Plot image with non-uniform rectangular patches
Usage: (1) v_imagescnu(log10(1:2:9),(1:3).^2,reshape(1:15,3,5)); % log x, quadratic y
colorbar; axis xy; % add colorbar + invert y-axis
Inputs: x(nx) or x(nx+1) x-axis patch centres or boundaries
y(ny) or y(ny+1) y-axis patch centres or boundaries
v(ny,nx) Values to plot (if db is non-zero then abs(v) will be displayed)
db dB range to plot relative to peak (+ve for mag, -ve for power, 0 [default] for linear scale)0001 function v_imagescnu(x,y,v,db) 0002 % Plot image with non-uniform rectangular patches 0003 % 0004 % Usage: (1) v_imagescnu(log10(1:2:9),(1:3).^2,reshape(1:15,3,5)); % log x, quadratic y 0005 % colorbar; axis xy; % add colorbar + invert y-axis 0006 % 0007 % Inputs: x(nx) or x(nx+1) x-axis patch centres or boundaries 0008 % y(ny) or y(ny+1) y-axis patch centres or boundaries 0009 % v(ny,nx) Values to plot (if db is non-zero then abs(v) will be displayed) 0010 % db dB range to plot relative to peak (+ve for mag, -ve for power, 0 [default] for linear scale) 0011 % 0012 if nargin<4 0013 db=0; % default to linear scale 0014 end 0015 [ny,nx]=size(v); 0016 x=x(:)'; % make x a row vector 0017 y=y(:)'; % make y a row vector 0018 if length(x)==nx % need to convert from column-centres to column-edges 0019 if nx==1 % if only one column ... 0020 x=x-0.5:x+0.5; % ... make it of unit width 0021 else 0022 x=0.5*[3*x(1)-x(2) x(1:nx-1)+x(2:nx) 3*x(nx)-x(nx-1)]; % place column-edges midway between centres 0023 end 0024 elseif length(x)~=nx+1 % error unless length(x) = either nx or nx+1 0025 error('size(v)=(%d,%d) so length(x) must be %d or %d',ny,nx,nx,nx+1); 0026 end 0027 if any(x(2:nx+1)-x(1:nx)<=0) % check that x is monotonically increasing 0028 error('x values must be monotonically increasing'); 0029 end 0030 if length(y)==ny % need to convert from row-centres to row-edges 0031 if ny==1 % if only one row ... 0032 y=y-0.5:y+0.5; % ... make it of unit width 0033 else 0034 y=0.5*[3*y(1)-y(2) y(1:ny-1)+y(2:ny) 3*y(ny)-y(ny-1)]; % place row-edges midway between centres 0035 end 0036 elseif length(y)~=ny+1 % error unless length(y) = either ny or ny+1 0037 error('size(v)=(%d,%d) so length(y) must be %d or %d',ny,nx,ny,ny+1); 0038 end 0039 if any(y(2:ny+1)-y(1:ny)<=0) % check that y is monotonically increasing 0040 error('y values must be monotonically increasing'); 0041 end 0042 if db~=0 % db nonzero means a log colour scale 0043 v=abs(v); 0044 dbmul=(db>0)*10+10; % db multiplier is 10 for power (db<0) or 20 for magnitude (db>0) 0045 v=dbmul*log10(max(v,max(v(:))*10^(-abs(db)/dbmul))); % clip data to a range of abs(db) 0046 end 0047 ix=reshape(repmat(1:nx,ny,1),1,nx*ny); % x index of each patch (column-major order) 0048 iy=reshape(repmat((1:ny),1,nx),1,nx*ny); % y index of each patch (column-major order) 0049 patx=[x(ix);x(ix+1);x(ix+1);x(ix)]; % x-coordinates of patch corners in order low-left, low-right, high-right, high-left(one patch per column) 0050 paty=[y(iy);y(iy);y(iy+1);y(iy+1)]; % y-coordinates of patch corners in order low-left, low-right, high-right, high-left(one patch per column) 0051 if ~ishold 0052 cla; % clear the axes unless hold is turned on 0053 end 0054 patch(patx,paty,v(:),'EdgeColor', 'none'); % plot the patches 0055 axis([x(1) x(nx+1) y(1) y(ny+1)]); % define the axis limits 0056 axis ij; % orient image to conform to imagesc()