Home > Articles

Styling SVG

This chapter is from the book

This chapter is from the book

Creating a Style Sheet

With an understanding of what a style sheet is fresh in your memory, you can actually begin the process of making one for your SVG content. You can start by creating an internal CSS style sheet.

To make sense of all this style information, you can modify the raindrop example from last hour, shown in Figure 6.1. Using Listing 5.10 as a foundation, you'll need to insert a style element into your new document (line 6 in Listing 6.1). Within this element, you will need to insert a CDATA section (line 7), which alerts the SVG viewer not to parse its contents.

Figure 6.1 An internal style sheet can provide the information to paint this raindrop.

Now it's time to create a rule. First take the two style declarations used to create the appearance of a yellow fill and a black stroke to create a declaration block on line 8. Then create a selector name, such as style1, to label this block. Lastly, use the class attribute (instead of the style property, as Listing 5.8 showed) to associate your new style with the path element on line 12.

Listing 6.1 Using a Style Sheet to Define an Object's Style

01: <?xml version="1.0" standalone="no"?>
02: <!DOCTYPE svg PUBLIC "-//W3C//DTD SVG 1.0//EN"
  "http://www.w3.org/TR/2001/REC-SVG-20010904/DTD/svg10.dtd">
03:
04: <svg width="500" height="300">
05:
06:   <style type="text/css">
07:     <![CDATA[
08:       .style1 {stroke:black; fill:yellow;}
09:     ]]>
10:   </style>
11:   
12:   <path class="style1"
        d="M250,140
        c 0,0 -16,24 -16,33
        c 0,9 7,15 16,15
        c 9,0 16,-7 16,-15
        c 0,-9 -16,-33 -16,-33"/>
13:
14: </svg>

Your style sheet now contains all your style information for the raindrop. Now, to demonstrate the efficiency of CSS style sheet application, you can create two more raindrops, each using the same class.

First, take Listing 6.1 and duplicate (via a copy and paste) the raindrop path twice. As you were working with relative path coordinates, you can change the first coordinates of the first drop (line 12 in Listing 6.2) and the last drop (line 16) by 100 horizontal pixels. Subsequently, that path's coordinates will follow the lead of their first coordinate, creating three evenly spaced drops in a straight horizontal line (see Figure 6.2).

Figure 6.2 An internal style sheet can provide the same information to paint several pieces of artwork.

As you duplicated the original drop, the two new drops will already have the class="style1" code applied. Now, load this new document in your browser, and you should see results similar to Figure 6.2.

Listing 6.2 Using a Style Sheet to Define an Object's Style

01: <?xml version="1.0" standalone="no"?>
02: <!DOCTYPE svg PUBLIC "-//W3C//DTD SVG 1.0//EN"
  "http://www.w3.org/TR/2001/REC-SVG-20010904/DTD/svg10.dtd">
03:
04: <svg width="500" height="300">
05:
06:   <style type="text/css">
07:     <![CDATA[
08:       .style1 {stroke:black; fill:yellow;}
09:     ]]>
10:   </style>
11:   
12:   <path class="style1"
        d="M150,140
        c 0,0 -16,24 -16,33
        c 0,9 7,15 16,15
        c 9,0 16,-7 16,-15
        c 0,-9 -16,-33 -16,-33"/>
13:   
14:   <path class="style1"
        d="M250,140
        c 0,0 -16,24 -16,33
        c 0,9 7,15 16,15
        c 9,0 16,-7 16,-15
        c 0,-9 -16,-33 -16,-33"/>
15:   
16:   <path class="style1"
        d="M350,140
        c 0,0 -16,24 -16,33
        c 0,9 7,15 16,15
        c 9,0 16,-7 16,-15
        c 0,-9 -16,-33 -16,-33"/>
17:
18: </svg>

Now you've successfully created a style sheet and figured out how to apply one of its classes to your artwork. Your next step will be to create multiple classes.

In Listing 6.2, you added two new raindrops to your document. If you decided that you wanted to change the appearance of these two new drops, giving one a black stroke and no designated fill and another a yellow fill but no black stroke, you would need to create two new classes.

To do so, duplicate the style1 rule twice and rename the two resulting rules' selectors style2 and style3 respectively. Listing 6.3 shows these two new rules on lines 9 and 10. Make each style unique by deleting the fill:yellow; declaration from the style2 class and the stroke:black; declaration from the style3 class. Finally, apply style2 to the second drop (line 16) and style3 to the third drop (line 18). When you're done, your results should look like Figure 6.3.

Listing 6.3 Using a Style Sheet to Define Several Different Objects' Style

01: <?xml version="1.0" standalone="no"?>
02: <!DOCTYPE svg PUBLIC "-//W3C//DTD SVG 1.0//EN"
  "http://www.w3.org/TR/2001/REC-SVG-20010904/DTD/svg10.dtd">
03:
04: <svg width="500" height="300">
05:
06:   <style type="text/css">
07:     <![CDATA[
08:       .style1 {stroke:black; fill:yellow;}
09:       .style2 {stroke:black;}
10:       .style3 {fill:yellow;}
11:     ]]>
12:   </style>
13:   
14:   <path class="style1"
        d="M150,140
        c 0,0 -16,24 -16,33
        c 0,9 7,15 16,15
        c 9,0 16,-7 16,-15
        c 0,-9 -16,-33 -16,-33"/>
15:   
16:   <path class="style2"
        d="M250,140
        c 0,0 -16,24 -16,33
        c 0,9 7,15 16,15
        c 9,0 16,-7 16,-15
        c 0,-9 -16,-33 -16,-33"/>
17:   
18:   <path class="style3"
        d="M350,140
        c 0,0 -16,24 -16,33
        c 0,9 7,15 16,15
        c 9,0 16,-7 16,-15
        c 0,-9 -16,-33 -16,-33"/>
19:
20: </svg>

Figure 6.3 Each raindrop is using a unique class to define its appearance.

Although this method accomplishes the goal of creating three differently styled objects, you've ended up duplicating your style declarations several times. Rather than defining your rules with multiple style declarations, you can instead give each declaration its own rule, allowing you the flexibility to change an object's appearance without first creating a new rule.

By naming each style declaration, you can free yourself to make class combinations on the artwork's element rather than inside the style sheet. As an example, consider an instance where you want to change the color of an object in your artwork. First, you must find the object you wish to modify. Once found, you see which selector name is being referenced, and then you must double back to your style sheet to modify the appropriate rules.

Instead of darting back and forth between two locations in your code (or in some cases between two documents, should you be using an external style sheet), you can simply replace one selector name with another if you have a unique selector name for each declaration (several fills, in this instance). By keeping the groupings of an object's style on the object level, rather than on the style sheet level, you are afforded a greater control over your artwork, allowing you to quickly edit it.

Try this out by creating a new document based on Listing 6.3. First, delete the style1 class, and then apply both style2 and style3 to the first raindrop. To apply more than one class to an object, separate class attribute values with a space (see line 14 of Listing 6.4).

Listing 6.4 Associating Only One Declaration with Each Selector

01: <?xml version="1.0" standalone="no"?>
02: <!DOCTYPE svg PUBLIC "-//W3C//DTD SVG 1.0//EN"
03:  "http://www.w3.org/TR/2001/REC-SVG-20010904/DTD/svg10.dtd">
04:
05: <svg width="500" height="300">
06:
07: <style type="text/css">
08:   <![CDATA[
09:     .style2{stroke:black;}
10:     .style3{fill:yellow;}
11:   ]]>
12: </style>
13:
14:   <path class="style2 style3"
15:     d="M150,140
16:     c 0,0 -16,24 -16,33
17:     c 0,9 7,15 16,15
18:     c 9,0 16,-7 16,-15
19:     c 0,-9 -16,-33 -16,-33"/>
20:
21:   <path class="style2"
22:     d="M250,140
23:     c 0,0 -16,24 -16,33
24:     c 0,9 7,15 16,15
25:     c 9,0 16,-7 16,-15
26:     c 0,-9 -16,-33 -16,-33"/>
27:
28:   <path class="style3"
29:     d="M350,140
30:     c 0,0 -16,24 -16,33
31:     c 0,9 7,15 16,15
32:     c 9,0 16,-7 16,-15
33:     c 0,-9 -16,-33 -16,-33"/>
34:
35: </svg>

Though the code may have changed, the result of your experiment here will look exactly the same as Figure 6.3. On a small level such as this three raindrop example, you may not see any value in naming each style declaration. The results, however, begin to manifest themselves once you start dealing with very long and complicated SVG documents.

Labeling Your Style Sheet's Rules

For simplicity's sake, the three rules you just dealt with were arbitrarily named to represent each style declaration: style1, style2, and style3, respectively. However, should you hand this SVG file to a fellow developer, these three names would seem rather meaningless. Not only would they rightfully appear to be a random naming scheme, but the names could also cause confusion in large-scale coding projects. For instance, if the developer knew she wanted to make a circle yellow, she would have no choice but to refer to the style sheet to see what class accomplished this task.

There is a simpler way, though. Naming a class's selector according to its purposes gives a development team a common language to work with. By creating a unified and descriptive class-naming system, developers (yourself included) will be able to quickly determine the name of their desired class.

For instance, rather than naming your first selector style2, use a name that reflects the actual style declaration, such as StrokeBlack. In Listing 6.5, style2 and style3 (lines 9 and 10) have been renamed to more closely reflect their respective declarations' functions.

