What happened to composite images for ClientBundles?

[Chris Lercher]

According to https://developers.google.com/web-toolkit/doc/latest/DevGuideUiImageBundles, multiple images in the same ClientBundle should usually be merged to a composite image, quote:

Multiple ImageResources are declared in a single ClientBundle, which is a composition of many images into a single image

And I remember, that I tried and confirmed this, when I first used it a few years ago. But I don't see this happening anymore:

- Either we get data URIs (for small images), 

- or we get separate "*.cache.jpg" images for each ImageResource in the ClientBundle (for large images, or if setting <set-property name="ClientBundle.enableInlining" value="false"/>)

Is this correct, or is it a bug? Can I maybe even rely on GWT not producing composite images anymore [*]?

[*] This would allow me to use "new Image(imageResource.getSafeUri())", which would be useful in certain circumstances (e.g. when printing the page), as it uses a foreground image instead of a background image.

[KevMo]

I believe it still makes composite images for older versions of IE, as those don't support data URIs. 

[Thomas Broyer]

On Wednesday, September 19, 2012 5:30:46 PM UTC+2, Chris Lercher wrote:

According to https://developers.google.com/web-toolkit/doc/latest/DevGuideUiImageBundles, multiple images in the same ClientBundle should usually be merged to a composite image, quote:

Multiple ImageResources are declared in a single ClientBundle, which is a composition of many images into a single image

And I remember, that I tried and confirmed this, when I first used it a few years ago. But I don't see this happening anymore:

- Either we get data URIs (for small images), 

- or we get separate "*.cache.jpg" images for each ImageResource in the ClientBundle (for large images, or if setting <set-property name="ClientBundle.enableInlining" value="false"/>)

Is this correct, or is it a bug?

That's correct. As KevMo says, "spriting" is actually only used for IE6/7.

 

Can I maybe even rely on GWT not producing composite images anymore [*]?

[*] This would allow me to use "new Image(imageResource.getSafeUri())", which would be useful in certain circumstances (e.g. when printing the page), as it uses a foreground image instead of a background image.

You shouldn't (not that I can think of anything that would make us change the way it is though; note however that technically it depends on the exact generator being used, so it's easy to break code that makes such assumptions by only changing the *.gwt.xml)

If you want to do a "new Image(someResourceInAClientBundle.getSafeUri())", you'd better use a DataResource.

[Tim]

Perhaps you want set some ImageOptions on the resource.  Check "preventInlining" and "RepeatStyle" 

On Wednesday, September 19, 2012 8:30:46 AM UTC-7, Chris Lercher wrote:

[Chris Lercher]

On Thursday, September 20, 2012 3:54:41 AM UTC+2, Tim wrote:

Perhaps you want set some ImageOptions on the resource.  Check "preventInlining" and "RepeatStyle" 

Thanks, according to the javadoc, ImageOptions.preventInlining actually seems to disable all kinds of optimizations:

Set to {@code true} to require the ImageResource to be downloaded as a  

separate resource at runtime. Specifically, this will disable the use of 

{@code data:} URLs or other bundling optimizations for the image. 

I assume, this also includes spriting (?). A quick look at com.google.gwt.resources.rg.ImageResourceGenerator seems to confirm this for the current implementation.

It's a bit counter-intuitive, because the option is just called "preventInlining", so to be on the safe side, I'll probably use a DataResource instead (I might miss ImageResource's getWidth()/getHeight() methods though).

And about RepeatStyle.Both: Here, the javadoc says:

The image is intended to be tiled both horizontally and vertically. Note

that this will prevent compositing of the particular image in most cases.