Issue Saving image with text overlay to png

10 vues (au cours des 30 derniers jours)
Erick Oberstar
Erick Oberstar le 16 Juil 2019
Déplacé(e) : Walter Roberson le 29 Oct 2025 à 17:00
I am having issues saving an image that has been displayed in a figure, with a couple markers plotted at specific coordinates and then text overlaid using the text function. I am trying to safe this off as a png via saveas(gcf,'filename.png'); and the figure exports but the overlaid text is missing. The title and the marker points I plotted show up but no text. Below is the figure.
Attached is the exported png using saveas
My code looks as follows:
figure; imshow(img,[]);
hold on;
plot(Stats(TestNum).Centroid(1),Stats(TestNum).Centroid(2),'b*');
set(gca, 'ActivePositionProperty', 'OuterPosition');
[filepath,name,ext] = fileparts(files(TestNum).name);
title({[];name;['Original Image With Centroid Marked']},'FontSize',FontSize);
text(20,500,{['Area = ',num2str(Stats(TestNum).Area.*pixel_scale^2,'%3.2f'),'mm^2'];...
['Eccentricity = ',num2str(Stats(TestNum).Eccentricity,'%3.2f')];...
['Orientation = ',num2str(Stats(TestNum).Orientation,'%3.2f'),char(176)];...
['Major Axis Length = ',num2str(Stats(TestNum).MajorAxisLength.*pixel_scale,'%3.2f'),'mm'];...
['Minor Axis Length = ',num2str(Stats(TestNum).MinorAxisLength.*pixel_scale,'%3.2f'),'mm']},...
'Color','white','FontSize',FontSize);
saveas(gcf,[pwd '\output\Test ',num2str(TestNum),'\TubeMidpointCrossSection - Test ',num2str(TestNum),'.png']);
  1 commentaire
Will Reeves
Will Reeves le 29 Oct 2025 à 16:10
Déplacé(e) : Walter Roberson le 29 Oct 2025 à 17:00
I have the same problem. My issue is, like the above, the image I'm writing text on top of is mostly black - I need white text. Please can "saveas" actually save "WYSIWYG-like"?

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Réponses (3)

Walter Roberson
Walter Roberson le 16 Juil 2019
I recommend you take a different approach. Instead of plotting on the image and text() on the image, use the Computer Vision insertText and insertShape routines to etch the information into an RGB array. After that is done, imwrite() the array.

Jia-Sheng Hong
Jia-Sheng Hong le 8 Jan 2020
The text do exist after you save it, however, it become black again. You can set the 'BackgroundColor' of the text to white instead of set the text to white, and it should work.

Will Reeves
Will Reeves le 29 Oct 2025 à 16:15
Modifié(e) : Will Reeves le 29 Oct 2025 à 16:16
Sorry! I knew I once had the answer to this somewhere...
You need to put the line:
set(gcf, 'InvertHardCopy', 'off');
immediatly before issuing the "saveas" command.

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