Custom Colours of a Pie Chart Sections
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Dima
am 8 Jan. 2012
Bearbeitet: Walter Roberson
am 27 Aug. 2020
Hello!
I wonder if it is possible to create a pie chart in such a way so as to have 6 equally sized sections - each of which is coloured in a specific shade of green or red -depending on the percentage input - 100% being the brightest red or green and 10% being very pale green or red. Thanks! Dima
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Akzeptierte Antwort
Walter Roberson
am 11 Jan. 2012
It was necessary to get rid of the "clc" to get it to work.
Note: the sectors go counter-clockwise in a "pie" chart.
% Program to apply red and green tinted colors to pie segments
% depending on the size of the pie segment.
function test1()
fontSize = 24;
X = [0 0.5 -0.2 0.3 0.8 -0.7];
fig = figure;
ax = axes('Parent', fig);
numberOfSegments = length(X);
rgbmatrix = [1+(X(:) < 0).*X(:), 1-(X(:) > 0).*X(:), 1-abs(X(:))];
hPieComponentHandles = pie(ax, ones(1,numberOfSegments));
title('Pie Chart with Custom Colors', 'Parent', ax, 'fontSize', fontSize);
% Enlarge figure to full screen.
set(fig, 'units', 'normalized', 'outerposition', [0 0 1 1]);
set(fig, 'name', 'Demo by ImageAnalyst & Tanuki', 'numbertitle', 'off')
% Assign custom colors.
for k = 1 : numberOfSegments
% Create a color for this sector of the pie
pieColorMap = rgbmatrix(k,:); % Color for this segment.
% Apply the colors we just generated to the pie chart.
set(hPieComponentHandles(k*2-1), 'FaceColor', pieColorMap);
set(hPieComponentHandles(k*2), 'String', num2str(X(k)), 'FontSize', fontSize );
end
7 Kommentare
Weitere Antworten (6)
Walter Roberson
am 8 Jan. 2012
Not using pie(). You could patch() this together yourself. You might want to start with the circle routines shown in the FAQ
Image Analyst
am 10 Jan. 2012
Dima: Try this:
% Create sample data and plot it.
X = [1 1 1 1 1 1 ] ;
numberOfSegments = length(X)
hPieComponentHandles = pie(X);
% Create custom colormap: 0=pure red, 1 = white.
ramp = [0 : 1/(numberOfSegments-1) : 1]'
pieColorMap = [ones(numberOfSegments, 1), ramp, ramp]
% Note: use flipud(pieColorMap) if you want it
% the other way: 0=white, 1 = pure red.
% pieColorMap = flipud(pieColorMap);
% Apply the colors we just generated to the pie chart.
SetPieChartColors(hPieComponentHandles, pieColorMap);
title('Pie Chart with Custom Colors', 'fontSize', fontSize);
5 Kommentare
Image Analyst
am 8 Jan. 2012
Dima:
Try this demo. Save it as test1.m and then run it. I think it will do exactly what you've asked for (and hopefully that's what you want).
% Program to apply red tinted colors to pie segments
% depending on the size of the pie segment.
function test1()
try
clc; % Clear the command window.
workspace; % Make sure the workspace panel is showing.
fontSize = 24;
X = [1 2 3 4 5 6];
hPieComponentHandles = pie(X);
title('Pie Chart with Custom Colors', 'fontSize', fontSize);
% Enlarge figure to full screen.
set(gcf, 'units','normalized','outerposition',[0 0 1 1]);
set(gcf,'name','Demo by ImageAnalyst','numbertitle','off')
% Ask user if they want to apply custom colors.
promptMessage = sprintf('These are the initial colors.\nDo you want to apply custom colors,\nor Cancel to exit the program?');
button = questdlg(promptMessage, 'Continue', 'Continue', 'Cancel', 'Continue');
if strcmp(button, 'Cancel')
return;
end
% Assign custom colors.
numberOfSegments = length(X)
for k = 1 : numberOfSegments
% Create a color for this sector of the pie
fractionOfPie = X(k) / sum(X)
thisColor = [1 1-fractionOfPie 1-fractionOfPie] % Display in command window.
pieColorMap(k,:) = thisColor; % Color for this segment.
% Apply the colors we just generated to the pie chart.
SetPieChartColors(hPieComponentHandles, pieColorMap);
if k < numberOfSegments
promptMessage = sprintf('Applied new color to sector %d,\nContinue or Cancel?', k);
button = questdlg(promptMessage, 'Continue', 'Continue', 'Cancel', 'Continue');
if strcmp(button, 'Cancel')
break;
end
end
end
catch ME
errorMessage = sprintf('Error in function test1.\n\nError Message:\n%s', ME.message);
fprintf(1,'%s\n', errorMessage);
uiwait(warndlg(errorMessage));
end
return; % from test1
%=====================================================================
% If you apply a colormap, MATLAB has a "feature" where it applies the
% colormap to ALL the axes on the figure, not just the current axes. So if
% you apply a colormap to the current axes (your pie chart) thinking it
% will affect only your pie chart, you will be surprised to find it affects
% all other charts and images on the dialog box. To get around that, use
% this function which the colors of the pie segments and does not affect
% any other objects in the dialog box. You need to pass in
% hPieComponentHandles which you get when you create the pie chart:
% hPieComponentHandles = pie([Value1, Value2, Value3],{'Label 1','Label 2','Label 3'});
% Then make up your color map like this:
% pieColorMap(1,:) = [.22 .71 .29]; % Color for segment 1.
% pieColorMap(2,:) = [.25 .55 .79]; % Color for segment 2.
% pieColorMap(3,:) = [.93 .11 .14]; % Color for segment 3.
% and finally, call this function
% SetPieChartColors(hPieComponentHandles, pieColorMap);
function SetPieChartColors(hPieComponentHandles, PieSegmentColors)
try
numberOfSegments = min([size(PieSegmentColors, 1) length(hPieComponentHandles)])
for s = 1 : numberOfSegments
set(hPieComponentHandles((s-1)*2+1),'FaceColor', PieSegmentColors(s,:));
end
catch ME
errorMessage = sprintf('Error in function SetPieChartColors.\n\nError Message:\n%s', ME.message);
fprintf(1,'%s\n', errorMessage);
uiwait(warndlg(errorMessage));
end
return; % from SetPieChartColors
17 Kommentare
Walter Roberson
am 9 Jan. 2012
No advance computation required:
rgbmatrix = [(X(:) > 0).*X(:), zeros(length(X),1), -(X(:) < 0).*X(:)];
Then slice K is color rgbmatrix(K,:)
Image Analyst
am 9 Jan. 2012
If that formula for arriving at colors works for you, then do it before the k loop and then in the loop, you can just do
pieColorMap(k,:) = rgbmatrix(k,:); % Color for this segment.
and get rid of thisColor computation. Heck, you don't even really need the k loop - that was just for tutorial purposes. You could assign the colors all in one call without any loop over k at all:
SetPieChartColors(hPieComponentHandles, rgbmatrix);
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