How to speed up to load enlarge TIFF File

[diuming]

Dear Master,

I had 4 TIFF files (C,M,Y,K) (1-bit TIFF, 63307x52914 pixels, 2400 DPI) that I want to resample each file to 300 DPI and then compose 4 channels file to a file.

I using convert command with -monitor option to monitor image processing status.

./convert -monitor -resample 300x300 Imput.TIF Output.jpg

Load/Image --> spent 3 mins
Resize/Image --> over 10 mins
The output file Can't finished.

How to improve this processing, If I want to develop with MagickCore which methods is appropriate to me.

My hardware profile :
4G Ram, 2.93GHz Intel Core 2Duo, Snow Leopard 10.6.5

Does ImageMagick have any plan to release a book about programming in ImageMagick (C language)

Thank you so much.

[diuming]

IM Version : 6.6.7-0

thanks

[anthony]

That really does seem slow. Expecially as it is slower for a CPU intensive operation, rather tha the Image decoding operation.

Hmm considering the image size I think you are running out of memory to hold the image!
That means it will need to switch image processing to using very very slow disk caching.

See IM Examples, Really Massive Image Handling
http://www.imagemagick.org/Usage/files/#massive

[diuming]

Wow, Thanks for quickly reply!!

[foxyshadis]

In this case, the Q8 version would be better than the Q16, since it'll halve the memory and some of the processing required. (Everything is natively stored in expanded 8- or 16-bit in memory, even if it's only 1-bit packed on disk.) You might have to use some form of partitioning, but it would be ugly: 4x load->crop->save->load->resample->save, then stitch.