1 #ifndef DALI_LINEAR_CONSTRAINER_H
2 #define DALI_LINEAR_CONSTRAINER_H
5 * Copyright (c) 2020 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
61 * @brief Enumeration for the instance of properties belonging to the LinearConstrainer class.
67 * @brief Enumeration for the instance of properties belonging to the LinearConstrainer class.
72 VALUE = DEFAULT_OBJECT_PROPERTY_START_INDEX, ///< name "value" type Array of float @SINCE_1_0.0
73 PROGRESS, ///< name "progress" type Array of float @SINCE_1_0.0
78 * @brief Creates an initialized LinearConstrainer handle.
81 * @return A handle to a newly allocated Dali resource
83 static LinearConstrainer New();
86 * @brief Downcasts a handle to LinearConstrainer handle.
88 * If handle points to a LinearConstrainer object, the downcast produces valid handle.
89 * If not, the returned handle is left uninitialized.
91 * @param[in] handle Handle to an object
92 * @return Handle to a LinearConstrainer object or an uninitialized handle
94 static LinearConstrainer DownCast(BaseHandle handle);
97 * @brief Creates an uninitialized LinearConstrainer handle.
99 * This can be initialized with @ref LinearConstrainer::New
100 * Calling member functions with an uninitialized LinearConstrainer handle is not allowed.
108 * This is non-virtual since derived Handle types must not contain data or virtual methods.
111 ~LinearConstrainer();
114 * @brief This copy constructor is required for (smart) pointer semantics.
117 * @param[in] handle A reference to the copied handle
119 LinearConstrainer(const LinearConstrainer& handle);
122 * @brief This assignment operator is required for (smart) pointer semantics.
125 * @param[in] rhs A reference to the copied handle
126 * @return A reference to this
128 LinearConstrainer& operator=(const LinearConstrainer& rhs);
131 * @brief Move constructor.
134 * @param[in] rhs A reference to the moved handle
136 LinearConstrainer(LinearConstrainer&& rhs);
139 * @brief Move assignment operator.
142 * @param[in] rhs A reference to the moved handle
143 * @return A reference to this
145 LinearConstrainer& operator=(LinearConstrainer&& rhs);
148 * @brief Applies the linear constraint to the target property.
151 * @param[in] target Property to be constrained
152 * @param[in] source Property used as a parameter for the linear map
153 * @param[in] range The range of values in the source property which will be mapped to [0,1]
154 * @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
156 void Apply(Dali::Property target, Dali::Property source, const Vector2& range, const Vector2& wrap = Vector2(-FLT_MAX, FLT_MAX));
159 * @brief Removes the linear constraint in the target object.
162 * @param[in] target A handle to an object constrained by the LinearConstrainer
164 void Remove(Dali::Handle& target);
166 public: // Not intended for application developers
169 * @brief This constructor is used by LinearConstrainer::New() methods.
172 * @param[in] internal A pointer to an internal LinearConstrainer resource
174 explicit DALI_INTERNAL LinearConstrainer(Internal::LinearConstrainer* internal);
183 #endif // DALI_LINEAR_CONSTRAINER_H