1 /* GStreamer Color Balance
2 * Copyright (C) 2003 Ronald Bultje <rbultje@ronald.bitfreak.net>
4 * colorbalance.c: image color balance interface design
5 * virtual class function wrappers
7 * This library is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU Library General Public
9 * License as published by the Free Software Foundation; either
10 * version 2 of the License, or (at your option) any later version.
12 * This library is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15 * Library General Public License for more details.
17 * You should have received a copy of the GNU Library General Public
18 * License along with this library; if not, write to the
19 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
20 * Boston, MA 02111-1307, USA.
27 #include "colorbalance.h"
28 #include "interfaces-marshal.h"
31 * SECTION:gstcolorbalance
32 * @short_description: Interface for adjusting color balance settings
35 * This interface is implemented by elements which can perform some color
36 * balance operation on video frames they process. For example, modifying
37 * the brightness, contrast, hue or saturation.
39 * Example elements are 'xvimagesink' and 'colorbalance'
44 /* FIXME 0.11: check if we need to add API for sometimes-supportedness
45 * (aka making up for GstImplementsInterface removal) */
47 /* FIXME 0.11: replace signals with messages (+ make API thread-safe) */
55 static void gst_color_balance_class_init (GstColorBalanceClass * klass);
57 static guint gst_color_balance_signals[LAST_SIGNAL] = { 0 };
60 gst_color_balance_get_type (void)
62 static GType gst_color_balance_type = 0;
64 if (!gst_color_balance_type) {
65 static const GTypeInfo gst_color_balance_info = {
66 sizeof (GstColorBalanceClass),
67 (GBaseInitFunc) gst_color_balance_class_init,
77 gst_color_balance_type = g_type_register_static (G_TYPE_INTERFACE,
78 "GstColorBalance", &gst_color_balance_info, 0);
81 return gst_color_balance_type;
85 gst_color_balance_class_init (GstColorBalanceClass * klass)
87 static gboolean initialized = FALSE;
91 * GstColorBalance::value-changed:
92 * @colorbalance: The GstColorBalance instance
93 * @channel: The #GstColorBalanceChannel
94 * @value: The new value
96 * Fired when the value of the indicated channel has changed.
98 gst_color_balance_signals[VALUE_CHANGED] =
99 g_signal_new ("value-changed",
100 GST_TYPE_COLOR_BALANCE, G_SIGNAL_RUN_LAST,
101 G_STRUCT_OFFSET (GstColorBalanceClass, value_changed),
103 gst_interfaces_marshal_VOID__OBJECT_INT,
104 G_TYPE_NONE, 2, GST_TYPE_COLOR_BALANCE_CHANNEL, G_TYPE_INT);
109 klass->balance_type = GST_COLOR_BALANCE_SOFTWARE;
111 /* default virtual functions */
112 klass->list_channels = NULL;
113 klass->set_value = NULL;
114 klass->get_value = NULL;
118 * gst_color_balance_list_channels:
119 * @balance: A #GstColorBalance instance
121 * Retrieve a list of the available channels.
123 * Returns: A GList containing pointers to #GstColorBalanceChannel objects.
124 * The list is owned by the #GstColorBalance instance and must not
128 gst_color_balance_list_channels (GstColorBalance * balance)
130 GstColorBalanceClass *klass = GST_COLOR_BALANCE_GET_CLASS (balance);
132 if (klass->list_channels) {
133 return klass->list_channels (balance);
140 * gst_color_balance_set_value:
141 * @balance: A #GstColorBalance instance
142 * @channel: A #GstColorBalanceChannel instance
143 * @value: The new value for the channel.
145 * Sets the current value of the channel to the passed value, which must
146 * be between min_value and max_value.
148 * See Also: The #GstColorBalanceChannel.min_value and
149 * #GstColorBalanceChannel.max_value members of the
150 * #GstColorBalanceChannel object.
153 gst_color_balance_set_value (GstColorBalance * balance,
154 GstColorBalanceChannel * channel, gint value)
156 GstColorBalanceClass *klass = GST_COLOR_BALANCE_GET_CLASS (balance);
158 if (klass->set_value) {
159 klass->set_value (balance, channel, value);
164 * gst_color_balance_get_value:
165 * @balance: A #GstColorBalance instance
166 * @channel: A #GstColorBalanceChannel instance
168 * Retrieve the current value of the indicated channel, between min_value
171 * See Also: The #GstColorBalanceChannel.min_value and
172 * #GstColorBalanceChannel.max_value members of the
173 * #GstColorBalanceChannel object.
175 * Returns: The current value of the channel.
178 gst_color_balance_get_value (GstColorBalance * balance,
179 GstColorBalanceChannel * channel)
181 GstColorBalanceClass *klass = GST_COLOR_BALANCE_GET_CLASS (balance);
183 if (klass->get_value) {
184 return klass->get_value (balance, channel);
187 return channel->min_value;
191 * gst_color_balance_get_balance_type:
192 * @balance: The #GstColorBalance implementation
194 * Get the #GstColorBalanceType of this implementation.
196 * Returns: A the #GstColorBalanceType.
201 gst_color_balance_get_balance_type (GstColorBalance * balance)
203 GstColorBalanceClass *klass = GST_COLOR_BALANCE_GET_CLASS (balance);
205 return klass->balance_type;
209 * gst_color_balance_value_changed:
210 * @balance: A #GstColorBalance instance
211 * @channel: A #GstColorBalanceChannel whose value has changed
212 * @value: The new value of the channel
214 * A helper function called by implementations of the GstColorBalance
215 * interface. It fires the #GstColorBalance::value-changed signal on the
216 * instance, and the #GstColorBalanceChannel::value-changed signal on the
220 gst_color_balance_value_changed (GstColorBalance * balance,
221 GstColorBalanceChannel * channel, gint value)
223 g_signal_emit (G_OBJECT (balance),
224 gst_color_balance_signals[VALUE_CHANGED], 0, channel, value);
226 g_signal_emit_by_name (G_OBJECT (channel), "value_changed", value);