plotting complex functions

the code

{ nonvisual component - does the mapping of coordinate system to screen
                        requires an image to plot on.

  uses two float plot fields, one for the amplitude and one for the phase

  advantage : multiple plots can be done onto one image

  the image has to exist before assigning the image

  use :

procedure TForm1.gobtnClick(Sender: TObject);
var
 S,D,U:ComplexPtr;
 x:integer;
begin
 cpw:=TComplexMapWin.create(image1);
 cpw.clear;
 cpw.flow:=1e6;
 cpw.fhigh:=3e7;
 cpw.mina:=1e-1;
 cpw.maxa:=1e4;
 Ra:=new(ComplexPtr);
 Ca:=new(ComplexPtr);
 La:=new(ComplexPtr);
 for x:=0 to image1.width-1 do begin // scan horizontally
   xs:=cpw.getx(x);			// get real x
   Ca^.a:=0;
   Ca^.b:=-1/(2*pi*xs*cav);
   La^.a:=0;
   La^.b:=2*pi*xs*lav;
   Ra^.a:=rav;
   Ra^.b:=0;
   s:=C_ParallelN(La,Ca);
   d:=C_ParallelN(S,Ra);
   C_R2P(d);
   cpw.putpixel(d^,xs,clblack);         // display this value
   dispose(S);
   dispose(D);
  end;
 cpw.destroy;
 cpw:=nil;
end;


}
unit ComplexPlotWin;

interface

uses
  Windows, Messages, SysUtils, Classes, Graphics, Controls, Forms, Dialogs,
  extctrls,ComplexRec,PlotWin;

type
  float=extended;

  cwmodetype=(saAP,saRI);   // real/imag or abs/phase

  TComplexMapWin = class(TObject)
  private
    { Private declarations }
   fimage:TImage;
   fmw1,fmw2:TMapWin;
   ftlx,ftly,fbrx,fbry,fwidth,fheight:integer;
   fflow,ffhigh,fmina,fmaxa:float;
   fmode:cwmodetype;
  protected
    { Protected declarations }
   procedure setimage(i:TImage);
   procedure setTLX(u:integer);
   procedure setTLY(u:integer);
   procedure setWidth(u:integer);
   procedure setHeight(u:integer);
   procedure setflow(f:float);
   procedure setfhigh(f:float);
   procedure setmina(a:float);
   procedure setmaxa(a:float);
  public
    { Public declarations }
   constructor create(image:TImage);    // must exist or NIL
   destructor destroy; override;
   procedure ComplexToScreen(z:Complex;f:float;var xs,ya,yp:integer); virtual;
   procedure ScreenToFloat(xs,ys:integer;var xf,yf:float); virtual;
   procedure clear;
   procedure putpixel(z:Complex;f:float;color:TColor); virtual;
   function getX(i:integer):float;             // i:=0..width-1
  published
    { Published declarations }
   property image:TImage read fimage write setimage;
   property left:integer read ftlx write setTLX;     // with respect to image
   property top:integer read ftly write setTLY;     // with respect to image
   property width:integer read fwidth write setWidth;     // with respect to image
   property height:integer read fheight write setHeight;     // with respect to image
   property mode:cwmodetype read fmode write fmode;
   property flow:float read fflow write setflow;        // frequency
   property fhigh:float read ffhigh write setfhigh;      // frequency
   property mina:float read fmina write setmina;        // absolute value
   property maxa:float read fmaxa write setmaxa;        // absolute value

  end;

procedure Register;

implementation


uses math;

type TMyPlotException=Class(Exception);

