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5732b1184f
Add example of a simple background color effect applied via pre_paint() implementation in a ClutterEffect subclass. This is a simple effect with an incomplete GObject implementation (no properties, setters or getters) to make it as easy to follow as possible.
111 lines
2.9 KiB
C
111 lines
2.9 KiB
C
#include "cb-background-effect.h"
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G_DEFINE_TYPE (CbBackgroundEffect, cb_background_effect, CLUTTER_TYPE_EFFECT);
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#define CB_BACKGROUND_EFFECT_GET_PRIVATE(obj) (G_TYPE_INSTANCE_GET_PRIVATE ((obj), \
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CB_TYPE_BACKGROUND_EFFECT, \
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CbBackgroundEffectPrivate))
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struct _CbBackgroundEffectPrivate
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{
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CoglMaterial *background;
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CoglColor *color;
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};
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/* ClutterEffect implementation */
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/* note that if pre_paint() returns FALSE
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* any post_paint() defined for the effect will not be called
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*/
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static gboolean
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cb_background_effect_pre_paint (ClutterEffect *self)
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{
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ClutterActor *actor;
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gfloat width;
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gfloat height;
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CbBackgroundEffectPrivate *priv;
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ClutterActorMeta *meta = CLUTTER_ACTOR_META (self);
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/* check that the effect is enabled before applying it */
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if (!clutter_actor_meta_get_enabled (meta))
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return TRUE;
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priv = CB_BACKGROUND_EFFECT (self)->priv;
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/* get the associated actor's dimensions */
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actor = clutter_actor_meta_get_actor (CLUTTER_ACTOR_META (self));
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clutter_actor_get_size (actor, &width, &height);
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/* draw a grey Cogl rectangle in the background */
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cogl_set_source (priv->background);
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cogl_rectangle (0, 0, width, height);
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return TRUE;
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}
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/* GObject implementation */
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static void
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cb_background_effect_dispose (GObject *gobject)
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{
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CbBackgroundEffectPrivate *priv = CB_BACKGROUND_EFFECT (gobject)->priv;
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if (priv->background != COGL_INVALID_HANDLE)
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{
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cogl_handle_unref (priv->background);
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priv->background = COGL_INVALID_HANDLE;
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}
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if (priv->color != NULL)
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{
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cogl_color_free (priv->color);
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priv->color = NULL;
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}
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G_OBJECT_CLASS (cb_background_effect_parent_class)->dispose (gobject);
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}
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static void
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cb_background_effect_class_init (CbBackgroundEffectClass *klass)
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{
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ClutterEffectClass *effect_class = CLUTTER_EFFECT_CLASS (klass);
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GObjectClass *gobject_class = G_OBJECT_CLASS (klass);
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effect_class->pre_paint = cb_background_effect_pre_paint;
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gobject_class->dispose = cb_background_effect_dispose;
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g_type_class_add_private (klass, sizeof (CbBackgroundEffectPrivate));
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}
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static void
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cb_background_effect_init (CbBackgroundEffect *self)
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{
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CbBackgroundEffectPrivate *priv;
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priv = self->priv = CB_BACKGROUND_EFFECT_GET_PRIVATE (self);
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priv->background = cogl_material_new ();
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/* grey color for filling the background material */
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priv->color = cogl_color_new ();
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cogl_color_init_from_4ub (priv->color, 122, 122, 122, 255);
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cogl_material_set_color (priv->background, priv->color);
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}
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/* public API */
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/**
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* cb_background_effect_new:
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*
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* Creates a new #ClutterEffect which adds a grey background
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* when applied to a rectangular actor.
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*/
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ClutterEffect *
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cb_background_effect_new ()
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{
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return g_object_new (CB_TYPE_BACKGROUND_EFFECT,
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NULL);
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}
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