Legacy ImageMagick Discussions Archive

For lossless JPEG rotation, a program needs to manipulate the data directly in the JPEG image file.

Is this still true? so I need directly call api of libjpeg other than IM?

I have some questions
1 Does it mean the cloned image is Copy-on-write or only reference to pixle data which looks like a reference pointer?
2 what is meaning of "registry"? I assume

Thanks
Chang

I spend a time on ConstituteImage, and found it eventually allocates the memory(line 4019 of cache.c) for the supplied pixel data .

My program will work on a memory limited system. I hope such memory allocation can be eliminated, is it possible?

Thanks
-Chang

If I can get a small but very distinct example image(s) to play with, I'll see about putting an example of this in Photo Handling in IM Examples hi anthony could you try left part of this image "http://www.naturescapes.net/062004/Figure1.jpg" to show how to use sigmoidal-contrast for adjusting ...

Hi kent

we are looking for such optimizaiton libraries for IM, where can i download the optimizated version for evaluation?

thanks
chang

Hi All

I have a memory section which is BGRA32 format, I know its width and height, how do I create an Image?

it looks like that BlobToImage won't work.

Any idea?

Thanks
Chang

Hi
Does anyone has experience on improving png decoder optimization by either changing libpng build parameter or IM options. from what i test, IM is much slower(1.25~1.6 times) than WIC in case of decoding larger PNG file(3000X2000).

thanks
Chang

Hi All

From http://www.imagemagick.org/Usage/thumbnails/, IM has a special optimization for jpeg, i.e. -define jpeg:size.

Is there corresponding optimization for tiff and png?

Thanks

The JPEG file that i used is very popular, and comes from Nikon D70s, I can extract the exif thumbnail from jhead with the same file.

where is the documentation about thumbnail:

thanks

• convert image.jpg thumbnail:thumb.jpg

[/quote]

it doesn't work

I took a look at code, it looks like that covert doesn't process the last parameter, it always treat it as output filename.

-Chang

Does IM support extracting exif thumbnail from tiff and jpeg?

I search the forum and documentation but can't find solution.

Thanks
Chang