Customizing Carousel Viewer

All visual customization and most behavior customization for the Carousel Viewer is done by creating a custom CSS.

The suggested workflow is to take the default CSS file for the appropriate viewer, copy it to a different location, customize it, and specify the location of the customized file in the style= command.

Default CSS files can be found at the following location:


The viewer is supplied with four out-of-the-box CSS files, for numeric and dotted set indicator, each in a “light” and “dark” color scheme. The “Dotted light” version is used by default, but it is easy to switch to a different version by using different standard CSS and setting the SetIndicator.mode parameter. Other standard CSS are found at the following location:




Custom CSS file must contain the same class declarations as the default one. If a class declaration is omitted, the viewer does not function properly because it does not provide built-in default styles for user interface elements.

An alternative way to provide custom CSS rules is to use embedded styles directly on the web page or in one of linked external CSS rules.

When creating custom CSS keep in mind that the viewer assigns .s7carouselviewer class to its container DOM element. If you are using an external CSS file passed with the style= command, use .s7carouselviewer class as parent class in descendant selector for your CSS rules. If you are adding embedded styles on the web page, additionally qualify this selector with an ID of the container DOM element as follows:


Building responsive designed CSS

It is possible to target different devices and embedding sizes in CSS to make your content display differently, depending on a user’s device or a particular web page layout. This includes, but is not limited to, different layouts, user interface element sizes, and artwork resolution.

The viewer supports two mechanisms of creating responsive designed CSS: CSS markers and standard CSS media queries. You can use these independently or together.

CSS markers

To assist in creating responsive designed CSS, the viewer supports CSS markers. These are special CSS classes that are dynamically assigned to the top-level viewer container element. They are based on the runtime viewer size and the input type used on the current device.

The first group of CSS markers contains .s7size_large, .s7size_medium, and .s7size_small classes. They are applied based on the runtime area of the viewer container. For example, if the viewer area is equal or bigger than the size of a common desktop monitor, use .s7size_large. If the area is close to a common tablet device, assign .s7size_medium. For areas similar to mobile phone screens, use .s7size_small. The primary purpose of these CSS markers is to create different user interface layouts for different screens and viewer sizes.

The second group of CSS markers contains .s7mouseinput and .s7touchinput. The CSS marker .s7touchinput is set if the current device is capable of touch input. Otherwise, .s7mouseinput is used. These markers are mostly intended to create user interface input elements with different screen sizes for different input types, because normally touch input requires larger elements.

The following sample CSS sets the zoom in button size to 28 x 28 pixels on systems with mouse input and to 56 x 56 pixels on touch input devices. If the viewer is sized even smaller, it is set to 20 x 20 pixels.

.s7carouselviewer.s7mouseinput .s7imagemapeffect .s7icon { 
.s7carouselviewer.s7touchinput .s7imagemapeffect .s7icon { 
.s7carouselviewer.s7size_small .s7imagemapeffect .s7icon { 

To target devices with different pixel density you need to use CSS media queries. The following media query block would contain CSS specific to high-density screens:

@media screen and (-webkit-min-device-pixel-ratio: 1.5) 

Using CSS markers is the most flexible way of building responsive designed CSS because it lets you target not only the device screen size but the actual viewer size, which is useful for responsive design layouts.

You can use the default viewer CSS file as an example of a CSS markers approach.

CSS media queries

You can also accomplish device sensing by using pure CSS media queries. Everything enclosed within a given media query block is applied only when it is run on a corresponding device.

When applied to Mobile Viewers use four CSS media queries, defined in your CSS, in the order listed below:

  1. Contains only rules specific for all touch devices.

    @media only screen and (max-device-width:13.5in) and (max-device- 
    height:13.5in) and (max-device-width:799px),  
    only screen and (max-device-width:13.5in) and (max-device-height:13.5in)  
    and (max-device-height:799px) 
  2. Contains only rules specific for tablets with high-resolution screens.

    @media only screen and (max-device-width:13.5in) and (max-device-height:13.5in) and (max-device-width:799px) and (-webkit-min-device-pixel-ratio:1.5), 
    only screen and (max-device-width:13.5in) and (max-device-height:13.5in) and (max-device-height:799px) and (-webkit-min-device-pixel-ratio:1.5)  
  3. Contains only rules specific for all mobile phones.

