Delphi - Two dimensional array - VarArrayCreate?

Hello all,

Is it possible to create a transformation matrix. This matrix is a Variant
(4x4 array of doubles)
Now I use
TransMatrix: OleVariant;
...
TransMatrix:=Drawing.ActiveUCS.GetUCSMatrix to create one and then clear
all the entries.

Thanks in advance,

Jack

 

How to do this depends on whether you're creating the
matrix (2D array) to pass back to AutoCAD (e.g., to
the TransformBy() method), or just to manipulate it in
Object Pascal.

For a matrix that you need to pass to AutoCAD, as a
variant, you would create a 2D variant array with 4
rows and 4 columns:

VarArrayCreate([0, 3, 0, 3], varDouble);

To represent a 4x4 matrix using a native language
array:

var
AMatrix : Array[0..3, 0..3] of Double;

To convert from one to the other, you define a type
for the array:

type
TMatrix4x4: Array[0..3, 0..3] of Double;

And then use these:

Function Matrix4x4ToVariant(const AMatrix: TMatrix4x4): OleVariant;
var
i, j: Integer;
begin
Result := VarArrayCreate([0, 3, 0, 3], varDouble);
For i := 0 to 3 do
For j := 0 to 3 do
Result[i, j] := AMatrix[i, j];
end;

Function VariantToMatrix4x4(const AMatrix: OleVariant): TMatrix4x4;
var
i, j: Integer;
begin
For i := 0 to 3 do
For j := 0 to 3 do
Result[i, j] := AMatrix[i, j];
end;




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Thanks Tony,

Your post was very educational again!
I missed the part [0,3,0,3]....

Kind regards,
Jack