Advertise here via BSAAs browser adoption of HTML5 continues apace, developers are finding more and more options for creating elegant, highly responsive UIs. In the case of Scalable Vector Graphics (SVG), what’s old is new again, and qui...
Advertise here via BSAAs browser adoption of HTML5 continues apace, developers are finding more and more options for creating elegant, highly responsive UIs. In the case of Scalable Vector Graphics (SVG), what’s old is new again, and quite slick.
The SVG spec has been around for a while now. Under development since 1999, the spec, or more accurately a family of specs, describes an XML-based file format for vector graphics. An SVG block defines the individual components of a vector image, such as paths, shapes, fills, strokes and other features. This provides a lightweight option for certain types of graphics that might otherwise have been created in Adobe Illustrator or Inkscape and then exported to a raster format. It also promises a raft of potential functionality in manipulating an image on the fly—hence the “scalable” part of SVG.
To demonstrate, this series of walkthroughs will aim to benefit humankind in two ways. One, it will cover SVG examples that are compatible across browsers, while pointing out some of the differences in SVG adoption. Two, it will more or less accurately predict one’s chances of surviving a zombie apocalypse.
Step One: Prepare
Before starting, it’s helpful to know which browser will be targeted. While all modern browsers have adopted SVG to some degree, its implementation still varies in many ways—some minor, some significant. For example, the Synchronized Multimedia Integration Language (SMIL) spec describes how to animate SVG through the element. This gives a developer the chance to add both user interactivity and independent attribute changes over time, without ever leaving the element. Unfortunately, not all browsers yet recognize SVG/SMIL animation (though alternative forms of SVG animation do exist).
“Can I Use…” provides a thorough side-by-side comparison of all major desktop and mobile Web browsers and indicates which of their versions recognize various HTML5 features. Particularly useful is its drill down on specific SVG features, like use of Inline SVG and SVG Filter Effects, which have just been added to Internet Explorer 10.
Step Two: Create the SVG Element
This particular SVG Zombie Apocalypse Survival Predictor will use three separate SVG elements: a pane for the “city,” a control panel for the risk factors, and a pane for the prediction meter itself.
To start, create a 600×400 root element called “cityBox”:
Planning for the Zombie Apocalypse with HTML5 and SVG
Voila. Invisible box. It’s winter in Zombieland. A border can be added through CSS styling, either with the “style” attribute in the element itself or by defining the style up in the header, thusly:
border: 1px solid #000000;
Step Three: Add Text
While developers have many ways of handling text on the page, doing it through SVG opens the door to a lot of interesting options, such as changing character offsets, stretching text, rotating sentences or fitting text to a path.
Before trying any of these, though, add a title to the cityBox element:
Surviving the Zombie Apocalypse
Figure 1: SVG Element with
The x,y coordinates define the baseline of the first character. Remove them from this example, and the text pretty much disappears off the top of the SVG element.
Styling for the SVG text element comes in three flavors: the “style” attribute, a defined style or individual SVG attributes. Note, however, that certain attributes seem to misbehave depending on the method used and the browser. For example, defining “font-family” works for all browsers no matter where it goes. However, “font-size” is implemented inconsistently. Defining it in the header doesn’t work in either Chrome or Internet Explor