This example shows you how to load a RGB tiff image, convert it to greyscale and save it as 32 and 8bit greyscale images. It will also write the same RGB image to another file.<\/p>\n
\r\n#include "tiffio.h"\r\n#include <iostream>\r\n#include <math.h>\r\n#include <vector>\r\n\r\nusing namespace std;\r\n\r\nclass Image {\r\n\r\npublic:\r\n\r\n Image() {\r\n }\r\n\r\n void load_tiff(string input_filename) {\r\n\r\n m_image_data.clear();\r\n\r\n TIFF* tif = TIFFOpen(input_filename.c_str(), "r");\r\n if (tif) {\r\n uint32 w, h;\r\n size_t npixels;\r\n uint32* raster;\r\n\r\n TIFFGetField(tif, TIFFTAG_IMAGEWIDTH, &w);\r\n TIFFGetField(tif, TIFFTAG_IMAGELENGTH, &h);\r\n npixels = w * h;\r\n m_width = w;\r\n m_height = h;\r\n\r\n raster = (uint32*) _TIFFmalloc(npixels * sizeof (uint32));\r\n if (raster != NULL) {\r\n\tif (TIFFReadRGBAImageOriented(tif, w, h, raster,ORIENTATION_TOPLEFT, 0)) {\r\n\t for(size_t n=0;n<npixels;n++) m_image_data.push_back(raster[n]);\r\n\t}\r\n\t_TIFFfree(raster);\r\n }\r\n TIFFClose(tif);\r\n }\r\n }\r\n\r\n void save_tiff_rgb(string output_filename) {\r\n TIFF *output_image;\r\n\r\n \/\/ Open the TIFF file\r\n if((output_image = TIFFOpen(output_filename.c_str(), "w")) == NULL){\r\n cerr << "Unable to write tif file: " << output_filename << endl;\r\n }\r\n\r\n \/\/ We need to set some values for basic tags before we can add any data\r\n TIFFSetField(output_image, TIFFTAG_IMAGEWIDTH, m_width);\r\n TIFFSetField(output_image, TIFFTAG_IMAGELENGTH, m_height);\r\n TIFFSetField(output_image, TIFFTAG_BITSPERSAMPLE, 8);\r\n TIFFSetField(output_image, TIFFTAG_SAMPLESPERPIXEL, 4);\r\n TIFFSetField(output_image, TIFFTAG_PLANARCONFIG, PLANARCONFIG_CONTIG);\r\n\r\n TIFFSetField(output_image, TIFFTAG_COMPRESSION, COMPRESSION_DEFLATE);\r\n TIFFSetField(output_image, TIFFTAG_PHOTOMETRIC, PHOTOMETRIC_RGB);\r\n\r\n \/\/ Write the information to the file\r\n TIFFWriteEncodedStrip(output_image, 0, &m_image_data[0], m_width*m_height * 4);\r\n\r\n \/\/ Close the file\r\n TIFFClose(output_image);\r\n }\r\n\r\n void save_tiff_grey_32bit(string output_filename) {\r\n TIFF *output_image;\r\n\r\n \/\/ Open the TIFF file\r\n if((output_image = TIFFOpen(output_filename.c_str(), "w")) == NULL){\r\n cerr << "Unable to write tif file: " << output_filename << endl;\r\n }\r\n\r\n \/\/ We need to set some values for basic tags before we can add any data\r\n TIFFSetField(output_image, TIFFTAG_IMAGEWIDTH, m_width);\r\n TIFFSetField(output_image, TIFFTAG_IMAGELENGTH, m_height);\r\n TIFFSetField(output_image, TIFFTAG_BITSPERSAMPLE, 32);\r\n TIFFSetField(output_image, TIFFTAG_SAMPLESPERPIXEL, 1);\r\n TIFFSetField(output_image, TIFFTAG_PLANARCONFIG, PLANARCONFIG_CONTIG);\r\n\r\n TIFFSetField(output_image, TIFFTAG_COMPRESSION, COMPRESSION_DEFLATE);\r\n TIFFSetField(output_image, TIFFTAG_PHOTOMETRIC, PHOTOMETRIC_MINISBLACK);\r\n\r\n \/\/ Write the information to the file\r\n TIFFWriteEncodedStrip(output_image, 0, &m_image_data[0], m_width*m_height * 4);\r\n\r\n \/\/ Close the file\r\n TIFFClose(output_image);\r\n }\r\n\r\n void save_tiff_grey_8bit(string output_filename) {\r\n TIFF *output_image;\r\n\r\n \/\/ Open the TIFF file\r\n if((output_image = TIFFOpen(output_filename.c_str(), "w")) == NULL){\r\n cerr << "Unable to write tif file: " << output_filename << endl;\r\n }\r\n\r\n \/\/ We need to set some values for basic tags before we can add any data\r\n TIFFSetField(output_image, TIFFTAG_IMAGEWIDTH, m_width);\r\n TIFFSetField(output_image, TIFFTAG_IMAGELENGTH, m_height);\r\n TIFFSetField(output_image, TIFFTAG_BITSPERSAMPLE, 8);\r\n TIFFSetField(output_image, TIFFTAG_SAMPLESPERPIXEL, 1);\r\n TIFFSetField(output_image, TIFFTAG_PLANARCONFIG, PLANARCONFIG_CONTIG);\r\n\r\n TIFFSetField(output_image, TIFFTAG_COMPRESSION, COMPRESSION_DEFLATE);\r\n TIFFSetField(output_image, TIFFTAG_PHOTOMETRIC, PHOTOMETRIC_MINISWHITE);\r\n\r\n \/\/ convert data to 8bit\r\n vector<uint8_t> data;\r\n for(size_t n=0;n<m_image_data.size();n++) {\r\n data.push_back(255-(m_image_data[n]\/(256*256*256)));\r\n }\r\n\r\n \/\/ Write the information to the file\r\n TIFFWriteEncodedStrip(output_image, 0, &data[0], m_width*m_height);\r\n\r\n \/\/ Close the file\r\n TIFFClose(output_image);\r\n }\r\n\r\n void make_greyscale() {\r\n\r\n for(size_t n=0;n<m_image_data.size();n++) {\r\n\r\n double r = TIFFGetR(m_image_data[n]);\r\n double g = TIFFGetG(m_image_data[n]);\r\n double b = TIFFGetB(m_image_data[n]);\r\n\r\n double grey = (0.3*r) + (0.59*g) + (0.11*b); \/\/ See http:\/\/en.wikipedia.org\/wiki\/Grayscale\r\n m_image_data[n] = grey * 256 * 256 * 256;\r\n }\r\n }\r\n\r\n vector<uint32_t> m_image_data;\r\n size_t m_width;\r\n size_t m_height;\r\n};\r\n\r\nint main(int argc, char* argv[])\r\n{\r\n\r\n Image input;\r\n\r\n input.load_tiff(string(argv[1]));\r\n input.save_tiff_rgb(string(argv[2]));\r\n input.make_greyscale();\r\n input.save_tiff_grey_32bit(string(argv[3]));\r\n input.save_tiff_grey_8bit(string(argv[4]));\r\n}\r\n<\/pre>\nCompile as:<\/p>\n
\r\ng++ makegrey.cpp -ltiff\r\n<\/pre>\nAnd run as:<\/p>\n
\r\n.\/a.out inputfilename.tif rgb.tif 8bitgrey.tif 32bitgrey.tif\r\n<\/pre>\nNote: The 8bit version is slightly different than the 32bit version. It converts the data such that 0 represents white. This is because Preview.app, at least in MacOS X Lion, does not seem to be able to cope with 0 being black.<\/p>\n
This has not been applied to the 32bit output, so this will display incorrectly in Preview. However it will display correctly in Imagemagick.<\/p>\n","protected":false},"excerpt":{"rendered":"
This example shows you how to load a RGB tiff image, convert it to greyscale and save it as 32 and 8bit greyscale images. It will also write the same RGB image to another file. #include "tiffio.h" #include <iostream> #include <math.h> #include <vector> using namespace std; class Image { public: Image() { } void load_tiff(string […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"jetpack_post_was_ever_published":false,"_jetpack_newsletter_access":"","_jetpack_dont_email_post_to_subs":false,"_jetpack_newsletter_tier_id":0,"_jetpack_memberships_contains_paywalled_content":false,"_jetpack_memberships_contains_paid_content":false,"footnotes":"","jetpack_publicize_message":"","jetpack_publicize_feature_enabled":true,"jetpack_social_post_already_shared":false,"jetpack_social_options":{"image_generator_settings":{"template":"highway","default_image_id":0,"font":"","enabled":false},"version":2}},"categories":[1],"tags":[17,15],"class_list":["post-549","post","type-post","status-publish","format-standard","hentry","category-uncategorized","tag-greyscale","tag-libtiff"],"jetpack_publicize_connections":[],"jetpack_featured_media_url":"","jetpack_shortlink":"https:\/\/wp.me\/p1RRoU-8R","jetpack_sharing_enabled":true,"_links":{"self":[{"href":"https:\/\/41j.com\/blog\/wp-json\/wp\/v2\/posts\/549","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/41j.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/41j.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/41j.com\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/41j.com\/blog\/wp-json\/wp\/v2\/comments?post=549"}],"version-history":[{"count":2,"href":"https:\/\/41j.com\/blog\/wp-json\/wp\/v2\/posts\/549\/revisions"}],"predecessor-version":[{"id":551,"href":"https:\/\/41j.com\/blog\/wp-json\/wp\/v2\/posts\/549\/revisions\/551"}],"wp:attachment":[{"href":"https:\/\/41j.com\/blog\/wp-json\/wp\/v2\/media?parent=549"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/41j.com\/blog\/wp-json\/wp\/v2\/categories?post=549"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/41j.com\/blog\/wp-json\/wp\/v2\/tags?post=549"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}