Title: A Class to Print Labels
Question: A very simple class to print labels
Answer:
A very simple class to print labels.
What do we need to print labels ?
1. The size (height and width) of every label.
2. The number of labels per row.
3. The top and left margin.
4. The kind of measure: pixels or inches.
5. The font to use.
6. And of course data to fill the labels.
With the next class we can do it very simply, Im going to use a pseudo-code to explain the use of the class TAlLabels:
var
xLabels: TAlLabels;
begin
xLabels:=TAlLabels.Create;
xLabels.Inches:=True; // im going to use inches instead of pixels
xLabels.Font:=FontDialog1.Font; // I get the font from a Font Dialog
xLabels.LabelsPerRow:=4; // 4 Label per row
xLabels.LabelWidthInch:=3; // only an example
xLabels.LabelHeightInch:=1.5; // only an example
xLabels.LeftMarginInch:=0; // only an example
xLabels.TopMarginInch:=0; // only an example
xLabels.Open; // open the printer
Table.First // Im going to read a customer table
while not Table.Eof do begin
xLabels.Fill(["Name","Street","City"]); // I fill the content of every label
Table.Next;
end;
xLabels.Close; // close the printer and print any label pending on the buffer
xLabels.Free;
end;
We need only 3 methods: Open, Fill and Close.
The properties that we need are:
Inches: True if the measure is on Inches, False if the measure is on Pixels.
Font
LabelsPerRow
LabelWidthInch
LabelHeightInch
LeftMarginInch
TopMarginInch
If we need to specify pixels instead of Inches we are going to use the next properties.
LabelWidth
LabelHeight
LeftMargin
TopMargin
Inches:=False
Thus, the same example with pixels will be
var
xLabels: TAlLabels;
begin
xLabels:=TAlLabels.Create;
xLabels.Inches:=False; // im going to use pixels instead of inches
xLabels.Font:=FontDialog1.Font; // I get the font from a Font Dialog
xLabels.LabelsPerRow:=4; // 4 Label per row
xLabels.LabelWidth:=300; // only an example
xLabels.LabelHeight:=200; // only an example
xLabels.LeftMargin:=0; // only an example
xLabels.TopMargin:=0; // only an example
xLabels.Open; // open the printer
Table.First // Im going to read a customer table
while not Table.Eof do begin
xLabels.Fill(["Name","Street","City"]); // I fill the content of every label
Table.Next;
end;
xLabels.Close; // close the printer and print any label pending on the buffer
xLabels.Free;
end;
The class :
/////////////////////////////////////////////////////////////////////////////
unit ULabels;
{
Class to print labels
Author: Alejandro Castro
Date 1/Abr/2002
}
interface
uses SysUtils, Windows, Graphics, Printers;
type
TAlLabels = class(TObject)
private
xWhichLabel: Integer;
xBuffer: Boolean;
xLabelsPerRow: Integer;
xRowsPerLabel: Integer;
function ReadLabxRow: Integer;
procedure WriteLabxRow(const Value : Integer);
function ReadRowxLab: Integer;
procedure WriteRowxLab(const Value : Integer);
function ReadFont: TFont;
procedure WriteFont(const Value : TFont);
public
LabelWidth: Integer; // width on pixels of every label
LabelWidthInch: Real; // width on inches of every label
LabelHeight: Integer; // height on pixels of every label
LabelHeightInch: Real; // height on inches of every label
TopMargin: Integer; // margin on pixels on top of every page
TopMarginInch: Real; // margin on inches on top of every page
