I have a problem with animation, using Octave 4.0.3 in Windows. Below is a very simple by-way-of-example
program of what I would eventually like to do. I will be creating a time-dependent evolution of
electric field plots versus time and I would like to make a movie of it. I have successfully used
the comet and comet3 functions in Octave and that works just fine, but I want to make a movie
that I can have on a file for a PowerPoint presentation. Now, you can get presentations by using
a *.gif file. If you think that this is not so good, that I should use another file type, then I will use
that one, but for now I’ll use *.gif .
Someone on Google suggested creating a series of plots versus time and writing each plot as a separate
page on a *.pdf file. The *.pdf file would contain, say, 1000 pages of one plot per page, then somehow
playing them back, one after the other, making a movie. Once the *.pdf was created, I could
use imread to input the *.pdf images into an image array, im. And imwrite would be used next to output
the im array to a *.gif file, thus, converting the *.pdf file to a *.gif file. The following script
is a very simple one to do this, but it does not work. I must tell you that I have tried many permutations
of function parameters, perhaps getting different errors. The following response has been the cleanest
error report of all that I’ve tried.
First, I installed Octave 4.0.3 by using the binary installer for Windows (I have two machines, Windows 7
and Windows 8.1).
Then I gave up on the imread built-in function in the Octave library and use Andy Adler’s version, which
gives less errors, but I still draw one error that I don’t understand. Adler’s version is the one that was
last modified 1 July 2008 by Thomas Scofield.
Here is my script, called animation00.m
x = (-5:.1:5);
for p = 1:5
plot (x, x.^p)
print 'C:\Octave\Octave-4.0.3\bin\animation.pdf' -append
endfor
z = 1.0
im = zeros(1:5);
z = 2.0
%system ('gm identify ./subset.pdf')
im = imread('C:\Octave\Octave-4.0.3\bin\animation.pdf');
z = 2.0
imwrite(im,'C:\Octave\Octave-4.0.3\bin\animation.gif',...
'gif','writemode','append','DelayTime',0)
z = 3.0
The z’s were put in to let me know where the code had progressed to.
The first loop worked just fine and created the multi-plot file. I have attached
all relevant files. I have tried it with and without the
im = zeros(1:5);
part, but I
get the same error. This is the error:
animation00
'identify' is not recognized as an internal or external command,
operable program or batch file.
z = 1
z = 2
error: imread: error running ImageMagick's 'identify' on C:\Octave\Octa
ve-4.0.3\bin\animation.pdf
error: called from
imread at line 86 column 7
animation00 at line 17 column 4
>>
Keep in mind, if the use the built-in version of imread I just get other
errors when I use the built-in version, such as:
>> animation00
z = 1
z = 2
warning: your version of GraphicsMagick limits images to 16 bits per pixel
warning: called from
imformats>default_formats at line 256 column 11
imformats at line 79 column 3
imageIO at line 106 column 11
imread at line 106 column 30
animation00 at line 17 column 4
error: Magick++ exception: Magick: Unable to access configuration file
(delegates.mgk) reported by magick/blob.c:1919 (GetConfigureBlob)
error: called from
__imread__ at line 86 column 10
imageIO at line 117 column 26
imread at line 106 column 30
animation00 at line 17 column 4
>>
In either case, the *.pdf file is successfully written the way I want it.
And I haven’t even gotten to the imwrite line yet.
Lee
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commitment to excellence, regardless of his chosen field
of endeavor.” –late Green Packer coach, Vince Lombardi
Leland Herder, Ph. D.
Colorado Springs, CO
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