1 /* GStreamer Color Balance
2 * Copyright (C) 2003 Ronald Bultje <rbultje@ronald.bitfreak.net>
3 *
4 * colorbalance.c: image color balance interface design
5 * virtual class function wrappers
6 *
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.
11 *
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.
16 *
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., 51 Franklin St, Fifth Floor,
20 * Boston, MA 02110-1301, USA.
21 */
22
23 #ifdef HAVE_CONFIG_H
24 #include "config.h"
25 #endif
26
27 #include "colorbalance.h"
28
29 /**
30 * SECTION:gstcolorbalance
31 * @title: GstColorBalance
32 * @short_description: Interface for adjusting color balance settings
33 *
34 * This interface is implemented by elements which can perform some color
35 * balance operation on video frames they process. For example, modifying
36 * the brightness, contrast, hue or saturation.
37 *
38 * Example elements are 'xvimagesink' and 'colorbalance'
39 *
40 */
41
42 /* FIXME 0.11: check if we need to add API for sometimes-supportedness
43 * (aka making up for GstImplementsInterface removal) */
44
45 /* FIXME 0.11: replace signals with messages (+ make API thread-safe) */
46
47 enum
48 {
49 VALUE_CHANGED,
50 LAST_SIGNAL
51 };
52
53 static void gst_color_balance_base_init (GstColorBalanceInterface * iface);
54
55 static guint gst_color_balance_signals[LAST_SIGNAL] = { 0 };
56
57 GType
gst_color_balance_get_type(void)58 gst_color_balance_get_type (void)
59 {
60 static GType gst_color_balance_type = 0;
61
62 if (!gst_color_balance_type) {
63 static const GTypeInfo gst_color_balance_info = {
64 sizeof (GstColorBalanceInterface),
65 (GBaseInitFunc) gst_color_balance_base_init,
66 NULL,
67 NULL,
68 NULL,
69 NULL,
70 0,
71 0,
72 NULL,
73 };
74
75 gst_color_balance_type = g_type_register_static (G_TYPE_INTERFACE,
76 "GstColorBalance", &gst_color_balance_info, 0);
77 }
78
79 return gst_color_balance_type;
80 }
81
82 static void
gst_color_balance_base_init(GstColorBalanceInterface * iface)83 gst_color_balance_base_init (GstColorBalanceInterface * iface)
84 {
85 static gboolean initialized = FALSE;
86
87 if (!initialized) {
88 /**
89 * GstColorBalance::value-changed:
90 * @colorbalance: The GstColorBalance instance
91 * @channel: The #GstColorBalanceChannel
92 * @value: The new value
93 *
94 * Fired when the value of the indicated channel has changed.
95 */
96 gst_color_balance_signals[VALUE_CHANGED] =
97 g_signal_new ("value-changed",
98 GST_TYPE_COLOR_BALANCE, G_SIGNAL_RUN_LAST,
99 G_STRUCT_OFFSET (GstColorBalanceInterface, value_changed),
100 NULL, NULL, NULL,
101 G_TYPE_NONE, 2, GST_TYPE_COLOR_BALANCE_CHANNEL, G_TYPE_INT);
102
103 initialized = TRUE;
104 }
105
106 /* default virtual functions */
107 iface->list_channels = NULL;
108 iface->set_value = NULL;
109 iface->get_value = NULL;
110 iface->get_balance_type = NULL;
111 }
112
113 /**
114 * gst_color_balance_list_channels:
115 * @balance: A #GstColorBalance instance
116 *
117 * Retrieve a list of the available channels.
118 *
119 * Returns: (element-type GstColorBalanceChannel) (transfer none): A
120 * GList containing pointers to #GstColorBalanceChannel
121 * objects. The list is owned by the #GstColorBalance
122 * instance and must not be freed.
123 */
124 const GList *
gst_color_balance_list_channels(GstColorBalance * balance)125 gst_color_balance_list_channels (GstColorBalance * balance)
126 {
127 GstColorBalanceInterface *iface;
128
129 g_return_val_if_fail (GST_IS_COLOR_BALANCE (balance), NULL);
130
131 iface = GST_COLOR_BALANCE_GET_INTERFACE (balance);
132
133 if (iface->list_channels) {
134 return iface->list_channels (balance);
135 }
136
137 return NULL;
138 }
139
140 /**
141 * gst_color_balance_set_value:
142 * @balance: A #GstColorBalance instance
143 * @channel: A #GstColorBalanceChannel instance
144 * @value: The new value for the channel.
