字体问题

1   GetTextMetrics(hdc,&tm);  
  2   cxChar=tm.tmAveCharWidth;        
  3   cxCaps=(tm.tmPitchAndFamily   &   1   ?   3:2)*cxChar/2;    
  4   cyChar=tm.tmHeight+tm.tmExternalLeading;        
  5   iMaxWidth=40*cxChar+22*cxCaps;  
   
  第3和5句是什么意思？ 问题点数：100、回复次数：4Top

1 楼AloneWolf（孤狼）回复于 2002-03-28 09:43:53 得分 50

3.  
  if(tm.tmPitchAndFamily   &   1   !=0)  
  {  
  cxCaps=3*cxChar/2;    
  }  
  else   cxCaps=2*cxChar/2;    
  tmPitchAndFamily    
  Specifies   information   about   the   pitch,   the   technology,   and   the   family   of   a   physical   font.    
  The   four   low-order   bits   of   this   member   specify   information   about   the   pitch   and   the   technology   of   the   font.   A   constant   is   defined   for   each   of   the   four   bits:   Constant   Meaning    
  TMPF_FIXED_PITCH   If   this   bit   is   set   the   font   is   a   variable   pitch   font.   If   this   bit   is   clear   the   font   is   a   fixed   pitch   font.   Note   very   carefully   that   those   meanings   are   the   opposite   of   what   the   constant   name   implies.    
  TMPF_VECTOR   If   this   bit   is   set   the   font   is   a   vector   font.    
  TMPF_TRUETYPE   If   this   bit   is   set   the   font   is   a   TrueType   font.    
  TMPF_DEVICE   If   this   bit   is   set   the   font   is   a   device   font.    
   
   
   
  An   application   should   carefully   test   for   qualities   encoded   in   these   low-order   bits,   making   no   arbitrary   assumptions.   For   example,   besides   having   their   own   bits   set,   TrueType   and   PostScript   fonts   set   the   TMPF_VECTOR   bit.   A   monospace   bitmap   font   has   all   of   these   low-order   bits   clear;   a   proportional   bitmap   font   sets   the   TMPF_FIXED_PITCH   bit.   A   Postscript   printer   device   font   sets   the   TMPF_DEVICE,   TMPF_VECTOR,   and   TMPF_FIXED_PITCH   bits.    
   
  The   four   high-order   bits   of   tmPitchAndFamily   designate   the   font's   font   family.   An   application   can   use   the   value   0xF0   and   the   bitwise   AND   operator   to   mask   out   the   four   low-order   bits   of   tmPitchAndFamily,   thus   obtaining   a   value   that   can   be   directly   compared   with   font   family   names   to   find   an   identical   match.   For   information   about   font   families,   see   the   description   of   the   LOGFONT   structure.    
   
  Top

2 楼rocmeteor（拄杖携残醉，扶风上九霄）回复于 2002-03-28 09:54:53 得分 50

是Programming   Windows上的代码吧？  
   
  #define   TMPF_FIXED_PITCH         0x01  
  #define   TMPF_VECTOR                   0x02  
  #define   TMPF_DEVICE                   0x08  
  #define   TMPF_TRUETYPE               0x04  
   
  tmPitchAndFamily   &   1是说如果字体宽度可变，则采用1.5倍于平均字符宽度，也就是的该字体的最大宽度了，如果字体宽度固定，则用平均字符宽度就可以了（实际上也是该字体的最大宽度了，）最大宽度与平均宽度的关系，参见原书。  
   
  iMaxWidth=40*cxChar+22*cxCaps;  
  是为了定义横行滚动条出现的条件，因为下面的WM_PAINT中就是这么TextOut的。  
   
  OK？  
  Top

3 楼ffuu（）回复于 2002-03-28 10:32:05 得分 0

牛！  
      这都看得出来，能把QQ号告诉我吗？以后我可以请教。---不是很过分吧？Top

4 楼rocmeteor（拄杖携残醉，扶风上九霄）回复于 2002-03-28 11:22:42 得分 0

是在说我吗？不是吧？是在说别人吧？:)  
  我没有QQ:(Top

相关问题

• 字体
• vector
• tmpf
• cxchar
• tmpitchandfamily
• cxcaps
• 宽度
• pitch
• bits
• font

• 帖主：ffuu
• AloneWolf
• rocmeteor

• Visual C++类图书
• Visual C++类源码下载