Fill transparency with log x axis

Hi all,

I am trying to make a plot with three semi-transparent fill areas. I require a log x-axis. It's not a problem getting this to work on a linear axis but the transparency disappears when you change to a log scale. Try:

figure;
theAxis = gca;
set(theAxis,'NextPlot','add');

%plot three shapes
t = (1/16:1/8:1)'*2*pi;t = t';
for i=1:3
  x = sin(t)+i;
  n = cos(t)+i;
  h = fill(x,n,'r');
  set(h,'FaceAlpha',0.5);
end
%pause to view
pause(2);
%now change to log scale on the x-axis and the transparency disappears
set(theAxis,'XScale','log');
pause(2);
%and change back and the transparency reappears
set(theAxis,'XScale','linear');

Any ways to get the transparency to work on a log scale plot? Thanks, Stephen

Answer 1

[Stephen Faul]

Question answered in: http://www.mathworks.com/matlabcentral/answers/13441-bizare-problem-with-facealpha-and-rendering

[Marshall Borrus]

lies.

[himura]

do you have a solution @Marshall Borrus?

Answer 2

[himura]

Pretty late, but for any future perspn looking at this, the accepted anser basically says "it is not supported, here's a work around"

I am here to pitch another workaround, which is to simply setting the color to be lighter. The example code here is for semilogy(), but it works for semilogx() and loglog()

x_axes = -10:0.1:10;
y_axes = x_axes .^ 2;
semilogy(x_axes, y_axes, '*', Color = [0   0   1]); % without transparency

semilogy(x_axes, y_axes, '*', Color = [0.7 0.7 1]); % with   "transparency". it only seems transparent, but not really

% or

semilogy(x_axes, y_axes, '*', 'Color', [0   0   1]); % without transparency

semilogy(x_axes, y_axes, '*', 'Color', [0.7 0.7 1]); % with   "transparency". it only seems transparent, but not really