Mercurial > hg > octave-image

changeset 624:92777e13512e

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im2xxx: use actual value rather than calls to intmax when we already know the class
author carandraug
date Wed, 26 Sep 2012 15:21:55 +0000
parents a923e5324064
children 300c22195a13
files inst/im2int16.m inst/im2uint16.m inst/im2uint8.m
diffstat 3 files changed, 14 insertions(+), 10 deletions(-) [+]
line wrap: on
line diff
--- a/inst/im2int16.m
+++ b/inst/im2int16.m
@@ -39,20 +39,22 @@
   ## Input checking (private function that is used for all im2class functions)
   im_class = imconversion (nargin, "im2int16", false, im);
 
-  switch im_class
+  ## for those who may wonder, 32767 = intmax ("int16")
+  ## for those who may wonder, 65535 = intmax ("uint16")
+    switch im_class
     case "int16"
       ## do nothing, return the same
     case {"single", "double"}
-      im = int16 (double (im * intmax ("uint16")) - double (intmax ("int16")) - 1);
+      im = int16 (double (im * uint16(65535)) - 32767 - 1);
     case "logical"
       im(im)  = intmax ("int16");
       im(!im) = intmin ("int16");
     case "uint8"
         ## 257 is the ratio between the max of uint8 and uint16
         ## double (intmax ("uint16")) / double (intmax ("uint8")) == 257
-        im = int16 (double (257 * uint16 (im)) - double (intmax ("int16")) - 1);
+        im = int16 (double (257 * uint16 (im)) - 32767 - 1);
     case "uint16"
-      im = int16 (double (im) - double (intmax ("int16")) - 1);
+      im = int16 (double (im) - 32767 - 1);
     otherwise
       error ("unsupported image class %s", im_class);
   endswitch
--- a/inst/im2uint16.m
+++ b/inst/im2uint16.m
@@ -40,21 +40,22 @@
   ## Input checking (private function that is used for all im2class functions)
   im_class = imconversion (nargin, "im2uint16", indexed, im);
 
+  ## for those who may wonder, 65535 = intmax ("uint16")
   switch im_class
     case "uint16"
       ## do nothing, return the same
     case {"single", "double"}
       if (indexed)
         imax = max (im(:));
-        if ( imax > intmax ("uint16"))
+        if ( imax > 65535)
           error ("Too many colors '%d' for an indexed uint16 image", imax);
         endif
         im = uint16 (im) - 1;
       else
-        im = uint16 (im * double (intmax ("uint16")));
+        im = uint16 (im * 65535);
       endif
     case "logical"
-      im = uint16 (im) * intmax ("uint16");
+      im = uint16 (im) * uint16 (65535);
     case "uint8"
       if (indexed)
         im = uint16 (im);
--- a/inst/im2uint8.m
+++ b/inst/im2uint8.m
@@ -42,11 +42,12 @@
 
   if (indexed)
     imax = max (im(:));
-    if (imax > intmax ("uint8"))
+    if (imax > 255)
       error ("Too many colors '%d' for an indexed uint8 image", imax);
     endif
   endif
 
+  ## for those who may wonder, 255 = intmax ("uint8")
   switch im_class
     case "uint8"
       ## do nothing, return the same
@@ -54,10 +55,10 @@
       if (indexed)
         im = uint8 (im) - 1;
       else
-        im = uint8 (im * double (intmax ("uint8")));
+        im = uint8 (im * 255);
       endif
     case "logical"
-      im = uint8 (im) * intmax ("uint8");
+      im = uint8 (im) * uint8 (255);
     case "uint16"
       if (indexed)
         im = uint8 (im);