Initial Bresenham line algorithm

include/etl/bresenham.h

@@ -0,0 +1,300 @@
+///\file
+
+/******************************************************************************
+The MIT License(MIT)
+
+Embedded Template Library.
+https://github.com/ETLCPP/etl
+https://www.etlcpp.com
+
+Copyright(c) 2020 jwellbelove
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files(the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and / or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions :
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.
+******************************************************************************/
+
+#ifndef ETL_BRESENHAM_LINE_INCLUDED
+#define ETL_BRESENHAM_LINE_INCLUDED
+
+#include <stddef.h>
+
+#include "platform.h"
+#include "iterator.h"
+#include "exception.h"
+
+namespace etl
+{
+  //***************************************************************************
+  /// A pseudo-container that generates points on a line, using Bresenham's
+  ///  line algorithm.
+  //***************************************************************************
+  template <typename TPoint, typename TIntegral = int>
+  class bresenham_line
+  {
+  public:
+
+    //***************************************************
+    /// Standard container types.
+    //***************************************************
+    typedef TPoint            value_type;
+    typedef size_t            size_type;
+    typedef ptrdiff_t         difference_type;
+    typedef value_type&       reference;
+    typedef const value_type& const_reference;
+    typedef value_type*       pointer;
+    typedef const value_type* const_pointer;
+
+    friend class const_iterator;
+
+    class const_iterator : public etl::iterator<ETL_OR_STD::forward_iterator_tag, TPoint>
+    {
+    public:
+
+      friend class bresenham_line;
+
+      //***************************************************
+      /// 
+      //***************************************************
+      const_iterator()
+        : p_bresenham_line(ETL_NULLPTR)
+      {
+      }
+
+      //***************************************************
+      /// 
+      //***************************************************
+      const_iterator(const const_iterator& other)
+        : p_bresenham_line(other.p_bresenham_line)
+      {
+      }
+
+      //***************************************************
+      /// 
+      //***************************************************
+      const_iterator& operator =(const const_iterator& rhs)
+      {
+        p_bresenham_line = rhs.p_bresenham_line;
+      }
+
+      //***************************************************
+      /// 
+      //***************************************************
+      const_iterator& operator ++()
+      {
+        // Has the end of the series has been reached?
+        if (p_bresenham_line->count == 0)
+        {
+          // Mark it as an end iterator.
+          p_bresenham_line = ETL_NULLPTR;
+        }
+        else
+        {
+          p_bresenham_line->next();
+        }
+
+        return *this;
+      }
+
+      //***************************************************
+      /// 
+      //***************************************************
+      value_type operator *() const
+      {
+        return p_bresenham_line->get_point();
+      }
+
+      //***************************************************
+      /// 
+      //***************************************************
+      value_type operator ->() const
+      {
+        return p_bresenham_line->get_point();
+      }
+
+    private:
+
+      //***************************************************
+      /// 
+      //***************************************************
+      const_iterator(bresenham_line<value_type>* pb)
+        : p_bresenham_line(pb)
+      {
+      }
+
+      bresenham_line<TPoint>* p_bresenham_line;
+    };
+
+    //***************************************************
+    /// Constructor.
+    //***************************************************
+    bresenham_line(const_reference start_, const_reference end_)
+      : start(start_)
+      , end(end_)
+      , current(start_)
+      , x_increment((end_.x < start_.x) ? -1 : 1)
+      , y_increment((end_.y < start_.y) ? -1 : 1)
+      , do_minor_increment(true)
+    {
+      dx = (end_.x < start_.x) ? start_.x - end_.x : end_.x - start_.x;
+      dy = (end_.y < start_.y) ? start_.y - end_.y : end_.y - start_.y;
+
+      major_axis = (dx < dy) ? Axis::Y : Axis::X;
+
+      if (major_axis == Axis::X)
+      {
+        total_count = dx;
+        dy          *= 2;
+        balance     = dy - dx;
+        dx          *= 2;
+      }
+      else
+      {
+        total_count = dy;
+        dx          *= 2;
+        balance     = dx - dy;
+        dy          *= 2;
+      }
+
+      current_count = total_count;
+    }
+
+    //***************************************************
+    /// 
+    //***************************************************
+    const_iterator begin() const
+    {
+      current_count = total_count;
+      current       = start;
+
+      return const_iterator(this);
+    }
+
+    //***************************************************
+    /// 
+    //***************************************************
+    const_iterator cbegin() const
+    {
+      current_count = total_count;
+      current       = start;
+
+      return const_iterator(this);
+    }
+
+    //***************************************************
+    /// 
+    //***************************************************
+    const_iterator end() const
+    {
+      return const_iterator();
+    }
+
+    //***************************************************
+    /// 
+    //***************************************************
+    const_iterator cend() const
+    {
+      return const_iterator();
+    }
+
+    //***************************************************
+    /// Get the size of the series.
+    //***************************************************
+    size_t size() const
+    {
+      return total_count;
+    }
+
+    //***************************************************
+    /// Get the current number of generated points.
+    //***************************************************
+    size_t count() const
+    {
+      return current_count;
+    }
+
+  private:
+
+    //***************************************************
+    /// The major axis.
+    //***************************************************
+    struct Axis
+    {
+      enum
+      {
+        X,
+        Y
+      };
+    };
+
+    //***************************************************
+    /// Calculate the next point.
+    //***************************************************
+    void next()
+    {
+      if (major_axis == Axis::X)
+      {
+        if (do_minor_increment)
+        {
+          current.y += y_increment;
+          balance -= dx;
+        }
+
+        current.x += x_increment;
+        balance += dy;
+      }
+      else
+      {
+        if (do_minor_increment)
+        {
+          current.x += x_increment;
+          balance -= dy;
+        }
+
+        current.y += y_increment;
+        balance += dx;
+      }
+
+      --current_count;
+
+      do_minor_increment = (balance >= 0);
+    }
+
+    //***************************************************
+    /// Get the current point.
+    //***************************************************
+    value_type get_point() const
+    {
+      return current;
+    }
+
+    const value_type start;
+    const value_type end;
+    value_type       current;
+    const TIntegral  x_increment;
+    const TIntegral  y_increment;
+    TIntegral        dx;
+    TIntegral        dy;
+    TIntegral        major_axis;
+    TIntegral        count;
+    TIntegral        current_count;
+    TIntegral        balance;
+    bool             do_minor_increment;
+  };
+
+#endif
+

