Morphing on a Square Mesh: Working Matrix Version (Horray!)
lazarus / 39-Graphics

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Boleeman · 2024-10-25 16:07

I tried to convert some VBNet code that performs morphing using a
square mesh.

Got the loading of the images and the mesh working.
Got the saving of the mesh points working.
Bmps saved after btnMorph click

Not working:

Moving the control points
The morphed bmps don't show the morphing correctly.


Ah, headaches over this one !

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DomingoGP · 2024-10-26 09:51

Fix for moving control points (barely tested) note the var parameters
r and c

Code: Pascal  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i procedure
TForm1.FindControlPoint(index, X, Y: Integer;var  r, c: Integer);var 
dx, dy: Single;begin  r:=0;  while r < NUM_POINTS do  begin    c:=0; 
 while c < NUM_POINTS  do    begin      dx := Abs(m_Point[index, r,
c].X - X);      dy := Abs(m_Point[index, r, c].Y - Y);      if (dx <
POINT_WID - 1) and (dy < POINT_WID - 1) then        Exit;      inc(c) 
  end;    inc(r);  end;   r := -1;  c := -1;end;

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TRon · 2024-10-26 09:58

As mentioned by DomingoGP, all byref's in the original basic code
should be a var parameter in pascal.

Thus also for method STToPoints and function PointsToST.

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Boleeman · 2024-10-26 13:10

Brilliant DomingoGP and TRon.

Thanks for the fixes to moving the points.

Now trying to work out why the rendered bmp are not rendering the
morphed pictures properly.

Looking at the bmps, there seems to be a triangular part which
shouldn't be there.
The VBNet code used clone to copy the pixels, whereas I am using draw
to white background
 
m_Bm[2] := TBGRABitmap.Create(m_Bm[0].Width, m_Bm[0].Height, clWhite);
  m_Bm[2].Draw(m_Bm[0].Canvas, 0, 0, True);

Also I used the TBgrabmp MergeBGRA to merge the morphed pixels:
m_Bm[2].SetPixel(x, y, MergeBGRA(AColor, Round((1 - fraction) * 255),
BColor, Round(fraction * 255)));

Perhaps something here is a bit off ?

Not sure if circular might have any idea on the morphed render anomaly
?

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Boleeman · 2024-10-26 18:37

I was also working on another version that uses Matrices, written in
Delphi by some French Programmer.
Contains a really good (High End) Matrix Unit.

Finally got it working so here it is.

It loads jpg on start up. Would be nice to convert to Bgrabmp.
On startup it loads 2  jpg pictures and their corresponding mesh
points (Need to have these in the startup folder)

The difficulty with the conversion came in getting the ReShape
procedure to overlay the grid of TShape dots over the loaded jpg.
After many attempts I realized that the TPanels were giving an
"index(1) out of bounds error" even thought that did not happen with
the Delphi version. The initial conversion was also making the dots
disappear each time one was clicked in the Lazarus version.

Also perhaps I wonder if someone could possibly add a save to Anigif
or Apng (Not entirely sure how to do it)

Lastly needed to mention that "When you click GO to do a Morph it
takes a while and then the magic happens"

Anyhow. Enjoy.