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Cleanup CMakeLists.txt and Update README.md
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| Original file line number | Diff line number | Diff line change |
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| @@ -1,30 +1,71 @@ | ||
| ## Format Introduction | ||
| https://developer.android.com/guide/topics/media/platform/hdr-image-format | ||
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| ## Getting Started | ||
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| Supports: | ||
| - x86_32/x86_64 on Linux | ||
| - macOS | ||
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| Preferred Compiler: Clang | ||
| Tested with: | ||
| - C compiler: Clang 15.0.7 | ||
| - CXX compiler: Clang 15.0.7 | ||
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| ## Building Commands | ||
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| ### For x86_32 on a x86_64 Linux machine | ||
| ``` | ||
| $ mkdir build | ||
| $ cd build | ||
| $ cmake .. | ||
| $ make | ||
| ``` | ||
| ### For macOS | ||
| ``` | ||
| $ mkdir build | ||
| $ cd build | ||
| $ cmake .. | ||
| $ make | ||
| ``` | ||
| Background | ||
| ========== | ||
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| libultrahdr is an image compression library that uses gain map technology | ||
| to store and distribute HDR images. Conceptually on the encoding side, the | ||
| library accepts SDR and HDR rendition of an image and from these a Gain Map | ||
| (quotient between the two renditions) is computed. The library then uses | ||
| backward compatible means to store the base image (SDR), gain map image and | ||
| some associated metadata. Legacy readers that dont support parsing the | ||
| gain map image and/or metadata, will display the base image. Readers that | ||
| support the format combine the base image with the gain map and render a | ||
| high dynamic range image on compatible displays. | ||
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| More information about libultrahdr can be found at | ||
| <https://developer.android.com/guide/topics/media/platform/hdr-image-format>. | ||
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| Building libultrahdr | ||
| ====================== | ||
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| libultrahdr compresses base image and gain map image in to jpeg format. | ||
| For this libjpeg is used. This is cloned from | ||
| <https://github.com/libjpeg-turbo/libjpeg-turbo.git> and included in the | ||
| build process. | ||
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| ### Requirements | ||
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| - [CMake](http://www.cmake.org) v3.5 or later | ||
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| - [NASM](http://www.nasm.us) or [Yasm](http://yasm.tortall.net) | ||
| (If libjpeg-turbo is building on x86 or x86-64 with SIMD extensions) | ||
| * If using NASM, 2.13 or later is required. | ||
| * If using Yasm, 1.2.0 or later is required. | ||
| * If building on macOS, NASM or Yasm can be obtained from | ||
| [MacPorts](http://www.macports.org/) or [Homebrew](http://brew.sh/). | ||
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| Tested with GCC v11.4 and Clang 14.0.0 on Linux and Mac Platforms. | ||
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| ### Building Commands | ||
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| To build libultrahdr and sample application: | ||
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| mkdir {build_directory} | ||
| cd {build_directory} | ||
| cmake ../ -DCMAKE_C_COMPILER=clang -DCMAKE_CXX_COMPILER=clang++ | ||
| make | ||
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| To build unit tests: | ||
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| mkdir {build_directory} | ||
| cd {build_directory} | ||
| cmake ../ -DCMAKE_C_COMPILER=clang -DCMAKE_CXX_COMPILER=clang++ -DENABLE_TESTS=1 | ||
| make | ||
| ctest | ||
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| This will generate the following files under *{build_directory}*: | ||
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| **libultrahdr.a**<br> Static link library for the ultrahdr API | ||
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| **ultrahdr_app**<br> Sample application demonstrating ultrahdr API | ||
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| **ultrahdr_unit_test**<br> Unit tests | ||
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| Using libultrahdr | ||
| =================== | ||
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| libultrahdr includes two classes of APIs, one to compress and the other to | ||
| decompress HDR images: | ||
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| - Refer to [jpegr.h](include/ultrahdr/jpegr.h) for detailed description of various encode and decode api. | ||
| - Refer to [ultrahdr_app.cpp](tests/ultrahdr_app.cpp) for examples of its usage. |