422 lines
11 KiB
C
422 lines
11 KiB
C
/* GTK - The GIMP Toolkit
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* Copyright (C) 2010 Carlos Garnacho <carlosg@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 2 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, write to the
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* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
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* Boston, MA 02111-1307, USA.
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*/
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#include "config.h"
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#include "gtkgradient.h"
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#include "gtkstylecontextprivate.h"
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#include "gtkstyleproperties.h"
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#include "gtkintl.h"
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/**
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* SECTION:gtkgradient
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* @Short_description: Gradients
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* @Title: GtkGradient
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*
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* GtkGradient is a boxed type that represents a gradient.
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* It is the result of parsing a
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* <link linkend="gtkcssprovider-gradients">gradient expression</link>.
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* To obtain the gradient represented by a GtkGradient, it has to
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* be resolved with gtk_gradient_resolve(), which replaces all
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* symbolic color references by the colors they refer to (in a given
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* context) and constructs a #cairo_pattern_t value.
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*
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* It is not normally necessary to deal directly with #GtkGradients,
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* since they are mostly used behind the scenes by #GtkStyleContext and
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* #GtkCssProvider.
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*/
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G_DEFINE_BOXED_TYPE (GtkGradient, gtk_gradient,
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gtk_gradient_ref, gtk_gradient_unref)
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typedef struct ColorStop ColorStop;
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struct ColorStop
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{
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gdouble offset;
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GtkSymbolicColor *color;
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};
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struct _GtkGradient
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{
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gdouble x0;
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gdouble y0;
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gdouble x1;
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gdouble y1;
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gdouble radius0;
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gdouble radius1;
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GArray *stops;
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guint ref_count;
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};
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/**
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* gtk_gradient_new_linear:
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* @x0: X coordinate of the starting point
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* @y0: Y coordinate of the starting point
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* @x1: X coordinate of the end point
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* @y1: Y coordinate of the end point
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*
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* Creates a new linear gradient along the line defined by (x0, y0) and (x1, y1). Before using the gradient
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* a number of stop colors must be added through gtk_gradient_add_color_stop().
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*
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* Returns: A newly created #GtkGradient
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*
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* Since: 3.0
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**/
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GtkGradient *
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gtk_gradient_new_linear (gdouble x0,
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gdouble y0,
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gdouble x1,
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gdouble y1)
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{
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GtkGradient *gradient;
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gradient = g_slice_new (GtkGradient);
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gradient->stops = g_array_new (FALSE, FALSE, sizeof (ColorStop));
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gradient->x0 = x0;
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gradient->y0 = y0;
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gradient->x1 = x1;
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gradient->y1 = y1;
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gradient->radius0 = 0;
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gradient->radius1 = 0;
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gradient->ref_count = 1;
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return gradient;
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}
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/**
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* gtk_gradient_new_radial:
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* @x0: X coordinate of the start circle
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* @y0: Y coordinate of the start circle
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* @radius0: radius of the start circle
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* @x1: X coordinate of the end circle
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* @y1: Y coordinate of the end circle
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* @radius1: radius of the end circle
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*
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* Creates a new radial gradient along the two circles defined by (x0, y0, radius0) and
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* (x1, y1, radius1). Before using the gradient a number of stop colors must be added
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* through gtk_gradient_add_color_stop().
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*
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* Returns: A newly created #GtkGradient
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*
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* Since: 3.0
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**/
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GtkGradient *
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gtk_gradient_new_radial (gdouble x0,
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gdouble y0,
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gdouble radius0,
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gdouble x1,
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gdouble y1,
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gdouble radius1)
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{
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GtkGradient *gradient;
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gradient = g_slice_new (GtkGradient);
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gradient->stops = g_array_new (FALSE, FALSE, sizeof (ColorStop));
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gradient->x0 = x0;
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gradient->y0 = y0;
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gradient->x1 = x1;
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gradient->y1 = y1;
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gradient->radius0 = radius0;
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gradient->radius1 = radius1;
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gradient->ref_count = 1;
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return gradient;
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}
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/**
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* gtk_gradient_add_color_stop:
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* @gradient: a #GtkGradient
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* @offset: offset for the color stop
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* @color: color to use
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*
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* Adds a stop color to @gradient.
