I have a simple code to show an image in Matlab. I use imread() to read it and imshow() to show it. the code it below, and the result in not shown properly. hope someone can help me.
img = imread('/home/samuelpedro/Desktop/API - Projecto/coimbra_aerea.jpg');
figure, imshow(img);
the resulting image is below.
also, if i choose to save it to file as a new jpg it is saved correctly.
UPDATE 1:
weirdly if i choose to show the axes in the preferences>image processing, it is corrected
Locking at your screen-shot, the x- and y-ticks are missing. They should appear in a standard-configuration of Matlab. Maybe something is just messed up in the Matlab-configuration. Try to do this with a clean new ~/.matlab folder (rename the old one before).
Alternatively ... again judging by your screen-shot, this looks like Ubuntu/Unity in the background. Unity needs acceleration (OpenGL), which can be randomly buggy for some Linux graphics drivers. You may want to try to launch matlab in a "clean" X-server (maybe the twm environment) to rule this out.
Save the image as an (uncompressed) bitmap (bmp) and read it with imread. If the jpg is messed up by the imread-routine, this should rule this out.
Last but not least, broken copy of your jpg on your disk, some flipped bits. Run md5sums on your file's copies.
Related
I am asking for a solution to the blurred image I get when I use copy figure option in Matlab. For example, when I plot 3d figure in matlab I get the following image (It is the result of printscreen!)..
However, when I use the option copy figure I get a blurred image as the following image
.
How can I avoid this as I need to get high resolution image using copy figure option. Thank you in advance for any help you may lend.
By default, the figure is copied as an Enhanced Metafile (a color graphics format) which works for basic plots such as bar plots, line plots, and other 2D plots but may yield undesirable results for more complex plots as in your case. This is because the rendering of the Metafile content is controlled my Microsoft Word and it may render things differently than MATLAB.
If you need a high resolution image, I would recommend using the print command where you can specify the desired resolution (using the -r option). Then you can import the resulting image into Word
print(gcf, 'myfile.png', '-dpng', '-r300')
Alternately, you can use export_fig from the File Exchange which better preserves the appearance
Another option would be to change the format used by Copy Figure to tell it to use a bitmap instead
Or you can call Copy Figure programmatically and specify a different format (either a bitmap or PDF)
print(gcf, '-clipboard', '-dpdf')
I normally save my matlab figures as .eps and then make them better looking using Adobe Illustrator. This works for most figures but not all.
For example I plotted my data using the violin.m function from file exchange. When I save it as .eps and open it in Illustrator, I don't get an editable figure as I usually do. Instead, My figure appears chopped in horizontal sections, and all I can do is delete them (like in the figure below).
Is there anything I can do in either matlab or Illustrator to be able to edit the figure?
I don't need an .eps file, I just need to be able to edit it.
EDITS:
I tried #MattSchmatt's suggestion of using the print2eps function but I had the same problem.
Saving as .pdf doesn't solve the problem, because the image I get is not editable in Illustrator (plus, I also get the horizontal 'chunks').
A minimal, complete and verifiable example requires matlab, the violin function linked above and illustrator. But if it helps, here's the matlab code to produce a similar figure. I save by clicking on Figure -> save as. (But as I said above I tried the print2eps function and that was the same).
X = rand(100,6);
figure; violin(X)
I tried the following, didn't work either.
set(gcf, 'Renderer', 'painters')
As the author of the question suggests, I also wasn't able to export an editable (vectorized) .eps file into Illustrator. However, exporting it as .pdf does the trick. The 'fill' for the violin plots is weird, though, and has horizontal sections (perhaps something to do with the way the density estimate is being plotted?) all over. I was able to fix this and make the plots normal (with solid filled shades): select all the horizontal sections/chunks using the magic wand tool, and then increase opacity to 100% (it is set to 50 based on the exported file). Once all the required edits are made, export the file as .tiff and it seems to look fine. Hope this replicates, and thus helps! (my MATLAB version is 2016, and Illustrator version is the CS5)
I'm using the still undocumented HG2-Update to create my MATLAB plots, because they just look that much nicer.
(Source: Yair Altman)
Actually, using the current version Release 2013b it works quite nicely and there are not much issues. Except one wants to export the figures as vector graphics (renderer: '-painters'), especially as pdf.
I use the commands:
saveas(gcf,'test.pdf','pdf')
or
print(gcf,'test.pdf','-dpdf')
There are rendering issues, the print does not contain the whole figure and some parts are cropped or non-default fonts are not recognized.
But I'd really like to stay with HG2 and I'd still like to use vector graphics. Is there any solution or workaround?
Exporting vector graphics using the yet not official HG2-Update is quite an issue. The .pdf-export is still totally screwed up.
What is working fine is the .svg-export, apart from that the boundary box is not set properly.
The long workaround would be:
Save the plot with '-dsvg' (print-command) or 'svg' (saveas-command) as vector graphic, open the file in the open source application Inkscape and save again as .pdf with the Export area is drawing checkmark set.
Quite complicated, so I found a way to do it via command-line directly from Matlab (Inkscape still required!):
filename = 'test';
inkscapepath = '"C:\Program Files (x86)\Inkscape\inkscape.exe"';
%// save as .svg
saveas(gcf,filename,'svg')
%// open and save with "export-area-drawing" set via command line
system( [inkscapepath ' ' filename ...
'.svg --export-area-drawing --export-pdf=' filename '.pdf'])
It takes some time, but works without any known issues for now.
