PA mode handling is wonky

Or. half baked.

We 'support' a mode called PA which is palette with alpha, stored in 4 bytes per pixel. (FWIW, I think this all applies to LA as well)

Image.putpalette (https://github.com/python-pillow/Pillow/blob/master/PIL/Image.py#L1447) only allows for L or P images when adding a palette:

        if self.mode not in ("L", "P"):
            raise ValueError("illegal image mode")

_imaging.c:_putpalette Also only accepts* L and P. This code was in PIL:

    if (strcmp(self->image->mode, "L") != 0 && strcmp(self->image->mode, "P")) {
        PyErr_SetString(PyExc_ValueError, wrong_mode);
        return NULL;

* or rather, it looks like it should but only actually accepts if mode ==Pand mode !='L'

TiffImagePlugin:_setup (https://github.com/python-pillow/Pillow/blob/master/PIL/TiffImagePlugin.py#L1137) only includes the palette for P images.

        if self.mode == "P":
            palette = [o8(b // 256) for b in self.tag_v2[COLORMAP]]
            self.palette = ImagePalette.raw("RGB;L", b"".join(palette))

All of this found while checking out #1597.

I've created PR #3728 to help this.

While I don't understand this comment, it does pass tests.

_imaging.c:_putpalette Also only accepts* L and P. This code was in PIL:
if (strcmp(self->image->mode, "L") != 0 && strcmp(self->image->mode, "P")) {
    PyErr_SetString(PyExc_ValueError, wrong_mode);
    return NULL;
or rather, it looks like it should but only actually accepts if mode ==Pand mode !='L'

I've created PR #3848 to resolve this.

Navigation Menu

Repository navigation

PA mode handling is wonky #1600

Metadata

Assignees

Labels

Type

Projects

Milestone

Relationships

Development

PA mode handling is wonky #1600

Description

Activity

radarhere commented on Mar 19, 2019

radarhere commented on May 18, 2019

Metadata

Metadata

Assignees

Labels

Type

Projects

Milestone

Relationships

Development

Issue actions