Robert Shiplett's Blog

Multiple Curl applets in a single HTML web page

grshiplett2@yahoo.com — Sat, 03 Jul 2010 22:17:42 GMT

Over at http://aule-browser.com/multi-curl/index.htm I have placed a new Curl example. This one shows two Curl applets embedded within a single web page.

It might not be obvious why you would want to do this, but I can think of at least three examples involving compliance monitoring, audit and annotations.

I have another example of running more than one EmbeddedBrowserGraphic against books.google.com within the same Curl applet, but this is somewhat different.

Each applet is embedded in one of two div elements within a main div in the HTML page's body element. The height of each div on the page is set by a style with a percent value.

Tested on webkit (Safari), Mozilla gecko, Opera 10.60 and IE8

Cross-browser Curl Pages

grshiplett2@yahoo.com — Tue, 29 Jun 2010 15:55:01 GMT

Enterprise development is very often for the company's approved browser only, but Curl pages on the internet have to address cross-browser issues.

For the past few days I have been trying to get all of my pages to resize and paginate correctly on a half-size netbook screen in an Ubuntu Web-Kit browser.

There is still a way to go: the worst problem is the MIME-type behavior. I have finally stopped embedding .curl URL's in the href of any of my public Curl { link } expressions and retreated to always wrapping Curl in HTML.

This has had the positive result of getting me to update my HTML and XHTML. In other blog posts here I have noted some of the changes that seem effective across all browsers: chief among them is setting a <div> inside the <body> and styling that div to have a height of 100%. Also I am now careful to place a <div> inside the embedding <object> element so that my HTML pages which embed Curl now end as

</div>

</object>

</div>

</body>

</html>

which lets me see at a glance that probably the page presents OK and validates as well.

You can test my HTML efforts at logiquewerks.com/index.htm and my XHTML+RDFa efforts at logiquewerks.com/index.html

Of course this effort is moot if my sitemap.xml file is not picked up by search engines such as Google.

Curl Corp. might want to consider updating the default HTML boilerplate for embedding Curl and the docs on embedding Curl in XHTML pages as at least one of the CSS issues was not obvious.

Curl Corp's Chris Barber has some very useful JavaScript snippets over at his Zuzu pages at code.google.com and I'll post a note on using those next time.

Curl MDI Framework

grshiplett2@yahoo.com — Wed, 23 Jun 2010 02:43:35 GMT

Over at www.logiquewerks.com there is now a Curl 7.0 version of Paul Sheehan's "Enterprise Curl" MDI framework as version 1.2. You will find it under the "Curl Examples" link.

I will update the code repository at code.google.com over the next 24-hours.

The worst issue was restoring window drag behavior to the AppCanvas. An MDI Window would only drag to a point where the cursor reached the bounds of its previous position! You could move a window across the screen in steps, but not in one sweep of the mouse. This was really odd and I could not find an error in the event handling.

Then in an odd moment of inspiration I went to flip the color of the background canvas to see if there was something obscure there - bingo! No background was set in the constructor and as soon as a {Background } was provided the strange behavior vanished. To test this, I removed the "fix"and redeployed. Fenced-in behavior returned. Made the one change, deployed that PCurl only: odd behavior vanished. But is it a bug?

Another nuisance was to track down the places where bits of web server context information were hard-coded. I forced the issue by moving all files, directories and even package names to lower-case ( I think of this as unix-friendly and a break with Java-file-mindset.) It took a little patience, but now that hard-coding issue is looked after.

There is still lots of work to do on this little demo framework: visit the project at code.google.com

Curl for beautiful images

grshiplett2@yahoo.com — Mon, 21 Jun 2010 17:15:57 GMT

Over at astro.aule-browser.com there is now a page with one of the most beautiful images returned to us from the Hubble Space Telescope: M13*.

One of Galileo's achievements had been establishing that some "nebulae" were not "clouds" but clusters of stars. One of the most beautiful of these can be seen even in a smal telescope by "looking off the fovea". It is a remarkable experience once you have learned not to "look" at the fuzzy patch, but just allow it to be seen by the outer areas of your retina.

I have tried to find an optimal layout for this beautiful image: at the moment I am using a 600px X 600px JPG. I will add more size options. The image is loaded without blocking, so you may see a reminder in white-on-black in the intended frame.

If you have a layout suggestion for this very fine image, please add a comment. The image preserves its aspect-ratio on resizing the browser and the ImageGraphic instance is wrapped in a black frame using black {Fill } and sits in a "silver" background using silver {Fill }. The title is centered in a { TextFlowBox }.

See the Curl documentation on ImageGraphic, ImageData and ImageLoader for more information.

The text-proc {image } is intended to be used in a simple document and an example can be found in the docs under Frame.

One issue about loading images async is that the target must be compatible with your server's Curl license. What this means in my case is that I am at the moment unable to target astro.aule-browser.com but must instead use the full www.aule-browser.com/astro as the path to the image. If a user enters from astro.aule-browser.com they get a warning when the applet tries to load from the available www path. Each time a subdomain is added to aule-browser, I face these license issues ... but only if the applet tries to go back for a resource after startup. I think this may also be an issue for the {image } text-proc.

*M13 or NGC 6205 is known as the Hercules Globular Cluster because it is in the "keystone" or "flower pot" of the constellation Hercules. In the northern hemisphere near summer solstice (about now) it is overhead before midnight and very visible in even good binoculars. Look in the "western" long-edge of the "keystone" asterism - the grey fuzzy area is not a star! Although called Messier 13, it is credited to Halley. M13 was recently shown to have captured a younger blue "field" star in the course of its movement in the Milky way. A cluster within a galaxy such as M13 should not be confused with a distant elliptical galaxy (itself likely part of a galactic group.)

Presenting Confidential Documents in a Curl Applet

grshiplett2@yahoo.com — Thu, 17 Jun 2010 11:45:44 GMT

There are a number of ways to ensure that a confidential document cannot be printed or screen-captured when presented in a Curl widget.

One essential thing to know about print suppression is that if you embed a Curl applet in HTML as an <object> then you can use the style for that page to control presentation on screen separately from presentation in print.

Here is a simple example of CSS that I use in a page presenting copyright material which is for eyes-only (no permission to reproduce)

The result for a page print is a minimal page with perhaps the title as header and the url as footer.

The key is in the media attribute of the style's type - in our case media="print".

The page has another style definition for media="screen".

For printing, the HTML has a minimal height, the body somewhat less, and the object element almost none. I avoid zero values if I can because some browsers have a history of reacting poorly to some zero values. And when I see SOMETHING print (a header and footer), I know what will NOT print.

And of course you will want to test your style against multiple browsers on the usual operating systems.

What is more: the Curl content itself should have a top-level graphic which is suppressing its context menu and the entire applet should suppress the inspection gesture.