I need to use the webpage to display the thumbnail of the local image, golang as the server, call imageMagick to generate the thumbnail, can I do it directly in memory?
I only found the mpc parameter but don't know how to use
mpr：This format permits you to write to and read images from memory. The filename is the registry key. The image persists until you explicity delete it or the program exits.
https://www.imagemagick.org/Usage/files/#mpr
Thanks for the reply, I already know this can't be done.
#Steffen Ullrich,thanks for the recommendation.
I tried imagick but it wasn't ideal, it took almost 30s to read a 20m image,it only takes less than 2s to use convert.exe.
So I decided to generate the thumbnail first and then read it
Related
I have a folder with about 750'000 images. Some images will change over time and new images will also be added every now and then. The folder-structure is about 4-5 levels deep with a maximum of 70'000 images per one single folder.
I now want to write a script that can do the following:
Loop through all the files
Check if the file is new (has not yet been converted) or changed since the last conversion
Convert the file from jpg or png to webp if above rules apply
My current solution is a python script that writes the conversion-times into a sqlite database. It works, but is really slow. I also thought about doing it in PowerShell due to better performance (I assume) but had no efficient way of storing the conversion-times.
What language would you recommend? Is there another way to convert jpg to webp without having to exernally call the command cwebp from within my script?
I have several 100,000 images that were sometimes copied incorrectly during a copy operation. Therefore, before training a neural network, all images must be checked.
So far I just use imread() and if it fails, I use try/catch to write the path of the corrupt image into a .csv file.
This works quite well, but it is also quite slow. Is there a way to check if an image file is corrupt using a faster method than imread()?
I'm generating animated GIF files from multiple source images using Ruby. I need to maximize throughput / minimize time spent to create each GIF. I'd prefer to keep the source images in memory (probably Memcached) rather than read them from disc every time I need them. I've been using convert in backticks to execute imagemagick commands directly from Ruby, e.g.
`convert -delay #{delay} -page #{w}x#{h}+0+0 src01.gif... etc`
I slightly prefer this over RMagick as I've found more examples, I can reference the ImageMagick docs directly. It seems that images passed to the convert command need to be paths to images on disc. Additionally it seems like the output of the convert commend is a file path so the generated image would be written to disc by ImageMagick and I'd need to read it back off disc using Ruby to access the resulting image data. It seems like I'm making ImageMagick read the source images from disc each time and write the generated GIF to disc each time. I think this is likely to be a bottleneck and unnecessary as I don't need to persist the generated images I just need to access their image data in Ruby momentarily.
I noticed that RMagick methods can take Magick::Images as parameters instead of filepaths. I could keep the source images in memory in this case. Additionally RMagick returns the generated image as data to Ruby which is what I need, I don't need it written to disc.
I'm thinking of using RMagick instead of
`convert...`
to reduce disc activity.
So question 1: Does this make sense though? Since RMagick presumably wraps ImageMagick, is RMagick actually reading and writing to disc under the hood or does it have some way of utilizing ImageMagick without disc activity?
And question 2: Is there any way to get image data in and out of ImageMagick's convert command without disc activity?
Hope this makes sense. Just trying to wrap my head around this and apologize if I'm unclear.
Does this make sense though?
Not really. We can argue about open fd's, and cost of shell environments over direct API, but there wouldn't be any disk I/O benefit between the convert utility & RMagick.
Is there any way to get image data in and out of ImageMagick's convert command without disc activity?
ImageMagick ships with stream utility. There's not much usage-documentation, but it could be leveraged to extract the image data to a blob that can be distributed via memcached.
There's also the mpr: protocol to handle label based memory access, but that might not be the distributed solution your looking for. Plus data is removed at time of process completion.
Personally, Marks comment about RAMdisk would be something I would recommend. A simple memory/tmpfs mount is easy to set-up on a system, and then it would just be a matter of updating policy.xml configuration to use said mount as a temporary directory.
I am using wkhtmltopdf on my ubuntu server to generate pdfs out of html-templates.
wkhtmltopdf is therefore started from a php-script with shell_exec.
My problem is, that I want to create up to 200 pdfs at (almost) the same time, which makes the runtime of wkhtmltopdf kind of stack for every pdf. One file needs 0.6 seconds, 15 files need 9 seconds.
My idea was to start wkhtmltopdf in a screen-session to decrease the runtime, but I can't make it work from php plus this might not make that much sense, because I want to additionally summarize all pdfs in one after creation, so I would have to check if every session is terminated?!
Do you have any ideas how I can decrease the runtime for this amount of pdfs or can you give me advice how to realize this correctly and smart with screen?
My script looks like the following:
loop up to 200times {
- get data for html-template from database
- fill template-string and write .html-file
- create pdf out of html-template via shell_exec("wkhtmltopdf....")
- delete template-file
}
merge all generated pdfs together to one and send it via mail
Thank you in advance and sorry for my bad english.
best wishes
Just create a single large HTML file and convert it in one pass instead of merging multiple PDFs afterwards.
I have a binary file that starts off with some data. After this data, the file has a JPEG image embedded in it. After the image, the file continues with some other data. I wish to use the image as an OpenGL texture.
At the moment, the only method I know of creating an OpenGL texture with Magick is to read the image file with Magick, write it into a blob, and upload the blob.data() to opengl (from this link: http://www.imagemagick.org/pipermail/magick-developers/2005-July/002276.html).
I am trying to use Magick++, but it only allows me to specify a filename, not a C-style filehandle or filestream...Are my only options the following? :
Save the JPEG image portion in the binary file as a separate temporary file and get Magick++ to read that image. I don't wish to do this as writing to disk will slow my program down.
Read the image portion into an array, create a Blob with the array as its data, and then read the Blob to obtain an image. I don't wish to do this either because after I get the image, I will need to again write the image data to another blob, and the entire code becomes unnecessarily long.
Switch to another library like DevIL, which offers support for what I want. Unfortunately, DevIL is not as feature rich as Magick.
I also looked into the core C API for Magick, where I can specify a filehandle, but the documentation says that the filehandle is closed by Magick after the image is read, which is definitely not good for my program (it is going to be pretty ugly to get the rest of my program to reopen the binary file to continue its processing...
If there is a way to provide Magick with custom I/O routines, or better still, a cleaner way of using Magick with OpenGL, please enlighten me!
The next release of GraphicsMagick does not close the input file handle after the image is read. You can try the latest development snapshot.
You could consider using mmap() (memory mapped file) to access the data and treat it as an in-memory BLOB using Magick++. The main issue with this is you might not know how long the data was in case you need to access data following the embedded JPEG image data.
It is trivial to add FILE* support to Magick++. The only reason I did not do so was for philosophical reasons (C++ vs C).