docs: Add effects chapter, with introduction and first recipe
Add an effects chapter which gives a broad overview of the abstract classes in the effects API, plus a short example of how to apply one of the stock Clutter effects (ClutterColorizeEffect). The recipe explains how to create a custom ClutterDeformEffect to produce a page fold (code based on ClutterPageTurnEffect). The example code includes the effect class plus a small application to apply it to a texture.
This commit is contained in:
Elliot Smith
@ -18,6 +18,8 @@ noinst_PROGRAMS = \
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animations-rotating \
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animations-scaling \
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animations-scaling-zoom \
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effects-built-in \
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effects-custom-deform \
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text-shadow \
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textures-reflection \
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textures-split-go \
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@ -81,6 +83,8 @@ animations_reuse_SOURCES = animations-reuse.c
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animations_rotating_SOURCES = animations-rotating.c
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animations_scaling_SOURCES = animations-scaling.c
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animations_scaling_zoom_SOURCES = animations-scaling-zoom.c
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effects_built_in_SOURCES = effects-built-in.c
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effects_custom_deform_SOURCES = cb-page-fold-effect.c cb-page-fold-effect.h effects-custom-deform.c
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text_shadow_SOURCES = text-shadow.c
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textures_reflection_SOURCES = textures-reflection.c
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textures_split_go_SOURCES = textures-split-go.c
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250
doc/cookbook/examples/cb-page-fold-effect.c
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250
doc/cookbook/examples/cb-page-fold-effect.c
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@ -0,0 +1,250 @@
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#include <math.h>
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#include "cb-page-fold-effect.h"
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G_DEFINE_TYPE (CbPageFoldEffect, cb_page_fold_effect, CLUTTER_TYPE_DEFORM_EFFECT);
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#define CB_PAGE_FOLD_EFFECT_GET_PRIVATE(obj) (G_TYPE_INSTANCE_GET_PRIVATE ((obj), \
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CB_TYPE_PAGE_FOLD_EFFECT, \
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CbPageFoldEffectPrivate))
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struct _CbPageFoldEffectPrivate
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{
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gdouble angle;
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gdouble period;
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};
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enum {
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PROP_0,
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PROP_PERIOD,
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PROP_ANGLE,
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PROP_LAST
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};
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static GParamSpec *obj_props[PROP_LAST];
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/* ClutterDeformEffect implementation */
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static void
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cb_page_fold_effect_deform_vertex (ClutterDeformEffect *effect,
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gfloat width,
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gfloat height,
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CoglTextureVertex *vertex)
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{
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CbPageFoldEffectPrivate *priv = CB_PAGE_FOLD_EFFECT (effect)->priv;
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gfloat radians = (priv->angle * priv->period) / (180.0f / G_PI);
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/* rotate from the center of the actor on the y axis */
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gfloat adjusted_x = vertex->x - (width / 2);
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/* only rotate vertices to the right of the middle of the actor */
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if (adjusted_x >= 0.0)
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{
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vertex->x = (vertex->z * sin (radians))
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+ (adjusted_x * cos (radians))
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+ width / 2;
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/* NB add 1 to z to prevent "z fighting"; otherwise, when fully-folded
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* the image has "stripes" where vertices from the folded part
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* of the actor interfere with vertices from the unfolded part
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*/
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vertex->z = (vertex->z * cos (radians))
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+ (adjusted_x * sin (radians))
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+ 1;
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}
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/* adjust depth of all vertices so they fit inside the actor while folding;
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* this has the effect of making the image smaller within the texture,
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* but does produce a cleaner fold animation
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*/
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vertex->z -= width / 2;
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}
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/* GObject implementation */
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static void
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cb_page_fold_effect_set_property (GObject *gobject,
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guint prop_id,
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const GValue *value,
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GParamSpec *pspec)
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{
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CbPageFoldEffect *effect = CB_PAGE_FOLD_EFFECT (gobject);
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switch (prop_id)
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{
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case PROP_PERIOD:
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cb_page_fold_effect_set_period (effect, g_value_get_double (value));
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break;
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case PROP_ANGLE:
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cb_page_fold_effect_set_angle (effect, g_value_get_double (value));
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break;
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default:
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G_OBJECT_WARN_INVALID_PROPERTY_ID (gobject, prop_id, pspec);
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break;
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}
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}
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static void
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cb_page_fold_effect_get_property (GObject *gobject,
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guint prop_id,
