1 #ifndef __DALI_RESOURCE_IMAGE_H__
2 #define __DALI_RESOURCE_IMAGE_H__
5 * Copyright (c) 2015 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/common/loading-state.h>
26 #include <dali/public-api/images/image.h>
27 #include <dali/public-api/signals/dali-signal.h>
28 #include <dali/public-api/images/image-operations.h>
33 * @addtogroup dali_core_images
37 namespace Internal DALI_INTERNAL
43 * @brief ResourceImage is an image loaded using a URL
45 * <h3>ResourceImage Loading</h3>
47 * When the ResourceImage is created, resource loading will be attempted unless
48 * the ResourceImage is created with ResourceImage::IMMEDIATE loading policy or a compatible resource is found in cache.
49 * In case of loading images ResourceImage::ON_DEMAND, resource loading will only be attempted if the associated Dali::Toolkit::ImageView
51 * Scaling of images to a desired smaller size can be requested by providing desired dimensions,
52 * scaling mode and filter mode to to ResourceImage::New().
54 * <i>Custom load requests</i>
56 * Size, scaling mode, filter mode, and orientation compensation can be set when requesting an image.
58 * <i>Compatible resources</i>
60 * Before loading a new ResourceImage the internal image resource cache is checked by DALi.
61 * If there is an image already loaded in memory and is deemed "compatible" with the requested image,
62 * that resource is reused.
63 * This happens for example if a loaded image exists with the same URL, scaling and filtering modes,
64 * and the difference between both of the dimensions is less than a few pixels.
66 * <i>Reloading images</i>
68 * The same request used on creating the ResourceImage is re-issued when reloading images.
69 * If the file changed since the last load operation, this might result in a different resource.
70 * Reload only takes effect if both of these conditions apply:
71 * - The ResourceImage has already finished loading
72 * - The ResourceImage is either on Stage or using ResourceImage::IMMEDIATE load policy
75 * | %Signal Name | Method |
76 * |----------------------|------------------------------|
77 * | imageLoadingFinished | @ref LoadingFinishedSignal() |
80 class DALI_IMPORT_API ResourceImage : public Image
84 * @brief Resource management options.
88 * @DEPRECATED_1_1.3. Image loading starts immediately in the frame when then ResourceImage object is created.
90 * @brief LoadPolicy controls the way images are loaded into memory.
92 * @remarks This is an experimental feature and might not be supported in the next release.
93 * We do recommend not to use it.
97 IMMEDIATE, ///< Load image once it is created (default) @SINCE_1_0.0
98 ON_DEMAND ///< Delay loading until the image is being used (a related actor is added to Stage) @SINCE_1_0.0
102 * @brief Type of signal for LoadingFinished and Uploaded.
105 typedef Signal< void (ResourceImage) > ResourceImageSignal;
110 * @brief Get the size of an image from disk.
112 * This function will read the header info from file on disk and is
113 * synchronous, so it should not be used repeatedly or in tight
117 * @param [in] url The URL of the image file.
118 * @return The width and height in pixels of the image.
120 static ImageDimensions GetImageSize( const std::string& url );
123 * @brief Constructor which creates an empty ResourceImage object.
125 * Use ResourceImage::New(...) to create an initialised object.
133 * This is non-virtual since derived Handle types must not contain data or virtual methods.
139 * @brief This copy constructor is required for (smart) pointer semantics.
142 * @param [in] handle A reference to the copied handle
144 ResourceImage( const ResourceImage& handle );
147 * @brief This assignment operator is required for (smart) pointer semantics.
150 * @param [in] rhs A reference to the copied handle
151 * @return A reference to this
153 ResourceImage& operator=( const ResourceImage& rhs );
156 * @name ResourceImageFactoryFunctions
157 * Create ResourceImage object instances using these functions.
162 * @brief Create an initialised ResourceImage object.
164 * Uses defaults for all options.
166 * @sa Dali::FittingMode::Type Dali::SamplingMode::Type
168 * @param [in] url The URL of the image file to use.
169 * @param [in] orientationCorrection Reorient the image to respect any orientation metadata in its header.
