To be able to create animated visual transitions between Web pages. To be able to modify filters dynamically, using DHTML. Prentice Hall, Inc. All rights. DHTML Filter Session There are two types of filters: visual filter and transitions. A visual filter affects the appearance of the content. greater variety of special effects. To be able to create animated visual transitions between Web pages. To be able to modify filters dynamically, using DHTML.
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Filters are considered subobjects of the object to which they are attached. You can use CSS filters to add special effects to text, images and other aspects of a webpage without using images or other graphics. Transirions simply, having layout means that an object has a defined height and width. The default value is left.
X-Ray effect grayscales and flattens the color depth. Another benefit of filters is that they dhhml easier to author and can be applied to entire classes of elements, because they use the declarative and inherited syntax of CSS. In this example, an interactive step is added to the previous television caption example, so that the caption displays only when the mouse pointer is over the inline image.
Dynamic HTML: Filters and Transitions
dhtm, A transition’s apply method freezes the appearance of an object when applying a transition. The Alpha filter is a good example of a visual filter. Visual effects can be animated filers a timer script. Best of all, this is all done in code and doesn’t require downloading additional graphics from a server.
The event object supplies the necessary information about the filter and the object involved. The first meta tag causes the Blinds transition to play when the user loads the page, lasting four seconds; the second meta tag causes a Slide transition to play when the user exits the page, lasting 2.
Transitions should follow any static filters in the filter string.
Interpage transitions enable you to provide effects for the entire window as a Web page is loaded or exited. Remember that image downloading is asynchronous, and the visual state of objects isn’t fully updated until after images are completely downloaded.
One way to avoid this is to apply the filter to a DIV that contains all of the elements of the document. Text with no background color or image automatically has transparency; the space around the characters shows through to the object or page behind it. Transitions have methods and events to manage the timing of the effect.
Computer-based training applications can use timed transitions to demonstrate their subject matter, as shown in the following example. If it is a transparent image, then glow is created around the opaque pixels of it.
Introduction to Filters and Transitions (Internet Explorer)
Clicking the button runs the doTrans script, which calls the apply method on the Blinds transition to stop painting the image. It is also possible to apply transitions while events are fired on the page.
Using filters simplifies the task of incorporating sophisticated effects in Web documents. The BasicImage and MotionBlur filters are both applied to the object.
The following example shows how to work around applying a filter to the BODY element. You can use timers to create cyclical effects. In this chapter, we will see the details of each CSS filter.
This example shows how both the BasicImage and Alpha filters can visually represent unavailable link states. The direction of the blur, going clockwise, rounded to degree increments. The following example uses transitions to display information in an interesting manner as the page loads. One example is changing the src attribute of an image to display a new image on-screen.
Motion Blur is used to create blurred pictures or text with the direction and strength. A filters collection is available on every object to provide access to the individual filters of each object.
Filters and Transitions
This article includes the following sections, dilters explain how to use filters ane transitions to add visual effects to your Web page. Number of pixels the drop shadow is offset from the visual object, along the x-axis. Click to view sample. When the filter will be displayed, the script can set the Enabled property of that filter to true.
For complex filter manipulation, you must keep track of the current states of the filter collections. This allows changes to be made without affecting the display immediately. In some cases, filters create simple behaviors that could be implemented as script.
The BODY element automatically has layout because it specifically contains the client area of the window. For example, the following HTML causes the image to be 20 percent opaque.
Four events can create instances of interpage transitions: The Style object also has a filter property.
Invert effect is used to map the colors of the object to their opposite values in the color spectrum, i. You can use the event object to access the srcFilter property.