dnrops
/
gimp
mirror of https://github.com/GNOME/gimp.git
1
0
Fork 0
Code Issues Packages Projects Releases Wiki Activity
gimp/plug-ins/common/colortoalpha.c

481 lines
13 KiB
C
Raw Blame History

/*
* Color To Alpha plug-in v1.0 by Seth Burgess, sjburges@gimp.org 1999/05/14
* with algorithm by clahey
*/
/* 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 <stdio.h>
#include <stdlib.h>
#include <gtk/gtk.h>
#include <libgimp/gimp.h>
#include <libgimp/gimpui.h>
#include "libgimp/stdplugins-intl.h"
#define PRV_WIDTH 40
#define PRV_HEIGHT 20
typedef struct
{
GimpRGB color;
} C2AValues;
typedef struct
{
gboolean run;
} C2AInterface;
typedef struct
{
GtkWidget *color_button;
} C2APreview;
/* Declare local functions.
*/
static void query (void);
static void run (gchar *name,
gint nparams,
GimpParam *param,
gint *nreturn_vals,
GimpParam **return_vals);
static void colortoalpha (GimpRGB *src,
const GimpRGB *color);
static void toalpha (GimpDrawable *drawable);
static void toalpha_render_row (const guchar *src_row,
guchar *dest_row,
gint row_width,
const gint bytes);
/* UI stuff */
static gboolean colortoalpha_dialog (GimpDrawable *drawable);
static void colortoalpha_ok_callback (GtkWidget *widget,
gpointer data);
static GimpRunModeType run_mode;
GimpPlugInInfo PLUG_IN_INFO =
{
NULL, /* init_proc */
NULL, /* quit_proc */
query, /* query_proc */
run, /* run_proc */
};
static C2AValues pvals =
{
{ 1.0, 1.0, 1.0, 1.0 } /* white default */
};
static C2AInterface pint =
{
FALSE
};
static C2APreview ppreview =
{
NULL
};
MAIN ()
static void
query (void)
{
static GimpParamDef args[] =
{
{ GIMP_PDB_INT32, "run_mode", "Interactive, non-interactive" },
{ GIMP_PDB_IMAGE, "image", "Input image (unused)" },
{ GIMP_PDB_DRAWABLE, "drawable", "Input drawable" },
{ GIMP_PDB_COLOR, "color", "Color to remove" }
};
static gint nargs = sizeof (args) / sizeof (args[0]);
gimp_install_procedure ("plug_in_colortoalpha",
"Convert the color in an image to alpha",
"This replaces as much of a given color as possible "
"in each pixel with a corresponding amount of alpha, "
"then readjusts the color accordingly.",
"Seth Burgess",
"Seth Burgess <sjburges@gimp.org>",
"7th Aug 1999",
N_("<Image>/Filters/Colors/Color to Alpha..."),
"RGB*",
GIMP_PLUGIN,
nargs, 0,
args, NULL);
}
static void
run (gchar *name,
gint nparams,
GimpParam *param,
gint *nreturn_vals,
GimpParam **return_vals)
{
static GimpParam values[1];
GimpDrawable *drawable;
gint32 image_ID;
GimpPDBStatusType status = GIMP_PDB_SUCCESS;
run_mode = param[0].data.d_int32;
*nreturn_vals = 1;
*return_vals = values;
INIT_I18N_UI();
values[0].type = GIMP_PDB_STATUS;
values[0].data.d_status = status;
/* Get the specified drawable */
drawable = gimp_drawable_get (param[2].data.d_drawable);
image_ID = param[1].data.d_image;
switch (run_mode)
{
case GIMP_RUN_INTERACTIVE:
gimp_palette_get_foreground (&pvals.color);
gimp_get_data ("plug_in_colortoalpha", &pvals);
if (! colortoalpha_dialog (drawable ))
{
gimp_drawable_detach (drawable);
return;
}
break;
case GIMP_RUN_NONINTERACTIVE:
if (nparams != 4)
status = GIMP_PDB_CALLING_ERROR;
if (status == GIMP_PDB_SUCCESS)
pvals.color = param[3].data.d_color;
break;
case GIMP_RUN_WITH_LAST_VALS:
gimp_get_data ("plug_in_colortoalpha", &pvals);
break;
default:
break;
}
if (status == GIMP_PDB_SUCCESS)
{
gimp_undo_push_group_start (image_ID);
