procedure rmath(case:integer);
var
  pid:integer;
  value:real;
begin
  pid:=PidNumber;
  value:=GetNumber('Constant:', 10.0);
  if case=1 then
    ImageMath('copy', pid, pid, 1, value, pid)
  else if case=2 then
    ImageMath('copy real', pid, pid, 1, value, 'Real Result')
  else  if case=3 then
    ImageMath('copy', pid, pid, value, 0, pid)
  else
    ImageMath('copy real', pid, pid, value, 0, 'Real Result');
end;

macro 'Add  Constant - 8-bit resultÉ'; begin rmath(1); end;
macro 'Add Constant - real resultÉ'; begin rmath(2); end;
macro 'Multiply by Constant - 8-bit resultÉ'; begin rmath(3); end;
macro 'Multiply by Constant - real resultÉ'; begin rmath(4); end;

macro '(---'; begin end;

procedure StackMath(op: string);
{Performs, slice by slice, the specied operation on two
stacks and stores the result in the second stack.}
var
   i, d1, d2, d3, scale: integer;
   offset, result: real;
begin
  if nPics<>2 then begin
     PutMessage('This macro operates on exactly two stacks.');
     exit;
  end;
  SelectPic(1);
  KillRoi;
  d1:=nSlices;
  SelectPic(2);
  KillRoi;
  d2:=nSlices;
  if d1<=d2
     then d3:=d1
     else d3:=d2;
  if d3<2  then begin
    PutMessage('This macro requires two stacks.');
    exit;
  end;
  scale := 1.0;
  offset := 0.0;
  if op = 'add' then
     scale := 0.5
  else if op = 'subtract' then begin
     scale := 0.5;
     offset := 128;
  end else if op = 'multiply' then
      scale := 1
  else if op = 'divide' then
      scale := 255;
  if (op = 'add') or (op = 'subtract') or (op = 'multiply') or (op = 'divide') then
      scale := GetNumber('Scale factor:', scale);
  if op = 'subtract'  then
      offset := GetNumber('Offset:', offset);
 SelectPic(2);
  result := PidNumber;
  for i:=1 to d3 do begin
     SelectPic(1);
     SelectSlice(i);
     SelectPic(2);
     SelectSlice(i);
     ImageMath(op, 1, 2, scale, offset, result);
  end;
end;

Macro 'Add Two Stacks';
begin
  StackMath('Add');
end;

Macro 'Subtract Two Stacks';
begin
  StackMath('Subtract');
end;

Macro 'Multiply Two Stacks';
begin
  StackMath('Multiply');
end;

Macro 'Divide Two Stacks';
begin
  StackMath('Divide');
end;

Macro 'AND Two Stacks';
begin
  StackMath('AND');
end;

Macro 'OR Two Stacks';
begin
  StackMath('OR');
end;

Macro 'Max of Two Stacks';
begin
  StackMath('Max');
end;

Macro 'Min of Two Stacks';
begin
  StackMath('Min');
end;

macro '(---'; begin end;

macro 'Absolute Difference';
begin
  if nPics <> 2 then begin
     beep;
     PutMessage('Exactly two images required.');
     exit;
  end;
  ImageMath('subtract', 1, 2, 1, 0, 'A-B');
  ImageMath('subtract', 2, 1, 1, 0, 'B-A');
  ImageMath('max', 3, 4, 1, 0, 'Absolute Difference');
  SelectWindow('A-B');
  Dispose;
  SelectWindow('B-A');
  Dispose;
end;