'image()' always creates png - but I do need jpg

Wednesday 01 June 2005 11:02:17 am

Hello!

I got ez Publish 3.5.2. on SuSE Linux 9.0.
The following code creates an PNG image:

{let postkarte=imagefile('design/gallery/images/logo.jpg')}
 {image($postkarte)}
{ /let}

But as the Source File is JPG - I do need JPG as output. (Because PNG looses qualitiy!)

in my image.ini I got:

[OutputSettings]
AllowedOutputFormat[]
AllowedOutputFormat[]=image/jpeg
AllowedOutputFormat[]=image/png
AllowedOutputFormat[]=image/gif

[MIMETypeSettings]
ConversionRules[]
ConversionRules[]=image/gif;image/png
ConversionRules[]=image/jpeg;image/jpeg
ConversionRules[]=image/x-xpixmap;image/jpeg
ConversionRules[]=*;image/jpeg

I tried ImageMagick, GD2 and GD... the Result has always been PNG

Can anyone help?

Thursday 02 June 2005 3:25:56 am

Hey,

I didn't see anyone else reply so I thought I would take a moment to think aloud about your situation.

In my experience jpeg has always held a higher resolution and general quality for certain kinds of images. No wonder that most manufacturers use jpeg for digital cameras.

So I think a jpeg to png conversion + eZ publish quality settings could be the root of your problems.

An example improvement you might consider making is in an override of the image.ini setting :
<i>settings/override/image.ini.append.php</i>

[MIMETypeSettings]
# A list of mimetypes and their image quality value
# The value varies from mime type to mime type.
Quality[]
# Set JPEG quality from 0 (worst quality, smallest file) to 100 (best quality, biggest file)
# Quality[]=image/jpeg;75
Quality[]=image/jpeg;100

ConversionRules[]
# Fallback, try to force jpeg to jpeg converstions instead of jpeg to png 
ConversionRules[]=image/jpeg;image/jpeg

Let me know if this helps any..

:| kracker
<i>Fiona Apple : Mistake</i>

Member since: 2001.07.13 || http://ezpedia.se7enx.com/

Thursday 02 June 2005 9:29:00 am

Thank You! I'm afraid I can't use the oroginal file, bacause this is just the first step!

In the next step I'd like to merge two images (two JPGs) - which works fine with the image()-operator, but the qualitiy is very poor....

Thursday 02 June 2005 5:46:55 pm

well...

I have been tearing through the lib/ code assocaiated with the actual createion of the image, adding quality controll tests which have not produced beter results.

Have found this very interesting bits of documentaiton regarding this.

See:

"ImageJPEG" in <i>http://us4.php.net/imageJPEG</i>
<i>http://forums.devarticles.com/archive/t-5678/resize-pics-makes-poor-quality
http://www.nyphp.org/content/presentations/GDintro/gd8.php</i>

One guy in the php.net documentation had this to say about quality of using GD image manipulation (fyi what version of GD are you using? this makes a difference)

gzink at zinkconsulting dot com
01-Jan-2004 04:17
Don't forget that JPEG compression has artifacts! And they're not all really obvious. The PHP JPEG compression is pretty decent, but it seems to generally:

-Lighten the image overall, by a reasonable amount (never seen this before, but it will drive graphic designers crazy, you might want to darken the image before compressing it)
-Reduce saturation, especially with images with lots of points of different color within a few pixels of each other (this is a documented feature of JPEG)
-Seriously mess with blue colors, which is common to all JPEG but really annoying in some situations with blue and black or other detailed blue parts

You might want to consider using imagepng() and outputting a PNG image instead of a JPEG if any of the above affect you, or your image is not very photo-like. Sometimes I have an algorithm compare JPEG to PNG for an image and send the smaller version to the user.

Also, when using imagepng(), you should use imageinterlace() before it 95% of the time. Interlaced JPEGs load progressively, improving in quality as the image loads, so users on slower connections see the whole image at low quality. All this happens without affecting the file size (actually, sometimes the file size is smaller!) or final quality.

Hope this helps a few people out. It's not all that obvious without lots of playing around.

I only bring up these references because 1) I am not coming up with a simple solution so I'm reverting to telling you everything and leaving the details in the <i>open</i> so you can perhaps pickup where I falter or fail.

I'd also like to note that I experience similar quality degradation even when I hack in static code to replace the key areas which generate the image.

I get varying degree's of quality per original, meaning for a red image i get a red haze on the whole image after it goes through the image() operator, if it's a white image i get a white haze.

So I think the quality setting really is not the key here. I think it has to do with the subsystem used specifically. Which pushes all of this just one more step outside the realm of my understanding and abilities.

I wonder if imagemagic can do a better job in this situation, how would one test each for differences ie force it to use image magic instead of gd?

