png export dpi problem

[kevinwalker]

I export PNG's without transparency

it is ok up to 300 percent to export

after 400 the program exports the png but photoshop cannot open the file "cannot open the file because of the program error"

[Karl DD]

I noticed that when exporting to bigger sizes, the whole thing shudders along but I didn't realise there was a hard limit at which the files get messed up.
Does the same thing happen with regular PNG or JPG?

[kevinwalker]

I did not get your question,

but no shudder or distortion happens at 300 percent. fine png and jpg s

but bigger than 300 do not work,

[Karl DD]

I tried it now on mac and I managed to export a transparent PNG at 400%.
What platform and version of Java are you using?
What is the size (in pixels) of the image?

[kevinwalker]

windows xp sp3

image size 10080 x 5706

Java 6 update 13

[Karl DD]

Hi Kevin,

I tried it and on mac it doesn't even create an image. I get a OutOfMemoryError.
So I figure that is probably what is happening on your end as well, only it is creating a dud file. I imagine the file is probably quite small in size?

Anyway, to do a bit of math...

Image size: 10080 x 5706 = 57,516,480 pixels
Byte count: 57,516,480 x 4 = 230,065,920 bytes (each pixels takes 4 bytes)
Megabytes: 219.4 meg

So right now we set the available to between 128 - 512 meg.
I bumped up the memory to max 1 gig, and managed to export to that size. But when 'profiling' the amount of memory used, I noticed that it was consuming as much as 600 meg rather than 219.4 meg... the mysteries of computing...

Anyway, the answer is to increase the amount of memory allocated to the Java Virtual Machine (JVM).
People get a bit concerned when applications start chewing up memory, so we have to be a bit careful.
I've uploaded a debug version of Alchemy 008 that has the 1 gig maximum. Give it a try and see if that solves the problem.
http://al.chemy.org/files/Alchemy-008-Debug.zip

Karl

[kevinwalker]

thanks a lot
now I am able to export 10.000 pixel wide png's