VC++实现图像处理：八叉树颜色量化源码解析

/******************************************************************
 CqOctree.CPP

  Performing Color Quantization using Octree algorithm

  The 2 functions for global use is
   HPALETTE CreateOctreePalette (HBITMAP hImage, UINT nMaxColors, UINT nColorBits)
   HPALETTE CreateOctreePalette (LPSTR lpDIB, UINT nMaxColors, UINT nColorBits)
  For using convenience, define it in DIBAPI.H
******************************************************************/

#include "stdafx.h"
#include "dibapi.h"

// Structure use internally
typedef struct _NODE 
{
    BOOL bIsLeaf;               // TRUE if node has no children
    UINT nPixelCount;           // Number of pixels represented by this leaf
    UINT nRedSum;               // Sum of red components
    UINT nGreenSum;             // Sum of green components
    UINT nBlueSum;              // Sum of blue components
    struct _NODE* pChild[8];    // Pointers to child nodes
    struct _NODE* pNext;        // Pointer to next reducible node
} NODE;

// Function prototypes
 //Global use, define it in dibapi.h
 //HPALETTE CreateOctreePalette (HDIB hDIB, UINT nMaxColors, UINT nColorBits)
 //HPALETTE CreateOctreePalette (LPSTR lpDIB, UINT nMaxColors, UINT nColorBits)

//Local use only
HPALETTE BuildOctreePalette(HANDLE hImage, UINT nMaxColors, UINT nColorBits);
void AddColor (NODE**, BYTE, BYTE, BYTE, UINT, UINT, UINT*, NODE**);
NODE* CreateNode (UINT, UINT, UINT*, NODE**);
void ReduceTree (UINT, UINT*, NODE**);
void DeleteTree (NODE**);
void GetPaletteColors (NODE*, PALETTEENTRY*, UINT*);
int GetRightShiftCount (DWORD);
int GetLeftShiftCount (DWORD);

// Function body

HPALETTE CreateOctreePalette(HDIB hDIB, UINT nMaxColors, UINT nColorBits)
{
 HANDLE hImage;

 hImage = DIBToDIBSection(hDIB);
 if (! hImage)
  return NULL;
 return BuildOctreePalette(hImage, nMaxColors, nColorBits);
}

HPALETTE CreateOctreePalette(LPBYTE lpDIB, UINT nMaxColors, UINT nColorBits)
{
 HANDLE hImage;

 hImage = DIBToDIBSection(lpDIB);
 if (! hImage)
  return NULL;
 return BuildOctreePalette(hImage, nMaxColors, nColorBits);