Comet 30 User's Manual

Layout

Layout » Colors

Layout » Images

Layout » Icon Sizes

Layout » Folder Menu

Layout » Thumbstrip

Layout » Maps

Layout » Map Tooltips

Layout » Other

Fonts

Fonts » Font Family

Fonts » Google Font

Fonts » WOFF File

Fonts » Styles

Code

Code » CSS

Code » HTML Head

Misc

Misc

About

About

Image-Specific Settings

To access image-specific settings, hover on a thumbnail in the main jAlbum editing window, and click More.

Then choose Edit.

Then choose the Comet panel on the right side of the editing window.

Info: HTML Tags and jAlbum Variables

HTML tags and jAlbum variables may be used in a number of different contexts, and will be honored in the album (including things like links). jAlbum variables will be passed to the jAlbum engine and will be evaluated before they are placed in the completed album. Almost all user entries are treated in this manner:

If you use a < or > character in a text string, it is assumed to be part of an HTML tag, and may produce errors if it isn't. If you want to use one of those characters as simple text, use its HTML entity code, instead.

Info: Google Fonts & WOFF Files

A longstanding problem with web pages is that fonts are not actually included in the page code. The page simply includes some text, along with an instruction in the CSS that tells the browser what font to use to display that text. But if the visitor's computer doesn't have that font installed, it falls back to a default, or works its way down whatever font stack is indicated in the CSS until it finds a font that it can use. The effect of this limitation is that web page designers are generally forced to rely on a small set of "web safe" fonts, fonts that can reliably be found on most visitors' computers.

Packaging fonts with web pages in a way that allows the site visitor to install the font on his computer, while possible, runs afoul of copyright protections. Most fonts, even those normally distributed with a new computer, are protected by copyright, and you don't have the right to make them available to others.

To address this problem, Google Fonts and Web Open Font Format (WOFF) files can be used. The font is not actually installed on the visitor's computer. It is used only for displaying text on your web page.

In Comet, you may add two Google Fonts and a WOFF file, and tell the skin which font to use for each text element, with the default being the selected regular font family. Decorative fonts can be difficult to read at smaller sizes, and are therefore best used only for page titles. You are likely to find that they look better when displayed with a larger font size than you would use for a regular font, and with normal weight, rather than bold. More traditional fonts may be suitable for all text.

To choose a Google Font, visit the Google Fonts page, and identify the font you want to use. Scroll down on the page to view suggested font pairings. You might want to use a more elaborate font for titles, and a simpler font for captions. Make a note of its name, and enter the name in the Comet settings. Comet does not support the use of Google Font multiple styles. If you see a font listed, and it indicates that there are multiple styles of that font available, when you enter its name in the Comet settings, the skin will use the basic style of that font.

There are now many hundreds of free WOFF files available. Search the web for free woff to find sources (some sites require registration). In most cases, the fonts are free for you to use on your website, even if the website is commercial, but the font designers retain copyright, so you don't have permission to redistribute the files directly to others. Often, these free fonts are provided in a variety of formats - WOFF, OTF, TTF, EOT, SVG, and so on. The format needed for Comet is indicated by a .woff file extension. In many cases, the download will be provided as a zip archive containing several formats - you need to extract the .woff file from that archive and use that one for inclusion in the skin.

The FontSquirrel site is a typical example, offering many free fonts. Find one you like, and then click on the name of the font (not on the Download link). Then look for a Webfont Kit link on the menu bar. There, you can choose the WOFF format. If a font is available in only one format, the Webfont Kit menu bar choice will be absent. In that case, you can download another format, like TTF, then use FontSquirrel's Webfont Generator to upload the TTF and convert it to WOFF - choose the Expert radio button after you've uploaded the TTF version. In short, it may take some exploration to find the WOFF file you need.

See Fonts to include a Google Font and/or WOFF file in your album.

Info: Linking to Originals

If you choose Link to originals in the main jAlbum settings (Album » Settings » Pages), your images will not be scaled or modified in any way. They will be used directly in the slide pages of the album. the skin will adjust the slide display to the visitor's viewport, but because the files have not been scaled, the file sizes may be very large, making this setting a poor choice for a web album. However, you can resize your images before using them in jAlbum, in which case choosing Link to originals might be suitable. If you also select HiDPI images, your original images will be shown at one-half their native dimensions, to preserve clarity on high-density displays.

