%'phys': transforms image (px) to real world (phys) coordinates using geometric calibration parameters
% OUTPUT: 
% DataOut:   structure representing the modified field
% DataOut_1: structure representing the second modified field

%INPUT:
% Data:  structure of input data 
%       with fields .A (image or scalar matrix), AX, AY
%       .X,.Y,.U,.V, .DjUi
%       .ZIndex: index of plane in multilevel case 
% Data.CoordType='phys' or 'px', The function ACTS ONLY IF .CoordType='px'
% Calib: structure containing calibration parameters or a subtree Calib.GeometryCalib =calibration data (tsai parameters)

function [DataOut,DataOut_1]=phys(varargin)
% A FAIRE: 1- verifier si DataIn est une 'field structure'(.ListVarName'):
% chercher ListVarAttribute, for each field (cell of variables):
%   .CoordType: 'phys' or 'px'   (default==phys, no transform)
%   .scale_factor: =dt (to transform displacement into velocity) default=1
%   .covariance: 'scalar', 'coord', 'D_i': covariant (like velocity), 'D^i': contravariant (like gradient), 'D^jD_i' (like strain tensor)
%   (default='coord' if .Role='coord_x,_y..., 
%            'D_i' if '.Role='vector_x,...',
%              'scalar', else (thenno change except scale factor)
Calib{1}=[];
if nargin==2||nargin==4 % nargin =nbre of input variables
    Data=varargin{1};
    DataOut=Data;%default
    DataOut_1=[];%default
    CalibData=varargin{2};
    if isfield(CalibData,'GeometryCalib')
        Calib{1}=CalibData.GeometryCalib;
    end
    Calib{2}=Calib{1};
else
    DataOut.Txt='wrong input: need two or four structures';
end
test_1=0;
if nargin==4
    test_1=1;
    Data_1=varargin{3};
    DataOut_1=Data_1;%default
    CalibData_1=varargin{4};
    if isfield(CalibData_1,'GeometryCalib')
        Calib{2}=CalibData_1.GeometryCalib;
    end
end
iscalar=0;
if  ~isempty(Calib{1})
    DataOut=phys_1(Data,Calib{1});
    %case of images or scalar: in case of two input fields, we need to project the transform of on the same regular grid
    if isfield(Data,'A') && isfield(Data,'AX') && ~isempty(Data.AX) && isfield(Data,'AY')&&...
                                           ~isempty(Data.AY) && length(Data.A)>1
        iscalar=1;
        A{1}=Data.A;
    end
end
%transform of X,Y coordinates for vector fields
if isfield(Data,'ZIndex')&&~isempty(Data.ZIndex)
    ZIndex=Data.ZIndex;
else
    ZIndex=0;
end
if test_1
    DataOut_1=phys_1(Data_1,Calib{2});
    if isfield(Data_1,'A')&&isfield(Data_1,'AX')&&~isempty(Data_1.AX) && isfield(Data_1,'AY')&&...
                                       ~isempty(Data_1.AY)&&length(Data_1.A)>1
          iscalar=iscalar+1;
          Calib{iscalar}=Calib{2};
          A{iscalar}=Data_1.A;
          if isfield(Data_1,'ZIndex') && ~isequal(Data_1.ZIndex,ZIndex)
              DataOut.Txt='inconsistent plane indexes in the two input fields';
          end
          if iscalar==1% case for which only the second field is a scalar
               [A,AX,AY]=phys_Ima(A,Calib,ZIndex);
               DataOut_1.A=A{1};
               DataOut_1.AX=AX; 
               DataOut_1.AY=AY;
               return
          end
    end
end
if iscalar~=0
    [A,AX,AY]=phys_Ima(A,Calib,ZIndex);%TODO : introduire interp2_uvmat ds phys_ima
    DataOut.A=A{1};
    DataOut.AX=AX; 
    DataOut.AY=AY;
    if iscalar==2
        DataOut_1.A=A{2};
        DataOut_1.AX=AX; 
        DataOut_1.AY=AY;
    end
end

