Re: [Gimp-developer] jpg memory allocation - bugreport 555033

2008-10-04 Thread Sven Neumann
Hi,

On Sun, 2008-10-05 at 00:29 +0200, fremobit wrote:

> In my opinion the needed memory for an image of  the dimensions 15000px
> to 15000px at 8bit depth is 214,57MB but Gimp allocates 1,1 GB.

GIMP is not an image viewer, it is an image editor. As such it needs to
allocate not only the memory to hold the image data. It also needs to
hold the image's selection mask and the image projection plus a number
of scaled down versions of that projection. The latter are needed for
accurate and efficient display of the zoomed out image. Depending on the
image type, this easily sums up to more then 10 bytes per pixel for a
single-layered image.

For a grayscale image, as in your example, the factor is about 4.666 (1
byte layer data, 1 byte selection mask, 2 bytes for the grayscale-alpha
projection multiplied by 1.333 to account for the tile pyramid).


Sven


___
Gimp-developer mailing list
Gimp-developer@lists.XCF.Berkeley.EDU
https://lists.XCF.Berkeley.EDU/mailman/listinfo/gimp-developer


Re: [Gimp-developer] jpg memory allocation - bugreport 555033

2008-10-04 Thread Daniel Hornung
On Sunday 05 October 2008, fremobit wrote:
> In my opinion the needed memory for an image of  the dimensions 15000px
> to 15000px at 8bit depth is 214,57MB but Gimp allocates 1,1 GB.

This is an old discussion, but your case seems simpler than the usual 
discussion/guesses: 8 bit means 8 bit per 
channel (RGB, and in some cases also alpha)

215MB sound as if you did calculations for an image with only one channel, 
such as a grayscale image.


signature.asc
Description: This is a digitally signed message part.
___
Gimp-developer mailing list
Gimp-developer@lists.XCF.Berkeley.EDU
https://lists.XCF.Berkeley.EDU/mailman/listinfo/gimp-developer


[Gimp-developer] jpg memory allocation - bugreport 555033

2008-10-04 Thread fremobit
for the interrested http://bugzilla.gnome.org/show_bug.cgi?id=555033

As stated by Sven Neumann that a bug report on this issue might be the
wrong attemption to clear this issue I'll try my luck with this list.
As written in the bug report, 555033, gimp tries to allocate more memory
than it mathematically needs to.
In my opinion the needed memory for an image of  the dimensions 15000px
to 15000px at 8bit depth is 214,57MB but Gimp allocates 1,1 GB.

Any Suggestions ?

Thanks in advance.
Uwe Liebrenz
___
Gimp-developer mailing list
Gimp-developer@lists.XCF.Berkeley.EDU
https://lists.XCF.Berkeley.EDU/mailman/listinfo/gimp-developer