/* Add alpha if not present */
gimp_layer_add_alpha (drawable->drawable_id);
drawable = gimp_drawable_get (drawable->drawable_id);
/* Make sure that the drawable is RGB color */
if (gimp_drawable_is_rgb (drawable->drawable_id) &&
gimp_drawable_is_layer (drawable->drawable_id))
{
if (run_mode != GIMP_RUN_NONINTERACTIVE)
gimp_progress_init (_("Removing color..."));
toalpha (drawable);
}
gimp_drawable_detach (drawable);
gimp_undo_push_group_end (image_ID);
gimp_displays_flush ();
}
else
{
gimp_drawable_detach (drawable);
}
if (run_mode == GIMP_RUN_INTERACTIVE)
gimp_set_data ("plug_in_colortoalpha", &pvals, sizeof (pvals));
values[0].data.d_status = status;
}
static void
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;
}
/*
<clahey> so if a1 > c1, a2 > c2, and a3 > c2 and a1 - c1 > a2-c2, a3-c3,
then a1 = b1 * alpha + c1 * (1-alpha)
So, maximizing alpha without taking b1 above 1 gives
a1 = alpha + c1(1-alpha) and therefore alpha = (a1-c1) / (1-c1).
<sjburges> clahey: btw, the ordering of that a2, a3 in the white->alpha didn't
matter
<clahey> sjburges: You mean that it could be either a1, a2, a3 or a1, a3, a2?
<sjburges> yeah
<sjburges> because neither one uses the other
<clahey> sjburges: That's exactly as it should be. They are both just getting
reduced to the same amount, limited by the the darkest color.
<clahey> Then a2 = b2 * alpha + c2 * ( 1- alpha). Solving for b2 gives
b2 = (a1-c2)/alpha + c2.
<sjburges> yeah
<clahey> That gives us are formula for if the background is darker than the
foreground? Yep.
<clahey> Next if a1 < c1, a2 < c2, a3 < c3, and c1-a1 > c2-a2, c3-a3, and by our
desired result a1 = b1 * alpha + c1 * (1-alpha), we maximize alpha
without taking b1 negative gives alpha = 1 - a1 / c1.
<clahey> And then again, b2 = (a2-c2) / alpha + c2 by the same formula.
(Actually, I think we can use that formula for all cases, though it
may possibly introduce rounding error.
<clahey> sjburges: I like the idea of using floats to avoid rounding error.
Good call.
*/
static void
toalpha_render_row (const guchar *src_data,
guchar *dest_data,
gint col, /* row width in pixels */
const gint bytes)
{
GimpRGB color;
while (col--)
{
gimp_rgba_set_uchar (&color,
src_data[col * bytes ],
src_data[col * bytes + 1],
src_data[col * bytes + 2],
src_data[col * bytes + 3]);
colortoalpha (&color, &pvals.color);
gimp_rgba_get_uchar (&color,
&dest_data[col * bytes],
&dest_data[col * bytes + 1],
&dest_data[col * bytes + 2],
&dest_data[col * bytes + 3]);
}
}
static void
toalpha_render_region (const GimpPixelRgn srcPR,
const GimpPixelRgn destPR)
{
gint row;
guchar *src_ptr = srcPR.data;
guchar *dest_ptr = destPR.data;
for (row = 0; row < srcPR.h ; row++)
{
if (srcPR.bpp!=4)
{
gimp_message ("Not the proper bpp! \n");
exit(1);
}
toalpha_render_row (src_ptr, dest_ptr,
srcPR.w,
srcPR.bpp) ;
src_ptr += srcPR.rowstride;
dest_ptr += destPR.rowstride;
}
}
static void
toalpha (GimpDrawable *drawable)
{
GimpPixelRgn srcPR, destPR;
gint x1, y1, x2, y2;
gpointer pr;
gint total_area, area_so_far;
gint progress_skip;
/* Get the input area. This is the bounding box of the selection in
* the image (or the entire image if there is no selection). Only
* operating on the input area is simply an optimization. It doesn't
* need to be done for correct operation. (It simply makes it go
* faster, since fewer pixels need to be operated on).