Info: HiDPI Images

High-density display devices, like Apple's retina displays, have twice the number of physical pixels (or more) within a given area, compared to regular devices. Images will appear sharper on these displays if they are larger, but displayed in half the CSS layout space. For example, an image that is 1200px wide is normally displayed in 1200 CSS pixels on a regular monitor, and is using 1200 physical pixels. But for a high-density device, it is better to provide an image that is 2400px wide, but then display it in 1200 CSS pixels on the monitor. When you do this, the display makes full use of the 2400 pixels that are available in the image, by using 2400 of its physical pixels.

jAlbum includes the option, under Settings » Images » General, of creating high-density thumbnails and/or slide images, referred to as HiDPI images. This doesn't actually produce images with a higher pixel density - there is no such thing. It simply produces images with double the image bounds - the skin, however, then displays these images in half the space.

Doing this produces a noticeably better image on a high-density monitor. The penalty is that the image files are typically several times the file size. They consume more bandwidth, taking longer to upload and longer to download when someone visits the site. The user with a regular monitor is forced to download much larger files, but gets no benefit from them.

Using HiDPI thumbnails produces better-looking thumbnails on high-density displays. For thumbnails, this does produce larger files, but they're still relatively small, so the bandwidth penalty is minor.

Using HiDPI images is a different matter entirely. The bandwidth penalty is substantial. As the bandwidth available to your site visitors continues to grow, this may not make any difference. In addition, the skin does a lot of image preloading, so as a visitor moves through the slides, there will often be no delay, even with HiDPI images. Improving technology will eventually make this a non-issue, and you will be able to use HiDPI images in all your albums.

It should be noted that if the images you are adding to your project aren't fairly large to begin with, perhaps 3000x2000 pixels, there is no benefit to be gained by using HiDPI images, and there is no reason to choose that option. jAlbum can't interpolate, and produce more image information than what is present in the original images.

Recent jAlbum versions include the ability to produce albums with two sets of images, but the image display script used in this skin is not constructed to make use of them. In addition, a "2X variant" image in jAlbum is not handled the same way as a HiDPI image - the benefit of the greater density is lost.

If you want to provide HiDPI images to visitors with high-density monitors, but not penalize visitors with regular monitors, the only solution is to produce two copies of the album. Create your project and call it, for example, mydogLR (for "low resolution"), using image bounds that produce good-looking slides on a regular monitor (the skin defaults, for example). Accept the default settings - HiDPI thumbnails, but not HiDPI images. Upload your album to https://mysite.com/mydogLR/.

Now duplicate the entire project - click the down-arrow to the right of the project name in the jAlbum project panel, choose Duplicate Project, and call it mydogHR (for "high resolution"). In this duplicate project, choose HiDPI images, make the album, and upload it to https://mysite.com/mydogHR/.

Now you need to provide a steering script on your site, so that visitors will be directed to the appropriate album. Create a directory on your site called https://mysite.com/mydog/ and upload an index.html to it that contains the following:

<!DOCTYPE html>
<meta charset='UTF-8'>
<title>Redirect</title>
<script>
if(screen.width >= 768 && screen.height >= 768 && window.devicePixelRatio >= 2) {
	window.location = "http://mysite.com/mydogHR/";
} else {
	window.location = "http://mysite.com/mydogLR/";
}
</script>

All visitors can now be provided with a single link to your album: https://mysite.com/mydog/. The steering script will automatically direct visitors to the high resolution album if they are on anything the size of an iPad or larger, and have a high-density display. These are the visitors who can benefit from the larger slide images. Other visitors will be directed to the low resolution album.

Info: Version Updating

New versions of Comet are published with some regularity. These new versions generally include new features, improvements, and bug fixes. The jAlbum application will let you know when a new version is available, and users are encouraged to download and install the new version.

Info: Browser Support

Comet produces albums that display properly in most browsers.

Comet License

The Comet skin for jAlbum, including all supporting files, source code, compiled code, and scripts, ©2021, Jeff Tucker.

The skin uses the following open-source scripts:

You may use the software to create albums for personal or commercial sites. You may distribute copies of the software to others, but for any reuse or distribution, you must make clear to others the license terms of this software. You may modify the software for your own use.

The copyright holder reserves the right to waive or to withdraw any of these terms on a case-by-case basis.

The jAlbum application is free for personal use during the initial trial period, but after that, a Standard license is required. For commercial use, a Pro license is required. Visit the jAlbum site for further information.