Re: Image scaling

On Sat, 20 Aug 2005, [iso-8859-2] Micha³ Kowalczuk wrote:

> Hello,
> I have a question - I need to scale large image (e.g. 10000x10000pix) in C.
> Its Format is unknown (it may be PNG, GIF, BMP or TIFF). The way I'm doing it
> is:
>
> im_in_gm = BlobToImage(image_info, mem_in, *size, &exception);
> im_out_gm = SampleImage(im_in_gm, 150, 150, &exception);
>
> but it consumes a lot of memory.
>
> Is there any way to load image to a image buffer 150x150, that has been set up
> before loading image to memory to avoid such behaviour?

While the SampleImage() algorithm is very simple, there is not 
currently a way to perform re-sampling while an image is read.  This 
is an interesting idea, but difficult to implement within 
GraphicsMagick.

You might want to take a look at VIPS 
(http://www.vips.ecs.soton.ac.uk/) since it supports incremental 
processing of images while they are being transcoded.  VIPS is less 
convenient to use than GraphicsMagick since it is research-oriented 
software.

Bob
======================================
Bob Friesenhahn
[email protected], http://www.simplesystems.org/users/bfriesen/
GraphicsMagick Maintainer,    http://www.GraphicsMagick.org/