# Show a photograph

A how-to guide: convert a real photograph to teletext cells with sextants and
place it on a page — full-screen, and as a thumbnail beside a post's text.

```{sextile-frame}
:page: "1"
:show-code:

import sextants

from sextile import OnOneFrame, Page, PageLayout, PageRequest, PageRouter, Sextile
from sextile.viewdata.tiles import Tile

router = PageRouter()

_photo = sextants.PRESETS["photo"]
_CELLS = sextants.convert_fragment(
    "docs/_static/blue-marble.jpg",
    40,
    20,
    fit=sextants.Fit.PAD,
    preprocess=_photo.preprocess,
    solve=_photo.solve,
).data


@router.page("1", name="photo", title="The Blue Marble")
async def photo(request: PageRequest) -> Page:
    return PageLayout(parts=[OnOneFrame(Tile.from_bytes(_CELLS, 40))]).build(request)


app = Sextile(name="Gallery", pages=[*router])
```

[sextants](https://pypi.org/project/sextants/) solves an image into teletext
cells; `convert_fragment(image, 40, 20, fit=Fit.PAD)` fills the content area and
`Tile.from_bytes` reads the bytes onto a `Tile` the page places. The `photo`
preset (`sextants.PRESETS["photo"]`) suits continuous-tone photographs, which
teletext has no in-between shades for — a bold, high-contrast subject like the
Earth still reads. Sextile never imports sextants; it only places the cells.

For a post that shows a picture beside its text, place a small thumbnail as one
part and the words as another:

```{sextile-frame}
:page: "2"
:show-code:

import sextants

from sextile import Lines, OnOneFrame, Page, PageLayout, PageRequest, PageRouter, Sextile
from sextile.viewdata.tiles import Tile

router = PageRouter()

_photo = sextants.PRESETS["photo"]
_fragment = sextants.convert_fragment(
    "docs/_static/blue-marble.jpg",
    16,
    8,
    fit=sextants.Fit.CONTAIN,
    preprocess=_photo.preprocess,
    solve=_photo.solve,
)


@router.page("2", name="post", title="A post")
async def post(request: PageRequest) -> Page:
    thumbnail = Tile.from_bytes(_fragment.data, _fragment.width)
    words = Lines(["The Blue Marble: Earth seen", "from Apollo 17, photographed", "in December 1972."])
    return PageLayout(parts=[OnOneFrame(thumbnail), OnOneFrame(words)]).build(request)


app = Sextile(name="Forum", pages=[*router])
```

`Fit.CONTAIN` sizes the thumbnail to the image's own proportions within the box;
the parts stack down the frame in order, the picture above the words. The full
API is {py:mod}`sextile.viewdata.tiles`; converting bold poster art rather than a
photograph is {doc}`show-a-picture`, and a chart or an icon is {doc}`draw-charts`
and {doc}`draw-icons`.
```

The photograph is *The Blue Marble (Earth from Apollo 17)* by the NASA/Apollo 17
crew — Harrison Schmitt or Ron Evans — December 1972, public domain, via
[Wikimedia Commons](https://commons.wikimedia.org/wiki/File:The_Earth_seen_from_Apollo_17.jpg).