Difference between revisions of "LazReport Tutorial"

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(moved function stuff around)
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==== A picture is worth... ====
 
==== A picture is worth... ====
to do: we'll need to add a database field for images. Also check how this works as Laz images have an image identifier prepended in the field data by default... which is useful to keep.
+
If you haven't already, we'll need to add a PHOTO field to our test database; using an SQL statement like this (note: unfortunately different databases use different syntax; BLOB can be CLOB,IMAGE,OLE...):
Now on the right side of the band, select an image. If you want to always show the same picture, you'd just need to double click on the picture and upload the desired image. However, let's press F11 to show the Object Inspector:
+
<syntaxhighlight>
 +
ALTER TABLE EMPLOYEE ADD PHOTO BLOB;
 +
</syntaxighlight>
 +
Now add some test data - to do: some kind of Laz program for that? For now, just added some jpgs to the records using FlameRobin, so we're using Delphi format dbimage, without the filetype header Laz would expect
  
[[Image:imagem13.jpg]]
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In File>Variables List, add the SQLQuery1.PHOTO field as variable Photo field, similarly to how you did this before. If you don't see the field, you may need to set the form's SQLQuery to inactive and active again to refresh the list of columns.
  
Enter the property with the Memo [ImageField] property. This turns the picture into an object associated with the data field. Our first stage is completed. Save it with same name rapff. A click on the preview gives us:
+
Click on the Insert image... icon on the left of the window; now click on the right side of the band to drop the image control. A Picture editor shows up:
 +
[[Image:lazreptutpictureeditor.png]]
 +
 
 +
If you want to always show the same picture, you'd just need to click Load ... (or double click on the picture control) and choose your image.
 +
 
 +
However, let's press the Memo button and insert your Photo variable:
 +
[[Image:lazreptutphotofield.png]]
 +
This turns the picture into an object associated with the data field. Press OK as needed to get back to the report designer.
 +
 
 +
to do: this does not seem to actually give any pictures. perhaps I'm doing something wrong
 +
 
 +
Adjust height and width as needed.
 +
 
 +
You can also press F11 to show the Object Inspector which allows you to edit more if needed:
 +
[[Image:lazreptutobjectinspector.png]]
 +
 
 +
Close the report editor and save the report definition (with the same name, '''lazreporttutorial.lrf''').
 +
 
 +
If you go to File>Preview, you'll see something like this:
  
 
[[Image:imagem14.jpg]]  
 
[[Image:imagem14.jpg]]  

Revision as of 15:09, 21 December 2013

Overview

This page started as a translation of the Portuguese language Tutorial de LazReport (which itself appears to be a translation from a French document). It was updated for LazReport (instead of FastReport) on Lazarus (instead of Delphi), using T*Connection instead of a DBase table.

Starting with LazReport

We're going to use a demo database which is provided by Delphi (DBDEMOS). You'll need to create a new application with a main form Form1.

We're assuming you already have your database set up as specified in SQLdb Tutorial0. If not, please do so.

Setting up your form

Place the following components on the form:

  • A T*Connection, e.g. TIBConnection:
    • DatabaseName := your database, e.g. C:\Program Files\Firebird\Firebird_2_5\examples\empbuild\EMPLOYEE.FDB
    • UserName, Password, HostName: as appropriatie (e.g. SYSDBA,password,<none> for Firebird embedded)
    • Transaction: TSQLTransaction1
  • TSQLTransaction
  • TSQLQuery:
    • Active: true
    • SQL: select * from employee
  • TDataSource
    • DataSource1.DataSet := SQLQuery1
  • TfrDBDataSet
    • frDbDataSet.DataSource := DataSource1
  • TfrReport
  • TfrDesigner
  • 2 TButton
  • Button1.Caption := 'Editing'
  • Button2.Caption := 'Preview'

This results in:

lazreptut01.png

Double-click on the TfrReport icon (or right-click, Design Report) to bring up the report designer:

lazreptut01b.png

Setting up variables

LazReport lets you link variable names to database fields or system values, in order to spare your end users from having to decipher cryptic field names. In our example, we're going to create a variable for our database fields FIRST_NAME, LAST_NAME etc.

In the File menu, click Variables list. Now you get an overview of the defined variables:

lazreptutvariableseditor.png

Click on the button Variables in order to define some variables. Write the contents according ot the following image. "Demo Variables" represents a category and the other entries (xxx field) represent variables. To differentiate the two, the variables start with a space.

lazreptutdefinevariables.png

Finally click on OK to confirm your entries, and you'll see this:

lazreptutvariablesdefined.png

As you can see, the category we defined is shown in the ComboBox above the variables. Each variable must be linked with a field. To do this, select the variable and then the field. Do this for all variables; the screenshot shows the link for Hire date:

lazreptutvarhiredatetofield.png

Objects and bands

After closing the variables editor, we're back in our report designer. You may have noticed a small number of objects in the object bar to the left of the report surface. These are:

  • the mouse icon pointer
  • rectangle object
  • band
  • picture object
  • subreport
  • draw lines
  • insert barcode object

lazreptut01b.png

Click the band icon, go to the report surface, and click on it to drop a band object.

lazreptutinsertnewband.png

You must click on the type of band you want to create. Select Report title and click OK.

