Printing figure alters content details
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I am trying to print some figures generated by imagesc into png images for portability. However, I found the output to lose some details in the figure and original data
load data.mat
fig=figure("visible","off");
imagesc([X(1),X(end)],[Y(1),Y(end)],Z)
colorbar
caxis([0,1])
axis equal
axis tight
fig.CurrentAxes.YDir = 'normal';
fig.CurrentAxes.FontSize=16;
fig.PaperPositionMode = 'auto';
fig.PaperUnits = 'inches';
fig.PaperPosition = [0,0,6,6];
print(fig,"imagesc.png",'-dpng','-r600')
close(fig)
imwrite(Z+1,parula(2),"direct.png")
imshow("imagesc.png")
imshow("direct.png")
If you zoom into the output (also attached), you will find that printing alters figure content, the origianlly continuous line becomes broken:
![](https://www.mathworks.com/matlabcentral/answers/uploaded_files/1065010/image.png)
while in the original figure or directly writing there is no such artifact:
![](https://www.mathworks.com/matlabcentral/answers/uploaded_files/1065015/image.jpeg)
However I still want the axes, colorbar, etc. to show up in the output images. Is there any way to get around this problem?
4 Kommentare
Antworten (2)
Jonas
am 14 Jul. 2022
Bearbeitet: Jonas
am 14 Jul. 2022
couldn't find a professional solution for this, but here is a ugly one by including the colormap as pixel values. imwrite should then lead to a correct result
%% your code
load('data.mat','X','Y','Z');
fig=figure("visible","on");
imagesc([X(1),X(end)],[Y(1),Y(end)],Z);
colorbar;
caxis([0,1])
axis equal
axis tight
% get max and min values and add the values to the right of your image
cm=linspace(max(Z,[],'all'),min(Z,[],'all'),size(Z,1))';
cm=repmat(cm,[1 round(0.1*size(Z,1))]);
% also add NaN values
newIm=[Z nan(size(cm)) cm];
% NaN values shall be seen as transparent ('as empty')
imAlpha=ones(size(newIm));
imAlpha(isnan(newIm))=0;
figure;
im=imagesc([X(1),X(end)*1.4],[Y(1),Y(end)],newIm,'AlphaData',imAlpha);
%colorbar();
%caxis([0,1])
axis equal
axis tight
% remove box and set xruler line to white to avoid visibility in the NaN
% gap
box off;
ax=gca;
ax.XRuler.Axle.ColorData = uint8([255,255,255,255])';
%% now we want also the ticks
ticks=0.1:0.1:0.9;
nrOfTicks=numel(ticks);
posX=size(newIm,2)*ones(nrOfTicks,1);
posY=round(size(Z,1)*ticks)';
posY=flip(posY);
colors=[repmat([1 1 1],[floor(nrOfTicks/2) 1]);repmat([0 0 0],[ceil(nrOfTicks/2) 1])]; % add color in black or white
% unfortunately this function changes newIm to an rgb image
newImWithTicks=insertText(newIm,[posX posY],ticks,'FontSize',130,'TextColor',colors,'BoxOpacity',0,'AnchorPoint','RightCenter');
newImWithTicks=rgb2gray(newImWithTicks);
figure; imagesc([X(1),X(end)*1.4],[Y(1),Y(end)],newImWithTicks,'AlphaData',imAlpha)
ax=gca;
ax.YAxis.TickLength = [0 0];
% imwrite .....
newImWithTicks=ind2rgb(uint8(mat2gray(newImWithTicks)*255),colormap());
imwrite(newImWithTicks,'exmpl.png','Alpha',imAlpha)
![](https://www.mathworks.com/matlabcentral/answers/uploaded_files/1065250/image.png)
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