%------------------------------------------------
function DataOut=phys_1(Data,Calib)
% for icell=1:length(Data)

DataOut=Data;%default
DataOut.CoordType='phys'; %put flag for physical coordinates
% The transform ACTS ONLY IF .CoordType='px'and Calib defined
if isfield(Data,'CoordType')&& isequal(Data.CoordType,'px')&& ~isempty(Calib)
    if isfield(Calib,'CoordUnit')
        DataOut.CoordUnit=Calib.CoordUnit;
    else
        DataOut.CoordUnit='cm'; %default
%     elseif isfield(DataOut,'CoordUnit')
%         DataOut=rmfield(DataOut,'CoordUnit');
    end
    DataOut.TimeUnit='s';
    %transform of X,Y coordinates for vector fields
    if isfield(Data,'ZIndex') && ~isempty(Data.ZIndex)
        Z=Data.ZIndex;
    else
        Z=0;
    end
    if isfield(Data,'X') &&isfield(Data,'Y')&&~isempty(Data.X) && ~isempty(Data.Y)
        [DataOut.X,DataOut.Y,DataOut.Z]=phys_XYZ(Calib,Data.X,Data.Y,Z); 
        if isfield(Data,'U')&&isfield(Data,'V')&&~isempty(Data.U) && ~isempty(Data.V)&& isfield(Data,'dt') 
            if ~isempty(Data.dt)
            [XOut_1,YOut_1]=phys_XYZ(Calib,Data.X-Data.U/2,Data.Y-Data.V/2,Z);
            [XOut_2,YOut_2]=phys_XYZ(Calib,Data.X+Data.U/2,Data.Y+Data.V/2,Z);
            DataOut.U=(XOut_2-XOut_1)/Data.dt;
            DataOut.V=(YOut_2-YOut_1)/Data.dt;
            end
        end
    end
    %transform of an image or scalar: done in phys_ima
      
    %transform of spatial derivatives
    if isfield(Data,'X') && ~isempty(Data.X) && isfield(Data,'DjUi') && ~isempty(Data.DjUi)...
          && isfield(Data,'dt')    
        if ~isempty(Data.dt)
            % estimate the Jacobian matrix DXpx/DXphys 
            for ip=1:length(Data.X) 
                [Xp1,Yp1]=phys_XYZ(Calib,Data.X(ip)+0.5,Data.Y(ip),Z);
                [Xm1,Ym1]=phys_XYZ(Calib,Data.X(ip)-0.5,Data.Y(ip),Z);
                [Xp2,Yp2]=phys_XYZ(Calib,Data.X(ip),Data.Y(ip)+0.5,Z);
                [Xm2,Ym2]=phys_XYZ(Calib,Data.X(ip),Data.Y(ip)-0.5,Z); 
            %Jacobian matrix DXpphys/DXpx
               DjXi(1,1)=(Xp1-Xm1);
               DjXi(2,1)=(Yp1-Ym1);
               DjXi(1,2)=(Xp2-Xm2);
               DjXi(2,2)=(Yp2-Ym2);
               DjUi(:,:)=Data.DjUi(ip,:,:);
               DjUi=(DjXi*DjUi')/DjXi;% =J-1*M*J , curvature effects (derivatives of J) neglected
               DataOut.DjUi(ip,:,:)=DjUi';
            end
            DataOut.DjUi =  DataOut.DjUi/Data.dt;   %     min(Data.DjUi(:,1,1))=DUDX                          
        end
    end
end


