The FastReport engine usually is responsible for report’s constructing. It shows report’s bands in a particular order as many times, as the datasource to which it is connected requires, thus forming a finished report. Sometimes it is necessary to create a report of a non-standard form, which FastReport’s engine is unable to produce. In this case, one can use the ability of constructing a report manually, with the help of the «TfrxReport.OnManualBuild» event. If to define a handler of this event, the FastReport engine sends management to it. At the same time, allocation of responsibilities for forming a report is changed in the following way:

FastReport engine:

- report’s preparation (script, data sources initialization, bands’ tree forming)

- all calculations (aggregate functions, event handlers)

- new pages/columns’ forming (automatic showing a page/column header/footer, report title/summary)

- other routine work

Handler:

- bands’ presentation in a certain order

The «OnManualBuild» handler’s essence is to issue commands concerning presenting certain bands to the FastReport’s engine. The engine itself will do the rest: a new page will be created, as soon as there is no place in the current one; execution of scripts will be performed, etc.

The engine is represented with the «TfrxCustomEngine» class. A link to the instance of this class is located in the «TfrxReport.Engine» property.

procedure NewColumn;

Creates a new column. If a column is the last one, it creates a new page.

procedure NewPage;

Creates a new page.

procedure ShowBand(Band: TfrxBand); overload;

Presents a band.

procedure ShowBand(Band: TfrxBandClass); overload;

Presents a band of the given type.

function FreeSpace: Extended;

Returns the amount of free space on the page (in pixels). After the next band is presented, this value descends.

property CurColumn: Integer;

Returns/sets the current column’s number

property CurX: Extended;

Returns/sets the current X position.

property CurY: Extended;

Returns/sets the current Y position. After the next band is presented, this value ascends.

property DoublePass: Boolean;

Defines whether a report is a two-pass one.

property FinalPass: Boolean;

Defines whether the current pass is the last one.

property FooterHeight: Extended;

Returns the page footer height.

property HeaderHeight: Extended;

Returns the page header height.

property PageHeight: Extended;

Returns the height of the page’s printable region.

property PageWidth: Extended;

Returns the width of the page’s printable region.

property TotalPages: Integer;

Returns the number of pages in a finished report (only on the second pass of the two-pass report).

Let us give an example of a simple handler. There is two «Master Data» bands in a report, which are not connected to data. The handler presents these bands in an interlaced order, six times each one. After six bands, a small gap is made.

var

{ find required bands }

Band1 := frxReport1.FindObject('MasterData1') as TfrxMasterData;

Band2 := frxReport1.FindObject('MasterData2') as TfrxMasterData;

for i := 1 to 6 do

begin

end;

The next example shows two groups of bands alongside each other.

var

Band1 := frxReport1.FindObject('MasterData1') as TfrxMasterData;

Band2 := frxReport1.FindObject('MasterData2') as TfrxMasterData;

SaveY := frxReport1.Engine.CurY;

for j := 1 to 2 do

begin

end;