Band type Use
Report title Shown only on the first page
Report summary Shown only on the last page
Page header Shown at the top of each page
Page footer Shown at the bottomof each page
Master header Shown at the beginning of the first detail band/level
Master data First detail level data; repeated for each record in dataset
Master footer Shown at the end of the first detail band/level
Detail header Shown at the beginning of the second detail band/level
Detail data Second detail level data
Detail footer Shown at the end of the second detail band/level
Subdetail header Shown at the beginning of the third detail band/level
Subdetail data Third detail level data
Subdetail footer Shown at the end of the third detail band/level
Overlay
Column header Shown at the top of every column
Column footer Shown at the bottom of every column
Group header Shown at the top of every group
Group footer Shown at the bottom of every group
Cross header Shown at the top of cross tables/pivot tables
Cross data Shows cross tables/pivot table data
Cross footer Shown at the bottom of cross tables/pivot tables

Report title

In the Report title band, add a rectangle. The text editor will show up. In the first line the title of the report should be indicated. On the the second, system date and time need to be added. They are obtained by clicking Variable and then Category Other, then double-click on the desired variable (once you are familiar with the variables, you can also just type them). Now we have:

lazreptutreporttitle.png

Click OK to exit the editor, then adjust the title rectangle to the desired size. Choose a color for the background with the Bucket Fill button on the toolbar.

The main event: showing data in the master data band

Let's insert a master data band. LazReport prompts you for a data source; choose frDBDataSet1, the main data source for our example. The master band will be repeated for each record in the data source. You can double-click later on the band if you want to change the data source.

lazreptutbanddatasource.png

In the left half of the band we insert a rectangle and double click. The familiar text editor appears.

Now we will add several fields in the one rectangle. If needed though, you can use one rectangle per field if you want to apply different formatting etc.

The first line Name [Full name field] is obtained by writing Name and then, with the Variable button, entering the variable [Field Name]. Alternatively, as indicated before, you can write the resulting text directly.

The next line Salary [Salary field] is written similarly.

The third line - Salary divided by job grade [[Salary field]/[Job grade field]] - is done likewise. This shows you can perform calculations with fields coming from the data source. Note the extra set of square brackets around the calculation. As you may guess, you can not only use the variables listed via the Variable button, but also database fields via DB Field'.

lazreptutmasterdata.png

Formatting output

You can control how the text in the rectangles are displayed. Let's define a format for the variables of a rectangle/object. A format is valid for all variables of a rectangle/object. To show the format editor, click the right button on a rectangle and then go to Variable Format.

imagem19.jpg

The first ComboBox indicates the type of data (text, numeric, date, time, logical/boolean). The second lets you select a preset format.... with some obvious restrictions:

  • The Text type does not allow any Number type formatting.
  • The Number type requires a decimal number with a comma (to do: verify this. Is this country specific?). Except for Text and Logic types, you can use the formatting strings you also use in Lazarus.

You can also set highlighting, which is very useful for emphasizing data. You can specify a condition that determines when highlighting is applied.

For that, use the keyword Value to indicate the value of the variable. Here is the highlighting for all values greater than 1000. By default highlighter is a simple bold on white background. You can set these parameters to an area by clicking the Highlight button.

imagem20.jpg

You can also set the color of the background and style and color of the used font by selecting Intensified brightness.

A picture is worth...

If you haven't already, we'll need to add a PHOTO field to our test database; using an SQL statement like this (note: unfortunately different databases use different syntax; BLOB can be CLOB,IMAGE,OLE...):

ALTER TABLE EMPLOYEE ADD PHOTO BLOB;
</syntaxighlight>
Now add some test data - to do: some kind of Laz program for that? For now, just added some jpgs to the records using FlameRobin, so we're using Delphi format dbimage, without the filetype header Laz would expect

In File>Variables List, add the SQLQuery1.PHOTO field as variable Photo field, similarly to how you did this before. If you don't see the field, you may need to set the form's SQLQuery to inactive and active again to refresh the list of columns.

Click on the Insert image... icon on the left of the window; now click on the right side of the band to drop the image control. A Picture editor shows up:
[[Image:lazreptutpictureeditor.png]]

If you want to always show the same picture, you'd just need to click Load ... (or double click on the picture control) and choose your image.

