重置delphi Printer对象

http://www.efg2.com/Lab/Library/UseNet/1999/0714b.txt

From: "Nick Ryan" <[e-mail]>
Subject: Re: D1 printing problem: incorrect font sizes
Date: 14 Jul 1999 00:00:00 GMT
Message-ID: <7mi4cp$[e-mail]>
References: <[e-mail]>
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Daniel Berg (Berg Soft) <[e-mail]> wrote in message
news:[e-mail]...
> Hi there,
>
> I've got the following the following problem using D1 (on D2 and later
> the problem does not occur)
>
>
> I can select different printers with different resolutions from the
> printdialog.我可以从打印机对话框里 选相应不同分辨率的不同打印机。
> Printing to any printer works fine when the prog just started (i.e:
> Printing to Printer1, then shutdown prog, run again, then print to
> Printer 2 works perfect). 当程序刚启动时，打印到任何一个打印机都是正常的。比如打印到 打印机1，然后关闭程序。 再次运行，然后打印 到 打印机2，一起正常。
>
> Printing to a second printer AFTER printing to a first printer scales
> all fonts by
>
> Resolution(Printer1)/resolution(Printer2);
打印到第一个打印机后，（不关闭程序）直接再打印到第二个打印机时，缩放了所有的字体 以
第一个打印机 分辨率 / 第二个打印机分辨率 的比例。
>
> I have already tried the following without success:
>
> -   Creation of the form that uses the printers unit at runtime AFTER
> printdialog.execute to create a new printer instance everytime
>
> -   I have checked printers resolution with GetDeviceCaps: printer
> change is  recognized correctly.
>
> Does anyone has an idea of whats wrong?

It's some weird bug in Delphi's TPrinter that causes information to be
retained from a previous print session. (It affects the line thickness of
printing using D3).

这是打印机对象中的一些奇怪BUG。导致信息 从前一次打印会话中 保留。

The following code forces a complete refresh of the Printer object in D3 -
it *should* work in D1 as well...

procedure ResetTPrinter;
var
  APrinter:TPrinter;
begin
    if (not Printer.Printing) then begin
      APrinter := SetPrinter(NIL);
      if (APrinter <> NIL) then APrinter.Free;
    end; {if}
end;
//我看新版的VCL源代码里直接 一行代码 就行了 SetPrinter(nil).Free;

Nick