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 * | %Signal Name | Method |
58 * |------------------------|------------------------------|
59 * | uploaded | @ref UploadedSignal() |
61 class DALI_IMPORT_API Image : public BaseHandle
65 * @brief Resource management options.
69 * @brief ReleasePolicy controls the way images are deleted from memory.
73 UNUSED, ///< release resource once image is not in use anymore (eg. all actors using it become offstage). Reload when resource is required again.
74 NEVER ///< keep image data for the lifetime of the object. (default)
78 * @brief Type of signal for Image Uploaded.
80 typedef Signal< void (Image) > ImageSignalType;
85 * @brief Constructor which creates an empty Image handle.
87 * Use Image::New(...) to create an initialised handle.
94 * This is non-virtual since derived Handle types must not contain data or virtual methods.
99 * @brief This copy constructor is required for (smart) pointer semantics.
101 * @param [in] handle A reference to the copied handle
103 Image(const Image& handle);
106 * @brief This assignment operator is required for (smart) pointer semantics.
108 * @param [in] rhs A reference to the copied handle
109 * @return A reference to this
111 Image& operator=(const Image& rhs);
114 * @brief Creates object with already loaded NativeImage.
116 * The maximum size of the image is limited by GL_MAX_TEXTURE_SIZE
117 * @pre nativeImg should be initialised
118 * @param [in] nativeImg already initialised NativeImage
119 * @return A handle to a newly allocated object
121 static Image New(NativeImage& nativeImg);
124 * @brief Downcast an Object handle to Image handle.
126 * If handle points to a Image object the
127 * downcast produces valid handle. If not the returned handle is left uninitialized.
128 * @param[in] handle to An object
129 * @return handle to a Image object or an uninitialized handle
131 static Image DownCast( BaseHandle handle );
134 * @brief Return resource release policy.
136 * @return resource release policy
138 ReleasePolicy GetReleasePolicy() const;
141 * @brief Returns the width of the image.
143 * Returns either the requested width or the actual loaded width if no specific size was requested.
145 * @return width of the image in pixels.
147 unsigned int GetWidth() const;
150 * @brief Returns the height of the image.
152 * Returns either the requested height or the actual loaded height if no specific size was requested.
154 * @return height of the image in pixels.
156 unsigned int GetHeight() const;
161 * @brief This signal is emitted when the image data gets uploaded to GL.
163 * It Will be sent after an actor using the image is added to
164 * the stage, when such a staged image is reloaded, or when a staged
165 * BitmapImage calls Update().
166 * @return A signal object to Connect() with.
168 ImageSignalType& UploadedSignal();
170 public: // Not intended for application developers
172 explicit DALI_INTERNAL Image(Internal::Image*);
177 #endif // __DALI_IMAGE_H__