SuperContainer image resizing degrading JPEG quality

[crayfish]

SuperContainer Companion Plugin 2.746

I'm having issues where Supercontainer is degrading image quality when I try to resize images using SCGetContainer.

First, I'm running SCSetContainer to move the original image into SuperContainer.

I then run SCGetContainer(path; 480;280) to reduce image size, and then export the file using Export Field Contents. When I do this I get this file:

SC 480x280 crop.jpg. (attached)

If I run SCGetContainer(path; 480;0) I also get the same file.

However, when I take the original image in Picasa and reduce it down to 480x280, I get this image:

Picasa 480x280 crop.jpg (attached)

There is a noticeable quality difference between the two. Picasa's image is much crisper and clearer than SuperContainer's.

Now, if I add the resolution parameter to SCGetContainer(path; 480;280;300), it completely overrides the 480x280 width and gives me an image which is the same dimensions as the original file, but with a file size is half as large.

Even if I run SCGetContainer(path; 0;0), which my understanding should leave the image unchanged, I get a file size half the size of the original.

Am I doing something wrong? Is SuperContainer's image resizer set to resize jpeg's at a lower quality? Any way to change this if so?

Thanks for any advice...

[Smef]

SuperContianer runs its preview generation when you pass width and height as parameters with the scgetcontainer function. Use the scgetcontainer function without a width or a height parameter to download the original file.

SuperContainer's preview generation is designed to provide a low-bandwidth way to view image previews in web viewers. The image you are resizing in picasa has a larger filesize, and so is able to be more crisp. SuperContainer applies higher compression than what you did in picasa so that you users downloads as small a file as possible.

The function flag you are using "300" is not a valid function flag for the SCDownload function. The parameters for that function are:

( folderPath { ; destinationFolder ; width ; height; key1=value1; key2=value2; ... } )

I'm guessing that you want to specify a dpi of 300. To do this you will need to increase the width and height of your image. Specifying "300" should not affect the image returned by the SCdownload function at all, as it is not a valid parameter. I've tested this and confirm that passing that number in there doesn't affect the download function. Please double-check your script and let me know if specifying that is affecting the size at all.

[crayfish]

Are there any plans to add an option to control the compression quality?

[Jesse Barnum]

How are you deploying SuperContainer? The code for image resizing is different depending on whether you are running as a standalone application in OS X (in which case it uses OS X Core Image library), compared to running in Tomcat / FileMaker Web Publishing on Mac or Windows.

[gdurniak]

I am considering switching to standalone ...

Does one deployment give "better" thumbnails than the other?

thanks,

greg

>How are you deploying SuperContainer?

The code for image resizing is different depending on whether you are running as a standalone application in OS X (in which case it uses OS X Core Image library), compared to running in Tomcat / FileMaker Web Publishing on Mac or Windows

[Jesse Barnum]

I honestly dont' know if one is 'better' than the other, but I do know that the code is completely separate and is likely to give different outputs. I also know that the OS X standalone option is much faster, deals with larger files, and can deal with many more file types (such as PDF, EPS, photoshop), so it seems like a good thing to try.

[john renfrew]

How does OSX server compare? is it he same as standalone?

[Jesse Barnum]

Yes.