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// Copyright 2009-2020 Intel Corporation
// SPDX-License-Identifier: Apache-2.0
#ifdef EMBREE_TUTORIALS_LIBJPEG
#include "image.h"
#include "jpeglib.h"
namespace embree
{
void compress(struct jpeg_compress_struct *cinfo, unsigned char *image)
{
/*! Start compression. */
jpeg_start_compress(cinfo, TRUE);
/*! Pointer to and size of a scanline in the image. */
JSAMPROW scanline[1]; size_t bytes = cinfo->image_width * cinfo->input_components;
/*! Here we use the library state variable 'next_scanline' as the loop index. */
while (cinfo->next_scanline < cinfo->image_height) {
scanline[0] = &image[cinfo->next_scanline * bytes];
jpeg_write_scanlines(cinfo, scanline, 1);
}
/*! Finish compression. */
jpeg_finish_compress(cinfo);
}
unsigned char *decompress(struct jpeg_decompress_struct *cinfo)
{
/*! Start decompression. */
jpeg_start_decompress(cinfo);
/*! Bytes per row in the scanline buffer. */
size_t bytes = cinfo->output_width * cinfo->output_components;
/*! Allocate scratch space for a single scanline. */
JSAMPARRAY scanline = (*cinfo->mem->alloc_sarray)((j_common_ptr) cinfo, JPOOL_IMAGE, bytes, 1);
/*! Allocate storage for the decompressed image. */
unsigned char* image = new unsigned char[cinfo->output_height * bytes];
/*! Here we use the library state variable 'output_scanline' as the loop index. */
while (cinfo->output_scanline < cinfo->output_height) {
jpeg_read_scanlines(cinfo, scanline, 1);
for (size_t i=0; i<bytes; i++)
image[(cinfo->output_scanline - 1) * bytes + i] = scanline[0][i];
}
/*! Finish decompression. */
jpeg_finish_decompress(cinfo);
return(image);
}
void encodeRGB8_to_JPEG(unsigned char *image, size_t width, size_t height, unsigned char **encoded, unsigned long *capacity)
{
#if JPEG_LIB_VERSION >= 80
/*! Compression parameters and scratch space pointers (allocated by the library). */
struct jpeg_compress_struct cinfo;
/*! The library error handler. */
struct jpeg_error_mgr jerror; cinfo.err = jpeg_std_error(&jerror);
/*! Initialize the JPEG compression object. */
jpeg_create_compress(&cinfo);
/*! Specify the incoming image resolution, color space, and color space components. */
cinfo.image_width = width; cinfo.image_height = height; cinfo.in_color_space = JCS_RGB; cinfo.input_components = 3;
/*! Fill in a sensible set of defaults. */
jpeg_set_defaults(&cinfo);
/*! Set the image quality. */
jpeg_set_quality(&cinfo, 90, TRUE);
/*! Specify the data source. */
jpeg_mem_dest(&cinfo, encoded, capacity);
/*! Compress and write the image into the target buffer. */
compress(&cinfo, image);
/*! At this point 'jerror.num_warnings' could be checked for corrupt-data warnings. */
jpeg_destroy_compress(&cinfo);
#else // JPEG_LIB_VERSION
THROW_RUNTIME_ERROR("JPEG encoding into a memory buffer requires LibJPEG 8a or higher");
#endif // JPEG_LIB_VERSION
}
Ref<Image> loadJPEG(const FileName &filename)
{
/*! Open the source JPEG file. */
FILE *file = fopen(filename.c_str(), "rb"); if (!file) THROW_RUNTIME_ERROR("Unable to open \"" + filename.str() + "\".");
/*! Decompression parameters and scratch space pointers allocated by the library. */
struct jpeg_decompress_struct cinfo;
/*! The library error handler. */
struct jpeg_error_mgr jerror; cinfo.err = jpeg_std_error(&jerror);
/*! Initialize the JPEG decompression object. */
jpeg_create_decompress(&cinfo);
/*! Specify the data source. */
jpeg_stdio_src(&cinfo, file);
/*! Read file parameters with jpeg_read_header(). */
jpeg_read_header(&cinfo, TRUE);
/*! Specify the color space and color space components of the decompressed image. */
cinfo.out_color_space = JCS_RGB; cinfo.output_components = 3;
/*! Decompress the image into an output buffer and get the image dimensions. */
unsigned char *rgb = decompress(&cinfo); size_t width = cinfo.output_width; size_t height = cinfo.output_height;
/*! Allocate the Embree image. */
Ref<Image> image = new Image4uc(width, height, filename);
/*! Convert the image from unsigned char RGB to unsigned char RGBA. */
for (size_t y=0, i=0 ; y < height ; y++) {
for (size_t x=0 ; x < width ; x++) {
const float r = (float) rgb[i++] / 255.0f;
const float g = (float) rgb[i++] / 255.0f;
const float b = (float) rgb[i++] / 255.0f;
image->set(x, y, Color4(r,g,b,1.0f));
}
}
/*! Clean up. */
jpeg_destroy_decompress(&cinfo);
delete[] rgb;
fclose(file);
return(image);
}
void storeJPEG(const Ref<Image> &image, const FileName &filename)
{
/*! Open the target JPEG file. */
FILE *file = fopen(filename.c_str(), "wb"); if (!file) THROW_RUNTIME_ERROR("Unable to open \"" + filename.str() + "\".");
/*! Compression parameters and scratch space pointers (allocated by the library). */
struct jpeg_compress_struct cinfo;
/*! The library error handler. */
struct jpeg_error_mgr jerror; cinfo.err = jpeg_std_error(&jerror);
/*! Initialize the JPEG compression object. */
jpeg_create_compress(&cinfo);
/*! Specify the incoming image resolution, color space, and color space components. */
cinfo.image_width = image->width; cinfo.image_height = image->height; cinfo.in_color_space = JCS_RGB; cinfo.input_components = 3;
/*! Fill in a sensible set of defaults. */
jpeg_set_defaults(&cinfo);
/*! Specify the data source. */
jpeg_stdio_dest(&cinfo, file);
/*! Allocate storage for the uncompressed packed image. */
unsigned char* rgb = new unsigned char [3 * image->height * image->width];
/*! Convert the image to unsigned char RGB. */
for (size_t y=0, i=0 ; y < image->height ; y++) {
for (size_t x=0 ; x < image->width ; x++) {
const Color4 pixel = image->get(x, y);
rgb[i++] = (unsigned char)(clamp(pixel.r) * 255.0f);
rgb[i++] = (unsigned char)(clamp(pixel.g) * 255.0f);
rgb[i++] = (unsigned char)(clamp(pixel.b) * 255.0f);
}
}
/*! Compress and write the image into the target file. */
compress(&cinfo, rgb);
/*! At this point 'jerror.num_warnings' could be checked for corrupt-data warnings. */
jpeg_destroy_compress(&cinfo);
delete [] rgb;
fclose(file);
}
}
#endif // EMBREE_TUTORIALS_LIBJPEG
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