275 lines
8.0 KiB
Markdown
275 lines
8.0 KiB
Markdown
# Tiny OpenEXR image library.
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[](https://ci.appveyor.com/project/syoyo/tinyexr/branch/master)
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[](https://travis-ci.org/syoyo/tinyexr)
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[](https://scan.coverity.com/projects/5827)
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`tinyexr` is a small, single header-only library to load and save OpenEXR(.exr) images.
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`tinyexr` is written in portable C++(no library dependency except for STL), thus `tinyexr` is good to embed into your application.
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To use `tinyexr`, simply copy `tinyexr.h` into your project.
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`tinyexr` currently supports:
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* OpenEXR version 1.x.
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* Normal image
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* Scanline format.
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* Uncompress("compress" = 0), ZIPS("compress" = 2), ZIP compression("compress" = 3) and PIZ compression("compress" = 4).
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* Half/Uint/Float pixel type.
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* Custom attributes(up to 128)
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* Deep image
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* Scanline format.
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* ZIPS compression("compress" = 2).
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* Half, float pixel type.
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* Litte endian machine.
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* Limited support for big endian machine.
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* read/write normal image.
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* C interface.
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* You can easily write language bindings(e.g. golang)
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* EXR saving
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* with ZIP compression.
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* JavaScript library
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* Through emscripten.
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# Use case
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* mallie https://github.com/lighttransport/mallie
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* PBRT v3 https://github.com/mmp/pbrt-v3
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* Cinder 0.9.0 https://libcinder.org/notes/v0.9.0
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* Piccante(develop branch) http://piccantelib.net/
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* Your project here!
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## Examples
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* [examples/deepview/](examples/deepview) Deep image view
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* [examples/rgbe2exr/](examples/rgbe2exr) .hdr to EXR converter
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* [examples/exr2rgbe/](examples/exr2rgbe) EXR to .hdr converter
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## Usage
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NOTE: **API is still subject to change**. See the source code for details.
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Include `tinyexr.h` with `TINYEXR_IMPLEMENTATION` flag(do this only for **one** .cc file).
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```
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#define TINYEXR_IMPLEMENTATION
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#include "tinyexr.h"
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```
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Quickly reading RGB(A) EXR file.
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```
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const char* input = "asakusa.exr";
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float* out; // width * height * RGBA
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int width;
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int height;
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const char* err;
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int ret = LoadEXR(&out, &width, &height, input, &err);
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```
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Loading EXR from a file.
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```
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const char* input = "asakusa.exr";
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const char* err;
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EXRImage exrImage;
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InitEXRImage(&exrImage);
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int ret = ParseMultiChannelEXRHeaderFromFile(&exrImage, input, &err);
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if (ret != 0) {
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fprintf(stderr, "Parse EXR err: %s\n", err);
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return;
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}
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//// Uncomment if you want reading HALF image as FLOAT.
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//for (int i = 0; i < exrImage.num_channels; i++) {
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// if (exrImage.pixel_types[i] = TINYEXR_PIXELTYPE_HALF) {
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// exrImage.requested_pixel_types[i] = TINYEXR_PIXELTYPE_FLOAT;
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// }
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//}
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ret = LoadMultiChannelEXRFromFile(&exrImage, input, &err);
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if (ret != 0) {
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fprintf(stderr, "Load EXR err: %s\n", err);
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return;
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}
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```
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Saving EXR file.
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```
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bool SaveEXR(const float* rgb, int width, int height, const char* outfilename) {
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float* channels[3];
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EXRImage image;
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InitEXRImage(&image);
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image.num_channels = 3;
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// Must be BGR(A) order, since most of EXR viewers expect this channel order.
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const char* channel_names[] = {"B", "G", "R"}; // "B", "G", "R", "A" for RGBA image
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std::vector<float> images[3];
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images[0].resize(width * height);
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images[1].resize(width * height);
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images[2].resize(width * height);
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for (int i = 0; i < width * height; i++) {
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images[0][i] = rgb[3*i+0];
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images[1][i] = rgb[3*i+1];
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images[2][i] = rgb[3*i+2];
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}
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float* image_ptr[3];
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image_ptr[0] = &(images[2].at(0)); // B
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image_ptr[1] = &(images[1].at(0)); // G
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image_ptr[2] = &(images[0].at(0)); // R
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image.channel_names = channel_names;
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image.images = (unsigned char**)image_ptr;
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image.width = width;
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image.height = height;
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image.compression = TINYEXR_COMPRESSIONTYPE_ZIP;
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image.pixel_types = (int *)malloc(sizeof(int) * image.num_channels);
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image.requested_pixel_types = (int *)malloc(sizeof(int) * image.num_channels);
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for (int i = 0; i < image.num_channels; i++) {
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image.pixel_types[i] = TINYEXR_PIXELTYPE_FLOAT; // pixel type of input image
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image.requested_pixel_types[i] = TINYEXR_PIXELTYPE_HALF; // pixel type of output image to be stored in .EXR
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}
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const char* err;
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int ret = SaveMultiChannelEXRToFile(&image, outfilename, &err);
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if (ret != 0) {
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fprintf(stderr, "Save EXR err: %s\n", err);
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return ret;
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}
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printf("Saved exr file. [ %s ] \n", outfilename);
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free(image.pixel_types);
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free(image.requested_pixel_types);
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return ret;
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}
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```
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Reading deep image EXR file.
