1 #ifndef __DALI_IMAGE_H__
2 #define __DALI_IMAGE_H__
5 * Copyright (c) 2014 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.
25 #include <dali/public-api/object/base-handle.h>
26 #include <dali/public-api/signals/dali-signal.h>
31 namespace Internal DALI_INTERNAL
39 * @brief An Image object represents an image resource that can be added to ImageActors.
41 * Image objects can be shared between ImageActors. This is practical if you have a visual element on screen
42 * which is repeatedly used. An example would be a button background image.
43 * The image resource is discarded when all ImageActors using the Image object are discarded or in case they
44 * were created with ReleasePolicy::Unused, taken off stage.
45 * Note: if a resource was shared between Image objects it exists until its last reference is gone.
47 * Image objects are responsible for the underlying resource's lifetime.
49 * <i>ReleasePolicies</i>
50 * - Unused: release resource once ImageActor using it is taken off stage.
51 * - Never: keep resource alive until Image object is thrown away.
53 * <i>Resolution of conflicting policies</i>
54 * If the same image is created more than once with conflicting policies, ReleasePolicy "Never" overrides "Unused".
57 class DALI_IMPORT_API Image : public BaseHandle
61 * @brief Resource management options.
65 * @brief ReleasePolicy controls the way images are deleted from memory.
69 UNUSED, ///< release resource once image is not in use anymore (eg. all actors using it become offstage). Reload when resource is required again.
70 NEVER ///< keep image data for the lifetime of the object. (default)
74 * @brief Type of signal for LoadingFinished and Uploaded.
76 typedef Signal< void (Image) > ImageSignalType;
79 static const char* const SIGNAL_IMAGE_UPLOADED; ///< Name of Uploaded signal
84 * @brief Constructor which creates an empty Image handle.
86 * Use Image::New(...) to create an initialised handle.
93 * This is non-virtual since derived Handle types must not contain data or virtual methods.
98 * @brief This copy constructor is required for (smart) pointer semantics.
100 * @param [in] handle A reference to the copied handle
102 Image(const Image& handle);
105 * @brief This assignment operator is required for (smart) pointer semantics.
107 * @param [in] rhs A reference to the copied handle
108 * @return A reference to this
110 Image& operator=(const Image& rhs);
113 * @brief Creates object with already loaded NativeImage.
115 * The maximum size of the image is limited by GL_MAX_TEXTURE_SIZE
116 * @pre nativeImg should be initialised
117 * @param [in] nativeImg already initialised NativeImage
118 * @return A handle to a newly allocated object
120 static Image New(NativeImage& nativeImg);
123 * @brief Downcast an Object handle to Image handle.
125 * If handle points to a Image object the
126 * downcast produces valid handle. If not the returned handle is left uninitialized.
127 * @param[in] handle to An object
128 * @return handle to a Image object or an uninitialized handle
130 static Image DownCast( BaseHandle handle );
133 * @brief Return resource release policy.
135 * @return resource release policy
137 ReleasePolicy GetReleasePolicy() const;
140 * @brief Returns the width of the image.
142 * Returns either the requested width or the actual loaded width if no specific size was requested.
144 * @return width of the image in pixels.
146 unsigned int GetWidth() const;
149 * @brief Returns the height of the image.
151 * Returns either the requested height or the actual loaded height if no specific size was requested.
153 * @return height of the image in pixels.
155 unsigned int GetHeight() const;
160 * @brief This signal is emitted when the image data gets uploaded to GL.
162 * It Will be sent after an actor using the image is added to
163 * the stage, when such a staged image is reloaded, or when a staged
164 * BitmapImage calls Update().
165 * @return A signal object to Connect() with.
167 ImageSignalType& UploadedSignal();
169 public: // Not intended for application developers
171 explicit DALI_INTERNAL Image(Internal::Image*);
176 #endif // __DALI_IMAGE_H__