Constantin Kaplinsky | 71a32f0 | 2007-07-24 12:10:16 +0000 | [diff] [blame] | 1 | #include <stdlib.h> |
| 2 | |
| 3 | #include <rfb/JpegCompressor.h> |
| 4 | |
| 5 | using namespace rfb; |
| 6 | |
| 7 | const int StandardJpegCompressor::ALLOC_CHUNK_SIZE = 65536; |
| 8 | const int StandardJpegCompressor::DEFAULT_QUALITY = 75; |
| 9 | |
| 10 | // |
| 11 | // Extend jpeg_destination_mgr struct with a pointer to our object. |
| 12 | // |
| 13 | |
| 14 | typedef struct { |
| 15 | struct jpeg_destination_mgr pub; |
| 16 | StandardJpegCompressor *_this; |
| 17 | } my_destination_mgr; |
| 18 | |
| 19 | // |
| 20 | // C-compatible interface to our destination manager. It just obtains |
| 21 | // a pointer to the right object and calls a corresponding C++ member |
| 22 | // function on that object. |
| 23 | // |
| 24 | |
| 25 | static void |
| 26 | init_destination(j_compress_ptr cinfo) |
| 27 | { |
| 28 | my_destination_mgr *dest_ptr = (my_destination_mgr *)cinfo->dest; |
| 29 | dest_ptr->_this->initDestination(); |
| 30 | } |
| 31 | |
| 32 | static boolean |
| 33 | empty_output_buffer (j_compress_ptr cinfo) |
| 34 | { |
| 35 | my_destination_mgr *dest_ptr = (my_destination_mgr *)cinfo->dest; |
| 36 | return (boolean)dest_ptr->_this->emptyOutputBuffer(); |
| 37 | } |
| 38 | |
| 39 | static void |
| 40 | term_destination (j_compress_ptr cinfo) |
| 41 | { |
| 42 | my_destination_mgr *dest_ptr = (my_destination_mgr *)cinfo->dest; |
| 43 | dest_ptr->_this->termDestination(); |
| 44 | } |
| 45 | |
| 46 | // |
| 47 | // Constructor and destructor. |
| 48 | // |
| 49 | |
| 50 | StandardJpegCompressor::StandardJpegCompressor() |
| 51 | : m_cdata(0), |
| 52 | m_cdata_allocated(0), |
| 53 | m_cdata_ready(0) |
| 54 | { |
| 55 | // Initialize JPEG compression structure. |
| 56 | m_cinfo.err = jpeg_std_error(&m_jerr); |
| 57 | jpeg_create_compress(&m_cinfo); |
| 58 | |
| 59 | // Set up a destination manager. |
| 60 | my_destination_mgr *dest = new my_destination_mgr; |
| 61 | dest->pub.init_destination = init_destination; |
| 62 | dest->pub.empty_output_buffer = empty_output_buffer; |
| 63 | dest->pub.term_destination = term_destination; |
| 64 | dest->_this = this; |
| 65 | m_cinfo.dest = (jpeg_destination_mgr *)dest; |
| 66 | |
| 67 | // Set up a destination manager. |
| 68 | m_cinfo.input_components = 3; |
| 69 | m_cinfo.in_color_space = JCS_RGB; |
| 70 | jpeg_set_defaults(&m_cinfo); |
| 71 | jpeg_set_quality(&m_cinfo, DEFAULT_QUALITY, true); |
| 72 | |
| 73 | // We prefer speed over quality. |
| 74 | m_cinfo.dct_method = JDCT_FASTEST; |
| 75 | } |
| 76 | |
| 77 | StandardJpegCompressor::~StandardJpegCompressor() |
| 78 | { |
| 79 | // Free compressed data buffer. |
| 80 | if (m_cdata) |
| 81 | free(m_cdata); |
| 82 | |
| 83 | // Clean up the destination manager. |
| 84 | delete m_cinfo.dest; |
| 85 | m_cinfo.dest = NULL; |
| 86 | |
| 87 | // Release the JPEG compression structure. |
| 88 | jpeg_destroy_compress(&m_cinfo); |
| 89 | } |
| 90 | |
| 91 | // |
| 92 | // Our implementation of destination manager. |
| 93 | // |
| 94 | |
| 95 | void |
