Any DOM element whose source format is not in RGB colorspace (e.g CYMK) is initially converted into RGB colorspace as usually performed by browsers [REF?] if access to at least one of R, G or B component is required.
Table XXX.Y summarizes the supported conversions with :
Arepresenting the alpha-channel component value, when it is unspecified the default value 1.0 is used.
Rrepresenting the red color-channel component value, if available, or the luminance-channel component value otherwise.
A sourcecolumn being given for completeness only, as browsers traditionally do not support image formats that can define just one alpha-channel.
|internalformat parameter||Storage representation||RGBA source||RGB source||RA source||R source||A source|
|A||0, 0, 0, A||0, 0, 0, 1||0, 0, 0, A||0, 0, 0, R||0, 0, 0, A|
|R||R, R, R, 1||R, R, R, 1||R, R, R, 1||R, R, R, 1||A, A, A, 1|
|RA||R, R, R, A||R, R, R, 1||R, R, R, A||R, R, R, 1||0, 0, 0, A|
|RGB||R, G, B, 1||R, G, B, 1||R, R, R, 1||R, R, R, 1||A, A, A, 1|
|RGBA||R, G, B, A||R, G, B, 1||R, R, R, A||R, R, R, 1||0, 0, 0, A|