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GValue *value,
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GParamSpec *pspec)
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{
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CbPageFoldEffectPrivate *priv = CB_PAGE_FOLD_EFFECT (gobject)->priv;
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switch (prop_id)
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{
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case PROP_PERIOD:
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g_value_set_double (value, priv->period);
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break;
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case PROP_ANGLE:
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g_value_set_double (value, priv->angle);
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break;
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default:
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G_OBJECT_WARN_INVALID_PROPERTY_ID (gobject, prop_id, pspec);
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break;
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}
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}
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/* GObject class and instance init */
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static void
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cb_page_fold_effect_class_init (CbPageFoldEffectClass *klass)
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{
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GParamSpec *pspec;
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ClutterDeformEffectClass *effect_class = CLUTTER_DEFORM_EFFECT_CLASS (klass);
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GObjectClass *gobject_class = G_OBJECT_CLASS (klass);
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effect_class->deform_vertex = cb_page_fold_effect_deform_vertex;
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gobject_class->set_property = cb_page_fold_effect_set_property;
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gobject_class->get_property = cb_page_fold_effect_get_property;
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g_type_class_add_private (klass, sizeof (CbPageFoldEffectPrivate));
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/**
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* CbPageFoldEffect:period:
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*
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* The period of the page fold, between 0.0 (no fold) and
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* 1.0 (fully folded)
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*/
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pspec = g_param_spec_double ("period",
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"Period",
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"The period of the page fold",
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0.0, 1.0,
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0.0,
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G_PARAM_READWRITE);
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obj_props[PROP_PERIOD] = pspec;
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g_object_class_install_property (gobject_class, PROP_PERIOD, pspec);
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/**
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* CbPageFoldEffect:angle:
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*
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* The angle of the page fold, in degrees, between 0.0 and 180.0
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*/
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pspec = g_param_spec_double ("angle",
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"Angle",
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"The angle of the page fold, in degrees",
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0.0, 180.0,
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0.0,
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G_PARAM_READWRITE);
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obj_props[PROP_ANGLE] = pspec;
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g_object_class_install_property (gobject_class, PROP_ANGLE, pspec);
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}
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static void
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cb_page_fold_effect_init (CbPageFoldEffect *self)
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{
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CbPageFoldEffectPrivate *priv;
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priv = self->priv = CB_PAGE_FOLD_EFFECT_GET_PRIVATE (self);
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priv->period = 0.0;
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priv->angle = 0.0;
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}
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/* public API */
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ClutterEffect *
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cb_page_fold_effect_new (gdouble angle,
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gdouble period)
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{
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return g_object_new (CB_TYPE_PAGE_FOLD_EFFECT,
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"angle", angle,
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"period", period,
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NULL);
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}
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/**
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* cb_page_fold_effect_set_period:
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* @effect: a #CbPageFoldEffect
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* @period: the period of the page fold, between 0.0 and 1.0
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*
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* Sets the period of the page fold, between 0.0 (no fold)
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* and 1.0 (fully folded)
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*/
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void
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cb_page_fold_effect_set_period (CbPageFoldEffect *effect,
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gdouble period)
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{
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g_return_if_fail (CB_IS_PAGE_FOLD_EFFECT (effect));
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g_return_if_fail (period >= 0.0 && period <= 1.0);
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effect->priv->period = period;
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clutter_deform_effect_invalidate (CLUTTER_DEFORM_EFFECT (effect));
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}
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/**
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* cb_page_fold_effect_get_period:
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* @effect: a #CbPageFoldEffect
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*
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* Retrieves the value set using cb_page_fold_effect_get_period()
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*
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* Return value: the period of the page fold
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*/
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gdouble
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cb_page_fold_effect_get_period (CbPageFoldEffect *effect)
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{
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g_return_val_if_fail (CB_IS_PAGE_FOLD_EFFECT (effect), 0.0);
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return effect->priv->period;
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}
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/**