Best wishes,
//kracker
<i>Buck 65 : Bandits</i>

For those who read the forum a lot, this topic was brought up previously ...
but I couldn't find the thread, but we have gone as far as it ever did I think :|

Member since: 2001.07.13 || http://ezpedia.se7enx.com/

Thursday 02 June 2005 7:16:49 pm

<b>End Game : Solutions</b>

I found a solution that I consider very acceptable. I don't exactly know which image system was being used before (I guess imagemagic as I don't think even had GD installed at all) but this is what I did ...

1. Checked my server's apache/php configuration by reviewing phpinfo();

2. Installed GD2 (v2.0.28, needs to be at least v2.0.1 using yum/rpm)

3. Enabled these setting in <i>settings/override/image.ini.append.php</i>

[GDSettings]
# If set to true more advanced functionality will be available
# which is present in GD2. This requires GD2 to be compiled in
# the PHP module. HasGD2=false
HasGD2=true

[MIMETypeSettings]
# A list of mimetypes and their image quality value
# The value varies from mime type to mime type.

Quality[]
# Set JPEG quality from 0 (worst quality, smallest file) to 100 (best quality, biggest file)
# Quality[]=image/jpeg;75
Quality[]=image/jpeg;100
Quality[]=image/jpg;100

I can't even begin to tell you how <i>amazing</i> GD2 jpg output looks using the image() operator. This should be turned into a solid faq / article in the future.

4. Add a setting to make the image operator which defaults to png in a hard coded (static) fashion for the outputted image to instead use an setting just before the image is created (dynamic).
<i>lib/eztemplate/classes/eztemplateimageoperator.php</i>

Make this an ini setting by adding these lines into the modify() function in the same file instead. Be sure to create the an override: settings/override/texttoimage.ini.append.php
With the following settings to make this a modular setting:

[ImageSettings]
UseCache=enabled
DefaultImageOperatorFormat=png
#DefaultImageOperatorFormat=jpg

Search for this code:

else if ( $operatorName == 'image' )
        {
            $useCache = $this->UseCache;

And insert the following just after $useCache.

$ini =& eZINI::instance( 'texttoimage.ini' );
            $StoreAs = $ini->variable( "ImageSettings", "DefaultImageOperatorFormat" );
            $this->StoreAs = $StoreAs;

5. In the end I see that on some of my full resolution images output by the image() template operator are of greater quality using png instead of jpg, especially images which start as jpg originals and are converted to png. Odd I know but GD2 does an even better quality job with png than jpg (IMHO). So I switched my setting back to the DefaultImageOperatorFormat=png

Thanks for the fun, I learned a lot! Here's hoping you can gleam out enough to solve your breakdown as well :)

//kracker
<i>eminem : patiently waiting</i>

Member since: 2001.07.13 || http://ezpedia.se7enx.com/

Thursday 09 June 2005 3:55:04 am

No worries Peter,

Do get back to let us know just how my little explosion of ideas (positively ?) affected your development.

cheers,
//kracker

<i>Film : Napoleon Dynamite</i>

Member since: 2001.07.13 || http://ezpedia.se7enx.com/

Monday 13 June 2005 4:27:54 am

Peter,

Your more than welcome. You and I had a very deep session here over the past few weeks. I'm very pleased that it has come around full circle to (at the end of the day) help you solve your primary breakdown. I hope it also serves to help others in the future.

Sorry I don't know about the transparency issue you mention :|

I would check to make sure your version of GD (or) imagemagic supports transparency and search in the code and settings heavily for any leads on how it (transparency) is implemented / used / or controlled via settings or defaults.

I am sure that if they say it's possible than it is possible, but exactly how it is possible is not always readily apparent.

best regards,
//kracker

<i>eminem : we came to party</i>

Member since: 2001.07.13 || http://ezpedia.se7enx.com/

Wednesday 03 March 2010 5:16:27 pm

I have found the reason why JPEGs are so degraded using GD : this is due to a bug in the file lib/ezimage/classes/ezimageinterface.php.

In the store() method, the ImageJPEG() method of GD is called to save the image in the JPEG format :

ImageJPEG( $imageObject, eZDir::path( array( $filePath, $fileName ) ) );

As you can see, the third parameter of this function, indicating quality of the JPEG to produce, is missing ; the GD documentation says that 75 is used in this case. That's why JPEG quality is so poor whatever the configuration.

You should modify this class to either set quality to a desired value (100 for max quality as of following) :

ImageJPEG( $imageObject, eZDir::path( array( $filePath, $fileName ) ), 100 );

... or (better solution) to load quality factor to use from [MIMETypeSettings] section of the image.ini configuration file.

Combined with modification of the eztemplateimageoperator.php file, it is now possible to get the image operator fully usable with JPEGs.

Concerning the "sepia tone" images, it is probably the HasGD2=true configuration missing in the image.ini file, section [GDSettings], or the version of GD which is not 2+.