Quoting David Gowers <00ai99@xxxxxxxxx>: > On 3/3/07, saulgoode@xxxxxxxxxxxxxxxxxxxxxxxxxxxxx < > saulgoode@xxxxxxxxxxxxxxxxxxxxxxxxxxxxx> wrote: >> >> Quoting zhang chi <zhangchipr@xxxxxxxxx>: >> >>> >> http://www.gimptalk.com/forum/topic/My-First-Tutorial-Blending-Images-In-Gimp-106-1.html >> <gimp-developer@xxxxxxxxxxxxxxxxxxxxxx> >>> >>> in this tut, after feather,C-i,and C-K is used, but what algorithm is >> used >>> when using Ctrl-k ? >>> >>> thank you <gimp-developer@xxxxxxxxxxxxxxxxxxxxxx> >> >> >> If the layer has an alpha channel then the value of the alpha is >> scaled by (1 - S) where "S" is the selection mask's value (which spans >> the range '0=not selected' to '1=fully selected' -- the selection is >> actually a value from 0 to 255). >> >> If there is no alpha channel then the value of each of the components >> (RGB) is scaled by (1 - S) and added to the product of the >> corresponding component of the active background color and (1 - S). >> >> For Indexed Mode images, the resulting pixel is the active BG color if >> S>0.5 and unchanged if S<0.5 > > > For Indexed Mode Images, the resulting pixel is the active BG color if the > layer has no alpha and S > 0.5, (emptiness) if S > 0.5 and the layer has an > alpha channel, and unchanged if S < 0.5. Oops, forgot that case. Also, there is an error in my description: >> If there is no alpha channel then the value of each of the components >> (RGB) is scaled by (1 - S) and added to the product of the >> corresponding component of the active background color and (1 - S). The very last term in the sentence should be "S" -- not "(1 - S)". _______________________________________________ Gimp-developer mailing list Gimp-developer@xxxxxxxxxxxxxxxxxxxxxx https://lists.XCF.Berkeley.EDU/mailman/listinfo/gimp-developer
