1 #ifndef DALI_LINEAR_CONSTRAINER_H
2 #define DALI_LINEAR_CONSTRAINER_H
5 * Copyright (c) 2019 Samsung Electronics Co., Ltd.
7 * Licensed under the Apache License, Version 2.0 (the "License");
8 * you may not use this file except in compliance with the License.
9 * You may obtain a copy of the License at
11 * http://www.apache.org/licenses/LICENSE-2.0
13 * Unless required by applicable law or agreed to in writing, software
14 * distributed under the License is distributed on an "AS IS" BASIS,
15 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
16 * See the License for the specific language governing permissions and
17 * limitations under the License.
22 #include <cfloat> //For FLT_MAX
25 #include <dali/public-api/object/handle.h>
26 #include <dali/public-api/object/property-index-ranges.h>
31 * @addtogroup dali_core_animation
35 namespace Internal DALI_INTERNAL
37 class LinearConstrainer;
41 * @brief LinearConstrainer applies constraints to objects, given a linear map.
43 * A linear map is defined by a set of value-progress pairs.
44 * Progress must be normalized between [0,1]. If no progress is defined, the values
45 * are considered to be equally spaced along the X axis.
47 * Basically, a linear constrainer allows constraining a property to another property
48 * with the changes mapped over a certain range. For example, if you want to change the
49 * opacity of an actor depending on its position along the X-axis, so that it's fully
50 * transparent on the edges and fully opaque in the center. To do this, an array with
51 * values, 0.0f, 1.0f, 0.0f, is created, which means that there are 3 control points.
52 * You can add as many control points as you want, but they will be linearly spaced.
53 * Then you can apply the linear constrainer by using the alpha of the actor as the
54 * target and the source as the actor's position.
57 class DALI_CORE_API LinearConstrainer : public Handle
62 * @brief Enumeration for the instance of properties belonging to the LinearConstrainer class.
68 * @brief Enumeration for the instance of properties belonging to the LinearConstrainer class.
73 VALUE = DEFAULT_OBJECT_PROPERTY_START_INDEX, ///< name "value" type Array of float @SINCE_1_0.0
74 PROGRESS, ///< name "progress" type Array of float @SINCE_1_0.0
79 * @brief Creates an initialized LinearConstrainer handle.
82 * @return A handle to a newly allocated Dali resource
84 static LinearConstrainer New();
87 * @brief Downcasts a handle to LinearConstrainer handle.
89 * If handle points to a LinearConstrainer object, the downcast produces valid handle.
90 * If not, the returned handle is left uninitialized.
92 * @param[in] handle Handle to an object
93 * @return Handle to a LinearConstrainer object or an uninitialized handle
95 static LinearConstrainer DownCast( BaseHandle handle );
98 * @brief Creates an uninitialized LinearConstrainer handle.
100 * This can be initialized with @ref LinearConstrainer::New
101 * Calling member functions with an uninitialized LinearConstrainer handle is not allowed.
109 * This is non-virtual since derived Handle types must not contain data or virtual methods.
112 ~LinearConstrainer();
115 * @brief This copy constructor is required for (smart) pointer semantics.
118 * @param[in] handle A reference to the copied handle
120 LinearConstrainer(const LinearConstrainer& handle);
123 * @brief This assignment operator is required for (smart) pointer semantics.
126 * @param[in] rhs A reference to the copied handle
127 * @return A reference to this
129 LinearConstrainer& operator=(const LinearConstrainer& rhs);
132 * @brief Applies the linear constraint to the target property.
135 * @param[in] target Property to be constrained
136 * @param[in] source Property used as a parameter for the linear map
137 * @param[in] range The range of values in the source property which will be mapped to [0,1]
138 * @param[in] wrap Wrapping domain. Source property will be wrapped in the domain [wrap.x,wrap.y] before mapping to [0,1]. See cfloat.h for FLT_MAX
140 void Apply( Dali::Property target, Dali::Property source, const Vector2& range, const Vector2& wrap = Vector2(-FLT_MAX, FLT_MAX) );
143 * @brief Removes the linear constraint in the target object.
146 * @param[in] target A handle to an object constrained by the LinearConstrainer
148 void Remove( Dali::Handle& target );
150 public: // Not intended for application developers
153 * @brief This constructor is used by LinearConstrainer::New() methods.
156 * @param[in] internal A pointer to an internal LinearConstrainer resource
158 explicit DALI_INTERNAL LinearConstrainer(Internal::LinearConstrainer* internal);
167 #endif // DALI_LINEAR_CONSTRAINER_H