effect of ROPs on background

reverse polish notation! read right to left!

P       Selected pen
D       Destination bitmap
a       Bitwise AND
n       Bitwise NOT (inverse)
o       Bitwise OR
x       Bitwise exclusive OR (XOR)

1       R2_BLACK        0       makes everything black
2       R2_NOTMERGEPEN  DPon    black outlining leaves bg unchanged, else pen is inverted and translucent (correct when bg is black, else darker)
3       R2_MASKNOTPEN   DPna    black outlining leaves bg unchanged, else pen is inverted and translucent (correct when bg is white, else darker)
4       R2_NOTCOPYPEN   Pn      overwrites bg, inverted drawing color
5       R2_MASKPENNOT   PDna    white outlining leaves bg unchanged, else pen is translucent (correct when bg is black, else darker)
6       R2_NOT          Dn      reverses bg: outlining or overlap shows bg unchanged (it's inverted twice)
7       R2_XORPEN       DPx     the coolest
8       R2_NOTMASKPEN   DPan    white outlining leaves bg unchanged, else pen is inverted and translucent (correct when bg is black, else lighter)
9       R2_MASKPEN      DPa     white outlining leaves bg unchanged, else pen is translucent (correct when bg is white, else darker)
10      R2_NOTXORPEN    DPxn    similar to xor
11      R2_NOP          D       drawing is invisible
12      R2_MERGENOTPEN  DPno    drawing in white leaves bg unchanged, else pen is inverted and translucent (opaque when bg is black)
13      R2_COPYPEN      P       straight copy
14      R2_MERGEPENNOT  PDno    black outlining leaves bg unchanged, else pen is translucent (correct when bg is white)
15      R2_MERGEPEN     DPo     black outlining leaves bg unchanged, else pen is translucent (correct when bg is black)
16      R2_WHITE        1       makes everything white