diff options
Diffstat (limited to 'Imaging/libImaging/JpegEncode.c')
| -rw-r--r-- | Imaging/libImaging/JpegEncode.c | 211 |
1 files changed, 211 insertions, 0 deletions
diff --git a/Imaging/libImaging/JpegEncode.c b/Imaging/libImaging/JpegEncode.c new file mode 100644 index 0000000..6bedcd8 --- /dev/null +++ b/Imaging/libImaging/JpegEncode.c @@ -0,0 +1,211 @@ +/* + * The Python Imaging Library. + * $Id: JpegEncode.c 2134 2004-10-06 08:55:20Z fredrik $ + * + * coder for JPEG data + * + * history: + * 1996-05-06 fl created + * 1996-07-16 fl don't drop last block of encoded data + * 1996-12-30 fl added quality and progressive settings + * 1997-01-08 fl added streamtype settings + * 1998-01-31 fl adapted to libjpeg 6a + * 1998-07-12 fl added YCbCr support + * 2001-04-16 fl added DPI write support + * + * Copyright (c) 1997-2001 by Secret Labs AB + * Copyright (c) 1995-1997 by Fredrik Lundh + * + * See the README file for details on usage and redistribution. + */ + + +#include "Imaging.h" + +#ifdef HAVE_LIBJPEG + +#undef HAVE_PROTOTYPES +#undef HAVE_STDLIB_H +#undef HAVE_STDDEF_H +#undef UINT8 +#undef UINT16 +#undef UINT32 +#undef INT16 +#undef INT32 + +#include "Jpeg.h" + +/* -------------------------------------------------------------------- */ +/* Suspending output handler */ +/* -------------------------------------------------------------------- */ + +METHODDEF(void) +stub(j_compress_ptr cinfo) +{ + /* empty */ +} + +METHODDEF(boolean) +empty_output_buffer (j_compress_ptr cinfo) +{ + /* Suspension */ + return FALSE; +} + +GLOBAL(void) +jpeg_buffer_dest(j_compress_ptr cinfo, JPEGDESTINATION* destination) +{ + cinfo->dest = (void*) destination; + + destination->pub.init_destination = stub; + destination->pub.empty_output_buffer = empty_output_buffer; + destination->pub.term_destination = stub; +} + + +/* -------------------------------------------------------------------- */ +/* Error handler */ +/* -------------------------------------------------------------------- */ + +METHODDEF(void) +error(j_common_ptr cinfo) +{ + JPEGERROR* error; + error = (JPEGERROR*) cinfo->err; + (*cinfo->err->output_message) (cinfo); + longjmp(error->setjmp_buffer, 1); +} + + +/* -------------------------------------------------------------------- */ +/* Encoder */ +/* -------------------------------------------------------------------- */ + +int +ImagingJpegEncode(Imaging im, ImagingCodecState state, UINT8* buf, int bytes) +{ + JPEGENCODERSTATE* context = (JPEGENCODERSTATE*) state->context; + int ok; + + if (setjmp(context->error.setjmp_buffer)) { + /* JPEG error handler */ + jpeg_destroy_compress(&context->cinfo); + state->errcode = IMAGING_CODEC_BROKEN; + return -1; + } + + if (!state->state) { + + /* Setup compression context (very similar to the decoder) */ + context->cinfo.err = jpeg_std_error(&context->error.pub); + context->error.pub.error_exit = error; + jpeg_create_compress(&context->cinfo); + jpeg_buffer_dest(&context->cinfo, &context->destination); + + /* Ready to encode */ + state->state = 1; + + } + + /* Load the destination buffer */ + context->destination.pub.next_output_byte = buf; + context->destination.pub.free_in_buffer = bytes; + + switch (state->state) { + + case 1: + + context->cinfo.image_width = state->xsize; + context->cinfo.image_height = state->ysize; + + switch (state->bits) { + case 8: + context->cinfo.input_components = 1; + context->cinfo.in_color_space = JCS_GRAYSCALE; + break; + case 24: + context->cinfo.input_components = 3; + if (strcmp(im->mode, "YCbCr") == 0) + context->cinfo.in_color_space = JCS_YCbCr; + else + context->cinfo.in_color_space = JCS_RGB; + break; + case 32: + context->cinfo.input_components = 4; + context->cinfo.in_color_space = JCS_CMYK; + break; + default: + state->errcode = IMAGING_CODEC_CONFIG; + return -1; + } + + /* Compressor configuration */ + jpeg_set_defaults(&context->cinfo); + if (context->quality > 0) + jpeg_set_quality(&context->cinfo, context->quality, 1); + if (context->progressive) + jpeg_simple_progression(&context->cinfo); + context->cinfo.smoothing_factor = context->smooth; + context->cinfo.optimize_coding = (boolean) context->optimize; + if (context->xdpi > 0 && context->ydpi > 0) { + context->cinfo.density_unit = 1; /* dots per inch */ + context->cinfo.X_density = context->xdpi; + context->cinfo.Y_density = context->ydpi; + } + switch (context->streamtype) { + case 1: + /* tables only -- not yet implemented */ + state->errcode = IMAGING_CODEC_CONFIG; + return -1; + case 2: + /* image only */ + jpeg_suppress_tables(&context->cinfo, TRUE); + jpeg_start_compress(&context->cinfo, FALSE); + break; + default: + /* interchange stream */ + jpeg_start_compress(&context->cinfo, TRUE); + break; + } + state->state++; + /* fall through */ + + case 2: + + ok = 1; + while (state->y < state->ysize) { + state->shuffle(state->buffer, + (UINT8*) im->image[state->y + state->yoff] + + state->xoff * im->pixelsize, state->xsize); + ok = jpeg_write_scanlines(&context->cinfo, &state->buffer, 1); + if (ok != 1) + break; + state->y++; + } + + if (ok != 1) + break; + state->state++; + /* fall through */ + + case 3: + + /* Finish compression */ + if (context->destination.pub.free_in_buffer < 100) + break; + jpeg_finish_compress(&context->cinfo); + + /* Clean up */ + jpeg_destroy_compress(&context->cinfo); + /* if (jerr.pub.num_warnings) return BROKEN; */ + state->errcode = IMAGING_CODEC_END; + break; + + } + + /* Return number of bytes in output buffer */ + return context->destination.pub.next_output_byte - buf; + +} + +#endif |