However, let's press the Memo button and insert your Photo variable:
[[Image:lazreptutphotofield.png]]
This turns the picture into an object associated with the data field. Press OK as needed to get back to the report designer.

to do: this does not seem to actually give any pictures. perhaps I'm doing something wrong

Adjust height and width as needed.

You can also press F11 to show the Object Inspector which allows you to edit more if needed:
[[Image:lazreptutobjectinspector.png]]

Close the report editor and save the report definition (with the same name, '''lazreporttutorial.lrf''').

If you go to File>Preview, you'll see something like this:

[[Image:imagem14.jpg]] 

Close the report editor and save the report definition as '''lazreporttutorial.lrf'''.

=== Loading the report from the form ===
Now let's write the code required to load and view or edit our report. To this add the following code to the project:
<syntaxhighlight>
TForm1.Button2Click(Sender procedure: TObject);  
begin 
  frReport1.LoadFromFile('lazreporttutorial.lrf');  
  frReport1.ShowReport;  
end;
TForm1.ButtonClick(Sender procedure: TObject);  
begin 
  frReport1.LoadFromFile('lazreporttutorial.lrf');  
  frReport1.DesignReport;  
end;

You have a preview option that gives end users a way to modify the report without changing the basic application.

Printing

Now we're going to add features to our basic example.

Add a TButton component with Caption := 'Print...', and a TPrintDialog. Behind the scenes, a project dependency on the Printer4Lazarus packages will be added by the IDE, so make sure that package is installed.

We end up with this:

lazreptutformwithprintbutton.png

Now add the printers unit to your form's uses clauses.

Put the following code in the OnClick event of the Print button:

procedure TForm1.Button3Click(Sender: TObject);
var
  FromPage, ToPage, NumberCopies: Integer;
  ind: Integer;
  AppDirectory: String;
  Collap: Boolean;
begin
  // Load report definition from application directory
  AppDirectory:=ExtractFilePath(ParamStr(0));
  frReport1.LoadFromFile(AppDirectory+'lazreporttutorial.lrf');
  // Need to keep track of which printer was originally selected to check for user changes
  ind:= Printer.PrinterIndex;
  // Prepare the report and just stop if we hit an error as continuing makes no sense
  if not frReport1.PrepareReport then Exit;
  // Set up dialog with some sensible defaults which user can change
  with PrintDialog1 do
  begin
    Options:=[poPageNums ]; // allows selecting pages/page numbers
    Copies:=1;
    Collate:=true; // ordened copies
    FromPage:=1; // start page
    ToPage:=frReport1.EMFPages.Count; // last page
    MaxPage:=frReport1.EMFPages.Count; // maximum allowed number of pages
    if Execute then // show dialog; if succesful, process user feedback
    begin
      if (Printer.PrinterIndex <> ind ) // verify if selected printer has changed
        or frReport1.CanRebuild // ... only makes sense if we can reformat the report
        or frReport1.ChangePrinter(ind, Printer.PrinterIndex) //... then change printer
        then
        frReport1.PrepareReport //... and reformat for new printer
      else
        exit; // we couldn't honour the printer change

      if PrintDialog1.PrintRange = prPageNums then // user made page range selection
      begin
        FromPage:=PrintDialog1.FromPage; // first page
        ToPage:=PrintDialog1.ToPage;  // last page
      end;
      NumberCopies:=PrintDialog1.Copies; // number of copies
      // Print the report using the supplied pages & copies
      frReport1.PrintPreparedReport(inttostr(FromPage)+'-'+inttostr(ToPage), NumberCopies);
    end;
  end;
end;

It's a bit long, but if needed, you can create a descendant of TfrReport with an easier printing method or class , create a PrintReport (Report: string) procedure to load the report and print.

When double clicking on frReport1, in the report designer File>Page Options menu you get this:

Select paper size:

lazreptutpapersize.png

Choose desired margins, number of columns, and the space between them, layout order etc. lazreptutprintoptions.png

Report options

Via File>Report Options you can set a default printer that will be used for the report (using the "Select when report loaded" checkbox).

If you want to include the total number of pages with the page number on each page, you need to select Two-pass report (which tells Lazreport to build the report twice, inserting total number of pages on the second run).

lazreptutreportoptions.png

On the Other tab, you can fill out some report metadata, as is done on the screenshot below: lazreptutreportoptionsother.png

General purpose variables

Now we'll add some report variables unrelated to the database data in our example. They let you e.g. show different names according to the context.

