gimp/plug-ins/script-fu/libscriptfu/scheme-marshal.c

450 lines
14 KiB
C

/* GIMP - The GNU 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 3 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, see <https://www.gnu.org/licenses/>.
*/
#include "config.h"
#include "libgimp/gimp.h"
#include "tinyscheme/scheme-private.h"
#include "scheme-marshal.h"
#include "script-fu-errors.h"
/* When include scheme-private.h, must undef cons macro */
#undef cons
static pointer get_item_from_ID_in_script (scheme *sc,
pointer a,
gint id,
GObject **object_handle);
/*
* Marshal arguments to, and return values from, calls to PDB.
* Convert Scheme constructs to/from a GValue.
*
* For each marshalling function:
* - a returned "pointer" is a scheme pointer to a foreign error or NULL.
* - marshal into a GValue holding a designated type,
* usually a GIMP type but also GLib types, e.g. GFile.
* The GValue's held type is already set, but value is uninitialized.
*
* When marshalling into a GimpObjectArray:
* Setting a GValue's value does not check the contained type.
* But validation of a GimpObjectArray does check the contained type.
* We call gimp_item_get_by_id
* GIMP_TYPE_ITEM is a superclass of most common uses.
* And then set the actual subclass type on the GimpObjectArray.
*/
/* Marshal single object ID from script into a single GObject.
*
* Requires ID's of instances of GimpItem, not for image, display, etc. also having ID.
* The GValue may hold a more specific type, e.g. GimpDrawable.
*/
pointer
marshal_ID_to_item (scheme *sc,
pointer a,
gint id,
GValue *value)
{
GObject *object;
pointer error = get_item_from_ID_in_script (sc, a, id, &object);
if (error)
return error;
/* object is NULL or valid */
/* Shallow copy, adding a reference while the GValue exists. */
g_value_set_object (value, object);
return NULL; /* no error */
}
/* Marshal a vector of ID into GimpObjectArray of same length.
* Requires ID's of instances of GimpItem
*/
pointer
marshal_vector_to_item_array (scheme *sc,
pointer vector,
GValue *value)
{
GObject **object_array;
gint id;
pointer error;
guint num_elements = sc->vptr->vector_length (vector);
g_debug ("vector has %d elements", num_elements);
/* empty vector will produce empty GimpObjectArray */
object_array = g_new0 (GObject *, num_elements + 1);
for (int j = 0; j < num_elements; ++j)
{
pointer element = sc->vptr->vector_elem (vector, j);
if (!sc->vptr->is_number (element))
{
g_free (object_array);
return script_error (sc, "Expected numeric in vector of ID", vector);
/* FUTURE more detailed error msg:
* return script_type_error_in_container (sc, "numeric", i, j, proc_name, vector);
*/
}
id = sc->vptr->ivalue (element);
error = get_item_from_ID_in_script (sc, element, id, &object_array[j]);
if (error)
{
g_free (object_array);
return error;
}
}
/* Shallow copy.
* This sets the contained type on the array.
* If the array is empty, contained type is GIMP_TYPE_ITEM.
* !!! Seems like validation checks the contained type of empty arrays,
* and fails if we default to G_TYPE_INVALID but passes if ITEM.
*/
g_value_set_boxed (value, (gpointer) object_array);
g_free (object_array);
return NULL; /* no error */
}
/* Marshal path string from script into a GValue holding type GFile */
void
marshal_path_string_to_gfile (scheme *sc,
pointer a,
GValue *value)
{
/* require sc->vptr->is_string (sc->vptr->pair_car (a)) */
GFile *gfile = g_file_new_for_path (sc->vptr->string_value (sc->vptr->pair_car (a)));
/* GLib docs say that g_file_new_for_path():
* "never fails, but the returned object might not support any I/O operation if path is malformed."
*/
g_value_set_object (value, gfile);
g_debug ("gfile arg is '%s'\n", g_file_get_parse_name (gfile));
}
/* Marshal values returned from PDB call in a GValue, into a Scheme construct to a script. */
/* Marshal a GValue holding a GFile into a string.
*
* Returns NULL or a string that must be freed.
