Save a contourf plot with transparent background and text labels

Question

Alan Meier 2020-7-12

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/563633-save-a-contourf-plot-with-transparent-background-and-text-labels

编辑： Alan Meier 2020-7-15

I've found this question dealing with the problem of a contourf plot with a transparent background. Basically the answer was found in this blog about undocumented matlab options.

I used the solution provided there but want to add some text labels for the contour plot. I can add these for a plot without any transparency modifications as well as for one with transpareny. Where I struggle is when it comes to saving one of these figures. The issue is best explained with the code below. It is possible to view a contouf plot with text as well as view and save one without text. When I then try to view and afterwards save a contourf plot with text the transparency gets lost during the saving progress.

I kindly ask if someone is able to reproduce this problem e.g. using the code below. And secondly if by chance someone has an idea to save a contourf plot with the option 'ShowText' set to 'on'.

figure
% generate a figure with text and display it -> works
[~, hContour] = contourf(peaks(20), 10,'ShowText','on');
drawnow;  % this is important, to ensure that FacePrims is ready in the next line!
hFills = hContour.FacePrims;  % array of TriangleStrip objects
[hFills.ColorType] = deal('truecoloralpha');  % default = 'truecolor'
for idx = 1 : numel(hFills)
   hFills(idx).ColorData(4) = 50;   % default=255
end
figure
% generate a figure without text and display+save it -> works
[~, hContour] = contourf(peaks(20), 10,'ShowText','off');
drawnow;  % this is important, to ensure that FacePrims is ready in the next line!
hFills = hContour.FacePrims;  % array of TriangleStrip objects
[hFills.ColorType] = deal('truecoloralpha');  % default = 'truecolor'
for idx = 1 : numel(hFills)
   hFills(idx).ColorData(4) = 50;   % default=255
end
saveas(gcf,"test_no_text.jpg")
figure
% generate a figure with text and display+save it -> doesn't work
[~, hContour] = contourf(peaks(20), 10,'ShowText','on');
drawnow;  % this is important, to ensure that FacePrims is ready in the next line!
hFills = hContour.FacePrims;  % array of TriangleStrip objects
[hFills.ColorType] = deal('truecoloralpha');  % default = 'truecolor'text as well a
for idx = 1 : numel(hFills)
   hFills(idx).ColorData(4) = 50;   % default=255
end
saveas(gcf,"test_with_text.jpg")