Coloring axis with gradients?

My humble script is taking shape :

Here's my code, for those interested :

global sRGBGamut AdobeRGBGamut EpsonGamut P3Gamut Rec2020Gamut ax;

figure;

ax=axes;

popup = uicontrol('Style', 'popup',...

'String', {'sRGB','AdobeRGB','P3','Epson','Rec2020'},...

'Position', [10 10 100 50],'background','green',...

'Value',1,'Callback',@popupCallback);

% 1 Créer l'échantillon RGB

[r,g,b] = meshgrid(linspace(0,1,20)); % linspace(0,1,50)

rgb = [r(:), g(:), b(:)];

% lab sert d'Input à la conversion de profil ICC

lab = rgb2lab(rgb); % Input - double (0.0 à 1.0)

lab2 = rgb2lab(rgb,'ColorSpace','adobe-rgb-1998');

a = lab(:,2);

b = lab(:,3);

L = lab(:,1);

k = boundary(a,b,L);

sRGBGamut = trisurf(k,a,b,L,'FaceColor','interp', 'FaceVertexCData',rgb,'EdgeColor','none');

xlabel('a*');

ylabel('b*');

zlabel('L*');

axis([-128 128 -128 128 0 100]);;grid on;hold on;

view(10,35);

title('sRGB gamut surface', 'in L*a*b* space'); % Add Title to Current Axes

ax.TitleHorizontalAlignment = 'left';

a = lab2(:,2);

b = lab2(:,3);

L = lab2(:,1);

k = boundary(a,b,L);

AdobeRGBGamut = trisurf(k,a,b,L,'FaceColor','interp', 'FaceVertexCData',rgb,'EdgeColor','none');

set(AdobeRGBGamut, 'Visible', 'off');

% 2 Profil Epson ------------------------------------------------------

EpsonProf = iccread('SC5M E240 FD9 basICColor (2021 12 11).icm');

cform_LabEpson = makecform('clut',EpsonProf,'AToB1')

LabEpson = applycform(rgb,cform_LabEpson);

a = LabEpson(:,2);

b = LabEpson(:,3);

L = LabEpson(:,1);

k = boundary(a,b,L);

EpsonGamut = trisurf(k,a,b,L,'FaceColor','interp', 'FaceVertexCData',rgb,'EdgeColor','none');

set(EpsonGamut, 'Visible', 'off');

% 3 Profil P3 ------------------------------------------------------

P3Prof = iccread('Display P3.icm');

cform_XYZP3 = makecform('mattrc',P3Prof,'Direction','forward') % Output is XYZ

xyzP3 = applycform(rgb, cform_XYZP3);

cform_XYZ2Lab = makecform('xyz2lab')

LabP3 = applycform(xyzP3, cform_XYZ2Lab)

a = LabP3(:,2);

b = LabP3(:,3);

L = LabP3(:,1);

k = boundary(a,b,L);

P3Gamut = trisurf(k,a,b,L,'FaceColor','interp', 'FaceVertexCData',rgb,'EdgeColor','none');

set(P3Gamut, 'Visible', 'off');

% 4 Profil Rec2020 ------------------------------------------------------

Rec2020Prof = iccread('Rec2020-Rec1886.icc');

cform_XYZrec2020 = makecform('mattrc',Rec2020Prof,'Direction','forward') % Output is XYZ

xyzRec2020 = applycform(rgb, cform_XYZrec2020);

LabRec2020 = applycform(xyzRec2020, cform_XYZ2Lab);

a = LabRec2020(:,2);

b = LabRec2020(:,3);

L = LabRec2020(:,1);

k = boundary(a,b,L);

Rec2020Gamut = trisurf(k,a,b,L,'FaceColor','interp', 'FaceVertexCData',rgb,'EdgeColor','none');

set(Rec2020Gamut, 'Visible', 'off');

function popupCallback(popup,event)

sels = get(popup,'String');

idx = get(popup,'Value');

Selection = sels{idx};

global sRGBGamut;

global AdobeRGBGamut;

global EpsonGamut;

global P3Gamut;

global Rec2020Gamut;

switch(Selection)

case 'sRGB'

title('sRGB gamut surface', 'in L*a*b* space');

set(AdobeRGBGamut, 'Visible', 'off');

set(EpsonGamut, 'Visible', 'off');

set(P3Gamut, 'Visible', 'off');

set(Rec2020Gamut, 'Visible', 'off');

set(sRGBGamut, 'Visible', 'on');

fprintf('sRGB\n' );

case 'AdobeRGB'

title('AdobeRGB gamut surface', 'in L*a*b* space');

set(sRGBGamut, 'Visible', 'off');

set(EpsonGamut, 'Visible', 'off');

set(P3Gamut, 'Visible', 'off');

set(Rec2020Gamut, 'Visible', 'off');

set(AdobeRGBGamut, 'Visible', 'on');

fprintf('AdobeRGB\n' );

case 'P3'

title('Display P3 gamut surface', 'in L*a*b* space');

set(EpsonGamut, 'Visible', 'off');

set(sRGBGamut, 'Visible', 'off');

set(AdobeRGBGamut, 'Visible', 'off');

set(Rec2020Gamut, 'Visible', 'off');

set(P3Gamut, 'Visible', 'on');

fprintf('P3\n' );

case 'Epson'

title('Epson P5000 gamut surface', 'in L*a*b* space');

set(sRGBGamut, 'Visible', 'off');

set(AdobeRGBGamut, 'Visible', 'off');

set(Rec2020Gamut, 'Visible', 'off');

set(P3Gamut, 'Visible', 'off');

set(EpsonGamut, 'Visible', 'on');

fprintf('Epson\n' );

case 'Rec2020'

title('Rec2020 gamut surface', 'in L*a*b* space');

set(EpsonGamut, 'Visible', 'off');

set(sRGBGamut, 'Visible', 'off');

set(AdobeRGBGamut, 'Visible', 'off');

set(P3Gamut, 'Visible', 'off');

set(Rec2020Gamut, 'Visible', 'on');

fprintf('Rec2020\n' );

%otherwise

% fprintf('Invalid grade\n' );

end

end

Any criticism is welcome, by the way, I'm by no means a Matlab expert... but I am a little bit knowledgeable about ICC profiles and their internal workings, which help untangle the many cform function calls.

I wasn't expecting the Rec2020 gamut to be truncated along the a* axis? Very interesting. I already have the axis defined between -128 to +128 which corresponds, in my understanding, to a signed 8bit value.

Question, if I may : how could I possibly add gradients axis? I would lilke to be able to create something along those lines, so that, when the student rotate the plot, we always have a visual reference point :

Are gradients possible at all in Matlab? I confess I have not found anything in the documentation...

Answer 1

[Matt J]

Do you mean colorbar()?