LeftMargin: Integer; // margin on inches on top of every page
LeftMarginInch: Real; // margin on inches on top of every page
Inches: Boolean; // true=size on inches, false=size on pixels
TabsStop: array of integer; // horizontal position on pixels of every label
Content: Array of Array of String; // content of every label
property Font: TFont read ReadFont write WriteFont; // font for all rows
property LabelsPerRow: Integer read ReadLabxRow write WriteLabxRow;
property RowsPerLabel: Integer read ReadRowxLab write WriteRowxLab;
constructor Create;
procedure Fill(xCont: Array of String); // fill a label
procedure PrintRow; // print a row of labels
procedure Clean; // clean the array CONTENT of labels
procedure Close; // close the printer and print pending labels
procedure Open; // open the printer
end;
implementation
constructor TAlLabels.Create;
begin
RowsPerLabel:= 1;
LabelsPerRow:= 1;
LabelWidth:= 0;
LabelWidthInch:=0;
LabelHeight:= 0;
LabelHeightInch:= 0;
TopMargin:= 0;
TopMarginInch:= 0;
LeftMargin:= 0;
LeftMarginInch:= 0;
Inches:=True;
xWhichLabel:=0;
xBuffer:=False;
end;
procedure TAlLabels.Open;
var
PixPerInX,PixPerInY,i: Integer;
begin
Printer.BeginDoc;
PixPerInX:=getDeviceCaps(Printer.Handle,LOGPIXELSX);
PixPerInY:=getDeviceCaps(Printer.Handle,LOGPIXELSY);
if Inches then begin
LabelWidth:=Trunc(LabelWidthInch*PixPerInX);
LabelHeight:=Trunc(LabelHeightInch*PixPerInY);
LeftMargin:=Trunc(LeftMarginInch*PixPerInX);
TopMargin:=Trunc(TopMarginInch*PixPerInY);
end;
for i:=0 to LabelsPerRow-1 do
TabsStop[i]:=LeftMargin+LabelWidth*(i);
Clean;
end;
procedure TAlLabels.Close;
begin
PrintRow;
Printer.EndDoc;
end;
function TAlLabels.ReadLabxRow: Integer;
begin
Result:=xLabelsPerRow;
end;
procedure TAlLabels.WriteLabxRow(const Value : Integer);
var i: Integer;
begin
xLabelsPerRow:=Value;
SetLength(TabsStop,Value);
for i:=0 to high(Content) do
SetLength(Content[i],Value);
Clean;
end;
function TAlLabels.ReadRowxLab: Integer;
begin
Result:=xRowsPerLabel;
end;
procedure TAlLabels.WriteRowxLab(const Value : Integer);
begin
SetLength(Content,Value);
xRowsPerLabel:=Value;
LabelsPerRow:=LabelsPerRow; // to call the WriteLabxRow function
Clean;
end;
function TAlLabels.ReadFont: TFont;
begin
Result:=Printer.Canvas.Font;
end;
procedure TAlLabels.WriteFont(const Value : TFont);
begin
Printer.Canvas.Font.Assign(Value);
end;
procedure TAlLabels.Clean;
var
i,j: Integer;
begin
for i:=0 to high(Content) do
For j:=0 to high(Content[i]) do
Content[i,j]:='';
xBuffer:=False;
xWhichLabel:=0;
end;
procedure TAlLabels.Fill(xCont: Array of String);
var
i: Integer;
begin
xBuffer:=True;
if High(xCont)+1RowsPerLabel then
RowsPerLabel:=High(xCont)+1;
for i:=0 to High(xCont) do
Content[i,xWhichLabel]:=xCont[i];
inc(xWhichLabel);
if xWhichLabel=LabelsPerRow then begin
PrintRow();
end;
end;
procedure TAlLabels.PrintRow;
var
i,j,k,y,y1: Integer;
begin
if xBuffer then begin
if Printer.Canvas.PenPos.y=0 then
Printer.Canvas.MoveTo(0,TopMargin);
y:=Printer.Canvas.PenPos.y;
y1:=y;
for i:=0 to RowsPerLabel-1 do begin
for j:=0 to xWhichLabel-1 do begin
Printer.Canvas.TextOut(TabsStop[j],y,Content[i,j]);
end;
inc(y,Printer.Canvas.Textheight('X'));
end;
k:=LabelHeight+y1;
if k+LabelHeight Printer.PageHeight then
Printer.NewPage
else
Printer.Canvas.MoveTo(0,LabelHeight+y1);
end;
Clean;
end;
end.