test/vs2019/etl.vcxproj

@@ -1015,6 +1015,7 @@
     <ClInclude Include="..\..\include\etl\basic_format_spec.h" />
     <ClInclude Include="..\..\include\etl\basic_string_stream.h" />
     <ClInclude Include="..\..\include\etl\bit_stream.h" />
+    <ClInclude Include="..\..\include\etl\bresenham.h" />
     <ClInclude Include="..\..\include\etl\callback_timer.h" />
     <ClInclude Include="..\..\include\etl\combinations.h" />
     <ClInclude Include="..\..\include\etl\compare.h" />

test/vs2019/etl.vcxproj.filters

@@ -79,6 +79,9 @@
     <Filter Include="Resource Files\CI\Github">
       <UniqueIdentifier>{c25471f3-451a-4279-925d-cbdcec912ef8}</UniqueIdentifier>
     </Filter>
+    <Filter Include="ETL\Pseudo Containers">
+      <UniqueIdentifier>{586d2c92-e504-4dea-9b1f-42d725a5272c}</UniqueIdentifier>
+    </Filter>
   </ItemGroup>
   <ItemGroup>
     <ClInclude Include="..\..\include\etl\enum_type.h">
@@ -876,6 +879,9 @@
     <ClInclude Include="..\..\include\etl\string_utilities.h">
       <Filter>ETL\Strings</Filter>
     </ClInclude>
+    <ClInclude Include="..\..\include\etl\bresenham.h">
+      <Filter>ETL\Pseudo Containers</Filter>
+    </ClInclude>
   </ItemGroup>
   <ItemGroup>
     <ClCompile Include="..\main.cpp">