how to cut two holes in a PNG one after the other

[ravikum]

Hello,
I have this image :

Image1.png :


I cut a hole in this image using the mask of same width and height :
mask1.png : (black and white image with no transparency)

Code: Select all

convert image1 mask1 -alpha Off -compose CopyOpacity -composite image2

and the result :
Image2.png :


I have another mask of same width and height :
Mask2.png : (black and white image with no transparency)



I wish to cut another hole in image 2 using mask 2 without erasing the first hole.

I tried the same command given above and it created the second hole, but erased the first hole.

If there is any other method, please inform.

Please help.
Thanks

[snibgo]

"CopyOpacity" replaces all the alpha values in the image with values from the mask. The trick is to manipulate the mask. There are many ways to do this. Windows BAT syntax; adjust for other shells. (For Unix, escape parentheses \( and \) and use \ instead of ^ at line ends.)

Method 1. If you have only two masks:

Code: Select all

convert ^
  Image1.png ^
  ( mask1.png ^
    mask2.png ^
    -compose Darken -composite ^
    -write x.png ^
  ) ^
  -alpha off ^
  -compose CopyOpacity -composite ^
  out.png

Method 2. If you have any number of masks, and want to have separate convert commands, chained together.

Code: Select all

convert ^
  Image1.png ^
  mask1.png ^
  -alpha off ^
  -compose CopyOpacity -composite ^
  out1.png

convert ^
  out1.png ^
  ( +clone ^
    -alpha extract ^
    mask2.png ^
    -compose Darken -composite ^
    -write x.png ^
  ) ^
  -alpha off ^
  -compose CopyOpacity -composite ^
  out2.png

[ravikum]

Thanks a lot for your reply.
I will use your code.