How to merge a transparent png image with another image using PIL

Question

I have a transparent png image  foo png  and I ve opened another image with   im   Image open  foo2 png      now what i need is to merge foo png with foo2 png     foo png contains some text and I want to print that text on foo2 png

User · Answer

Had a similar question and had difficulty finding an answer  The following function allows you to paste an image with a transparency parameter over another image at a specific offset      import Image  def trans paste fg img bg img alpha 1 0 box  0 0        fg img trans   Image new  RGBA  fg img size      fg img trans   Image blend fg img trans fg img alpha      bg img paste fg img trans box fg img trans      return bg img  bg img   Image open  bg png   fg img   Image open  fg png   p   trans paste fg img bg img  7  250 100   p show

User · Answer

from PIL import Image  background   Image open  quot test1 png quot   foreground   Image open  quot test2 png quot    background paste foreground   0  0   foreground  background show    First parameter to  paste   is the image to paste  Second are coordinates  and the secret sauce is the third parameter  It indicates a mask that will be used to paste the image  If you pass a image with transparency  then the alpha channel is used as mask  Check the docs

User · Answer

As olt already pointed out  Image paste doesn t work properly  when source and destination both contain alpha   Consider the following scenario   Two test images  both contain alpha      layer1   Image open  layer1 png   layer2   Image open  layer2 png     Compositing image using Image paste like so   final1   Image new  RGBA   layer1 size  final1 paste layer1   0 0   layer1  final1 paste layer2   0 0   layer2    produces the following image  the alpha part of the overlayed red pixels is completely taken from the 2nd layer  The pixels are not blended correctly      Compositing image using Image alpha composite like so   final2   Image new  RGBA   layer1 size  final2   Image alpha composite final2  layer1  final2   Image alpha composite final2  layer2    produces the following  correct  image

User · Answer

I ended up coding myself the suggestion of this comment made by the user  P Melch and suggested by  Mithril on a project I m working on  I coded out of bounds safety as well  here s the code for it   I linked a specific commit because things can change in the future of this repository  Note  I expect numpy arrays from the images like so np array Image open       as the inputs A and B from copy from and this linked function overlay arguments  The dependencies are the function right before it  the copy from method  and numpy arrays as the PIL Image content for slicing  Though the file is very class oriented  if you want to use that function overlay transparent  be sure to rename the self frame to your background image numpy array  Or you can just copy the whole file  probably remove some imports and the Utils class  and interact with this Frame class like so    Assuming you named the file frame py in the same directory from frame import Frame  background   Frame   overlay   Frame    background load from path  quot your path here quot   overlay load from path  quot your path here quot    background overlay transparent overlay frame  x 300  y 200   Then you have your background frame as the overlayed and alpha composited array  you can get a PIL image from it with overlayed   Image fromarray background frame  or something like  overlayed   Frame   overlayed load from array background frame   Or just background save  quot save path quot   as that takes directly from the alpha composited internal self frame variable  You can read the file and find some other nice functions with this implementation I coded like the methods get rgb frame array  resize by ratio  resize to resolution  rotate  gaussian blur  transparency  vignetting    You d probably want to remove the resolve pending method as that is specific for that project  Glad if I helped you  be sure to check out the repo of the project I m talking about  this question and thread helped me a lot on the development

User · Answer

def trans paste bg img fg img box  0 0        fg img trans   Image new  RGBA  bg img size      fg img trans paste fg img box mask fg img      new img   Image alpha composite bg img fg img trans      return new img

User · Answer

Image paste does not work as expected when the background image also contains transparency  You need to use real Alpha Compositing   Pillow 2 0 contains an alpha composite function that does this    background   Image open  test1 png   foreground   Image open  test2 png    Image alpha composite background  foreground  save  test3 png     EDIT  Both images need to be of the type RGBA  So you need to call convert  RGBA   if they are paletted  etc   If the background does not have an alpha channel  then you can use the regular paste method  which should be faster

User · Answer

One can also use blending   im1   Image open  im1 png   im2   Image open  im2 png   blended   Image blend im1  im2  alpha 0 5  blended save  blended png

[python] How to merge a transparent png image with another image using PIL

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