Additionally delete the svg-File afterwards:
delete([filename '.svg'])
I had the same problem and used the workaround from thewaywewalk. Now I discovered the MATLAB function "hgexport" works under HG2 (in R2014a).
An issue still was the paper size. I want to use the same size for all graphs with as little white frame as possible. Here you have to set two sizes:
The papersize is set with set(gcf,'PaperSize',[width height]) and the size of your chart is set through export styles. These are set in "Export Setup" or command line:
exp_style=hgexport('readstyle','default');
exp_style.Width = 'width';
exp_style.Height = 'height';
exp_style.Renderer = 'painters';
Now you can export your pdf:
hgexport(gcf,'pdfname',exp_style,'Format','pdf');
PS: In HG2 you may also use Latex for tick labels:
set(gca,'TickLabelInterpreter','latex');
I'm very new to Matlab, though I know a few other programming languages, so please forgive me if this is something simple. I have not been able to find any answers to this, either on StackOverflow or elsewhere.
I produce a figure using the following code:
figure(6),imageplot(P); drawnow;
Which looks like this:
I then save this image to my computer using the following commands:
imwrite(P, 'images/plot.png');
And the resulting image is tiny, and missing some of the color information:
If, however, I utilize the save function in the open figure (image #1) and save it manually, I get exactly what I want, which is that exact image stored on my computer.
How would I program that? I assumed that imwrite() would just write the image directly, but apparently I'm doing something wrong. Any advice? Perhaps it has something to do with the imageplot command? I cannot seem to get that to work in imwrite.
Update: Based on the comments below, I have begun using "imresize" with the "nearest" option. This scales the image properly, but the resulting image is still curiously darker (and therefore has less information) than if I hit the "save" button in the figure.
Image saved from figure:
Image using "imresize" with "nearest" option:
The MATLAB imwrite command saves exactly the number of pixels as specified in your image matrix. This is the actual result of your computation; the reason the output is "tiny" is because it is supposed to be. To make it larger, would be to simply scale/zoom it as required.
The save figure option however does something quite different: it rasterizes the the output you obtain in the figure window and gives you the option for saving it as an image. This is evident in the fact that when you do so, you obtain a white background in addition to your result which is really just the grey background you see before you save it; this can be adjusted by resizing the figure window before utilizing the save option.
If you're looking to simply make the output figure larger, I would recommend using something along the lines of the imresize command.
Say, if you want the default size to be twice the size of the real result, simply use:
imresize(P, 2.0);
For more options, try help imresize.
The command you need for the "Save As..." functionality of figures is called "print". I often use
print(gcf, '-dpng', 'some_filename.png')
or
print(gcf, '-depsc', 'some_filename.eps','-r0')
to save a figure as it is shown on screen. The format png offers a small filesize and excellent quality, and it is understood by most image viewers and browsers. The eps format is a vector format, which I use for printig. The '-r0' option specifies "use the same size as given by the screen resolution" for the vector format properties.
Is there any way to print the figure to the clipboard so that the quality is identical to what the Edit-->Copy Figure option provides?
I used to save the figure to powerpoint file by using saveppt.m obtained from Matlab Central. It worked well until yesterday. I noticed that the stored image quality was somehow degraded. I tried to re-generate some ppt slides with exactly the same script and the same source data, but the new slides are simply of worse quality.
I investigated into this problem a little bit and discovered that when the figure is copied to clipboard by running print -dmeta, the image in the clipboard is already degraded, while if I use the Edit-->Copy Figure option in the figure window, I get the image as clear as the original image in the figure window.
Following is an example for your reference. I copied the image from a figure to the clipboard by two different methods, and paste it to Microsoft Paint program, and cut a piece of it to show below:
The image using print -dmeta:
The image using Edit-->Copy Figure:
If you compare the Xtick label '50', you may see that the image from Edit-->Copy Figure is smoother.
At the beginning I thought it was a problem of the resolution, but setting -rN to change the resolution does not seem to resolve my problem, at least not for N<=300.
Thank you for your help.
The short answer... Use the same function invoked in the callback for that menu item:
editmenufcn(gcf,'EditCopyFigure');
The longer answer... How exactly did I find this? You can look at my previous answer to a related question about reproducing what is done by a File menu option. The concept is the same, just for a different figure menu. For example, this will find the callback you want for the currently active figure window:
>> hCopyFigure = findall(gcf,'Label','Copy &Figure'); %# Handle for the "Copy
%# Figure" menu item
>> get(hCopyFigure,'Callback') %# Callback invoked when that item is selected
ans =
editmenufcn(gcbf,'EditCopyFigure')
The function EDITMENUFCN is another one of those sparsely documented functions, but looking through the code (by typing edit editmenufcn.m) shows that it either invokes Java (if you're on a Mac) or the undocumented function UIMENUFCN.
I think I found the answer myself. Using print -dmeta -painters to specify the renderer resolves my problem.
In File-->Preference-->Figure Copy Template-->Copy Option I noticed there are 3 options:
Metafile
Preserve information
Bitmap
I found that if I select 1, the Edit-->Copy Figure outputs the same image as print -dmeta. So I kind of confirmed the information I need is in the Preserve information option. A quick google search led me to the discussion about the potential difference of the applied renderer, and eventually I confirmed that using painters will print the image to the clipboard in the way I wanted.
The image in the question seems to be generated by the renderer zbuffer and painters, respectively. I still don't know why the default renderer of paint -dmeta changes, though.