*/
gchar *
marshal_returned_gfile_to_string (GValue *value)
{
gchar * filepath = NULL;
GObject *object = g_value_get_object (value);
/* object can be NULL, the GValue's type only indicates what should have been returned. */
if (object)
{
filepath = g_file_get_parse_name ((GFile *) object);
/* GLib docs:
* For local files with names that can safely be converted to UTF-8 the pathname is used,
* otherwise the IRI is used (a form of URI that allows UTF-8 characters unescaped).
*/
}
return filepath;
}
/* Marshal a GimpObjectArray into a Scheme list of ID's.
*
* Before v3.0, PDB procedure's return type was say INT32ARRAY,
* preceded by a type INT32 designating array length.
* Now return type is GimpObjectArray preceded by length.
*
* Returns a vector, since most arrays in Scriptfu are returned as vectors.
* An alternate implementation would be return list.
*
* Existing scheme plugins usually expect PDB to return values: len, vector.
* If ever the PDB is changed to be more object-oriented,
* scripts could use a scheme call: (vector-length vector)
* to get the length of the vector.
*/
pointer
marshal_returned_object_array_to_vector (scheme *sc,
GValue *value)
{
GObject **object_array;
gint32 n;
pointer vector;
object_array = g_value_get_boxed (value);
n = gimp_core_object_array_get_length (object_array);
vector = sc->vptr->mk_vector (sc, n);
/* Iterate starting at the back of the array, and prefix to container
* so the order of objects is not changed.
*/
for (int j = n - 1; j >= 0; j--)
{
GObject *object = object_array[j];
gint id;
if (object)
g_object_get (object, "id", &id, NULL); /* get property "id" */
else
/* Scriptfu language represents NULL object by ID of -1*/
id = -1;
sc->vptr->set_vector_elem (vector, j, sc->vptr->mk_integer (sc, id));
/* Alt: list = sc->vptr->cons (sc, sc->vptr->mk_integer (sc, id), list); */
}
/* ensure container's len equals object array's len and all elements are ID's or -1 */
return vector;
}
/* From a script numeric (a object ID) set a handle to a object.
* When ID is -1, sets handle to NULL and returns no error.
* When ID is valid, sets handle and returns no error.
* Otherwise (ID is not -1 and not valid ID of a object) returns error.
*
* Require ID is of a GIMP object, some subclass of GimpItem.
*/
static pointer
get_item_from_ID_in_script (scheme *sc,
pointer a,
gint id,
GObject **object_handle)
{
if (id == -1)
{
/* -1 is scriptfu language for NULL i.e. none for an optional */
*object_handle = NULL;
}
else
{
*object_handle = (GObject *) gimp_item_get_by_id (id);
if (! *object_handle)
return script_error (sc, "Invalid ID of GIMP item", a);
}
/* ensure *object_handle is NULL or a valid reference to a object */
return NULL; /* no error */
}
/* Walk a Scheme list of numerics, clamping into a C array of bytes.
* Expects one to four numerics.
* Returns length of list, in range [0,4]
* Length zero denotes an error: not a numeric, or list is empty.
* A list longer than expected (>4) is not an error, but extra list is not used.
*/
static void
marshal_list_of_numeric_to_rgba (scheme *sc,
pointer color_list,
guchar (*rgba)[4], /* OUT */
guint *length) /* OUT */
{
*length = 0;
for (guint i=0; i<4; i++)
{
if (sc->vptr->is_number (sc->vptr->pair_car (color_list)))
{
(*rgba)[i] = CLAMP (sc->vptr->ivalue (sc->vptr->pair_car (color_list)),
0, 255);
*length = *length + 1;
color_list = sc->vptr->pair_cdr (color_list);
}
else
{
/* Reached end of list or non-numeric. */
return;
}
}
/* *length is in [0,4] and *rgba is filled in with same count. */
}
/* Walk a C array of bytes (rgba) creating Scheme list of numeric.
* Returns list whose length is in range [0,4].
* The list is memory managed by scheme.
