public void setTransparentRGB(int[] transparentRGB) {
            transparency = (int[])(transparentRGB.clone());
            transparencySet = true;
        }
Sets the RGB value to be used to denote transparency.

<p> Setting this attribute will cause the alpha channel
of the input image to be ignored.

<p> The 'tRNS' chunk will encode this information.
plugins/svg-plugin/batik-codec-fix/src/main/java/org/apache/batik/ext/awt/image/codec/png/PNGEncodeParam.java