Question

所以，我有一个ppm文件，在ppmformat.cpp中，我有 imaging :: component_t * buffer = new imaging :: component_t [3 * numCol * numRow]; 。我对此声明了什么？我想要一个带（3 * numCol * numRow）大小的缓冲区，但我不明白component_t的用途是什么？

  class Color.h
     #include <ostream>
     #ifndef _COLOR
     #define _COLOR


     namespace imaging
     {
     /*! An alias for the floating point representation of color components (32bit per color channel).
      *
      * Each color channel goes from 0.0f (darkness) to 1.0f (full color brightness).
      * For example, bright red is (1,0,0), white is (1,1,1), magenta is (1,0,1) etc.
     */
     typedef float component_t;

     /*! Represents a triplet of Red, Green, Blue (RGB) values.
     */
    class Color
    {
    public:
    // members
    component_t r, //! The red color channel (component)
        g, //! The green color channel (component)
        b; //! The blue color channel (component)

           // member functions

           /*! This operator returns the index-th component of the image.
           *
           *    For speed, no bounds for index values are checked.
           *
           *  \param index is the index of the component to obtain. Values should be 0, 1 or 2.
           *
           *  \return a reference to the respective color component.
           */
         component_t & operator [] (size_t index)
         {
         return *(&r + index);
         }

         /*! Addition operator.
         *
         *  Adds a color to the current one and returns the result.
         *
         *  \param right is the right Color operand of the + sign.
         *
         *  \return the resulting color after the component-wise addition of the two colors.
         */
         Color operator + (Color & right)
         {
         Color left;
         left.r = r + right.r;
         left.g = g + right.g;
         left.b = b + right.b;
         return left;
         }

         // constructors

    /*! Parameterized constructor.
    *
    * \param r is the red component of the color.
    * \param g is the green component of the color.
    * \param b is the blue component of the color.
    */
    Color(component_t r, component_t g, component_t b) : r(r), g(g), b(b) {}

    /*! Default constructor.
    *
    *  All components set to zero, i.e. a black color.
    */
    Color() : r(0), g(0), b(0) {}
   };
  }

  #endif _COLOR

Answer 1

您可以看到component_t是浮点数据类型的别名。因此，在声明中使用float或component_t没有区别。

typedef float component_t;

但我建议您使用代表颜色组件的component_t，这样可以使代码更具可读性。

ppm文件，对组件的对象声明

1 个答案: