DesktopX 2.4 Developer’s Guide
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Page 18
transparency information with the file, which means that although the saved image may be a
rectangle, the actual image that you see on your screen can be any shape you want, because the
background is visible when transparent areas of the object exist.
This image on the left is a PNG image created in
Macromedia Fireworks with a checkerboard effect
showing the transparency.
When this image is used in DesktopX all
transparency is preserved and the background
shows through as you can see on the right.
DesktopX even allows this sort of effect in image formats that don't support transparency such as
BMP. In these image formats, DesktopX will interpret the color referred to as magic pink to be
transparent. 'Magic pink' is pure pink with an RGB value of 255,0,255.
Although using this method you can't have a graduated transparency as you
find in the PNG example, you can make a close approximation. Note, that you
need hard crisp edges as if you 'anti-alias' to soften the object edges, your
object will have a pink glow as these colors are not pure 'magic pink'.
One final advanced tip for you. If you're forced to use BMP images 'magic
pink' for transparency there is a final enhancement you can make to achieve
graduated transparency like PNG files can provide.
What you need to do is double the height of your source image and in the lower
half use grayscales to indicate the level of transparency. This is best explained
by looking at the image on the right.
Black represents total transparency, and the closer you get to white the more
the object will appear.
If you use this graphic normally you will see the grayscale part, so you need to
go to the transparency tab and check the box that says “The object’s
transparency is set by the graphic used”.
