Mercurial > octave-libtiff

changeset 31209:bbb41a5f377a

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__tiff_imread__: improved performance of read_tiled_data * scripts/image/privat/__tiff_imread__.m (read_tiled_data): added logic to skip over tiles that are not needed so they aren't unnecessarily read from disk.
author magedrifaat <magedrifaat@gmail.com>
date Sun, 04 Sep 2022 15:57:47 +0200
parents 1a564892fef1
children e83a62df599b
files scripts/image/private/__tiff_imread__.m
diffstat 1 files changed, 12 insertions(+), 8 deletions(-) [+]
line wrap: on
line diff
--- a/scripts/image/private/__tiff_imread__.m	Sun Sep 04 15:30:27 2022 +0200
+++ b/scripts/image/private/__tiff_imread__.m	Sun Sep 04 15:57:47 2022 +0200
@@ -202,11 +202,13 @@
         ## Calculate the indices of the same columns in the output array
         data_cols = idivide (cols_in_tile - cols (1), col_stride, "fix") + 1;
 
-        tile = img.readEncodedTile (tile_idx);
+        ## Skip over tiles that are not needed
+        if (numel (rows_in_tile) != 0 || numel (cols_in_tile) != 0)
+          tile = img.readEncodedTile (tile_idx);
+          ## Copy the needed data from the tile array to the output array
+          data (data_rows, data_cols, :) = tile (tile_rows, tile_cols, :);
+        endif
         tile_idx += 1;
-
-        ## Copy the needed data from the tile array to the output array
-        data (data_rows, data_cols, :) = tile (tile_rows, tile_cols, :);
       endfor
     endfor
   else
@@ -234,11 +236,13 @@
           ## Calculate the indices of the same columns in the output array
           data_cols = idivide (cols_in_tile - cols (1), col_stride, "fix") + 1;
 
-          tile = img.readEncodedTile (tile_idx);
+          ## Skip over tiles that are not needed
+          if (numel (rows_in_tile) != 0 || numel (cols_in_tile) != 0)
+            tile = img.readEncodedTile (tile_idx);
+            ## Copy the needed data from the tile array to the output array
+            data (data_rows, data_cols, ch) = tile (tile_rows, tile_cols);
+          endif
           tile_idx += 1;
-
-          ## Copy the needed data from the tile array to the output array
-          data (data_rows, data_cols, ch) = tile (tile_rows, tile_cols);
         endfor
       endfor
     endfor