From c5a8ccd7cf841ae491e905b709cb702f3c86bedf Mon Sep 17 00:00:00 2001
From: giraffedata <giraffedata@9d0c8265-081b-0410-96cb-a4ca84ce46f8>
Date: Sun, 25 Jan 2009 19:13:21 +0000
Subject: Move stuff into new editor/specialty/ directory

git-svn-id: http://svn.code.sf.net/p/netpbm/code/trunk@831 9d0c8265-081b-0410-96cb-a4ca84ce46f8
---
 editor/specialty/ppmshift.c | 132 ++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 132 insertions(+)
 create mode 100644 editor/specialty/ppmshift.c

(limited to 'editor/specialty/ppmshift.c')

diff --git a/editor/specialty/ppmshift.c b/editor/specialty/ppmshift.c
new file mode 100644
index 00000000..a765daa5
--- /dev/null
+++ b/editor/specialty/ppmshift.c
@@ -0,0 +1,132 @@
+
+/*********************************************************************/
+/* ppmshift -  shift lines of a picture left or right by x pixels    */
+/* Frank Neumann, October 1993                                       */
+/* V1.1 16.11.1993                                                   */
+/*                                                                   */
+/* version history:                                                  */
+/* V1.0    11.10.1993  first version                                 */
+/* V1.1    16.11.1993  Rewritten to be NetPBM.programming conforming */
+/*********************************************************************/
+
+#include "ppm.h"
+
+/**************************/
+/* start of main function */
+/**************************/
+int
+main(int    argc,
+     char * argv[]) {
+
+    FILE * ifP;
+    unsigned int row;
+    int argn, rows, cols, format;
+    pixel * srcrow;
+    pixel * destrow;
+    pixval maxval;
+    int shift, nowshift;
+    int shiftArg;
+
+    const char * const usage = "shift [ppmfile]\n        shift: maximum number of pixels to shift a line by\n";
+
+    /* parse in 'default' parameters */
+    ppm_init(&argc, argv);
+
+    argn = 1;
+
+    /* parse in shift number */
+    if (argn == argc)
+        pm_usage(usage);
+    if (sscanf(argv[argn], "%d", &shiftArg) != 1)
+        pm_usage(usage);
+    if (shiftArg < 0)
+        pm_error("shift factor must be 0 or more");
+    ++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);
+
+    /* read first data from file */
+    ppm_readppminit(ifP, &cols, &rows, &maxval, &format);
+
+    if (shiftArg > cols) {
+        shift = cols;
+        pm_message("shift amount is larger than picture width - reset to %d",
+                   shift);
+    } else
+        shift = shiftArg;
+
+    srcrow = ppm_allocrow(cols);
+
+    destrow = ppm_allocrow(cols);
+
+    ppm_writeppminit(stdout, cols, rows, maxval, 0);
+
+    srand(pm_randseed());
+
+    /** now do the shifting **/
+    /* the range by which a line is shifted lays in the range from */
+    /* -shift/2 .. +shift/2 pixels; however, within this range it is */
+    /* randomly chosen */
+    for (row = 0; row < rows; ++row) {
+        pixel * pP;
+        pixel * pP2;
+
+        if (shift != 0)
+            nowshift = (rand() % (shift+1)) - ((shift+1) / 2);
+        else
+            nowshift = 0;
+
+        ppm_readppmrow(ifP, srcrow, cols, maxval, format);
+
+        pP  = &srcrow[0];
+        pP2 = &destrow[0];
+
+        /* if the shift value is less than zero, we take the original
+           pixel line and copy it into the destination line translated
+           to the left by x pixels. The empty pixels on the right end
+           of the destination line are filled up with the pixel that
+           is the right-most in the original pixel line.
+        */
+        if (nowshift < 0) {
+            unsigned int col;
+            pP += abs(nowshift);
+            for (col = 0; col < cols; ++col) {
+                PPM_ASSIGN(*pP2, PPM_GETR(*pP), PPM_GETG(*pP), PPM_GETB(*pP));
+                ++pP2;
+                if (col < (cols + nowshift) - 1)
+                    ++pP;
+            }
+        } else {
+            unsigned int col;
+            /* The shift value is 0 or positive, so fill the first
+               <nowshift> pixels of the destination line with the
+               first pixel from the source line, and copy the rest of
+               the source line to the dest line
+            */
+            for (col = 0; col < cols; ++col) {
+                PPM_ASSIGN(*pP2, PPM_GETR(*pP), PPM_GETG(*pP), PPM_GETB(*pP));
+                ++pP2;
+                if (col >= nowshift)
+                    ++pP;
+            }
+        }
+
+        ppm_writeppmrow(stdout, destrow, cols, maxval, 0);
+    }
+
+    pm_close(ifP);
+    ppm_freerow(srcrow);
+    ppm_freerow(destrow);
+
+    return 0;
+}
-- 
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