processing/JPEG.cpp

#include "JPEG.h"
#include "Demosaic.h"

#include <iostream>

using namespace std;

extern "C" {
#include <jpeglib.h>
}

namespace FCam {
    void saveJPEG_(Image im, string filename, int quality) {
        struct jpeg_compress_struct cinfo;
        struct jpeg_error_mgr jerr;

    cout << "Saving jpeg" << endl;
    
        FILE *f = fopen(filename.c_str(), "wb");
    if (!f) {
        cerr << "Could not open file: " << filename;
        return;
    }
    
        cinfo.err = jpeg_std_error(&jerr);
        jpeg_create_compress(&cinfo);
        jpeg_stdio_dest(&cinfo, f);

        cinfo.image_width = im.size.width;
        cinfo.image_height = im.size.height;
        cinfo.input_components = 3;
    if (im.type == RGB24) {
        cinfo.in_color_space = JCS_RGB;  
    } else if (im.type == YUV24) {
        cinfo.in_color_space = JCS_YCbCr;
    }

        jpeg_set_defaults(&cinfo);
        jpeg_set_quality(&cinfo, quality, TRUE);

        jpeg_start_compress(&cinfo, TRUE);

    JSAMPLE *row;

    if (im.type == RGB24 || im.type == YUV24) {
        while (cinfo.next_scanline < cinfo.image_height) {
        row = im.data + cinfo.next_scanline * im.size.width * 3;
        jpeg_write_scanlines(&cinfo, &row, 1);
        }
    } else if (im.type == UYVY) {
        row = new JSAMPLE[cinfo.image_width*3];
        while (cinfo.next_scanline < cinfo.image_height) {
        // convert the row to YUV
        JSAMPLE *rowPtr = row;
        unsigned char *dataPtr = im.data + cinfo.next_scanline * im.size.width * 2;
        for (size_t i = 0; i < cinfo.image_width/2; i++) {
            rowPtr[0] = dataPtr[1];
            rowPtr[1] = dataPtr[0];
            rowPtr[2] = dataPtr[2];
            rowPtr[3] = dataPtr[3];
            rowPtr[4] = dataPtr[0];
            rowPtr[5] = dataPtr[2];
            rowPtr += 6;
            dataPtr += 4;
        }
        jpeg_write_scanlines(&cinfo, &row, 1);
        }       
        delete[] row;
    }

        jpeg_finish_compress(&cinfo);
        fclose(f);
        jpeg_destroy_compress(&cinfo);

    cout << "Done saving jpeg" << endl;
    }

    void saveJPEG(Frame::Ptr frame, string filename, int quality, Lens *lens, Flash *flash) {
    if (!frame || !frame->image.valid()) {
        cerr << "Cannot save an invalid image" << endl;
        return;
    }

    Image im = frame->image;
    
    switch (frame->image.type) {
    case RAW:
        im = demosaic(frame);
        // fall through to rgb24
    case RGB24: case YUV24: case UYVY:
        saveJPEG_(im, filename, quality);
        break;
    default:
        cerr << "Cannot save a jpeg from a frame in this format" << endl;
    }
    }
};

---