To do this, open the report editor and select the File menu and the Variable List. Add a Test category, and a test1 variable the same way we did earlier (with a space before the variable name):

lazreptutvariableseditortestvar.png

The only difference is that you will not select a value field, but leave None (the default value): lazreptutvariabletest.png

Return to Lazarus (do not forget to save your report, if necessary) and set up the OnGetValue event of the frReport1' component by adding the following code:

procedure TForm1.frReport1GetValue(const ParName: String; var ParValue: Variant
  );
begin
 // Conditionally assign value:
 if UpperCase(ParName)=' TEST' then 
   ParValue:='Answer: Variable "test1"'; //perhaps replace with a call to a random function or something?
end;

to do: should the test for ParName really be (category) TEST and not TEST1? Also, don't we need to add a rectangle somewhere and show variable test1?

Alternatively, you can also pass the value directly to the variable using the following code:

procedure TForm1.Button1Click(Sender:TObject);
begin
  frReport1.Values.FindVariable('test').Field := QuotedStr('test1');
  frReport1.ShowReport;
end;

The below(?) is not used for data iself, but to enable formatting the data with DisplayFormat.

Now let's see how to create a calculated variable. As before, we will create a new category (optional) and a variable. Test Calculation(?).

Select a new variable and select a value from the ComboBox "Other" and "Expression". This selection activates data entry for Expression. Type the following: [Table1 "SIZE".] + [Table1 "WEIGHT."]. That way you will get the sum of the fields of Size and Weight data (which is a bit ridiculous but it shows the principle). You can also use the variable name.

See LazReport Documentation#Documentation for an overview of existing functions and operators.

Adding your own functions

Though it is probably not needed much, LazReport allows you to define your own functions. As mentioned, see LazReport Documentation#Documentation for an overview of existing functions.

To add your own functions:

Add template to definition file

You need to define your functions following the following template in the file FR.lng (is this still the correct name for Lazreprot?):

, FCT = CATEGORY|FCT (<X> <Y>, <z>)|Help

where:

  • FCT is the function name.
  • CATEGORY is the category name.
  • FCT (<X> <Y>, <z>), is the layout of the required parameters, with a maximum of 3 parameters.
  • Help Is a small help text which should allow the user to understand the purpose of the function.
  • | is a separator.

Each parameter is separated by commas and can be an expression, a constant, a variable, a field or data. Alphanumeric type constants should be limited by a character. The variables are delimited by and.

Data fields are limited to the variables and have the following format:

Dataset_Name. "Field_Name"

Let's add the SQRT and POS functions by adding the following lines to FR.lng todo: still the same name?

SQRT = Mathematics and Trigonometry|SQRT(<X>)|Returns the square root of <X>
POS = Strings|POS(<X>,<Y>) Returns the position of string <X> within string <Y>

Add function source code

A function definition is nice, but we haven't specified how these functions work. Therefore, some source code to add the functions POS and SQRT below:

Unit FR_OGFct;
interface 
implementation 
uses FR_Pars, FR_Class; // Standard declarations needed for Lazreport!! Note: FR_pars etc? Are these names ok?
type 
 // Our own functions are declared here.
TfrOGFunctionLibrary = class(TfrFunctionLibrary)
 public  
  constructor Create; override;  
  procedure DoFunction(FNo:integer procedure;  p1, p2,
             p3:Variant; var valley:string); override;  
             p3:Variant; var valley:string);
 end;  
//************************** 
// * TfrOGFunctionLibrary 
constructor TfrOGFunctionLibrary.Create;
begin  
 inherited Create;  
 // Add our functions to the list of available functions:
 with List do 
 begin
  Add('POS');
  Add('SQRT');
 end;
end;

Procedure TfrOGFunctionLibrary.DoFunction(FNo:Integer procedure;  p1,
p2, p3:Variant; Var valley:String); //valley?
Var 
  Par1, Par2:  Varying;
  Result:  Variantying; //variantying? variant?
begin
Try
 Case FNo of  //this is the index of the functions as added in the constructor
  0 : 
	begin   // POS  function
    Par1:=VarToStr(Parser.Calc(p1)); 
    Par2:=VarToStr(Parser.Calc(P2)); 
    Result:=Pos(Par1,Par2);
  end;
  1 :  // SQRT function
	Result:=SQRT(Parser.Calc(P1));
 end;
Except   
 // String with error details
 Result:='Error in function '+List.Strings[FNo];
end;
Val:=VarToStr(Result); // Resulting string
end;

Procedure DoInit;
begin
 frRegisterFunctionLibrary(TfrOGFunctionLibrary);
end;

Save the report then File>List and this window will appear:

imagem21.jpg

You may notice the appearance of a small (...) button, active only in the case of an expression. Click below to open the editor:

imagem22.jpg

You may notice the similarity. If you click the Add button it will load the editor parameters:

imagem23.jpg

Depending on the number of parameters, you have more or less edit areas. The (...) button makes it possible to open the expression generator to set the parameter.

See also