Re: Using Imager module to resample images

On Tue, 29 Jan 2008 03:08:11 -0800 (PST), Jason Carlton
<jwcarlton@xxxxxxxxx> wrote:

I've been forcing my visitors to resample their images manually to
keep them below 50kb, but this has only had so-so results. A lot of my
visitors don't understand how to resample their image, so I'm getting
high-resolution images that are something like 20px x 20px, but still
take up 50kb!

So, I've been thinking about resampling the images on the fly. The
images would be restricted to JPG, JPEG, GIF, and PNG.

I was planning to use a combination of Image::Resize and Imager, which
I've never used before, but since the load on the server is ALWAYS
high, I had a few questions first:

1. Will the use of Imager take up a lot of CPU resources?

Never noticed an excessive cpu usage, but check it yourself.

2. How do I recognize an animated GIF from a static GIF?

I believe it's safe to assume a static gif begins with GIF87, and
an animated with GIF89. But I'm not sure it's an absolute.

3. Does Imager compress JPG images automatically? I didn't see an
option to set a compression level in the docs, but it may be called
something else that I'm not recognizing.

4. I assume that I'll need to use Image::Resize to get the current
width and height, and if it exceeds the maximum that I input then I'll
use Imager to resample it. Is there a smarter (read: simpler and/or
less resource-heavy) option that this?

Your best bet is to read
perldoc Imager::Files for the jpegquality parameter
perldoc Imager::Transformations for converting and scaling
perldoc Imager::ImageTypes
perldoc Imager will give an overview

Also http://groups.google.com will have many examples.
Search for things like:
"perl Imager resize", etc

zentara


Jason

--
I'm not really a human, but I play one on earth.
http://zentara.net/japh.html
.

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