%%%%%%%%%%%%%%%%%%%%
function [A_out,Rangx,Rangy]=phys_Ima(A,CalibIn,ZIndex)
xcorner=[];
ycorner=[];
npx=[];
npy=[];
for icell=1:length(A)
    siz=size(A{icell});
    npx=[npx siz(2)];
    npy=[npy siz(1)];
    Calib=CalibIn{icell};
    xima=[0.5 siz(2)-0.5 0.5 siz(2)-0.5];%image coordiantes of corners
    yima=[0.5 0.5 siz(1)-0.5 siz(1)-0.5];
    [xcorner_new,ycorner_new]=phys_XYZ(Calib,xima,yima,ZIndex);%corresponding physical coordinates
    xcorner=[xcorner xcorner_new];
    ycorner=[ycorner ycorner_new];
end
Rangx(1)=min(xcorner);
Rangx(2)=max(xcorner);
Rangy(2)=min(ycorner);
Rangy(1)=max(ycorner);
test_multi=(max(npx)~=min(npx)) | (max(npy)~=min(npy)); 
npx=max(npx);
npy=max(npy);
x=linspace(Rangx(1),Rangx(2),npx);
y=linspace(Rangy(1),Rangy(2),npy);
[X,Y]=meshgrid(x,y);%grid in physical coordiantes
vec_B=[];
A_out={};
for icell=1:length(A) 
    Calib=CalibIn{icell};
    if (isfield(Calib,'R') && ~isequal(Calib.R(2,1),0) && ~isequal(Calib.R(1,2),0)) ||...
        ((isfield(Calib,'kappa1')&& ~isequal(Calib.kappa1,0))) || test_multi || ~isequal(Calib,CalibIn{1})
        zphys=0; %default
        if isfield(Calib,'SliceCoord') %.Z= index of plane
           SliceCoord=Calib.SliceCoord(ZIndex,:);
           zphys=SliceCoord(3); %to generalize for non-parallel planes
        end
        [XIMA,YIMA]=px_XYZ(CalibIn{icell},X,Y,zphys);%corresponding image indices for each point in the real space grid
        XIMA=reshape(round(XIMA),1,npx*npy);%indices reorganized in 'line'
        YIMA=reshape(round(YIMA),1,npx*npy);
        flagin=XIMA>=1 & XIMA<=npx & YIMA >=1 & YIMA<=npy;%flagin=1 inside the original image
        testuint8=isa(A{icell},'uint8');
        testuint16=isa(A{icell},'uint16');
        if numel(siz)==2 %(B/W images)
            vec_A=reshape(A{icell},1,npx*npy);%put the original image in line
            ind_in=find(flagin);
            ind_out=find(~flagin);
            ICOMB=((XIMA-1)*npy+(npy+1-YIMA));
            ICOMB=ICOMB(flagin);%index corresponding to XIMA and YIMA in the aligned original image vec_A
            vec_B(ind_in)=vec_A(ICOMB);
            vec_B(ind_out)=zeros(size(ind_out));
            A_out{icell}=reshape(vec_B,npy,npx);%new image in real coordinates
        elseif numel(siz)==3     
            for icolor=1:siz(3)
                vec_A=reshape(A{icell}(:,:,icolor),1,npx*npy);%put the original image in line
                ind_in=find(flagin);
                ind_out=find(~flagin);
                ICOMB=((XIMA-1)*npy+(npy+1-YIMA));
                ICOMB=ICOMB(flagin);%index corresponding to XIMA and YIMA in the aligned original image vec_A
                vec_B(ind_in)=vec_A(ICOMB);
                vec_B(ind_out)=zeros(size(ind_out));
                A_out{icell}(:,:,icolor)=reshape(vec_B,npy,npx);%new image in real coordinates
            end
        end
        if testuint8
            A_out{icell}=uint8(A_out{icell});
        end
        if testuint16
            A_out{icell}=uint16(A_out{icell});
        end
    else%
        
        A_out{icell}=A{icell};%no transform
        Rangx=[0.5 npx-0.5];%image coordiantes of corners
        Rangy=[npy-0.5 0.5];
        [Rangx]=phys_XYZ(Calib,Rangx,[0.5 0.5],[ZIndex ZIndex]);%case of translations without rotation and quadratic deformation
        [xx,Rangy]=phys_XYZ(Calib,[0.5 0.5],Rangy,[ZIndex ZIndex]);
    end
end