6caae9c53b
Ratio expressions have the form 'x : y' (the ':' operator has the
highest precedence for a binary operator, and is left-associative).
Given a reference value 'a', the expression evaluates to
'a * (x / y)'.
Ratio expressions can be controlled by the caller by:
- Enabling or disabling them: They're meant to be used when the
eevl servers two paired entries, and can be disabled otherwise.
- Setting the reference value: That's normally the value of the
"other" entry of the pair--the one not currently being
evaluated.
- Inverting the ratios: Normally, one entry refers to the
antecedent term of the ratio, and the other entry refers to the
consequent term of the ratio. When evaluating the latter one,
the ratio should be inverted.
98 lines
3.4 KiB
C
98 lines
3.4 KiB
C
/* LIBGIMP - The GIMP Library
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* Copyright (C) 1995-1997 Peter Mattis and Spencer Kimball
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*
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* gimpeevl.h
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* Copyright (C) 2008-2009 Fredrik Alstromer <roe@excu.se>
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* Copyright (C) 2008-2009 Martin Nordholts <martinn@svn.gnome.org>
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*
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* This library is free software: you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 3 of the License, or (at your option) any later version.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with this library. If not, see
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* <http://www.gnu.org/licenses/>.
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*/
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#ifndef __GIMP_EEVL_H__
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#define __GIMP_EEVL_H__
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G_BEGIN_DECLS
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/**
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* GimpEevlQuantity:
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* @value: In reference units.
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* @dimension: in has a dimension of 1, in^2 has a dimension of 2 etc
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*/
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typedef struct
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{
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gdouble value;
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gint dimension;
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} GimpEevlQuantity;
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/**
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* GimpEevlUnitResolverProc:
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* @identifier: Identifier of unit to resolve or %NULL if default unit
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* should be resolved.
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* @result: Units per reference unit. For example, in GIMP the
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* reference unit is inches so resolving "mm" should
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* return 25.4 since there are 25.4 millimeters per inch.
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* @data: Data given to gimp_eevl_evaluate().
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*
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* Returns: If the unit was successfully resolved or not.
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*
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*/
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typedef gboolean (* GimpEevlUnitResolverProc) (const gchar *identifier,
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GimpEevlQuantity *result,
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gpointer data);
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/**
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* GimpEevlOptions:
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* @unit_resolver_proc: Unit resolver callback.
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* @data: Data passed to unit resolver.
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* @ratio_expressions: Allow ratio expressions
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* @ratio_invert: Invert ratios
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* @ratio_quantity: Quantity to multiply ratios by
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*/
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typedef struct
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{
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GimpEevlUnitResolverProc unit_resolver_proc;
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gpointer data;
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gboolean ratio_expressions;
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gboolean ratio_invert;
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GimpEevlQuantity ratio_quantity;
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} GimpEevlOptions;
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#define GIMP_EEVL_OPTIONS_INIT \
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((const GimpEevlOptions) \
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{ \
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.unit_resolver_proc = NULL, \
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.data = NULL, \
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\
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.ratio_expressions = FALSE, \
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.ratio_invert = FALSE, \
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.ratio_quantity = {0.0, 0} \
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})
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gboolean gimp_eevl_evaluate (const gchar *string,
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const GimpEevlOptions *options,
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GimpEevlQuantity *result,
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const gchar **error_pos,
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GError **error);
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G_END_DECLS
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#endif /* __GIMP_EEVL_H__ */
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