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author | giraffedata <giraffedata@9d0c8265-081b-0410-96cb-a4ca84ce46f8> | 2009-03-29 22:19:36 +0000 |
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committer | giraffedata <giraffedata@9d0c8265-081b-0410-96cb-a4ca84ce46f8> | 2009-03-29 22:19:36 +0000 |
commit | ac138b159f6a208dd964a8147cb39a2571092008 (patch) | |
tree | 5a4dfa10a5923670c9e160e96a29967f9aa76700 /editor/specialty/ppmspread.c | |
parent | 56fbd619bbac49a77ec0b48f06e6ed7bfb84468a (diff) | |
download | netpbm-mirror-ac138b159f6a208dd964a8147cb39a2571092008.tar.gz netpbm-mirror-ac138b159f6a208dd964a8147cb39a2571092008.tar.xz netpbm-mirror-ac138b159f6a208dd964a8147cb39a2571092008.zip |
Release 10.46.00
git-svn-id: http://svn.code.sf.net/p/netpbm/code/advanced@869 9d0c8265-081b-0410-96cb-a4ca84ce46f8
Diffstat (limited to 'editor/specialty/ppmspread.c')
-rw-r--r-- | editor/specialty/ppmspread.c | 117 |
1 files changed, 117 insertions, 0 deletions
diff --git a/editor/specialty/ppmspread.c b/editor/specialty/ppmspread.c new file mode 100644 index 00000000..6753f4fe --- /dev/null +++ b/editor/specialty/ppmspread.c @@ -0,0 +1,117 @@ +/*********************************************************************/ +/* ppmspread - randomly displace a PPM's pixels by a certain amount */ +/* Frank Neumann, October 1993 */ +/* V1.1 16.11.1993 */ +/* */ +/* version history: */ +/* V1.0 12.10.1993 first version */ +/* V1.1 16.11.1993 Rewritten to be NetPBM.programming conforming */ +/*********************************************************************/ + +#include <string.h> + +#include "ppm.h" + + + +int +main(int argc, + char * argv[]) { + + FILE * ifP; + int argn, rows, cols; + unsigned int row; + pixel ** destarray, ** srcarray; + pixel * pP; + pixel * pP2; + pixval maxval; + pixval r1, g1, b1; + int amount; + const char * const usage = "amount [ppmfile]\n amount: # of pixels to displace a pixel by at most\n"; + + /* parse in 'default' parameters */ + ppm_init(&argc, argv); + + argn = 1; + + /* parse in amount & seed */ + if (argn == argc) + pm_usage(usage); + if (sscanf(argv[argn], "%d", &amount) != 1) + pm_usage(usage); + if (amount < 0) + pm_error("amount should be a positive number"); + ++argn; + + /* parse in filename (if present, stdin otherwise) */ + if (argn != argc) + { + ifP = pm_openr(argv[argn]); + ++argn; + } + else + ifP = stdin; + + if (argn != argc) + pm_usage(usage); + + srcarray = ppm_readppm(ifP, &cols, &rows, &maxval); + + destarray = ppm_allocarray(cols, rows); + + /* clear out the buffer */ + for (row = 0; row < rows; ++row) + memset(destarray[row], 0, cols * sizeof(pixel)); + + srand(pm_randseed()); + + /* start displacing pixels */ + for (row = 0; row < rows; ++row) { + unsigned int col; + pP = &srcarray[row][0]; + + for (col = 0; col < cols; ++col) { + int const xdis = (rand() % (amount+1)) - ((amount+1) / 2); + int const ydis = (rand() % (amount+1)) - ((amount+1) / 2); + + int const xnew = col + xdis; + int const ynew = row + ydis; + + /* only set the displaced pixel if it's within the bounds + of the image + */ + if (xnew >= 0 && xnew < cols && ynew >= 0 && ynew < rows) { + /* displacing a pixel is accomplished by swapping it + with another pixel in its vicinity - so, first + store other pixel's RGB + */ + pP2 = &srcarray[ynew][xnew]; + r1 = PPM_GETR(*pP2); + g1 = PPM_GETG(*pP2); + b1 = PPM_GETB(*pP2); + /* set second pixel to new value */ + pP2 = &destarray[ynew][xnew]; + PPM_ASSIGN(*pP2, PPM_GETR(*pP), PPM_GETG(*pP), PPM_GETB(*pP)); + + /* now, set first pixel to (old) value of second */ + pP2 = &destarray[row][col]; + PPM_ASSIGN(*pP2, r1, g1, b1); + } else { + /* displaced pixel is out of bounds; leave the old + pixel there + */ + pP2 = &destarray[row][col]; + PPM_ASSIGN(*pP2, PPM_GETR(*pP), PPM_GETG(*pP), PPM_GETB(*pP)); + } + ++pP; + } + } + + ppm_writeppm(stdout, destarray, cols, rows, maxval, 0); + + pm_close(ifP); + ppm_freearray(srcarray, rows); + ppm_freearray(destarray, rows); + + return 0; +} |