From eda2d8dfbab1ed4d8f6788d8860a0c0aa92368fa Mon Sep 17 00:00:00 2001 From: Robert Osfield Date: Fri, 30 Jan 2004 13:52:12 +0000 Subject: [PATCH] From Stephane, added support for writing JPEG images. --- src/osgPlugins/jpeg/ReaderWriterJPEG.cpp | 120 ++++++++++++++++++++++- 1 file changed, 118 insertions(+), 2 deletions(-) diff --git a/src/osgPlugins/jpeg/ReaderWriterJPEG.cpp b/src/osgPlugins/jpeg/ReaderWriterJPEG.cpp index d1d044799..b5b82e677 100644 --- a/src/osgPlugins/jpeg/ReaderWriterJPEG.cpp +++ b/src/osgPlugins/jpeg/ReaderWriterJPEG.cpp @@ -302,8 +302,116 @@ int *numComponents_ret) class ReaderWriterJPEG : public osgDB::ReaderWriter { + WriteResult::WriteStatus write_JPEG_file (const char* filename,int image_width,int image_height,JSAMPLE* image_buffer,int quality = 100) + { + /* This struct contains the JPEG compression parameters and pointers to + * working space (which is allocated as needed by the JPEG library). + * It is possible to have several such structures, representing multiple + * compression/decompression processes, in existence at once. We refer + * to any one struct (and its associated working data) as a "JPEG object". + */ + struct jpeg_compress_struct cinfo; + /* This struct represents a JPEG error handler. It is declared separately + * because applications often want to supply a specialized error handler + * (see the second half of this file for an example). But here we just + * take the easy way out and use the standard error handler, which will + * print a message on stderr and call exit() if compression fails. + * Note that this struct must live as long as the main JPEG parameter + * struct, to avoid dangling-pointer problems. + */ + struct jpeg_error_mgr jerr; + /* More stuff */ + FILE * outfile; /* target file */ + JSAMPROW row_pointer[1]; /* pointer to JSAMPLE row[s] */ + int row_stride; /* physical row width in image buffer */ + + /* Step 1: allocate and initialize JPEG compression object */ + + /* We have to set up the error handler first, in case the initialization + * step fails. (Unlikely, but it could happen if you are out of memory.) + * This routine fills in the contents of struct jerr, and returns jerr's + * address which we place into the link field in cinfo. + */ + cinfo.err = jpeg_std_error(&jerr); + /* Now we can initialize the JPEG compression object. */ + jpeg_create_compress(&cinfo); + + /* Step 2: specify data destination (eg, a file) */ + /* Note: steps 2 and 3 can be done in either order. */ + + /* Here we use the library-supplied code to send compressed data to a + * stdio stream. You can also write your own code to do something else. + * VERY IMPORTANT: use "b" option to fopen() if you are on a machine that + * requires it in order to write binary files. + */ + if (!(outfile = fopen(filename, "wb"))) + { + return WriteResult::ERROR_IN_WRITING_FILE; + } + jpeg_stdio_dest(&cinfo, outfile); + + /* Step 3: set parameters for compression */ + + /* First we supply a description of the input image. + * Four fields of the cinfo struct must be filled in: + */ + cinfo.image_width = image_width; /* image width and height, in pixels */ + cinfo.image_height = image_height; + cinfo.input_components = 3; /* # of color components per pixel */ + cinfo.in_color_space = JCS_RGB; /* colorspace of input image */ + /* Now use the library's routine to set default compression parameters. + * (You must set at least cinfo.in_color_space before calling this, + * since the defaults depend on the source color space.) + */ + jpeg_set_defaults(&cinfo); + /* Now you can set any non-default parameters you wish to. + * Here we just illustrate the use of quality (quantization table) scaling: + */ + jpeg_set_quality(&cinfo, quality, TRUE /* limit to baseline-JPEG values */); + + /* Step 4: Start compressor */ + + /* TRUE ensures that we will write a complete interchange-JPEG file. + * Pass TRUE unless you are very sure of what you're doing. + */ + jpeg_start_compress(&cinfo, TRUE); + + /* Step 5: while (scan lines remain to be written) */ + /* jpeg_write_scanlines(...); */ + + /* Here we use the library's state variable cinfo.next_scanline as the + * loop counter, so that we don't have to keep track ourselves. + * To keep things simple, we pass one scanline per call; you can pass + * more if you wish, though. + */ + row_stride = image_width * 3; /* JSAMPLEs per row in image_buffer */ + + while (cinfo.next_scanline < cinfo.image_height) + { + /* jpeg_write_scanlines expects an array of pointers to scanlines. + * Here the array is only one element long, but you could pass + * more than one scanline at a time if that's more convenient. + */ + row_pointer[0] = & image_buffer[cinfo.next_scanline * row_stride]; + (void) jpeg_write_scanlines(&cinfo, row_pointer, 1); + } + + /* Step 6: Finish compression */ + + jpeg_finish_compress(&cinfo); + /* After finish_compress, we can close the output file. */ + fclose(outfile); + + /* Step 7: release JPEG compression object */ + + /* This is an important step since it will release a good deal of memory. */ + jpeg_destroy_compress(&cinfo); + + /* And we're done! */ + return WriteResult::FILE_SAVED; + } public: - virtual const char* className() { return "JPEG Image Reader"; } + virtual const char* className() { return "JPEG Image Reader/Writer"; } virtual bool acceptsExtension(const std::string& extension) { return osgDB::equalCaseInsensitive(extension,"jpeg") || osgDB::equalCaseInsensitive(extension,"jpg"); @@ -350,7 +458,15 @@ class ReaderWriterJPEG : public osgDB::ReaderWriter osg::Image::USE_NEW_DELETE); return pOsgImage; - + } + virtual WriteResult writeImage(const osg::Image &img,const std::string& fileName, const osgDB::ReaderWriter::Options*) + { + std::string ext = osgDB::getFileExtension(fileName); + if (!acceptsExtension(ext)) return WriteResult::FILE_NOT_HANDLED; + osg::ref_ptr tmp_img = new osg::Image(img); + tmp_img->flipVertical(); + WriteResult::WriteStatus ws = write_JPEG_file(fileName.c_str(),img.s(),img.t(),(JSAMPLE*)(tmp_img->data())); + return ws; } };