170 * @return A handle to a newly allocated object
172 static ResourceImage New( const std::string& url, bool orientationCorrection = true );
175 * @DEPRECATED_1_1.3. Use New( const std::string& url ) instead.
177 * @brief Create an initialised ResourceImage object.
180 * @param [in] url The URL of the image file to use.
181 * @param [in] loadPol The LoadPolicy to apply when loading the image resource.
182 * @param [in] releasePol The ReleasePolicy to apply to Image.
183 * @param [in] orientationCorrection Reorient the image to respect any orientation metadata in its header.
184 * @return A handle to a newly allocated object
186 static ResourceImage New( const std::string& url, LoadPolicy loadPol, ReleasePolicy releasePol, bool orientationCorrection = true );
189 * @brief Create an initialised ResourceImage object.
192 * @param [in] url The URL of the image file to use.
193 * @param [in] size The width and height to fit the loaded image to.
194 * @param [in] fittingMode The method used to fit the shape of the image before loading to the shape defined by the size parameter.
195 * @param [in] samplingMode The filtering method used when sampling pixels from the input image while fitting it to desired size.
196 * @param [in] orientationCorrection Reorient the image to respect any orientation metadata in its header.
197 * @return A handle to a newly allocated object
199 static ResourceImage New( const std::string& url,
200 ImageDimensions size,
201 FittingMode::Type fittingMode = FittingMode::DEFAULT,
202 SamplingMode::Type samplingMode = SamplingMode::DEFAULT,
203 bool orientationCorrection = true );
206 * @DEPRECATED_1_1.3. Use New( const std::string& url, ImageDimensions size ) instead.
208 * @brief Create an initialised ResourceImage object.
211 * @param [in] url The URL of the image file to use.
212 * @param [in] loadPol The LoadPolicy to apply when loading the image resource.
213 * @param [in] releasePol The ReleasePolicy to apply to Image.
214 * @param [in] size The width and height to fit the loaded image to.
215 * @param [in] fittingMode The method used to fit the shape of the image before loading to the shape defined by the size parameter.
216 * @param [in] samplingMode The filtering method used when sampling pixels from the input image while fitting it to desired size.
217 * @param [in] orientationCorrection Reorient the image to respect any orientation metadata in its header.
218 * @return A handle to a newly allocated object
220 static ResourceImage New( const std::string& url,
222 ReleasePolicy releasePol,
223 ImageDimensions size,
224 FittingMode::Type fittingMode = FittingMode::DEFAULT,
225 SamplingMode::Type samplingMode = SamplingMode::DEFAULT,
226 bool orientationCorrection = true );
231 * @brief Downcast a handle to ResourceImage handle.
233 * If handle points to a ResourceImage object the
234 * downcast produces valid handle. If not the returned handle is left uninitialized.
236 * @param[in] handle Handle to an object
237 * @return Handle to a Image object or an uninitialized handle
239 static ResourceImage DownCast( BaseHandle handle );
244 * @brief Return load policy.
247 * @remarks This is an experimental feature and might not be supported in the next release.
248 * We do recommend not to use it.
249 * @return Resource load policy
251 LoadPolicy GetLoadPolicy() const;
254 * @brief Query whether the image data has loaded.
256 * The asynchronous loading begins when the Image object is created.
257 * After the Image object is discarded, the image data will be released from memory.
259 * @return The loading state, either Loading, Success or Failed.
261 LoadingState GetLoadingState() const;
264 * @brief Returns the URL of the image.
267 * @return The URL of the image file.
269 std::string GetUrl() const;
272 * @brief Reload image from filesystem.
274 * The original set of image loading attributes (requested dimensions, scaling
275 * mode and filter mode) are used when requesting the image again.
277 * @note If image is offstage and OnDemand policy is set, the reload request is
285 * @brief Emitted when the image data loads successfully, or when the loading fails.
288 * @return A signal object to Connect() with.
290 ResourceImageSignal& LoadingFinishedSignal();
292 public: // Not intended for application developers
294 explicit DALI_INTERNAL ResourceImage( Internal::ResourceImage* );
302 #endif // __DALI_RESOURCE_IMAGE_H__