    @media only screen and (max-device-width:9in) and (max-device-height:9in) 
  4. Contains only rules specific for mobile phones with high-resolution screens.

    @media only screen and (max-device-width:9in) and (max-device-height:9in) and (-webkit-min-device-pixel-ratio: 1.5), 
      only screen and (device-width:720px) and (device-height:1280px) and (-webkit-device-pixel-ratio: 2), 
      only screen and (device-width:1280px) and (device-height:720px) and (-webkit-device-pixel-ratio: 2) 

Using a media queries approach, you should organize CSS with device sensing as follows:

  • First, the desktop-specific section defines all properties that are either desktop-specific or common to all screens.
  • And second, the four media queries go in the order defined above and provide CSS rules that are specific for the corresponding device type.

There is no need to duplicate the entire viewer CSS in each media query. Only properties that are specific to given devices are redefined inside a media query.

CSS sprites

Many viewer user interface elements are styled using bitmap artwork and have more than one distinct visual state. A good example is a button that normally has at least three different states: up, over, and down. Each state requires its own bitmap artwork assigned.

With a classic approach to styling, the CSS would have a separate reference to the individual image file on the server for each state of the user interface element. The following is a sample CSS for styling a zoom-in button:

.s7carouselviewer .s7imagemapeffect .s7icon { 
background-image: url(images/v2/imagemap/ImageMapEffect_icon1_light_up_touch.png); 
.s7carouselviewer .s7imagemapeffect .s7icon:hover { 
background-image: url(images/v2/imagemap/ImageMapEffect_icon1_light_over_touch.png); 

The drawback to this approach is that the end user experiences flickering or delayed user interface response when the element is interacted with for the first time. This action occurs because the image artwork for the new element state is not yet downloaded. Also, this approach may have a slight negative impact on performance because of an increase in the number of HTTP calls to the server.

CSS sprites is a different approach where image artwork for all element states is combined into a single PNG file called a “sprite”. Such “sprite” has all visual states for the given element positioned one after another. When styling a user interface element with sprites the same sprite image is referenced for all different states in the CSS. Also, the background-position property is used for each state to specify which part of the “sprite” image is used. You can structure a “sprite” image in any suitable way. Viewers normally have it vertically stacked.

The following is a “sprite”-based example of styling the same hot spot icon:

.s7carouselviewer .s7imagemapeffect .s7icon { 
background-image: url(images/v2/imagemap/ImageMapEffect_icon1_light_up_touch.png); 
background-position: -0px -56px; width: 56px; height: 56px; 
.s7carouselviewer .s7imagemapeffect .s7icon:hover { 
background-position: -0px -0px; width: 56px; height: 56px; 

General styling notes and advice

  • When customizing the viewer user interface with CSS the use of the !IMPORTANT rule is not supported to style viewer elements. In particular, !IMPORTANT rule should not be used to override any default or runtime styling provided by the viewer or Viewer SDK. The reason for this is that it may affect the behavior of proper components. Instead, you should use CSS selectors with the proper specificity to set CSS properties that are documented in this Viewers Reference guide.
  • All paths to external assets within CSS are resolved against the CSS location, not the viewer HTML page location. Be aware of this rule when you copy the default CSS to a different location. Either copy the default assets as well or update all the paths within the custom CSS.
  • The preferred format for bitmap artwork is PNG.
  • Bitmap artwork is assigned to user interface elements using the background-image property.
  • The width and height properties of a user interface element define its logical size. The size of the bitmap passed to background-image does not affect its logical size.
  • To use the high pixel density of high-resolution screens like Retina, specify bitmap artwork twice as large as the logical user interface element size. Then, apply the -webkit-background-size:contain property to scale the background down to the logical user interface element size.
  • To remove a button from the user interface, add display:none to its CSS class.
  • You can use various formats for color value that CSS supports. If you need transparency, use the format rgba(R,G,B,A). Otherwise, you can use the format #RRGGBB.

Common user interface elements

The following is user interface elements reference documentation that applies to the Video Image Viewer:

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