R – Printing image in Rave Reports

delphirave-reports

I have an application being developed in Delphi 2009 and Rave Reports. I would like to have an image printed in the reports. How am I going to implement this?

Any suggestion would be very much appreciated.

Best Answer

Use the Draw(X, Y: Double; Graphic: TGraphic); method of a TBaseReport descendant, unless you're drawing a bitmap. In that case, use TBaseReport.PrintBitmap(X, Y: Double; ScaleX, ScaleY: Double; Bitmap: TBitmap); or PrintBitmapRect(X1, Y1, X2, Y2: Double; Bitmap: TBitmap);

Draw() is documented in the D2009 help file in ms-help://embarcadero.rs2009/Rave/draw.htm

var   
  MyLogo: TGraphic;
begin
  MyLogo := TMetafile.Create;
  try
    MyLogo.LoadFromFile('MYLOGO.WMF');
    RvNDRWriter1.Draw(1.0,2.0,MyLogo);
  finally
    MyLogo.Free;
  end; { tryf }
end;

You can find an example of PrintBitmap in the Delphi 2009 help file, topic ms-help://embarcadero.rs2009/Rave/printbitmap.htm - there's a link on that page for PrintBitmapRect().

// Print MyBitmap in upper left corner four times its size
RvNDRWriter1.PrintBitmap( 1.0, 1.0, 2.0, 2.0, MyBitmap );

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R – Landscaping in Rave Reports using Delphi 7

Just drop TRvSystem component and set SystemPrinter.Orientation to poLandScape. exemple:

RvSystem1.SystemPrinter.Orientation := poLandScape;

An idempotent operation

In computing, an idempotent operation is one that has no additional effect if it is called more than once with the same input parameters. For example, removing an item from a set can be considered an idempotent operation on the set.

In mathematics, an idempotent operation is one where f(f(x)) = f(x). For example, the abs() function is idempotent because abs(abs(x)) = abs(x) for all x.

These slightly different definitions can be reconciled by considering that x in the mathematical definition represents the state of an object, and f is an operation that may mutate that object. For example, consider the Python set and its discard method. The discard method removes an element from a set, and does nothing if the element does not exist. So:

my_set.discard(x)

has exactly the same effect as doing the same operation twice:

my_set.discard(x)
my_set.discard(x)

Idempotent operations are often used in the design of network protocols, where a request to perform an operation is guaranteed to happen at least once, but might also happen more than once. If the operation is idempotent, then there is no harm in performing the operation two or more times.

See the Wikipedia article on idempotence for more information.

^{The above answer previously had some incorrect and misleading examples. Comments below written before April 2014 refer to an older revision.}

Best Answer

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R – Landscaping in Rave Reports using Delphi 7

An idempotent operation

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