */
      orig = gimp_paint_tool_get_orig_image (paint_tool, drawable, x1, y1, x2, y2);

      srcPR.bytes = orig->bytes;
      srcPR.x = 0; srcPR.y = 0;
      srcPR.w = x2 - x1;
      srcPR.h = y2 - y1;
      srcPR.rowstride = srcPR.bytes * orig->width;
      srcPR.data = temp_buf_data (orig);

      /*  configure the destination  */
      destPR.bytes = area->bytes;
      destPR.x = 0; destPR.y = 0;
      destPR.w = srcPR.w;
      destPR.h = srcPR.h;
      destPR.rowstride = destPR.bytes * area->width;
      destPR.data = temp_buf_data (area);

      /* I am not sure, if this really is necessary.
       * Probably the orig Tempbuf has the same size as the area Tempbuf */
      pr = pixel_regions_register (2, &srcPR, &destPR);

      for (; pr != NULL; pr = pixel_regions_process (pr))
        {
          s = srcPR.data;
          d = destPR.data;
          for (y = 0; y < destPR.h; y++)
            {
              for (x = 0; x < destPR.w; x++)
                {
                  
                  gimp_rgba_set_uchar (&color, 
                                       s[x*srcPR.bytes    ],
                                       s[x*srcPR.bytes + 1],
                                       s[x*srcPR.bytes + 2],
                                       s[x*srcPR.bytes + 3]);

                  gimp_eraser_tool_colortoalpha (&color, &bgcolor);

                  gimp_rgba_get_uchar (&color, 
                                       &(d[x*destPR.bytes    ]),
                                       &(d[x*destPR.bytes + 1]),
                                       &(d[x*destPR.bytes + 2]),
                                       &(d[x*destPR.bytes + 3]));
                }

              s += srcPR.rowstride;
              d += destPR.rowstride;
            }
        }

      opacity = 255 * gimp_context_get_opacity (context);

      if (pressure_options->opacity)
        opacity = opacity * 2.0 * paint_tool->cur_coords.pressure;

      /*  paste the newly painted canvas to the gimage which is
       *  being worked on  */
      gimp_paint_tool_replace_canvas (paint_tool, drawable, 
                                    MIN (opacity, 255),
                                    gimp_context_get_opacity (context) * 255,
                                    hard ? HARD : (pressure_options->pressure ? PRESSURE : SOFT),
                                    scale,
                                    incremental ? INCREMENTAL : CONSTANT);
    }
}


/*  non-gui stuff  */

gboolean
eraser_non_gui_default (GimpDrawable *drawable,
			gint          num_strokes,
			gdouble      *stroke_array)
{
  gboolean  hard        = ERASER_DEFAULT_HARD;
  gboolean  incremental = ERASER_DEFAULT_INCREMENTAL;
  gboolean  anti_erase  = ERASER_DEFAULT_ANTI_ERASE;
  gboolean  color_erase = ERASER_DEFAULT_COLOR_ERASE;

  EraserOptions *options = eraser_options;

  if (options)
    {
      hard        = options->hard;
      incremental = options->paint_options.incremental;
      anti_erase  = options->anti_erase;
      color_erase = options->color_erase;
    }

  return eraser_non_gui (drawable, num_strokes, stroke_array,
			 hard, incremental, anti_erase, color_erase);
}

gboolean
eraser_non_gui (GimpDrawable *drawable,
    		gint          num_strokes,
		gdouble      *stroke_array,
		gint          hard,
		gint          incremental,
		gboolean      anti_erase,
		gboolean      color_erase)
{
  static GimpEraserTool *non_gui_eraser = NULL;

  GimpPaintTool *paint_tool;
  gint           i;
  
  if (! non_gui_eraser)
    {
      non_gui_eraser = g_object_new (GIMP_TYPE_ERASER_TOOL, NULL);
    }

  paint_tool = GIMP_PAINT_TOOL (non_gui_eraser);

  if (gimp_paint_tool_start (paint_tool, drawable,
			     stroke_array[0],
			     stroke_array[1]))
    {
      non_gui_hard        = hard;
      non_gui_incremental = incremental;
      non_gui_anti_erase  = anti_erase;
      non_gui_color_erase = color_erase;

      paint_tool->start_coords.x = paint_tool->last_coords.x = stroke_array[0];
      paint_tool->start_coords.y = paint_tool->last_coords.y = stroke_array[1];

      gimp_paint_tool_paint (paint_tool, drawable, MOTION_PAINT);

      for (i = 1; i < num_strokes; i++)
	{
          paint_tool->cur_coords.x = stroke_array[i * 2 + 0];
          paint_tool->cur_coords.y = stroke_array[i * 2 + 1];

          gimp_paint_tool_interpolate (paint_tool, drawable);

          paint_tool->last_coords.x = paint_tool->cur_coords.x;
          paint_tool->last_coords.y = paint_tool->cur_coords.y;
	}

