Adobe Flash Professional CS3 Instrukcja Użytkownika Pobierz pdf (Strona 493)

FLASH CS3

User Guide

487

Optimizing graphics and animation

Before you create optimized and streamlined animations or graphics, outline and plan your project. Make a target

for the file size and length of the animation, and test throughout the development process.

Follow these guidelines to optimize graphics and animation:

• Avoid using gradients, because they require many colors and calculations to be processed, which is more difficult

for a computer processor to render.

• For the same reason, keep the amount of alpha or transparency you use in a SWF file to a minimum.

Animating objects that include transparency is processor-intensive and should be kept to a minimum. Animating

transparent graphics over bitmaps is a particularly processor-intensive kind of animation, and must be kept to a

minimum or avoided completely.

Note: ThebestbitmapformattoimportintoFlashisPNG,whichisthenativefileformatofMacromediaFireworksfrom

Adobe. PNG files have RGB and alpha information for each pixel. If you import a Fireworks PNG file into Flash, you

retain some ability to edit the graphic objects in the FLA file.

• Optimize bitmaps without overcompressing them. A 72-dpi resolution is optimal for the web. Compressing a

bitmap image reduces file size, but compressing it too much compromises the quality of the graphic. Check that

the settings for JPEG quality in the Publish Settings dialog box do not overcompress the image. Representing an

image as a vector graphic is preferable in most cases. Using vector images reduces file size, because the images are

made from calculations instead of many pixels. Limit the number of colors in your image while still retaining

quality.

Note: Avoid scaling bitmaps larger than their original dimensions, because it reduces the quality of the image and is

processor intensive.

• Set the _visible property to false instead of changing the _alpha levelto0or1inaSWFfile.Calculatingthe

_alpha level for an instance on the Stage is processor intensive. If you disable the instance’s visibility, it saves CPU

cycles and memory, which can give your SWF files smoother animations. Instead of unloading and possibly

reloading assets, set the

_visible property to false, which is less processor-intensive.

• Reduce the number of lines and points you use in a SWF file. Use the Optimize Curves dialog box (Modify >

Shape>Optimize)toreducethenumberofvectorsinadrawing.SelecttheUseMultiplePassesoptionformore

optimization. Optimizing a graphic reduces file size, but compressing it too much compromises its quality.

However, optimizing curves reduces your file size and improves SWF file performance. Third-party options are

available for specialized optimization of curves and points that yield different results.

To get the best results, try different ways of producing animated content, and test each of the options.

A higher frame rate (measured in frames per second, or fps)producessmoothanimationinaSWFfilebutitcanbe

processor-intensive, particularly on older computers. Test your animations at different frame rates to find the lowest

frame rate possible.

For a sample of scripted animation, see the Flash Samples web page at www.adobe.com/go/learn_fl_samples.

Download and decompress the Samples zip file and navigate to the ActionScript2.0/Animation folder to access the

sample.

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Adobe Flash Professional CS3 Instrukcja Użytkownika Strona 493