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Updated scanline_read_iterator code sample.

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[SVN r83144]
This commit is contained in:
Christian Henning
2013-02-25 00:36:49 +00:00
committed by Stefan Seefeld
parent bfc78c1438
commit 622cfc4dd0
1 changed files with 24 additions and 21 deletions
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45
io/doc/io.qbk
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@@ -259,37 +259,40 @@ During the review it became clear that there is a need to read big images scanli
a scanline_reader is implemented for all supported image formats. The scanline_read_iterators will then allow to traverse
through the image. The following code sample shows the usage:
// define the reader type
typedef tiff_tag tag_t;
typedef scanline_reader< typename get_read_device< const char*
, FormatTag
, tag_t
>::type
, FormatTag
> reader_t;
, tag_t
> reader_t;
reader_t reader = make_scanline_reader( file_name, FormatTag() );
reader_t reader = make_scanline_reader( "C:/boost/libs/gil/io/test_images/tiff/test.tif", tag_t() );
Image dst( reader._info._width, reader._info._height );
vector< byte_t > buffer( reader._scanline_length );
typedef rgba8_image_t image_t;
typedef scanline_read_iterator< reader_t > iterator_t;
image_t dst( reader._info._width, reader._info._height );
fill_pixels( view(dst), image_t::value_type() );
iterator_t it = iterator_t( reader, &buffer.front() );
iterator_t end = iterator_t();
typedef reader_t::iterator_t iterator_t;
iterator_t it = reader.begin();
iterator_t end = reader.end();
for( int row = 0; it != end; ++it, ++row )
{
copy_pixels( interleaved_view( reader._info._width
, 1
, ( typename Image::view_t::x_iterator ) *it
, reader._scanline_length
)
, subimage_view( view( dst )
, 0
, row
, reader._info._width
, 1
)
);
, 1
, ( image_t::view_t::x_iterator ) *it
, reader._scanline_length
)
, subimage_view( view( dst )
, 0
, row
, reader._info._width
, 1
)
);
}
There are many ways to travese an image but for as of now only by scanline is supported.