[Pillow] Kako shranit PNG (mode P) sliko v JPEG?

Dobro zgodnje jutro.

Evo, fantje in dekline, nov dan, nov izziv.

Source image je tole:
Zdej me pa zanima, kako konvertat to sliko v jpeg format, in to tako, da tist "transparenten" background okrog konzerve ne postane zelen (ali črn)?

Trenutni sample:

import io;
import PIL.Image;

image = PIL.Image.open("/home/sepultura/arise/minerva_in.png");

print("image mode [1]: " + str(image.mode));
print("image format [1]: " + str(image.format));

plan = "a";

if image.mode in ["1", "8", "L", "P", "CMYK", "RGBA", "LA"]:

    # plan a
    if plan == "a":

        image = image.convert("RGB");

    # plan b
    elif plan == "b":

        if image.format == "PNG":

            image = image.convert("RGBA");

        else:

            image = image.convert("RGB");

    print("image mode [2]: " + str(image.mode));
    print("image format [2]: " + str(image.format));

image.save("/home/sepultura/arise/minerva_out.jpeg", format="JPEG", optimize=True);

image.close();

Če grem plan a, dobim na output-u warning:

UserWarning: Palette images with Transparency expressed in bytes should be converted to RGBA images

Print:

image mode [1]: P
image format [1]: PNG
image mode [2]: RGB
image format [2]: None

In končno sliko:



Če grem plan b, dobim na output-u error:

OSError: cannot write mode RGBA as JPEG

Print:

image mode [1]: P
image format [1]: PNG
image mode [2]: RGBA
image format [2]: None

Že od prej imam link na tole: PIL remove error "UserWarning: Palette images with Transparency expressed in bytes should be converted to RGBA images"

No, zdej moram to nekako rešit. Kako PNG sliko, ki je v mode P, shranit v JPEG format? Pa da bo lepo zgledalo, kot na izvoru.

if image.format == "PNG":
    image = image.convert("RGBA");
    bg = Image.new('RGBA', image.size, (0, 155, 0, 0))
    final_image = Image.alpha_composite(bg,image)
    ...

No comment ...

Uporabljaj raje TIFF.

*sigh*

Sem prebral, da želiš zeleno ozadje. JPEG ne podpira prosojnosti, saj to veš, ne?
In moja koda ni bila popolna. Če želiš shraniti JPEG, moraš najprej narediti nazaj convert v RGB mode. Na primer:

>>> from PIL import Image
>>> img = Image.open("Minerva-in.png")
>>> img = img.convert("RGBA")
>>> bg = Image.new("RGBA",img.size,(255,255,255,255))
>>> end = Image.alpha_composite(bg,img)
>>> end_jpg = end.convert("RGB")
>>> end_jpg.save("Minerva-out.jpeg")

To naredi JPG z belim ozadjem, kar si si verjetno želel.

Je pa python koda s podpičji res zakon. Thumbs up!

Odlično.