[Ipe-discuss] Performance and file-size with embedded images

Nikolaus Rath nrath at trialphaenergy.com
Sat Oct 29 00:17:12 CEST 2016

Hi Otfried,

Thanks for the quick response! These are line plots, so they should 
compress very well. Each individual image is between 100 kB and 300 kB.

I'm on Linux 4.7 and ipe 7.1.8, and there is plenty of memory available 
(32 GB total, 2.3 GB free (not including buffered/cached)).

I'll send you the document in a private email.


On 10/28/2016 03:00 PM, Otfried Cheong wrote:
> When you increase the resolution in both x- and y-direction by a factor
> three, the number of pixels increases by a factor nine. That seems
> pretty much in line with your numbers.
> What kind of pictures are these? Apparently they do not compress well.
> You couldn't use JPG images?
> You don't say what OS you are on. The drastic slow-down might be because
> Ipe doesn't get enough memory to keep everything in memory and starts
> thrashing. But this is definitely something that should be investigated:
> When you select an image, it does not get redrawn, and the backing
> bitmap should not need to be accessed.
> Would you be willing to upload your document somewhere so I can have a
> look?
> Cheers,
>   Otfried
> On Fri, Oct 28, 2016, at 23:31, Nikolaus Rath wrote:
>> Hello,
>> I have an ipe document that contains about 15 images in .png format,
>> rendered at 100 dpi. This document takes 16 MB as .pdf and 21 MB as
>> .ipe, and can be edited smoothly.
>> However, when I replace the images with higher resolutions (300 dpi),
>> then the file size changes to 183 MB for .ipe, and 135 MB for .pdf.
>> Furthermore, even just selecting an image with a single click takes
>> several seconds. The document becomes essentially un-editable.
>> Why is this? Shouldn't the file size grow at most by a factor of 3, if
>> the image resolution is increased by this factor? And why this extreme
>> slowdown?
>> Thanks,
>> -Nikolaus
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Nikolaus Rath, Ph.D.
Senior Scientist
Tri Alpha Energy, Inc.
+1 949 830 2117 ext 211

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