Mercurial > octave-antonio
diff scripts/image/imread.m @ 16996:a1d091243d11
Read alpha values from indexed images. Always read indexes from indexed images.
* __magick_read__.cc (read_indexed_images): turn function into template to
remove duplicated loop. Create alpha channel from alpha values colormap.
Skip reading of colormap unless requested. Use fortran_vec to fill the
image instead of indexing the Array<T> with a dim_vector which requires
multiple calls to dim_vector::operator() per iteration.
(__magick_read__): Always read the indexes of an indexed image and not the
RGB or grayscale values when no colormap is requested for output (Matlab
compatibility).
* imread.m: document that an indexed image is always read as such,
independently of the colormap having been requested or not.
* NEWS: add note on the change for reading indexed images.
| author | Carnë Draug <carandraug@octave.org> |
|---|---|
| date | Thu, 18 Jul 2013 01:52:09 +0100 |
| parents | 997efb8d0b19 |
| children | 3db796f89695 |
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--- a/scripts/image/imread.m Wed Jul 17 14:47:46 2013 -0700 +++ b/scripts/image/imread.m Thu Jul 18 01:52:09 2013 +0100 @@ -42,6 +42,9 @@ ## The bit depth of the image determines the ## class of the output: "uint8" or "uint16" for gray ## and color, and "logical" for black and white. +## Note that indexed images always return the indexes for a colormap, +## independent if @var{map} is a requested output. To obtain the actual +## RGB image, use @code{ind2rgb}. ## See the Octave manual for more information in representing images. ## ## Some file formats, such as TIFF and GIF, are able to store multiple @@ -53,12 +56,12 @@ ## of images with @var{param}, @var{val} pairs. The following options ## are supported: ## -## @table @asis -## @item Frames or Index +## @table @samp +## @item "Frames" or "Index" ## This is an alternative method to specify @var{idx}. When specifying it ## in this way, its value can also be the string "all". ## -## @item Info +## @item "Info" ## This option exists for @sc{Matlab} compatibility and has no effect. For ## maximum performance while reading multiple images from a single file, ## use the Index option.