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* cb_page_fold_effect_set_angle:
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* @effect: #CbPageFoldEffect
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* @angle: the angle of the page fold, in degrees
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*
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* Sets the angle of the page fold, in degrees; must be a value between
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* 0.0 and 180.0
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*/
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void
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cb_page_fold_effect_set_angle (CbPageFoldEffect *effect,
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gdouble angle)
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{
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g_return_if_fail (CB_IS_PAGE_FOLD_EFFECT (effect));
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g_return_if_fail (angle >= 0.0 && angle <= 180.0);
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effect->priv->angle = angle;
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clutter_deform_effect_invalidate (CLUTTER_DEFORM_EFFECT (effect));
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}
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/**
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* cb_page_fold_effect_get_angle:
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* @effect: a #CbPageFoldEffect:
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*
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* Retrieves the angle of the page fold, in degrees
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*
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* Return value: the angle of the page fold
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*/
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gdouble
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cb_page_fold_effect_get_angle (CbPageFoldEffect *effect)
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{
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g_return_val_if_fail (CB_IS_PAGE_FOLD_EFFECT (effect), 0.0);
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return effect->priv->angle;
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}
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49
doc/cookbook/examples/cb-page-fold-effect.h
Normal file
49
doc/cookbook/examples/cb-page-fold-effect.h
Normal file
@ -0,0 +1,49 @@
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#ifndef __CB_PAGE_FOLD_EFFECT_H__
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#define __CB_PAGE_FOLD_EFFECT_H__
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#include <clutter/clutter.h>
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GType cb_page_fold_effect_get_type (void);
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#define CB_TYPE_PAGE_FOLD_EFFECT (cb_page_fold_effect_get_type ())
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#define CB_PAGE_FOLD_EFFECT(obj) (G_TYPE_CHECK_INSTANCE_CAST ((obj), \
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CB_TYPE_PAGE_FOLD_EFFECT, \
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CbPageFoldEffect))
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#define CB_IS_PAGE_FOLD_EFFECT(obj) (G_TYPE_CHECK_INSTANCE_TYPE ((obj), \
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CB_TYPE_PAGE_FOLD_EFFECT))
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#define CB_PAGE_FOLD_EFFECT_CLASS(klass) (G_TYPE_CHECK_CLASS_CAST ((klass), \
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CB_TYPE_PAGE_FOLD_EFFECT, \
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CbPageFoldEffectClass))
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#define CB_IS_PAGE_FOLD_EFFECT_CLASS(klass) (G_TYPE_CHECK_CLASS_TYPE ((klass), \
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CB_TYPE_PAGE_FOLD_EFFECT))
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#define CB_PAGE_FOLD_EFFECT_GET_CLASS(obj) (G_TYPE_INSTANCE_GET_CLASS ((obj), \
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CB_TYPE_PAGE_FOLD_EFFECT, \
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CbPageFoldEffectClass))
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typedef struct _CbPageFoldEffectPrivate CbPageFoldEffectPrivate;
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typedef struct _CbPageFoldEffect CbPageFoldEffect;
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typedef struct _CbPageFoldEffectClass CbPageFoldEffectClass;
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/* object */
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struct _CbPageFoldEffect
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{
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ClutterDeformEffect parent_instance;
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CbPageFoldEffectPrivate *priv;
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};
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/* class */
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struct _CbPageFoldEffectClass
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{
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ClutterDeformEffectClass parent_class;
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};
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ClutterEffect *cb_page_fold_effect_new (gdouble angle,
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gdouble period);
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void cb_page_fold_effect_set_angle (CbPageFoldEffect *effect,
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gdouble angle);
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void cb_page_fold_effect_set_period (CbPageFoldEffect *effect,
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gdouble period);
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gdouble cb_page_fold_effect_get_period (CbPageFoldEffect *effect);
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gdouble cb_page_fold_effect_get_angle (CbPageFoldEffect *effect);
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#endif /* __CB_PAGE_FOLD_EFFECT_H__ */
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58
doc/cookbook/examples/effects-built-in.c
Normal file
58
doc/cookbook/examples/effects-built-in.c
Normal file
@ -0,0 +1,58 @@
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#include <clutter/clutter.h>
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int
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main (int argc,
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char *argv[])
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{
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ClutterActor *stage;
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ClutterActor *texture;
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ClutterConstraint *constraint_x;
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ClutterConstraint *constraint_y;
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ClutterColor *pink;
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ClutterEffect *effect;
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gchar *filename;
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if (argc < 2)
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{
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g_print ("Usage: %s <path to image file>\n", argv[0]);
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return 1;
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}
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filename = argv[1];
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clutter_init (&argc, &argv);
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stage = clutter_stage_new ();
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clutter_actor_set_size (stage, 400, 400);
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g_signal_connect (stage, "destroy", G_CALLBACK (clutter_main_quit), NULL);
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texture = clutter_texture_new ();
