Legacy ImageMagick Discussions Archive

well So each convert gets a pixel cache of 256MB. Thank you for making it clear.

In http://www.imagemagick.org/script/architecture.php Note, the cache limits are global, meaning if you create several images, the combined resource requirements are compared to the limit to determine the pixel cache storage disposition Just want to double-check: given following configuration ...

yep your right I did as you said and got the code to work.

convert img.png -crop 1000x1000 -set "filename:t" "%[fx:page.y/256]" +repage +adjoin cropped_%[filename:t].png I would like to do some work after the first crop maybe another crop so I would like use something like convert img.png -crop 1000x1000 -set "filename:t" "%[fx:page.y/256]" +repage +adjoin ...

If I do a I get for a 20500x8000 img.png a 500M out.bmp

So can I conclude that when imagmagick reads the img.png in it uses about 500M RAM?

I would also assume that the second cmd is first putting all input images in memory.
there is probably no way to hint the first command to behave memory-wise like the second for loop command?
Since of a stream pipeline?

ping does not help.. also all cropped images are all black now....

I found out that this code is about 60% slower: convert image_*.png -background white -gravity center -extent 20400x -crop 400x400 -set "filename:data" "%t_%[fx:page.x/400]" +repage +adjoin "cropped_%[filename:data].png" than using a loop (pseudo code): for (y=0;y < 34;y++) { convert image_{y}.png ...

I am afraid if I ask such a question on the dev forum the guys will make fun of me ....
I quess it is just not possible

the option -quality 1 got me a 20% performance push! I am now with the cutting into stripes and using -quality 1 down to 38 secs...

that's what I am actually doing. I am calling convert from php. But since this is a server app with lots of io load it would be nice if I could save my script from generating those tmp files

I am achieving quite good results now if I preprocess the crop and cut the large image before in stripes. Because the stripes have for example only a height of 256 px the crop can use much less memory. Thanks glennrp for pointing out how important memory is for cropping. I tried to chain the ...

thanks In my use case it does make sense since I am using SQLite and am transferring the db over the net...

on convert -list I File Area Memory Map Disk Thread Throttle Time -------------------------------------------------------------------------------- 192 4.295GB 2GiB 4GiB unlimited 1 0 unlimited I tried a limit of 4GiB but got no improvement (even 5 secs worse) I read the link http://www.imagemagick ...

Can I somehow skip the writing to the filesytem and plug in to imagemagick and write directly to a database?