Listing 6.5 Name Selectors to Mirror Their Declarations' Functions

01: <?xml version="1.0" standalone="no"?>
02: <!DOCTYPE svg PUBLIC "-//W3C//DTD SVG 1.0//EN"
03:  "http://www.w3.org/TR/2001/REC-SVG-20010904/DTD/svg10.dtd">
04:
05: <svg width="500" height="300">
06:
07: <style type="text/css">
08:   <![CDATA[
09:     .StrokeBlack{stroke:black;}
10:     .FillYellow{fill:yellow;}
11:   ]]>
12: </style>
13:
14:   <path class="StrokeBlack FillYellow"
15:     d="M150,140
16:     c 0,0 -16,24 -16,33
17:     c 0,9 7,15 16,15
18:     c 9,0 16,-7 16,-15
19:     c 0,-9 -16,-33 -16,-33"/>
20:
21:   <path class="StrokeBlack"
22:     d="M250,140
23:     c 0,0 -16,24 -16,33
24:     c 0,9 7,15 16,15
25:     c 9,0 16,-7 16,-15
26:     c 0,-9 -16,-33 -16,-33"/>
27:
28:   <path class="FillYellow"
29:     d="M350,140
30:     c 0,0 -16,24 -16,33
31:     c 0,9 7,15 16,15
32:     c 9,0 16,-7 16,-15
33:     c 0,-9 -16,-33 -16,-33"/>
34:
35: </svg>

Again, this listing will appear the same as Figure 6.3. However, when another developer examines this code, she will be able to quickly identify the function of the class being applied without needing to look up the selector in the style sheet. Should you follow a naming convention such as this and your style sheet be two pages long with 50 fills and 50 strokes, the same developer would be able to guess (with a high probability at success) at the selector name of a red fill: FillRed. When faced with large documents of code and an impending deadline, such naming conventions can be a lifesaver for your development team.

CAUTION

Be certain to be consistent in naming conventions. If you name one class StrokeGreen and another class BlueStroke, you will destroy the usefulness of your system. If done inconsistently, a developer will be forced to look up every selector name, as a naming convention (such as <propertyName><propertyValue>) is not being followed.

InformIT Promotional Mailings & Special Offers

I would like to receive exclusive offers and hear about products from InformIT and its family of brands. I can unsubscribe at any time.

Overview


Pearson Education, Inc., 221 River Street, Hoboken, New Jersey 07030, (Pearson) presents this site to provide information about products and services that can be purchased through this site.

This privacy notice provides an overview of our commitment to privacy and describes how we collect, protect, use and share personal information collected through this site. Please note that other Pearson websites and online products and services have their own separate privacy policies.

Collection and Use of Information


To conduct business and deliver products and services, Pearson collects and uses personal information in several ways in connection with this site, including:

Questions and Inquiries

For inquiries and questions, we collect the inquiry or question, together with name, contact details (email address, phone number and mailing address) and any other additional information voluntarily submitted to us through a Contact Us form or an email. We use this information to address the inquiry and respond to the question.

Online Store

For orders and purchases placed through our online store on this site, we collect order details, name, institution name and address (if applicable), email address, phone number, shipping and billing addresses, credit/debit card information, shipping options and any instructions. We use this information to complete transactions, fulfill orders, communicate with individuals placing orders or visiting the online store, and for related purposes.

Surveys

Pearson may offer opportunities to provide feedback or participate in surveys, including surveys evaluating Pearson products, services or sites. Participation is voluntary. Pearson collects information requested in the survey questions and uses the information to evaluate, support, maintain and improve products, services or sites, develop new products and services, conduct educational research and for other purposes specified in the survey.

Contests and Drawings

Occasionally, we may sponsor a contest or drawing. Participation is optional. Pearson collects name, contact information and other information specified on the entry form for the contest or drawing to conduct the contest or drawing. Pearson may collect additional personal information from the winners of a contest or drawing in order to award the prize and for tax reporting purposes, as required by law.

Newsletters

If you have elected to receive email newsletters or promotional mailings and special offers but want to unsubscribe, simply email information@informit.com.

Service Announcements

On rare occasions it is necessary to send out a strictly service related announcement. For instance, if our service is temporarily suspended for maintenance we might send users an email. Generally, users may not opt-out of these communications, though they can deactivate their account information. However, these communications are not promotional in nature.

Customer Service

We communicate with users on a regular basis to provide requested services and in regard to issues relating to their account we reply via email or phone in accordance with the users' wishes when a user submits their information through our Contact Us form.