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clutter_texture_set_keep_aspect_ratio (CLUTTER_TEXTURE (texture), TRUE);
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clutter_actor_set_width (texture, 300);
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/* NB ignoring missing file errors here for brevity */
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clutter_texture_set_from_file (CLUTTER_TEXTURE (texture),
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filename,
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NULL);
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/* align the texture on the x and y axes */
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constraint_x = clutter_align_constraint_new (stage, CLUTTER_ALIGN_X_AXIS, 0.5);
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constraint_y = clutter_align_constraint_new (stage, CLUTTER_ALIGN_Y_AXIS, 0.5);
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clutter_actor_add_constraint (texture, constraint_x);
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clutter_actor_add_constraint (texture, constraint_y);
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/* create a colorize effect with pink tint */
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pink = clutter_color_new (230, 187, 210, 255);
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effect = clutter_colorize_effect_new (pink);
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/* apply the effect to the texture */
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clutter_actor_add_effect (texture, effect);
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clutter_container_add_actor (CLUTTER_CONTAINER (stage), texture);
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clutter_actor_show (stage);
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clutter_main ();
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return 0;
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}
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119
doc/cookbook/examples/effects-custom-deform.c
Normal file
119
doc/cookbook/examples/effects-custom-deform.c
Normal file
@ -0,0 +1,119 @@
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/* Example of using a custom CbPageFoldEffect to do
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* an animated fold of a texture containing an image
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*
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* Pass the full path to the image on the command line;
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* click on the texture to trigger the folding animation
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*/
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#include <stdlib.h>
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#include <clutter/clutter.h>
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#include "cb-page-fold-effect.h"
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static const ClutterColor stage_color = { 0x33, 0x33, 0x55, 0xff };
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static gboolean
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button_pressed_cb (ClutterActor *actor,
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ClutterEvent *event,
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gpointer user_data)
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{
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ClutterState *transitions = CLUTTER_STATE (user_data);
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if (g_strcmp0 (clutter_state_get_state (transitions), "folded") == 0)
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clutter_state_set_state (transitions, "unfolded");
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else
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clutter_state_set_state (transitions, "folded");
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return TRUE;
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}
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int
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main (int argc,
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char *argv[])
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{
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ClutterActor *stage;
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ClutterActor *texture;
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ClutterEffect *effect;
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ClutterState *transitions;
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GError *error = NULL;
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gchar *filename;
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if (argc < 2)
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{
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g_print ("Usage: %s <path to image file>\n", argv[0]);
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return EXIT_FAILURE;
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||||
}
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filename = argv[1];
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clutter_init (&argc, &argv);
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stage = clutter_stage_new ();
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clutter_actor_set_size (stage, 400, 300);
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clutter_stage_set_color (CLUTTER_STAGE (stage), &stage_color);
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g_signal_connect (stage, "destroy", G_CALLBACK (clutter_main_quit), NULL);
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texture = clutter_texture_new ();
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clutter_texture_set_keep_aspect_ratio (CLUTTER_TEXTURE (texture), TRUE);
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clutter_actor_set_width (texture, 400);
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clutter_actor_set_reactive (texture, TRUE);
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clutter_texture_set_from_file (CLUTTER_TEXTURE (texture),
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filename,
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&error);
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||||
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if (error != NULL)
|
||||
{
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||||
g_critical ("Error loading texture from file %s; error was:\n%s",
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||||
filename,
|
||||
error->message);
|
||||
return EXIT_FAILURE;
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||||
}
|
||||
|
||||
/* create the page fold effect instance with destination fold angle
|
||||
* of 180 degrees and starting period of 0 (no folding)
|
||||
*/
|
||||
effect = cb_page_fold_effect_new (180.0, 0.0);
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||||
|
||||
/* add the effect to the texture actor */
|
||||
clutter_actor_add_effect (texture, effect);
|
||||
|
||||
clutter_container_add_actor (CLUTTER_CONTAINER (stage), texture);
|
||||
|
||||
/* animation for the period property of the effect,
|
||||
* to animate its value between 0.0 and 1.0 and back
|
||||
*/
|
||||
transitions = clutter_state_new ();
|
||||
clutter_state_set_duration (transitions, NULL, NULL, 500);
|
||||
|
||||
clutter_state_set_duration (transitions,
|
||||
"partially-folded",
|
||||
"folded",
|
||||
375);
|
||||
|
||||
clutter_state_set (transitions, NULL, "folded",
|
||||
effect, "period", CLUTTER_LINEAR, 1.0,
|
||||
NULL);
|
||||
|
||||
clutter_state_set (transitions, NULL, "partially-folded",
|
||||
effect, "period", CLUTTER_LINEAR, 0.25,
|
||||
NULL);
|
||||
|
||||
clutter_state_set (transitions, NULL, "unfolded",
|
||||
effect, "period", CLUTTER_LINEAR, 0.0,
|
||||
NULL);
|
||||
|
||||
clutter_state_warp_to_state (transitions, "partially-folded");
|
||||
|
||||
g_signal_connect (texture,
|
||||
"button-press-event",
|
||||
G_CALLBACK (button_pressed_cb),
|
||||
transitions);
|
||||
|
||||
clutter_actor_show (stage);
|
||||
|
||||
clutter_main ();
|
||||
|
||||
g_object_unref (transitions);
|
||||
|
||||
return EXIT_SUCCESS;
|
||||
}
|
||||
Reference in New Issue
Block a user