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*
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* Since: 3.0
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**/
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void
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gtk_gradient_add_color_stop (GtkGradient *gradient,
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gdouble offset,
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GtkSymbolicColor *color)
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{
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ColorStop stop;
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g_return_if_fail (gradient != NULL);
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stop.offset = offset;
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stop.color = gtk_symbolic_color_ref (color);
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g_array_append_val (gradient->stops, stop);
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}
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/**
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* gtk_gradient_ref:
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* @gradient: a #GtkGradient
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*
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* Increases the reference count of @gradient.
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*
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* Returns: The same @gradient
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*
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* Since: 3.0
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**/
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GtkGradient *
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gtk_gradient_ref (GtkGradient *gradient)
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{
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g_return_val_if_fail (gradient != NULL, NULL);
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gradient->ref_count++;
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return gradient;
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}
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/**
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* gtk_gradient_unref:
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* @gradient: a #GtkGradient
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*
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* Decreases the reference count of @gradient, freeing its memory
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* if the reference count reaches 0.
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*
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* Since: 3.0
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**/
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void
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gtk_gradient_unref (GtkGradient *gradient)
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{
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g_return_if_fail (gradient != NULL);
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gradient->ref_count--;
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if (gradient->ref_count == 0)
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{
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guint i;
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for (i = 0; i < gradient->stops->len; i++)
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{
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ColorStop *stop;
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stop = &g_array_index (gradient->stops, ColorStop, i);
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gtk_symbolic_color_unref (stop->color);
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}
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g_array_free (gradient->stops, TRUE);
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g_slice_free (GtkGradient, gradient);
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}
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}
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/**
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* gtk_gradient_resolve:
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* @gradient: a #GtkGradient
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* @props: #GtkStyleProperties to use when resolving named colors
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* @resolved_gradient: (out): return location for the resolved pattern
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*
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* If @gradient is resolvable, @resolved_gradient will be filled in
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* with the resolved gradient as a cairo_pattern_t, and %TRUE will
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* be returned. Generally, if @gradient can't be resolved, it is
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* due to it being defined on top of a named color that doesn't
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* exist in @props.
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*
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* Returns: %TRUE if the gradient has been resolved
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*
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* Since: 3.0
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**/
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gboolean
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gtk_gradient_resolve (GtkGradient *gradient,
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GtkStyleProperties *props,
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cairo_pattern_t **resolved_gradient)
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{
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cairo_pattern_t *pattern;
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guint i;
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g_return_val_if_fail (gradient != NULL, FALSE);
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g_return_val_if_fail (GTK_IS_STYLE_PROPERTIES (props), FALSE);
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g_return_val_if_fail (resolved_gradient != NULL, FALSE);
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if (gradient->radius0 == 0 && gradient->radius1 == 0)
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pattern = cairo_pattern_create_linear (gradient->x0, gradient->y0,
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gradient->x1, gradient->y1);
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else
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pattern = cairo_pattern_create_radial (gradient->x0, gradient->y0,
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gradient->radius0,
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gradient->x1, gradient->y1,
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gradient->radius1);
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for (i = 0; i < gradient->stops->len; i++)
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{
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ColorStop *stop;
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GdkRGBA color;
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stop = &g_array_index (gradient->stops, ColorStop, i);
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if (!gtk_symbolic_color_resolve (stop->color, props, &color))
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{
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cairo_pattern_destroy (pattern);
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return FALSE;
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}
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cairo_pattern_add_color_stop_rgba (pattern, stop->offset,
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color.red, color.green,
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color.blue, color.alpha);
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}
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*resolved_gradient = pattern;
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return TRUE;
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}
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cairo_pattern_t *
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gtk_gradient_resolve_for_context (GtkGradient *gradient,
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GtkStyleContext *context)
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{
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cairo_pattern_t *pattern;
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guint i;
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g_return_val_if_fail (gradient != NULL, FALSE);
