VC++开发PhotoShop插件之选区

void PluginMain (const short selector,
PISelectionParams *selectionParamBlock,long *data,short *result);

globals-＞selectionParamBlock

//=============================PluginMain Start====================== 
DLLExport MACPASCAL void PluginMain (const short selector, 
    PISelectionParams *selectionParamBlock, 
    long *data,short *result) 
{ 
 //显示About对话框 
 if (selector == selectionSelectorAbout) 
 { 
  DoAbout((AboutRecordPtr)selectionParamBlock); 
 } 
 else 
 {  
  static const FProc routineForSelector [] = 
  { 
   /* selectionSelectorAbout  DoAbout, */ 
   /* selectionSelectorExecute */DoExecute 
  }; 
   
  Ptr globalPtr = NULL;// Pointer for global structure 
  GPtr globals = NULL; // actual globals 
   
  //包装selectionParamBlock到globals中，真正有用的还是globals-＞selectionParamBlock 
  globalPtr = AllocateGlobals ((uint32)result, 
   (uint32)selectionParamBlock, 
   selectionParamBlock-＞handleProcs, 
   sizeof(Globals), 
   data, 
   InitGlobals); 
   
  if (globalPtr == NULL) 
  { 
   *result = memFullErr;return; 
  } 
   
  globals = (GPtr)globalPtr; 
   
  //调用 DoExecute 函数 
  if (selector ＞ selectionSelectorAbout && selector ＜= selectionSelectorExecute) 
   (routineForSelector[selector-1])(globals); 
  else 
   gResult = selectionBadParameters; 
   
  if ((Handle)*data != NULL) 
   PIUnlockHandle((Handle)*data); 
   
 } // about selector special 
  
} 
//=============================PluginMain End================================= 


//=============================DoExecute Start================================= 
void DoExecute (GPtr globals) 
{ 
 //一些变量声明，省略... 
 //... 
 // 
  
 //从剪贴板中读取自己定义格式的选区信息，保存到全局变量中，我加的 
  
 //省略部分内容 
 gQueryForParameters = ReadScriptParams (globals); 
 gStuff-＞treatment = 0;//KeyToEnum(EnumToKey(gCreate,typeMyCreate),typeMyPISel);
//忽略原程序的UI参数处理 
  
 //获取读取端口 
 gResult = ReadFromWritePort(&selectionRead, selection-＞port); 
 //省略部分内容 
  
 //分配内存 
 gResult = AllocateBuffer (kBufferSize, &sBuffer); 
 if (gResult != noErr) goto CleanUp; 
  
 gResult = AllocateBuffer (kBufferSize, &dBuffer); 
 if (gResult != noErr) goto CleanUp; 
  
 gResult = AllocateBuffer (kBufferSize, &rBuffer); 
 if (gResult != noErr) goto CleanUp; 
 sData = LockBuffer (sBuffer, false); 
 dData = LockBuffer (dBuffer, false); 
 rData = LockBuffer (rBuffer, false); 
  
 //省略部分内容 
 //统计要处理的通道 
 curChannel = composite; 
 while (curChannel != NULL) 
 { 
  if (DoTarget  curChannel-＞target : curChannel-＞shown) 
   total += AccountChannel (curChannel, transparency, selection); 
   
  curChannel = curChannel-＞next; 
 } 
 //进行实际的处理工作 
 while (curChannel != NULL) 
 { 
  if (DoTarget  curChannel-＞target : curChannel-＞shown) 
  { 
   ApplyChannel (globals, curChannel, &sDesc, 
    transparency, &mDesc, 
    selection, selectionRead, &dDesc, 
    &rDesc, &done, total); 
   if (gResult != noErr) goto CleanUp; 
  } 
  curChannel = curChannel-＞next; 
 } 
  
 //善后工作... 
} 
//=========DoExecute End===========

//========ApplyChannel Start======== 
static void ApplyChannel (GPtr globals, 
   ReadChannelDesc *source, 
   PixelMemoryDesc *sDesc, 
   ReadChannelDesc *mask,  
   PixelMemoryDesc *mDesc, 
   WriteChannelDesc *dest, 
   ChannelReadPort destRead, 
   PixelMemoryDesc *dDesc, 
   PixelMemoryDesc *rDesc, 
   int32 *done,int32 total) 
{ 
 //声明变量，参数检查，省略 
 //内层循环中，每次读取64×64的块处理 
 //#define kBlockRows 64 
 for (row = limit.top; row ＜ limit.bottom; row += kBlockRows) 
  for (col = limit.left; col ＜ limit.right; col += kBlockCols) 
  { 
   //省略部分内容 
   gResult = ReadPixels (destRead, &scaling, &area, dDesc, &wrote); 
   //省略部分内容 
   gResult = ReadPixels (source-＞port, &scaling, &area, sDesc, &wrote); 
   s = (unsigned8 *) sDesc-＞data;//这里是原图象数据 
   d = (unsigned8 *) dDesc-＞data;//这里保存处理结果 
   //逐个象素处理64×64的块 
   for (row2 = 0; row2 ＜ kBlockRows; ++row2) 
   { 
    int y = row + row2; 

    for (col2 = 0; col2 ＜ kBlockCols; ++col2) 
    { 
     int x = col + col2; 
     int nRc = 0; 
     bool bFound = false; 
     while(nRc ＜ g_rcCount)//g_rcCount是一共要显示的区域数，通过剪贴板传递计算 
     { 
      if(PtInRect(&g_rcArr[nRc],x,y))//g_rcArr存放所有要显示的区域 
      { 
       *d = 255;//这个象素处于选区内 
       bFound = true; 
       break; 
      } 
      ++nRc; 
     } 
     //if(!bFound) *d = 0; 
     ++s; 
     ++d; 
     ++r; 
    } 
   } 
   //处理完毕一小块，写回 
   gResult = WritePixels (dest-＞port, &area, dDesc); 
   //省略部分内容 
  } 
   
   
} 
//========ApplyChannel End=====