Blackberry BROWSER VERSION 4.7.0 - FUNDAMENTALS GUIDE Fundamentos - Página 33

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Fundamentals Guide
Property
image color depth
Enhanced image optimization is included in the BlackBerry MDS Connection Service network gateway (version 4.1.3 or later) and
the BlackBerry Internet Service Browsing network gateway. Enhanced image optimization is designed to provide an additional
15 to 20% size reduction. Higher quality images can be sent to the BlackBerry device without an increase in the use of bandwidth.
Enhanced image optimization applies only to GIF, PNG, and JPEG image formats.
Users with BlackBerry devices running BlackBerry® Device Software version 4.2.1 or later can specify the level of quality as low,
medium, or high for images sent to the BlackBerry device. For BlackBerry devices running earlier versions of the BlackBerry Device
Software, the network gateway sets the image quality as medium.

Progressive downloading of images

The BlackBerry® MDS Connection Service network gateway (version 4.1.3 or later) and the BlackBerry Internet Service Browsing
network gateway support progressive downloading of images. When the network gateway compresses an image, it also divides
the file into segments. It sends the file segments to the BlackBerry® Browser incrementally.
As the web page is rendered in the BlackBerry Browser, low quality placeholder versions of the images render quickly. After the
entire page is rendered, the browser receives the additional image file segments. As the additional file segments arrive, the
placeholder images are enhanced until the images meet the image quality that is specified by the user.

Pushed content delivery

You can notify users that new content is available or, depending on the network gateway, you can push new content directly to
the BlackBerry® device.
The level of support for pushing content depends on the network gateway.
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BlackBerry® MDS Connection Service: Among the three network gateways, the BlackBerry MDS Connection Service offers
the most support for pushed content delivery. Content is pushed directly to the BlackBerrydevice and is stored in a dedicated
cache for pushed content. You can develop the push service to place an icon on the Home screen (the icon changes to notify
the user of new content), to send the content to the message list (that appears like any other message), or to deliver the
content directly to the cache without any user notification. When the user next views the content, it is available on the
BlackBerry device; the user does not need to download it.
Description
The network gateway maintains the aspect ratio when it scales images.
Users can download the full image. The BlackBerry® Browser sends a secondary request to the
network gateway to deliver the image in its original form, with no optimization.
The BlackBerry MDS Connection Service and the BlackBerry Internet Service Browsing network
gateways reduce the color depth of the image to match the number of colors that the destination
BlackBerry device supports. This results in smaller file sizes and minimizes the use of bandwidth.
Pushed content delivery
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