andres, it seems a lot of the problems were fixed with your recent alterations to the source code. I just downloaded and compiled the latest svn-build 0216. And then I re-tested the three code examples from this thread with my WinXP+Radeon system. Good news. All three of them work correctly now!
Example 1
Setting transparent pixels works now under all smooth() and noSmooth() settings. Subsequent calls to begin-endDraw also leave both the transparant and opaque pixels intact.
Example 2
The drawing is cumulative when no background() call is made under all smooth() settings and for both opaque and transparent backgrounds.
Example 3
As you mentioned the mirror pixel issue has been solved, so this example now draws correctly.
Example 1
Setting transparent pixels works now under all smooth() and noSmooth() settings. Subsequent calls to begin-endDraw also leave both the transparant and opaque pixels intact.
Example 2
The drawing is cumulative when no background() call is made under all smooth() settings and for both opaque and transparent backgrounds.
Example 3
As you mentioned the mirror pixel issue has been solved, so this example now draws correctly.