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g_return_val_if_fail (GTK_IS_STYLE_CONTEXT (context), FALSE);
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if (gradient->radius0 == 0 && gradient->radius1 == 0)
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pattern = cairo_pattern_create_linear (gradient->x0, gradient->y0,
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gradient->x1, gradient->y1);
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else
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pattern = cairo_pattern_create_radial (gradient->x0, gradient->y0,
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gradient->radius0,
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gradient->x1, gradient->y1,
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gradient->radius1);
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for (i = 0; i < gradient->stops->len; i++)
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{
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ColorStop *stop;
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GdkRGBA rgba;
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stop = &g_array_index (gradient->stops, ColorStop, i);
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/* if color resolving fails, assume transparency */
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if (!_gtk_style_context_resolve_color (context, stop->color, &rgba))
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rgba.red = rgba.green = rgba.blue = rgba.alpha = 0.0;
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cairo_pattern_add_color_stop_rgba (pattern, stop->offset,
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rgba.red, rgba.green,
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rgba.blue, rgba.alpha);
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}
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return pattern;
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}
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static void
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append_number (GString *str,
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double d,
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const char *zero,
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const char *half,
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const char *one)
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{
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if (zero && d == 0.0)
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g_string_append (str, zero);
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else if (half && d == 0.5)
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g_string_append (str, half);
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else if (one && d == 1.0)
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g_string_append (str, one);
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else
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{
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char buf[G_ASCII_DTOSTR_BUF_SIZE];
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g_ascii_dtostr (buf, sizeof (buf), d);
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g_string_append (str, buf);
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}
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}
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/**
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* gtk_gradient_to_string:
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* @gradient: the gradient to print
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*
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* Creates a string representation for @gradient that is suitable
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* for using in GTK CSS files.
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*
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* Returns: A string representation for @gradient
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**/
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char *
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gtk_gradient_to_string (GtkGradient *gradient)
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{
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GString *str;
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guint i;
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g_return_val_if_fail (gradient != NULL, NULL);
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str = g_string_new ("-gtk-gradient (");
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if (gradient->radius0 == 0 && gradient->radius1 == 0)
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{
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g_string_append (str, "linear, ");
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append_number (str, gradient->x0, "left", "center", "right");
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g_string_append_c (str, ' ');
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append_number (str, gradient->y0, "top", "center", "bottom");
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g_string_append (str, ", ");
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append_number (str, gradient->x1, "left", "center", "right");
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g_string_append_c (str, ' ');
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append_number (str, gradient->y1, "top", "center", "bottom");
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}
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else
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{
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g_string_append (str, "radial, ");
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append_number (str, gradient->x0, "left", "center", "right");
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g_string_append_c (str, ' ');
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append_number (str, gradient->y0, "top", "center", "bottom");
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g_string_append (str, ", ");
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append_number (str, gradient->radius0, NULL, NULL, NULL);
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g_string_append (str, ", ");
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append_number (str, gradient->x1, "left", "center", "right");
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g_string_append_c (str, ' ');
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append_number (str, gradient->y1, "top", "center", "bottom");
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g_string_append (str, ", ");
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append_number (str, gradient->radius1, NULL, NULL, NULL);
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}
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for (i = 0; i < gradient->stops->len; i++)
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{
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ColorStop *stop;
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char *s;
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stop = &g_array_index (gradient->stops, ColorStop, i);
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g_string_append (str, ", ");
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if (stop->offset == 0.0)
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g_string_append (str, "from (");
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else if (stop->offset == 1.0)
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g_string_append (str, "to (");
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else
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{
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g_string_append (str, "color-stop (");
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append_number (str, stop->offset, NULL, NULL, NULL);
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g_string_append (str, ", ");
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}
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s = gtk_symbolic_color_to_string (stop->color);
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g_string_append (str, s);
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g_free (s);
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g_string_append (str, ")");
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}
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g_string_append (str, ")");
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return g_string_free (str, FALSE);
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}
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