MACROMEDIA FLASH
PNG publish settings
PNG is the only cross-platform bitmap format that supports transparency
(alpha channel). It is also the native file format for Macromedia
Fireworks.
Flash exports the first frame in the movie as a PNG, unless you mark a
different keyframe for export by entering the frame label #Static.
Use the controls in the PNG panel of the Publish Settings dialog box to
change the following settings:
Dimensions Sets the size of the exported bitmap image to the
number of pixels you enter in the Width and Height fields. If you turn on
Match Movie, the entries in the Width and Height fields have no effect and
Flash makes the PNG the same size as the movie. Flash ensures that the
size you specify always has the same aspect ratio as your original image.
Bit Depth Specifies the number of bits per pixel to use in
creating the image. The bit depth determines the number of colors to be
used in the image. For a 256-color image, choose 8-bit; for thousands of
colors, choose 24-bit; for thousands of colors with transparency (32 bits)
choose 24-bit with Alpha. The higher the bit depth, the larger the file.
Options Specify a range of appearance settings for the exported
PNG.
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Optimize Colors removes any unused colors from the color table
of a PNG file. This can reduce the size of a PNG file by 1000-1500
bytes with no sacrifice in image quality. It does, however, cause
a small increase in the memory requirements and processing
required on the server. Note that this option has no effect with
an adaptive palette. |
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Smooth enables or disables anti-aliasing in the exported bitmap.
Smoothing produces a higher quality bitmapped image. Text display
quality is poor without anti-aliasing. However, a halo of gray
pixels may appear around an image placed on a colored background.
Export without smoothing if a halo appears, or if you are creating
a transparent PNG that will be placed over a multicolored
background. Turning this option off makes PNG files smaller. |
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Interlace makes the exported PNG display in a browser
incrementally as it downloads. An interlaced PNG provides the user
with basic graphic content before the file has completely
downloaded and may download faster over a slow network connection. |
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Dither Solids applies dithering to solid colors as well as
gradients and images. see the definition of dithering that
follows. |
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Transparent displays a transparent PNG. A transparent PNG allows
the background of your web browser to show through the portions of
the PNG where you have not drawn any images. If you create a
transparent PNG, set the background color by choosing Modify >
Movie to match the web page background. Use the Smooth options to
further optimize the color match. |
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Remove Gradients converts all gradient fills in the movie to
solid colors using the first color in the gradient. Gradients
increase the size of a PNG and often are of poor quality. When
using this option you must choose the first color of your
gradients carefully to prevent unexpected results. The default is
false. |
Dither Enables or disables dithering and specifies the method.
Dithering displays pixels of a range of similar colors to simulate colors
not available in the current palette. With dithering off, Flash replaces
colors not in the basic color table with the solid color from the table
that most closely approximates the specified color; not dithering can
produce smaller files, but check the results to see if the colors are
satisfactory. Dithering can help if a transparent image contains
artifacts. Dithering increases the files size. Choose from the following
dithering options:
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None disables dithering. |
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Ordered provides good quality dithering with the least possible
file size increase. |
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Diffusion provides the best quality dithering but increases file
size more than Ordered dithering. It also only works with the Web
216 color palette selected. |
Palette Type Defines the color palette to use for the image.
Choose from the following options:
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Web 216 uses the standard 216-color browser-safe color palette
to create the PNG image. This provides good image quality and the
fewest color problems in all types of browsers. |
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Adaptive analyzes the colors in the image and creates a unique
color table for the particular PNG. This creates the most accurate
color for the image but the resulting file size is larger than a
PNG created with the Web 216 palette. You can reduce the size of a
PNG created with an adaptive palette by decreasing the number of
colors in the palette (see the Max Colors option that follows). An
adaptive palette works best for systems displaying thousands or
millions of colors. |
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Web Snap Adaptive is the same as the Adaptive palette option
except that it "snaps" close colors to the Web 216 color
palette. The resulting color palette is optimized for the image,
but when possible, Flash uses colors from Web 216. This produces
better colors for the image when the Web 216 palette is active on
a 256-color system. |
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Custom lets you specify a palette that you have optimized for
the current image. To use this option you must be familiar with
creating and using custom palettes. To choose a custom palette,
click "..." to the right of the Palette box at the
bottom of the dialog box and select a palette file. Flash supports
palettes saved in the ACT format. This is the same format exported
by Macromedia Fireworks and other leading graphics applications. |
Max Colors Sets the number of colors used in the PNG image.
Choosing a smaller number of colors can produce a smaller file, but may
degrade the colors in the image. You can specify a value for the maximum
colors only when you have selected Adaptive or Web Snap as the Palette
Type option.
Filter Options Specifies the filtering method for the PNG. Prior
to compression, a PNG image is filtered line-by-line to make it more
compressible. Compare the results of the different options to see which
works best for a particular image. The choices are the standard PNG
filtering options:
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None provides no filtering. |
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Sub transmits the difference between each byte and the value of
the corresponding byte of the prior pixel. |
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Up transmits the difference between each byte and the value of
the corresponding byte of the pixel immediately above. |
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Average uses the average of the two neighboring pixels (left and
above) to predict the value of a pixel. |
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Paeth computes a simple linear function of the three neighboring
pixels (left, above, upper left), then chooses as predictor the
neighboring pixel closest to the computed value. |
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