With transparency, you can make chart elements such as background pictures and gradients that apply to the entire chart
completely invisible in the chart
area. Also note that this setting can be applied to any chart element that
receives a color. For example, if you have a scatter chart and you want to hide
certain points, you can use the Point property and assign a transparent
color to only certain points in the chart.
Essentially, transparency is achieved by setting the 4th
parameter in the Color constructor as follows:
chart1.setInsideColor(java.awt.Color(0,0,0,0));
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Note: Setting the BackColor property to transparent
is only supported when generating PNG images using the Chart
FX for Java.
Semi-Transparency
In Chart FX for Java, the alpha blending feature is used
to display a chart element that has semi-transparent pixels.
In addition to a red, green and blue color channel, each pixel
in an alpha bitmap has a transparency component known as its
alpha channel. The alpha channel typically contains as many
bits as a color channel. For example, an 8-bit alpha channel
can represent 256 levels of transparency, from 0 (the entire
pixel is transparent) to 255 (the entire pixel is opaque).
For example, if you want to make the third series of your
chart a semi-transparent green, you will use the code as follows:
chart1.getSeries(2).setColor(java.awt.Color.(120,0,255,50));
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Changing the transparency of an object evenly reveals the image elements that
lie beneath the object and because semi-transparency can be applied to any
chart element that supports a color, you can create a myriad of effects. For
example, in a 3D oblique chart, you can make the first series semi-transparent
so other series are revealed in the 3D view or you can use the Point object to
have particular marker(s) display semi-transparency. Similarly, you can make
the chart background semi-transparent so a background image is blended into the
chart, create a nice watermark effect.
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