Author Topic: Blockiness at 100%  (Read 3283 times)

Offline drmrbrewer

  • Full Member
  • ***
  • Posts: 122
    • View Profile
Blockiness at 100%
« on: February 02, 2008, 11:17:46 PM »
When I have two adjacent images I want to compare at 100% (with similar compositions), I Ctrl-click on one to get to 100%, then roll the mouse wheel down and up a few times to flick back and forth.

Initially, when you change image, the image is blocky, before it is properly rendered.  That's understandable.  The good thing is that the 100% image then seems to be cached in some way, so that you can flick very quickly between the two without seeing the initial blockiness upon image change.

But, and this brings me to my question finally...

Sometimes the blockiness DOES return when I change the image.  I can't work out why.  Most of the time the transition is clean, but sometimes PM seems to think it necessary to show the blocks and then the detail, as if it has lost its cached copy.

Why is that?  Makes image comparisons in this way a little irritating sometimes.  I know I can do a side-by-side comparison, but sometimes it's just more convenient just to flick back and forth between two images at 100% in full view.

Thanks,

Mike

Offline Kirk Baker

  • Senior Software Engineer
  • Camera Bits Staff
  • Superhero Member
  • *****
  • Posts: 24756
    • View Profile
    • Camera Bits, Inc.
Re: Blockiness at 100%
« Reply #1 on: February 03, 2008, 01:09:10 AM »
Mike,

When I have two adjacent images I want to compare at 100% (with similar compositions), I Ctrl-click on one to get to 100%, then roll the mouse wheel down and up a few times to flick back and forth.

Initially, when you change image, the image is blocky, before it is properly rendered.  That's understandable.  The good thing is that the 100% image then seems to be cached in some way, so that you can flick very quickly between the two without seeing the initial blockiness upon image change.

But, and this brings me to my question finally...

Sometimes the blockiness DOES return when I change the image.  I can't work out why.  Most of the time the transition is clean, but sometimes PM seems to think it necessary to show the blocks and then the detail, as if it has lost its cached copy.

Why is that?  Makes image comparisons in this way a little irritating sometimes.  I know I can do a side-by-side comparison, but sometimes it's just more convenient just to flick back and forth between two images at 100% in full view.

You'll need to increase Photo Mechanic's Memory Cache size.  The default is 64 MB which is fairly small.  Try increasing it to 128 MB.  If you have a lot of RAM on your system, you can increase it further.  You'll get diminishing returns beyond 1024 MB.

-Kirk


Offline drmrbrewer

  • Full Member
  • ***
  • Posts: 122
    • View Profile
Re: Blockiness at 100%
« Reply #2 on: February 03, 2008, 02:14:22 AM »
Thanks for the quick reply, Kirk, and at a weekend too ;)

I'll try what you say.  Before that... what interests me is that when I'm flicking between two images, the transition is clean, and then... for the SAME two images (without straying onto another)... the blockiness returns suddenly.  Even if the cache were too small, surely it was big enough to store data for those two images, and so it should be big enough to keep hold of that data... I'm only flicking between the same two images, and I'm not trying to load new data for a new image.  Why does it suddenly decide it needs to re-render when it's been happy for a number of transitions?

Mike


Offline Kirk Baker

  • Senior Software Engineer
  • Camera Bits Staff
  • Superhero Member
  • *****
  • Posts: 24756
    • View Profile
    • Camera Bits, Inc.
Re: Blockiness at 100%
« Reply #3 on: February 03, 2008, 02:20:36 AM »
Mike,

Thanks for the quick reply, Kirk, and at a weekend too ;)

I'll try what you say.  Before that... what interests me is that when I'm flicking between two images, the transition is clean, and then... for the SAME two images (without straying onto another)... the blockiness returns suddenly.  Even if the cache were too small, surely it was big enough to store data for those two images, and so it should be big enough to keep hold of that data... I'm only flicking between the same two images, and I'm not trying to load new data for a new image.  Why does it suddenly decide it needs to re-render when it's been happy for a number of transitions?

Photo Mechanic is also caching other images at 100% in the 'direction' you're viewing images.  Those other images that are being cached are very likely using up the remaining memory cache space.

-Kirk


Offline drmrbrewer

  • Full Member
  • ***
  • Posts: 122
    • View Profile
Re: Blockiness at 100%
« Reply #4 on: February 03, 2008, 06:55:33 AM »
Kirk, makes perfect sense. 

I've increased it now to 256 MB and there is a definite improvement.

Thanks,

Mike