| 96 | StandardJpegCompressor::initDestination() |
| 97 | { |
| 98 | if (!m_cdata) { |
| 99 | size_t new_size = ALLOC_CHUNK_SIZE; |
| 100 | m_cdata = (unsigned char *)malloc(new_size); |
| 101 | m_cdata_allocated = new_size; |
| 102 | } |
| 103 | |
| 104 | m_cdata_ready = 0; |
| 105 | m_cinfo.dest->next_output_byte = m_cdata; |
| 106 | m_cinfo.dest->free_in_buffer = m_cdata_allocated; |
| 107 | } |
| 108 | |
| 109 | bool |
| 110 | StandardJpegCompressor::emptyOutputBuffer() |
| 111 | { |
| 112 | size_t old_size = m_cdata_allocated; |
| 113 | size_t new_size = old_size + ALLOC_CHUNK_SIZE; |
| 114 | |
| 115 | m_cdata = (unsigned char *)realloc(m_cdata, new_size); |
| 116 | m_cdata_allocated = new_size; |
| 117 | |
| 118 | m_cinfo.dest->next_output_byte = &m_cdata[old_size]; |
| 119 | m_cinfo.dest->free_in_buffer = new_size - old_size; |
| 120 | |
| 121 | return true; |
| 122 | } |
| 123 | |
| 124 | void |
| 125 | StandardJpegCompressor::termDestination() |
| 126 | { |
| 127 | m_cdata_ready = m_cdata_allocated - m_cinfo.dest->free_in_buffer; |
| 128 | } |
| 129 | |
| 130 | // |
| 131 | // Set JPEG quality level (0..100) |
| 132 | // |
| 133 | |
| 134 | void |
| 135 | StandardJpegCompressor::setQuality(int level) |
| 136 | { |
| 137 | if (level < 0) |
| 138 | level = 0; |
| 139 | if (level > 100) |
| 140 | level = 100; |
| 141 | |
| 142 | jpeg_set_quality(&m_cinfo, level, true); |
| 143 | } |
| 144 | |
| 145 | // |
| 146 | // Perform JPEG compression. |
| 147 | // |
| 148 | // FIXME: This function assumes that (fmt->bpp == 32 && |
| 149 | // fmt->depth == 24 && fmt->redMax == 255 && |
| 150 | // fmt->greenMax == 255 && fmt->blueMax == 255). |
| 151 | // |
| 152 | |
| 153 | void |
| 154 | StandardJpegCompressor::compress(const rdr::U32 *buf, |
| 155 | const PixelFormat *fmt, |
| 156 | int w, int h, int stride) |
| 157 | { |
| 158 | m_cinfo.image_width = w; |
| 159 | m_cinfo.image_height = h; |
| 160 | |
| 161 | jpeg_start_compress(&m_cinfo, TRUE); |
| 162 | |
| 163 | const rdr::U32 *src = buf; |
| 164 | |
| 165 | // We'll pass up to 8 rows to jpeg_write_scanlines(). |
| 166 | JSAMPLE *rgb = new JSAMPLE[w * 3 * 8]; |
| 167 | JSAMPROW row_pointer[8]; |
| 168 | for (int i = 0; i < 8; i++) |
| 169 | row_pointer[i] = &rgb[w * 3 * i]; |
| 170 | |
| 171 | // Feed the pixels to the JPEG library. |
| 172 | while (m_cinfo.next_scanline < m_cinfo.image_height) { |
| 173 | int max_rows = m_cinfo.image_height - m_cinfo.next_scanline; |
| 174 | if (max_rows > 8) { |
| 175 | max_rows = 8; |
| 176 | } |
| 177 | for (int dy = 0; dy < max_rows; dy++) { |
| 178 | JSAMPLE *dst = row_pointer[dy]; |
| 179 | for (int x = 0; x < w; x++) { |
| 180 | dst[x*3] = (JSAMPLE)(src[x] >> fmt->redShift); |
| 181 | dst[x*3+1] = (JSAMPLE)(src[x] >> fmt->greenShift); |
| 182 | dst[x*3+2] = (JSAMPLE)(src[x] >> fmt->blueShift); |
| 183 | } |
| 184 | src += stride; |
| 185 | } |
| 186 | jpeg_write_scanlines(&m_cinfo, row_pointer, max_rows); |
| 187 | } |
| 188 | |
| 189 | delete[] rgb; |
| 190 | |
| 191 | jpeg_finish_compress(&m_cinfo); |
| 192 | } |
| 193 | |