*/
static pointer
marshal_rgba_to_list_of_numeric (scheme *sc,
guchar rgba[4],
guint length)
{
pointer result_list = sc->NIL;
/* Walk rgba in reverse. */
for (gint i=length-1; i>=0; i--)
{
/* Prepend to list, returning new list. */
result_list = sc->vptr->cons (sc,
sc->vptr->mk_integer (sc, rgba[i]),
result_list);
}
/* list is numerics from rgba and length (list) == length. */
return result_list;
}
/* Returns a GeglColor from a scheme list.
* Caller owns the returned GeglColor.
* Returns NULL on failure:
* - list wrong length, not >1
* - list elements not numbers.
*/
GeglColor *
marshal_component_list_to_color (scheme *sc,
pointer color_list)
{
GeglColor *color_result;
guchar rgba[4];
guint list_length;
marshal_list_of_numeric_to_rgba (sc, color_list, &rgba, &list_length);
/* list_length is the count of numerics used. */
/* Dispatch on list length and create different format colors */
if (list_length == 3 || list_length == 4)
{
/* RGBA */
if (list_length == 3)
{
/* gegl has no three byte rgb. * ScriptFu sets alpha to 1.0 */
rgba[3] = 255;
}
/* Assert rgba is full */
color_result = gegl_color_new ("black");
gegl_color_set_rgba_with_space (color_result,
(gdouble) rgba[0] / 255.0,
(gdouble) rgba[1] / 255.0,
(gdouble) rgba[2] / 255.0,
(gdouble) rgba[3] / 255.0,
NULL); /* NULL defaults to sRGB */
}
else if (list_length == 1)
{
/* GRAY */
GBytes *bytes = g_bytes_new (rgba, 1);
color_result = gegl_color_new ("black");
gegl_color_set_bytes (color_result, babl_format ("Y' u8"), bytes);
g_free (bytes);
}
else if (list_length == 2)
{
/* GRAYA */
GBytes *bytes = g_bytes_new (rgba, 2);
color_result = gegl_color_new ("black");
gegl_color_set_bytes (color_result, babl_format ("Y'A u8"), bytes);
g_free (bytes);
}
else
{
color_result = NULL;
}
return color_result;
}
/* Returns a Scheme list of integers or empty list,
* the same length as the count of components in the color.
* List is length:
* 1 GRAY
* 2 GRAYA
* 3 RGB
* 4 RGBA
* Returns NIL when color is NULL.
*/
pointer
marshal_color_to_component_list (scheme *sc,
GeglColor *color)
{
pointer result;
guint count_components;
guchar rgba[4] = { 0 };
if (color == NULL)
{
result = sc->NIL;
}
else
{
count_components = babl_format_get_n_components (gegl_color_get_format (color));
switch (count_components)
{
case 3:
gegl_color_get_pixel (color, babl_format ("R'G'B' u8"), rgba);
result = marshal_rgba_to_list_of_numeric (sc, rgba, 3);
break;
case 4:
gegl_color_get_pixel (color, babl_format ("R'G'B'A u8"), rgba);
result = marshal_rgba_to_list_of_numeric (sc, rgba, 4);
break;
case 1:
/* Grayscale with TRC from space */
gegl_color_get_pixel (color, babl_format ("Y' u8"), rgba);
result = marshal_rgba_to_list_of_numeric (sc, rgba, 1);
break;
case 2:
/* Grayscale with TRC from space, separate alpha. */
gegl_color_get_pixel (color, babl_format ("Y'A u8"), rgba);
result = marshal_rgba_to_list_of_numeric (sc, rgba, 2);
break;
default:
g_warning ("%s unhandled count of color components: %d", G_STRFUNC, count_components);
result = sc->NIL;
}
}
return result;
}
/* ColorArray */
/* Returns a vector of lists, where each list is a pixel i.e.
* list of numerics, each the intensity component in a channel.
*
* array is a null-terminated array of pointers to GeglColor which is-a GObject.
*
* The returned vector can be empty, when the passed array is empty.
*/
pointer
marshal_color_array_to_vector (scheme *sc,
GimpColorArray array)
{
guint array_length = gimp_color_array_get_length (array);
pointer result = sc->vptr->mk_vector (sc, array_length);
for (guint j = 0; j < array_length; j++)
{
pointer component_list = marshal_color_to_component_list (sc, array[j]);
sc->vptr->set_vector_elem (result, j, component_list);
}
return result;
}