Other Collection and Use of Information


Application and System Logs

Pearson automatically collects log data to help ensure the delivery, availability and security of this site. Log data may include technical information about how a user or visitor connected to this site, such as browser type, type of computer/device, operating system, internet service provider and IP address. We use this information for support purposes and to monitor the health of the site, identify problems, improve service, detect unauthorized access and fraudulent activity, prevent and respond to security incidents and appropriately scale computing resources.

Web Analytics

Pearson may use third party web trend analytical services, including Google Analytics, to collect visitor information, such as IP addresses, browser types, referring pages, pages visited and time spent on a particular site. While these analytical services collect and report information on an anonymous basis, they may use cookies to gather web trend information. The information gathered may enable Pearson (but not the third party web trend services) to link information with application and system log data. Pearson uses this information for system administration and to identify problems, improve service, detect unauthorized access and fraudulent activity, prevent and respond to security incidents, appropriately scale computing resources and otherwise support and deliver this site and its services.

Cookies and Related Technologies

This site uses cookies and similar technologies to personalize content, measure traffic patterns, control security, track use and access of information on this site, and provide interest-based messages and advertising. Users can manage and block the use of cookies through their browser. Disabling or blocking certain cookies may limit the functionality of this site.

Do Not Track

This site currently does not respond to Do Not Track signals.

Security


Pearson uses appropriate physical, administrative and technical security measures to protect personal information from unauthorized access, use and disclosure.

Children


This site is not directed to children under the age of 13.

Marketing


Pearson may send or direct marketing communications to users, provided that

  • Pearson will not use personal information collected or processed as a K-12 school service provider for the purpose of directed or targeted advertising.
  • Such marketing is consistent with applicable law and Pearson's legal obligations.
  • Pearson will not knowingly direct or send marketing communications to an individual who has expressed a preference not to receive marketing.
  • Where required by applicable law, express or implied consent to marketing exists and has not been withdrawn.

Pearson may provide personal information to a third party service provider on a restricted basis to provide marketing solely on behalf of Pearson or an affiliate or customer for whom Pearson is a service provider. Marketing preferences may be changed at any time.

Correcting/Updating Personal Information


If a user's personally identifiable information changes (such as your postal address or email address), we provide a way to correct or update that user's personal data provided to us. This can be done on the Account page. If a user no longer desires our service and desires to delete his or her account, please contact us at customer-service@informit.com and we will process the deletion of a user's account.

Choice/Opt-out


Users can always make an informed choice as to whether they should proceed with certain services offered by InformIT. If you choose to remove yourself from our mailing list(s) simply visit the following page and uncheck any communication you no longer want to receive: www.informit.com/u.aspx.

Sale of Personal Information


Pearson does not rent or sell personal information in exchange for any payment of money.

While Pearson does not sell personal information, as defined in Nevada law, Nevada residents may email a request for no sale of their personal information to NevadaDesignatedRequest@pearson.com.

Supplemental Privacy Statement for California Residents


California residents should read our Supplemental privacy statement for California residents in conjunction with this Privacy Notice. The Supplemental privacy statement for California residents explains Pearson's commitment to comply with California law and applies to personal information of California residents collected in connection with this site and the Services.

Sharing and Disclosure


Pearson may disclose personal information, as follows:

  • As required by law.
  • With the consent of the individual (or their parent, if the individual is a minor)
  • In response to a subpoena, court order or legal process, to the extent permitted or required by law
  • To protect the security and safety of individuals, data, assets and systems, consistent with applicable law
  • In connection the sale, joint venture or other transfer of some or all of its company or assets, subject to the provisions of this Privacy Notice
  • To investigate or address actual or suspected fraud or other illegal activities
  • To exercise its legal rights, including enforcement of the Terms of Use for this site or another contract
  • To affiliated Pearson companies and other companies and organizations who perform work for Pearson and are obligated to protect the privacy of personal information consistent with this Privacy Notice
  • To a school, organization, company or government agency, where Pearson collects or processes the personal information in a school setting or on behalf of such organization, company or government agency.

Links


This web site contains links to other sites. Please be aware that we are not responsible for the privacy practices of such other sites. We encourage our users to be aware when they leave our site and to read the privacy statements of each and every web site that collects Personal Information. This privacy statement applies solely to information collected by this web site.

Requests and Contact


Please contact us about this Privacy Notice or if you have any requests or questions relating to the privacy of your personal information.

Changes to this Privacy Notice


We may revise this Privacy Notice through an updated posting. We will identify the effective date of the revision in the posting. Often, updates are made to provide greater clarity or to comply with changes in regulatory requirements. If the updates involve material changes to the collection, protection, use or disclosure of Personal Information, Pearson will provide notice of the change through a conspicuous notice on this site or other appropriate way. Continued use of the site after the effective date of a posted revision evidences acceptance. Please contact us if you have questions or concerns about the Privacy Notice or any objection to any revisions.

Last Update: November 17, 2020