//...........................................................................
procedure TComplexMapWin.setimage(i:TImage);
begin
 fimage:=i;
 fmw1.image:=i;
 fmw2.image:=i;
end;
procedure TComplexMapWin.setTLX(u:integer);
begin ftlx:=u; end;
procedure TComplexMapWin.setTLY(u:integer);
begin ftly:=u; end;
procedure TComplexMapWin.setWidth(u:integer);
begin fbrx:=ftlx+u; fwidth:=u; end;
procedure TComplexMapWin.setHeight(u:integer);
begin fbry:=ftly+u; fheight:=u; end;
procedure TComplexMapWin.setflow(f:float);
begin
 fflow:=f;
 fmw1.xlow:=f;
 fmw2.xlow:=f;
end;
procedure TComplexMapWin.setfhigh(f:float);
begin
 ffhigh:=f;
 fmw1.xhigh:=f;
 fmw2.xhigh:=f;
end;
procedure TComplexMapWin.setmina(a:float);
begin
 fmina:=a;
 fmw1.ylow:=a;
end;
procedure TComplexMapWin.setmaxa(a:float);
begin
 fmaxa:=a;
 fmw1.yhigh:=a;
end;

constructor TComplexMapWin.create(image:TImage);
begin
 inherited create;
 fimage:=image;
 fmode:=saAP;
 fmw1:=TMapwin.create(image);
 fmw2:=TMapWin.create(image);
 if fmode=saAP then begin
  flow:=0.1; fhigh:=100;
  fmina:=1e-9; fmaxa:=1;
  fmw1.xlow:=flow;           fmw2.xlow:=flow;
  fmw1.xhigh:=fhigh;         fmw2.xhigh:=fhigh;
  fmw1.YLow:=fmina;          fmw2.YLow:=-pi;
  fmw1.YHigh:=fmaxa;             fmw2.YHigh:=pi;
  fmw1.xlog:=true;           fmw2.xlog:=true;
  fmw1.ylog:=true;           fmw2.ylog:=false;
  fmw1.protectlog:=true;
  fmw1.top:=0;               fmw2.top:=image.height div 2;
  fmw1.height:=
    image.height div 2-1;    fmw2.height:=fmw1.height;
  fmw1.left:=0;              fmw2.left:=0;
  fmw1.width:=image.width;  fmw2.width:=image.width;
  end
 else begin//fmode=saRI

  end;
end;

destructor TComplexMapWin.destroy;
begin
 fmw1.destroy;
 fmw2.destroy;
 inherited destroy;
end;


procedure TComplexMapWin.ComplexToScreen(z:Complex;f:float;var xs,ya,yp:integer);
var ax,ay,bx,by:integer;
begin
 if fmode=saAP then begin   // z:=a,p
  fmw1.floattoscreen(f,z.a,ax,ay);
  fmw2.floattoscreen(f,z.b,bx,by);
  xs:=ax; ya:=ay; yp:=by;
 end;
end;

procedure TComplexMapWin.ScreenToFloat(xs,ys:integer;var xf,yf:float);
begin
 if fmode=saAP then begin
  if (ys>=fheight div 2) then  // in the phase part
   fmw2.ScreenToFloat(xs,ys-(fheight div 2),xf,yf)
  else // absolute part
   fmw1.ScreenToFloat(xs,ys,xf,yf);
 end;
end;
procedure TComplexMapWin.clear;
begin
 if assigned(fimage) then begin
  fimage.canvas.Pen.color:=clWhite;
  fimage.canvas.brush.color:=clWhite;
  fimage.canvas.rectangle(ftlx,ftly,fbrx,fbry);
  fimage.canvas.Pen.color:=clblack;
  fimage.canvas.moveto(0,fimage.height div 2);
  fimage.canvas.lineto(fimage.width,fimage.height div 2);
  fimage.canvas.Pen.color:=clWhite;
  end;
end;
procedure TComplexMapWin.putpixel(z:Complex;f:float;color:TColor);
begin
 fmw1.putpixel(f,z.a,color);
 fmw2.putpixel(f,z.b,color);
end;

function TComplexMapWin.getX(i:integer):float;             // i:=0..width-1
begin
 result:=fmw1.getx(i);
end;



procedure Register;
begin
 // RegisterComponents('Samples', [TComplexMapWin]);
end;

end.
 

notes

This component is not yet complete, it just served the purpose
it was designed for.
I'll update it at a later date.