| Image file: |
PNG or GIF images with bright colours and sharp edges usually yield the
best results. JPEG images produce poor shadows since edges are
not sharp and the background colour is indistinct. If you leave
the file name blank, a sample image
will be used; this permits experimenting with various settings
without the need to upload your image file each time.
In addition to PNG, GIF, and JPEG, you can also submit files in
TIFF; X Windows Bitmap, Pixmap, and Window Dump formats;
all variants of the PBMplus and Netpbm portable raster formats; and
Silicon Graphics RGB format, assuming your browser is configured to understand
them and you've given the file a name which identifies its
contents to your browser. In case of difficulty, convert the file
to PNG and try again.
|
| Output image format: |
JPEG images are usually smaller than PNGs but often
contain unattractive artifacts of lossy compression,
especially if the original image had sharp edges and
and prominent colour contrasts. JPEG sometimes produces
better results when translucent shadows or a small
image scale is selected. GIF is provided for compatibility
with legacy systems; files are smaller but limited in colour
gamut.
|
| Blur size: |
0 = no blur, 25 = maximum blur
The larger the blur size, the more diffuse the shadow. A blur size
of zero results in a sharp-edged shadow, as cast by the Sun.
|
| Shadow offset: |
Horizontal:
Vertical:
The offsets specify the number of pixels the shadow is shifted to
the right and below the original image. If the image submitted does
not contain sufficient space to the right and bottom to hold the shadow,
it will be truncated.
If unspecified, offsets default to half the blur size or two pixels,
whichever is less.
|
| Shadow colour: |
Transmission:
By default, shadows are always black, as cast by opaque
objects. If Translucent is selected, shadows take on the
colour of the object which casts them.
Depending on the image, this may create an attractive
“stained glass” effect. Translucent shadows generally
look best when the shadow is darkened compared to the casting
object (as occurs due to absorption). The transmission field
controls how much simulated light passes through the object.
Transmission of 0.0, complete absorption, is equivalent to checking
Black shadows, while 1.0, total transmission, yields shadows as
bright as the casting object. Intermediate settings often produce
the most attractive results.
|
| Output image scale: |
Shadow generation works best when the original image has sharp
boundaries between the content and the background colour. After
the shadow is added, the appearance of the image may be improved by
resampling it into a smaller image, smoothing jagged edges
by the averaging process. To create a smooth image with
a good-looking shadow, prepare the original image at a larger scale
than the image you want to publish, then select the corresponding
image scale so the image with shadow is reduced in size to yield
the desired image.
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