optionalize

Prototype

template<class Raster>
optional_raster_view<Raster> optionalize(Raster raster)

Description

Takes a raster view with value_type input_value_type as input and returns a raster view of to the same values but wrapped as an optional. The resulting raster is non-mutable, even if the input raster is.

Definition

<pronto/raster/optional_raster_view.h> (open in Github)

Requirements on types

Raster must implement the RasterView concept.

Preconditions

raster must be initialized

Complexity

O(1)

Example of use

//example_optional_raster_view.cpp

#include <pronto/raster/io.h>
#include <pronto/raster/optional.h>
#include <pronto/raster/optional_raster_view.h>
#include <pronto/raster/padded_raster_view.h>
#include <pronto/raster/plot_raster.h>

namespace pr = pronto::raster;

int main()
{
  auto raster = pr::create_temp<int>(3, 4, GDT_Byte);
  auto i = 0;
  for (auto&& v : raster) {
    i = (i + 3) % 7;
    v = i;
  }
  auto optional_raster = pr::optionalize(raster);
  auto padded_optional_raster = pr::pad(optional_raster, 2, 2, 2, 2, pr::none);
  
  plot_raster(raster);
  plot_raster(optional_raster);
  plot_raster(padded_optional_raster);
  
  return 0;
}

Output:

Rows: 3, Cols: 4, Value type: int
3       6       2       5
1       4       0       3
6       2       5       1

Rows: 3, Cols: 4, Value type: class std::optional<int>
3       6       2       5
1       4       0       3
6       2       5       1

Rows: 7, Cols: 8, Value type: class std::optional<int>
-       -       -       -       -       -       -       -
-       -       -       -       -       -       -       -
-       -       3       6       2       5       -       -
-       -       1       4       0       3       -       -
-       -       6       2       5       1       -       -
-       -       -       -       -       -       -       -
-       -       -       -       -       -       -       -