*/
gimp_drawable_mask_bounds (drawable->drawable_id, &x1, &y1, &x2, &y2);
total_area = (x2 - x1) * (y2 - y1);
area_so_far = 0;
progress_skip = 0;
if (total_area < 1)
return;
/* Initialize the pixel regions. */
gimp_pixel_rgn_init (&srcPR, drawable, x1, y1, (x2 - x1), (y2 - y1),
FALSE, FALSE);
gimp_pixel_rgn_init (&destPR, drawable, x1, y1, (x2 - x1), (y2 - y1),
TRUE, TRUE);
for (pr = gimp_pixel_rgns_register (2, &srcPR, &destPR);
pr != NULL;
pr = gimp_pixel_rgns_process (pr))
{
toalpha_render_region (srcPR, destPR);
if ((run_mode != GIMP_RUN_NONINTERACTIVE))
{
area_so_far += srcPR.w * srcPR.h;
if (++progress_skip % 10 == 0)
gimp_progress_update ((gdouble) area_so_far / (gdouble) total_area);
}
}
/* update the processed region */
gimp_drawable_flush (drawable);
gimp_drawable_merge_shadow (drawable->drawable_id, TRUE);
gimp_drawable_update (drawable->drawable_id, x1, y1, (x2 - x1), (y2 - y1));
}
static gboolean
colortoalpha_dialog (GimpDrawable *drawable)
{
GtkWidget *dlg;
GtkWidget *frame;
GtkWidget *table;
GtkWidget *button;
GtkWidget *label;
gimp_ui_init ("colortoalpha", TRUE);
dlg = gimp_dialog_new (_("Color to Alpha"), "colortoalpha",
gimp_standard_help_func, "filters/colortoalpha.html",
GTK_WIN_POS_MOUSE,
FALSE, TRUE, FALSE,
GTK_STOCK_OK, colortoalpha_ok_callback,
NULL, NULL, NULL, TRUE, FALSE,
GTK_STOCK_CANCEL, gtk_widget_destroy,
NULL, 1, NULL, FALSE, TRUE,
NULL);
gtk_signal_connect (GTK_OBJECT (dlg), "destroy",
GTK_SIGNAL_FUNC (gtk_main_quit),
NULL);
frame = gtk_frame_new (_("Color"));
gtk_container_set_border_width (GTK_CONTAINER (frame), 6);
gtk_box_pack_start (GTK_BOX (GTK_DIALOG (dlg)->vbox), frame, FALSE, FALSE, 0);
gtk_widget_show (frame);
table = gtk_table_new (1, 3, FALSE);
gtk_table_set_col_spacings (GTK_TABLE (table), 6);
gtk_container_set_border_width (GTK_CONTAINER (table), 4);
gtk_container_add (GTK_CONTAINER (frame), table);
gtk_widget_show (table);
label = gtk_label_new (_("From:"));
gtk_misc_set_alignment (GTK_MISC (label), 1.0, 0.5);
gtk_table_attach_defaults (GTK_TABLE(table), label, 0, 1, 0, 1);
gtk_widget_show (label);
button = gimp_color_button_new (_("Color to Alpha Color Picker"),
PRV_WIDTH, PRV_HEIGHT,
&pvals.color,
GIMP_COLOR_AREA_FLAT);
gtk_signal_connect (GTK_OBJECT (button), "color_changed",
GTK_SIGNAL_FUNC (gimp_color_button_get_color),
&pvals.color);
gtk_table_attach (GTK_TABLE (table), button, 1, 2, 0, 1,
GTK_FILL, GTK_SHRINK, 0, 0) ;
gtk_widget_show (button);
ppreview.color_button = button;
label = gtk_label_new (_("to Alpha"));
gtk_misc_set_alignment (GTK_MISC (label), 0.0, 0.5);
gtk_table_attach_defaults (GTK_TABLE(table), label, 2, 3, 0, 1);
gtk_widget_show (label);
gtk_widget_show (dlg);
gtk_main ();
gdk_flush ();
return pint.run;
}
static void
colortoalpha_ok_callback (GtkWidget *widget,
gpointer data)
{
pint.run = TRUE;
gtk_widget_destroy (GTK_WIDGET (data));
}
Reference in New Issue View Git Blame Copy Permalink