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//  武汉探索电脑工作室    //
//  http://tansuo.51.net  //
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//增加规格自定义纸张
//PaperName: 自定义纸张名称
//PaperWidth: 纸张的宽度，以0.1mm为单位
//PaperLength: 纸张的高度，以0.1mm为单位
procedure TDM.AddCustomPaper(const PaperName: string; PaperWidth, PaperLength:integer);
var
PrintDevice, PrintDriver, PrintPort : array[0..255] of Char;
hDMode   : THandle;
hPrinter : THandle;
FormInfo : TFormInfo1;
begin
Printer.GetPrinter(PrintDevice, PrintDriver, PrintPort, hDMode);
OpenPrinter(PrintDevice, hPrinter, nil);
if hPrinter = 0 then
raise Exception.Create('联接打印机失败!');

with FormInfo do
begin
Flags := FORM_USER;
pName := PChar(PaperName);
Size.cx := PaperWidth*100;
Size.cy := PaperLength*100;
ImageableArea.Left := 0;
ImageableArea.Top := 0;
ImageableArea.Right := PaperWidth*100;
ImageableArea.Bottom := PaperLength*100;
end;

//修改纸型，如果没有就新增
if not SetForm(hPrinter, PChar(PaperName), 1, @FormInfo) then
AddForm(hPrinter, 1, @FormInfo);

ClosePrinter(hPrinter);
end;

//删除自定义规格纸张
//PaperName: 自定义纸张名称
procedure TDM.DeleteCustomPaper(const PaperName: string);
var
PrintDevice, PrintDriver, PrintPort : array[0..255] of Char;
hDMode   : THandle;
hPrinter : THandle;
begin
Printer.GetPrinter(PrintDevice, PrintDriver, PrintPort, hDMode);
OpenPrinter(PrintDevice, hPrinter, nil);
if hPrinter = 0 then
raise Exception.Create('联接打印机失败!');
DeleteForm(hPrinter, PChar(PaperName));
ClosePrinter(hPrinter);
end;

（出处：DelphiFans.com）