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changeset 17144:96526baf7423

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Fix reading of images using PixelRegion with ranges ending before the limit. * __magick_read__.cc (calculate_region): reduce image cache being loaded into memory by checking max() instead of limit(). Simplify calculation of output size by using nelem(). Fix calculation of the pointer shift required when moving to next column in cases where limit() and max () were different.
author Carnë Draug <carandraug@octave.org>
date Thu, 01 Aug 2013 18:37:07 +0100
parents 603ce503babd
children dcac71776ae8
files libinterp/dldfcn/__magick_read__.cc
diffstat 1 files changed, 22 insertions(+), 13 deletions(-) [+]
line wrap: on
line diff
--- a/libinterp/dldfcn/__magick_read__.cc
+++ b/libinterp/dldfcn/__magick_read__.cc
@@ -55,20 +55,22 @@
   const Range cols     = pixel_region (1).range_value ();
   region["row_start"]  = rows.base () -1;
   region["col_start"]  = cols.base () -1;
-  region["row_end"]    = rows.limit () -1;
-  region["col_end"]    = cols.limit () -1;
+  region["row_end"]    = rows.max ()  -1;
+  region["col_end"]    = cols.max ()  -1;
 
-  // Length of the area to load into the Image Pixel Cache
+  // Length of the area to load into the Image Pixel Cache.  We use max and
+  // min to account for cases where last element of range is the range limit.
   region["row_cache"] = region["row_end"] - region["row_start"] +1;
   region["col_cache"] = region["col_end"] - region["col_start"] +1;
 
   // How much we have to shift in the memory when doing the loops.
   region["row_shift"] = region["col_cache"] * rows.inc ();
-  region["col_shift"] = region["col_cache"] * region["row_cache"] - cols.inc ();
+  region["col_shift"] = region["col_cache"] *
+                        (region["row_cache"] + rows.inc () -1) - cols.inc ();
 
   // The actual height and width of the output image
-  region["row_out"] = floor ((region["row_end"] - region["row_start"]) / rows.inc ()) + 1;
-  region["col_out"] = floor ((region["col_end"] - region["col_start"]) / cols.inc ()) + 1;
+  region["row_out"] = rows.nelem ();
+  region["col_out"] = cols.nelem ();
 
   return region;
 }
@@ -649,15 +651,18 @@
     {
       if (depth <= 1)
         {
-          output = read_indexed_images <boolNDArray> (imvec, frameidx, nargout, options);
+          output = read_indexed_images <boolNDArray>   (imvec, frameidx,
+                                                        nargout, options);
         }
       else if (depth <= 8)
         {
-          output = read_indexed_images <uint8NDArray> (imvec, frameidx, nargout, options);
+          output = read_indexed_images <uint8NDArray>  (imvec, frameidx,
+                                                        nargout, options);
         }
       else if (depth <= 16)
         {
-          output = read_indexed_images <uint16NDArray> (imvec, frameidx, nargout, options);
+          output = read_indexed_images <uint16NDArray> (imvec, frameidx,
+                                                        nargout, options);
         }
       else
         {
@@ -670,19 +675,23 @@
     {
       if (depth <= 1)
         {
-          output = read_images<boolNDArray> (imvec, frameidx, nargout, options);
+          output = read_images<boolNDArray>   (imvec, frameidx,
+                                               nargout, options);
         }
       else if (depth <= 8)
         {
-          output = read_images<uint8NDArray> (imvec, frameidx, nargout, options);
+          output = read_images<uint8NDArray>  (imvec, frameidx,
+                                               nargout, options);
         }
       else if (depth <= 16)
         {
-          output = read_images<uint16NDArray> (imvec, frameidx, nargout, options);
+          output = read_images<uint16NDArray> (imvec, frameidx,
+                                               nargout, options);
         }
       else if (depth <= 32)
         {
-          output = read_images<FloatNDArray> (imvec, frameidx, nargout, options);
+          output = read_images<FloatNDArray>  (imvec, frameidx,
+                                               nargout, options);
         }
       else
         {