      gimp_paint_tool_finish (paint_tool, drawable);

      return TRUE;
    }

  return FALSE;
}


/*  tool options stuff  */

static EraserOptions *
gimp_eraser_tool_options_new (void)
{
  EraserOptions *options;
  GtkWidget     *vbox;

  options = g_new0 (EraserOptions, 1);
  paint_options_init ((PaintOptions *) options,
		      GIMP_TYPE_ERASER_TOOL,
		      gimp_eraser_tool_options_reset);

  options->hard        = options->hard_d        = ERASER_DEFAULT_HARD;
  options->anti_erase  = options->anti_erase_d  = ERASER_DEFAULT_ANTI_ERASE;
  options->color_erase = options->color_erase_d = ERASER_DEFAULT_COLOR_ERASE;

  /*  the main vbox  */
  vbox = ((GimpToolOptions *) options)->main_vbox;

  /* the hard toggle */
  options->hard_w = gtk_check_button_new_with_label (_("Hard Edge"));
  gtk_box_pack_start (GTK_BOX (vbox), options->hard_w, FALSE, FALSE, 0);
  g_signal_connect (G_OBJECT (options->hard_w), "toggled",
                    G_CALLBACK (gimp_toggle_button_update),
                    &options->hard);
  gtk_toggle_button_set_active (GTK_TOGGLE_BUTTON (options->hard_w),
				options->hard_d);
  gtk_widget_show (options->hard_w);

  /* the anti_erase toggle */
  options->anti_erase_w = gtk_check_button_new_with_label (_("Anti Erase"));
  gtk_box_pack_start (GTK_BOX (vbox), options->anti_erase_w, FALSE, FALSE, 0);
  g_signal_connect (G_OBJECT (options->anti_erase_w), "toggled",
                    G_CALLBACK (gimp_toggle_button_update),
                    &options->anti_erase);
  gtk_toggle_button_set_active (GTK_TOGGLE_BUTTON (options->anti_erase_w),
				options->anti_erase_d);
  gtk_widget_show (options->anti_erase_w);

  /* the color_erase toggle */
  options->color_erase_w = gtk_check_button_new_with_label (_("Color Erase"));
  gtk_box_pack_start (GTK_BOX (vbox), options->color_erase_w, FALSE, FALSE, 0);
  g_signal_connect (G_OBJECT (options->color_erase_w), "toggled",
                    G_CALLBACK (gimp_toggle_button_update),
                    &options->color_erase);
  gtk_toggle_button_set_active (GTK_TOGGLE_BUTTON (options->color_erase_w),
				options->color_erase_d);
  gtk_widget_show (options->color_erase_w);

  return options;
}

static void
gimp_eraser_tool_options_reset (GimpToolOptions *tool_options)
{
  EraserOptions *options;

  options = (EraserOptions *) tool_options;

  paint_options_reset (tool_options);

  gtk_toggle_button_set_active (GTK_TOGGLE_BUTTON (options->hard_w),
				options->hard_d);
  gtk_toggle_button_set_active (GTK_TOGGLE_BUTTON (options->anti_erase_w),
				options->anti_erase_d);
  gtk_toggle_button_set_active (GTK_TOGGLE_BUTTON (options->color_erase_w),
				options->color_erase_d);
}


static void
gimp_eraser_tool_colortoalpha (GimpRGB       *src,
                               const GimpRGB *color)
{
  GimpRGB alpha;
  
  alpha.a = src->a;

  if (color->r < 0.0001)
    alpha.r = src->r;
  else if ( src->r > color->r )
    alpha.r = (src->r - color->r) / (1.0 - color->r);
  else if (src->r < color->r)
    alpha.r = (color->r - src->r) / color->r;
  else alpha.r = 0.0;

  if (color->g < 0.0001)
    alpha.g = src->g;
  else if ( src->g > color->g )
    alpha.g = (src->g - color->g) / (1.0 - color->g);
  else if ( src->g < color->g )
    alpha.g = (color->g - src->g) / (color->g);
  else alpha.g = 0.0;

  if (color->b < 0.0001)
    alpha.b = src->b;
  else if ( src->b > color->b )
    alpha.b = (src->b - color->b) / (1.0 - color->b);
  else if ( src->b < color->b )
    alpha.b = (color->b - src->b) / (color->b);
  else alpha.b = 0.0;

  if ( alpha.r > alpha.g )
    {
      if ( alpha.r > alpha.b )
        {
          src->a = alpha.r;
        }
      else
        {
          src->a = alpha.b;
        }
    }
  else if ( alpha.g > alpha.b )
    {
      src->a = alpha.g;
    }
  else
    {
      src->a = alpha.b;
    }
      
  if (src->a < 0.0001)
    return;

  src->r = (src->r - color->r) / src->a + color->r;
  src->g = (src->g - color->g) / src->a + color->g;
  src->b = (src->b - color->b) / src->a + color->b;

  src->a *= alpha.a;
}