How to make pie charts with transparency on matlab? - matlab

Question

I am currently having trouble while adding transparency to my pie charts.
I can't set using FaceAlpha or EdgeAlpha and using alpha alone kind of rips the edges of the chart when compiling the eps file.
Any tips?
figure;
subplot(1,2,1)
h=pie3(P1,[0 0 0 1 1])
set(h,'EdgeColor','none','LineStyle','none')
hold on
colormap cool
hold on
subplot(1,2,2)
h=pie3([PF PG],[1 0 ],{'X1','X2'})
set(h,'EdgeColor','none')
colormap cool
%alpha(0.5)
print teste -depsc2

Answer 1

The output of pie3 is an array of handles. Some are handles to surfaces, some are to patches, and others are for text. You need to select the sub-set of these handles that actually have EdgeAlpha and FaceAlpha properties. You can do this using findobj.
h = pie3(rand(1,5), [0 0 0 1 1]);
set(findobj(h, '-property', 'FaceAlpha'), 'FaceAlpha', 0.2);
set(findobj(h, '-property', 'EdgeAlpha'), 'EdgeAlpha', 0);
When exporting to an EPS though, transparency is not supported. Also, since you have transparency in your figure, MATLAB will use the OpenGL renderer which causes EPS files to not be rendered as you expect. You could try to use export_fig to get a better result.

Answer 2

It is really difficult to figure out what you are asking.
My code sample shows a way for tighter control over objects inside a figure.
I hope you can modify my example to something you can work with.
(If it isn't, please insert images, and more detailed information about your problem, and also add values of P1, PF, PG).
Matlab orders figure objects is a kind of "tree" structure.
The structure is:
figure -> axes-> object
object
...
object
-> axes-> object
object
...
object
The axes is a children of a figure, and objects are children of axes.
The following code gets array of axes handles:
%Get handles to two axes inside figure;
h_axes_arr = get(gcf, 'Children');
The following code gets array of objects handles (children of first axes):
%Array of handles - children of first axes.
h_arr = get(h_axes_arr(1), 'Children');
h = h_arr(1);
get(h, 'Type') Query the type of the first object.
Here is my code sample:
P1 = [1,3,0.5,2.5,2];
PF = 1;
PG = 2;
figure;
subplot(1,2,1)
h=pie3(P1,[0 0 0 1 1]);
set(h,'EdgeColor','none','LineStyle','none')
hold on
colormap cool
hold on
subplot(1,2,2)
h=pie3([PF PG],[1 0 ],{'X1','X2'});
set(h,'EdgeColor','none')
colormap cool
%alpha(0.5)
%Get handles to two axes inside figure;
h_axes_arr = get(gcf, 'Children');
%Array of handles - children of first axes.
h_arr = get(h_axes_arr(1), 'Children');
for i = 1:length(h_arr)
%Handle to specific children.
h = h_arr(i);
if (isequal(get(h, 'Type'), 'surface'))
%Set trasparency only if handle type is 'surface'
set(h, 'FaceAlpha', 0.5); %Set Alpha to 0.5
end
end
%Array of handles - children of second axes.
h_arr = get(h_axes_arr(2), 'Children');
for i = 1:length(h_arr)
%Handle to specific children.
h = h_arr(i);
if (isequal(get(h, 'Type'), 'surface'))
%Set trasparency only if handle type is 'surface'
set(h, 'FaceAlpha', 0.3); %Set Alpha to 0.5
end
end
%print teste -depsc2
Result:
I know it's ugly...
I hope you can make something useful out of it.