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See `example/deepview` for actual usage.
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```
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const char* input = "deepimage.exr";
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const char* err;
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DeepImage deepImage;
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int ret = LoadDeepEXR(&deepImage, input, &err);
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// acccess to each sample in the deep pixel.
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for (int y = 0; y < deepImage.height; y++) {
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int sampleNum = deepImage.offset_table[y][deepImage.width-1];
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for (int x = 0; x < deepImage.width-1; x++) {
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int s_start = deepImage.offset_table[y][x];
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int s_end = deepImage.offset_table[y][x+1];
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if (s_start >= sampleNum) {
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continue;
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}
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s_end = (s_end < sampleNum) ? s_end : sampleNum;
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for (int s = s_start; s < s_end; s++) {
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float val = deepImage.image[depthChan][y][s];
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...
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}
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}
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}
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```
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### deepview
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`examples/deepview` is simple deep image viewer in OpenGL.
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## TODO
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Contribution is welcome!
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- [ ] Compression
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- [ ] NONE("compress" = 0, load)
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- [ ] RLE("compress" = 1, load)
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- [x] ZIPS("compress" = 2, load)
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- [x] ZIP("compress" = 3, load)
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- [x] PIZ("compress" = 4, load)
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- [x] NONE("compress" = 0, save)
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- [ ] RLE("compress" = 1, save)
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- [x] ZIPS("compress" = 2, save)
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- [x] ZIP("compress" = 3, save)
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- [ ] PIZ("compress" = 4, save)
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- [ ] Custom attributes
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- [x] Normal image(EXR 1.x)
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- [ ] Deep image(EXR 2.x)
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- [ ] JavaScript library
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- [x] LoadEXRFromMemory
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- [ ] SaveMultiChannelEXR
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- [ ] Deep image save/load
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- [ ] Write from/to memory buffer.
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- [x] SaveMultiChannelEXR
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- [x] LoadMultiChannelEXR
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- [ ] Deep image save/load
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- [ ] Tile format.
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- [ ] Support for various compression type.
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- [x] zstd compression(Not in OpenEXR spec, though)
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- [x] Multi-channel.
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- [ ] Multi-part(EXR2.0)
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- [ ] Line order.
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- [x] Increasing, decreasing(load)
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- [ ] Random?
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- [ ] Increasing, decreasing(save)
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- [ ] Pixel format(UINT, FLOAT).
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- [x] UINT, FLOAT(load)
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- [x] UINT, FLOAT(deep load)
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- [x] UINT, FLOAT(save)
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- [ ] UINT, FLOAT(deep save)
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- [ ] Full support for big endian machine.
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- [x] Loading multi channel EXR
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- [x] Saving multi channel EXR
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- [ ] Loading deep image
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- [ ] Saving deep image
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- [ ] Optimization
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- [ ] ISPC?
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- [x] OpenMP multi-threading in EXR loading.
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- [x] OpenMP multi-threading in EXR saving.
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- [ ] OpenMP multi-threading in deep image loading.
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- [ ] OpenMP multi-threading in deep image saving.
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## Similar or related projects
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* miniexr: https://github.com/aras-p/miniexr (Write OpenEXR)
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* stb_image_resize.h: https://github.com/nothings/stb (Good for HDR image resizing)
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## License
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3-clause BSD
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`tinyexr` uses miniz, which is developed by Rich Geldreich <richgel99@gmail.com>, and licensed under public domain.
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`tinyexr` tools uses stb, which is licensed under public domain: https://github.com/nothings/stb
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`tinyexr` uses some code from OpenEXR, which is licensed under 3-clause BSD license.
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## Author(s)
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Syoyo Fujita(syoyo@lighttransport.com)
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## Contributor(s)
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* Matt Ebb (http://mattebb.com) : deep image example. Thanks!
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* Matt Pharr (http://pharr.org/matt/) : Testing tinyexr with OpenEXR(IlmImf). Thanks!
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* Andrew Bell (https://github.com/andrewfb) & Richard Eakin (https://github.com/richardeakin) : Improving TinyEXR API. Thanks!
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* Mike Wong (https://github.com/mwkm) : ZIPS compression support in loading. Thanks!
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