所见即所得的Unicode

问题描述

我用Delphi编写了一个Windows程序，该程序使用GetCharWidth和Em-Square将文本非常精确地放置并包装到屏幕和打印机上。这对于ANSI文本效果很好，在ANSI文本中，您只需要检索和计算255个字符的宽度，但是当您使用65535个字符进入Unicode时，速度太慢。由于必须创建2个宽度的数组，这个问题变得更糟，一个数组用于常规，另一个数组用于粗体。

I've written a Windows program in Delphi that places and wraps text very precisely to both the screen and printer using GetCharWidth and Em-Square. This has worked well with ANSI text where you only need to retrieve and calculate the widths of 255 characters but when you go to Unicode with 65535 characters its too slow. The problem is made worse by having to create 2 arrays of width, one for normal and one for bold.

 //Setup a reference canvas for measuring purposes
  RefDC := CreateCompatibleDC ( FCanvas.Handle ) ;
  DPI := GetDeviceCaps ( RefDC , LOGPIXELSY ) ;

  //find EmSquare
  GetOutlineTextMetrics ( RefDC , sizeof(otm) , @otm[0] ) ;
  EmSq := otm[0].otmEmSquare ;

  //calc NORMAL char sizes
  GetObject ( FCanvas.Font.Handle , SizeOf ( lf ) , @lf ) ;

  lf.lfHeight := -EmSq ;
  lf.lfWidth  := 0 ;
  lf.lfWeight   := FW_NORMAL ;

  hf := CreateFontIndirect ( lf ) ;
  hold := SelectObject ( RefDC , hf ) ;

  GetCharWidth ( RefDC , 0 , $FFFF , nCharWidth ) ;
  for a := 0 to $FFFF do
    fCharWidth[a] := nCharWidth[a]* PixelSize / EmSq ;

  SelectObject ( RefDC , hold ) ;
  DeleteObject ( hf ) ;

  //calculate line height
  PixelSize := abs ( fCanvas.Font.Size * DPI / 72 ) ;
  GetOutlineTextMetrics ( RefDC , sizeof(otm) , @otm[0] ) ;
  LineHt := round ( ( otm[0].otmTextMetrics.tmHeight +
                      otm[0].otmTextMetrics.tmExternalLeading ) *
                      PixelSize / EmSq ) ;

  //calculate Bold char sizes
  lf.lfWeight := FW_BOLD ;
  hf := CreateFontIndirect ( lf ) ;
  hold := SelectObject ( RefDC , hf ) ;

  GetCharWidth ( RefDC , 0 , $FFFF , nCharWidth ) ;
  for a := 0 to $FFFF do
    fBoldWidth[a] := nCharWidth[a] * PixelSize / EmSq ;

  SelectObject ( RefDC , hold ) ;
  DeleteObject ( hf ) ;

  DeleteDC ( RefDC ) ;`

推荐答案

计算单个字符的宽度并将它们加到Unicode中不仅很慢，而且是错误的，并且将无法正常工作。 Unicode有时会以复杂的方式将字符标记组合在一起。

Calculating individual character widths and adding them up in Unicode is not only very slow, but it's wrong and will not work correctly. Unicode combines character marks together, sometimes in complex ways.

使用Unicode，正确的方法是将整个字符串传递给Windows API函数以及行的宽度，它会计算出来

With Unicode, the correct way to do it is to pass your whole string to the windows API function GetTextExtentExPoint along with the width of your line, and it will figure out how many characters will fit on the line for you.

有。

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