Band lines and brush

rbuser

Hello,

I wish to print a bottom line for each detail band without using a TppShape.
I also wish to paint a background color at every to detail bands. These two
features are selectable by the end users.

What do you sugest me to do ? Inherit from TppDetailBand ? Can I register a
new band class with the report designer ?

Thanks,

--
Fabio Lindner

digitalmetaphors

You can create draw commands if you don't want to create components in the
report layout.

The easiest way to get alternate colors in a band is to toggle a TppShape's
color or visibility. You can also use the RBAddOn component set which has a
feature to do this. Surf www.bancoems.com\RBAddOn.htm

Here are some draw command examples which are related to what you are
asking:

{alternate detail band color}
http://www.digital-metaphors.com/tips/GreenBarDrawCommand.zip

{adds the line at the bottom of a group of detail bands per page}
http://www.digital-metaphors.com/tips/BorderAroundGroupProj.zip


Cheers,

Jim Bennett
Digital Metaphors

---------------------------------------
Article: Draw Command Architecture
---------------------------------------

Page Objects
-------------

When a report prints it generates Page objects. Each Page object contains an
array of DrawCommand objects (Page.DrawCommands[]) that describe what needs
to be rendered for the page.

Report --> Pages.DrawCommands[] ---> Device (Printer, Screen, ..) --> final
output


DrawCommands Objects
--------------------

Component --> DrawCommand

Each TppComponent generates a DrawCommand object each time
it prints on a page. For example if the component is a TppLabel and prints
at the top of the page - one draw command object will be created for each
page. If the Label is in the detail band, many draw commands will be created
for each page.

A DrawCommand contains a complete description of the location and content to
draw. See ppDrwCmd.pas for the existing DrawCommand class descendants
(DrawText, DrawImage, etc.)

Some of the basic DrawCommand classes such as DrawImage and DrawText, rely
on the ScreenDevice and PrinterDevice classes to render their content. Other
DrawCommand classes such as TppDrawBarCode and TppDrawRichText render
themselves to the appropriate device canvas directly.


Creating Custom Components
--------------------------

Each component has an associated DrawCommand class that is
is the value of its DrawCommandClass property. For a Label,
the DrawCommandClass is TppDrawText. This value is normally
set in the constructor. Examples of the common components
are located in ppCtrls.pas.



constructor TmyComponent.Create(AOwner: TComponent);
begin

inherited Create(AOwner);

DrawCommandClass := TppDrawText;

end;


Each time the component prints, a DrawCommand object of
the designated DrawCommand class will automatically be
created and the components PropertiesToDrawCommand method
will be called. You override this method to transfer the
appropriate property values from the component to
the drawcommand object.


{------------------------------------------------------------------------}
{ TmyComponent.PropertiesToDrawCommand }

procedure TmyComponent.PropertiesToDrawCommand(aDrawCommand:
TppDrawCommand);
var
lWrappedText: TStrings;
lTextBuf: PChar;
lPrinter: TObject;
lDrawText: TppDrawText;
llCharPos: Longint;
begin

inherited PropertiesToDrawCommand(aDrawCommand);

if not(aDrawCommand is TppDrawText) then Exit;

lDrawText := TppDrawText(aDrawCommand);

{set properties here}

lDrawText.Alignment := Alignment;
lDrawText.AutoSize := AutoSize;
lDrawText.Color := Color;
lDrawText.Left := PrintPosRect.Left;
lDrawText.Top := PrintPosRect.Top;
lDrawText.Height := PrintPosRect.Bottom - PrintPosRect.Top;
lDrawText.Width := PrintPosRect.Right - PrintPosRect.Left;
lDrawText.Text := Text;
lDrawText.Transparent := Transparent;
lDrawText.WordWrap := WordWrap;
lDrawText.Font := Font;


end;



Creating Custom DrawCommands
----------------------------

When you create a descendant component you can either
use an existing draw command class or create a new one.
For the TeeChart wrapper components, we chose to use
the existing DrawImage class to specify the TeeChart
as a metafile image. So it is not always necessary to
create a draw command class.

Examples of DrawCommand classes are located in ppDrwCmd.pas.
A drawcommand will contain published properties that
contain a complete description of the location and
content to be rendered.

DrawCommand classes must be registered - see the
initization and finalization sections at the bottom
of the ppDrwCmd.pas unit for an example.

DrawCommand classes should publish all properties
used to describe the object.

DrawCommand classes must implment the Assign
method to assign the values of all published
properties from one draw command to another.


--
Tech Support mailto:support@digital-metaphors.com
Digital Metaphors http://www.digital-metaphors.com

rbuser

Thanks.

Maybe I can descend from TppReport and implement these features build-in.

--
Fabio Lindner

digitalmetaphors

We don't recommend creating report descendents from a maintenance
standpoint, but it may be possible to do this. Off the top of my head, in
the Create override, start with adding ciEngineEndPage to the EventNotifies
inherited set.

EventNotifes := EventNotifies + [ciEngineEndPage];

Then in the EventNotify override routine, you can check to see if the engine
has finished the page by checking the aEventID parameter. Then add you draw
commands in that timing to the Engine.Page property as shown in the demos.
You could add new properties to the report and then modify the designer
MergeMenu property to add a menu item to check or a dialog to allow the end
user to control this feature.

The other part is tracking where to add a draw command. One way to approach
it is to create a class registry where you can register a draw command
generator class to a report template or report description. This way you can
let the user more easily choose how to alter the report layout, without
hardcoding the features into the report descendent. You will have to setup
the commnication (via TppCommunicator in ppComm.pas) in order to track the
position of the detail band or group footer band, parallel to what the demos
show how to do using Delphi event handlers.

Cheers,

Jim Bennett
Digital Metaphors

rbuser

Thanks, I'll try something like that.

--
Fabio Lindner

EventNotifies
engine
draw
end
approach
can
demos