145 *
146 * Sets the current value of the channel to the passed value, which must
147 * be between min_value and max_value.
148 *
149 * See Also: The #GstColorBalanceChannel.min_value and
150 * #GstColorBalanceChannel.max_value members of the
151 * #GstColorBalanceChannel object.
152 */
153 void
gst_color_balance_set_value(GstColorBalance * balance,GstColorBalanceChannel * channel,gint value)154 gst_color_balance_set_value (GstColorBalance * balance,
155 GstColorBalanceChannel * channel, gint value)
156 {
157 GstColorBalanceInterface *iface = GST_COLOR_BALANCE_GET_INTERFACE (balance);
158
159 if (iface->set_value) {
160 iface->set_value (balance, channel, value);
161 }
162 }
163
164 /**
165 * gst_color_balance_get_value:
166 * @balance: A #GstColorBalance instance
167 * @channel: A #GstColorBalanceChannel instance
168 *
169 * Retrieve the current value of the indicated channel, between min_value
170 * and max_value.
171 *
172 * See Also: The #GstColorBalanceChannel.min_value and
173 * #GstColorBalanceChannel.max_value members of the
174 * #GstColorBalanceChannel object.
175 *
176 * Returns: The current value of the channel.
177 */
178 gint
gst_color_balance_get_value(GstColorBalance * balance,GstColorBalanceChannel * channel)179 gst_color_balance_get_value (GstColorBalance * balance,
180 GstColorBalanceChannel * channel)
181 {
182 GstColorBalanceInterface *iface;
183
184 g_return_val_if_fail (GST_IS_COLOR_BALANCE (balance), 0);
185
186 iface = GST_COLOR_BALANCE_GET_INTERFACE (balance);
187
188 if (iface->get_value) {
189 return iface->get_value (balance, channel);
190 }
191
192 return channel->min_value;
193 }
194
195 /**
196 * gst_color_balance_get_balance_type:
197 * @balance: The #GstColorBalance implementation
198 *
199 * Get the #GstColorBalanceType of this implementation.
200 *
201 * Returns: A the #GstColorBalanceType.
202 */
203 GstColorBalanceType
gst_color_balance_get_balance_type(GstColorBalance * balance)204 gst_color_balance_get_balance_type (GstColorBalance * balance)
205 {
206 GstColorBalanceInterface *iface;
207
208 g_return_val_if_fail (GST_IS_COLOR_BALANCE (balance),
209 GST_COLOR_BALANCE_SOFTWARE);
210
211 iface = GST_COLOR_BALANCE_GET_INTERFACE (balance);
212
213 g_return_val_if_fail (iface->get_balance_type != NULL,
214 GST_COLOR_BALANCE_SOFTWARE);
215
216 return iface->get_balance_type (balance);
217 }
218
219 /**
220 * gst_color_balance_value_changed:
221 * @balance: A #GstColorBalance instance
222 * @channel: A #GstColorBalanceChannel whose value has changed
223 * @value: The new value of the channel
224 *
225 * A helper function called by implementations of the GstColorBalance
226 * interface. It fires the #GstColorBalance::value-changed signal on the
227 * instance, and the #GstColorBalanceChannel::value-changed signal on the
228 * channel object.
229 */
230 void
gst_color_balance_value_changed(GstColorBalance * balance,GstColorBalanceChannel * channel,gint value)231 gst_color_balance_value_changed (GstColorBalance * balance,
232 GstColorBalanceChannel * channel, gint value)
233 {
234
235 g_return_if_fail (GST_IS_COLOR_BALANCE (balance));
236
237 g_signal_emit (G_OBJECT (balance),
238 gst_color_balance_signals[VALUE_CHANGED], 0, channel, value);
239
240 g_signal_emit_by_name (G_OBJECT (channel), "value_changed", value);
241 }
242