Better allergen icons: mdi:barley for rye, and distinct icons across the board

[krissen]

Spun off from #63, where @zeus86 suggested changing the rye icon from mdi:grain to mdi:barley. Good call: mdi:grain is a dot pattern (grain as in film grain) and has nothing to do with cereal, while mdi:barley is an actual ear of grain.

Looking at the icon map as a whole, there is more to do than rye. Today 7 allergens share mdi:leaf (beech, dock/sorrel, linden, nettle family, oak, olive, plantain), 8 share mdi:tree (ash, birch, elm, plane tree, sweet chestnut, tree of heaven, willow, and alder on the outline variant), and mugwort/ragweed share mdi:flower-pollen with the default. In a device list they are hard to tell apart at a glance.

Plan for 0.5.4 (planned for about a week out):

• rye: mdi:grain → mdi:barley (already implemented on the dev branch)
• Differentiate the remaining allergen icons: from 9 distinct icons today to 13, grouped by pollen source (deciduous trees, catkin trees, conifers, evergreens, grasses, cereals, weeds, leafy herbs, fungal spores). The MDI catalog has no species-specific plant icons, so meaningful groups beat arbitrary uniqueness; the groups roughly follow cross-reactivity, which is a bonus.

Note: these icons only show in Home Assistant's own UI (device page, entity lists, auto-generated dashboards). Pollenprognos-card uses its own icons and is unaffected.

[zeus86]

some other useable icons would be:

mdi:clover
mdi:corn
mdi:flower
mdi:flower-poppy
mdi:flower-tulip
mdi:mushroom
mdi:nature
mdi:palm-tree
mdi:seed
mdi:sprout

...and their respective "outline" variants if available. a list that is somewhat easy browseable can be found here

[krissen]

Thanks for the list! Four of your suggestions are in fact already part of the new map on the dev branch: mdi:flower, mdi:flower-poppy, mdi:sprout and mdi:mushroom, plus mdi:tree-outline from the outline variants.

Here is the full mapping as it stands on dev, planned for 0.5.4. The guiding idea: MDI has no species-specific plant icons, so icons group the allergens by pollen source, and a shared group icon beats an icon that depicts the wrong plant. The name next to the icon then tells the species apart.

Group	Allergens	Icon
Catkin trees (early spring)	alder, birch, willow	mdi:tree-outline
Catkin trees	hazel	mdi:hops (a hazel catkin has the shape of a hop cone)
Broadleaf trees	ash, beech, elm, linden, oak, sweet chestnut, tree of heaven	mdi:tree
Broadleaf trees	plane tree	mdi:leaf-maple (the one species with a maple-like leaf)
Evergreens	cypress family	mdi:pine-tree
Evergreens	olive	mdi:leaf-circle
Grasses	grasses	mdi:grass
Cereals	rye	mdi:barley
Weeds	mugwort	mdi:flower
Weeds	ragweed	mdi:flower-poppy
Weeds	dock/sorrel	mdi:sprout
Herbs	nettle family, plantain	mdi:leaf
Fungal spores	fungal spores	mdi:mushroom
Fallback	anything unrecognized	mdi:flower-pollen

On the remaining six from your list: mdi:clover, mdi:corn, mdi:flower-tulip and mdi:palm-tree all depict plants that are not among the allergens this API reports. Corn would put a maize cob on rye, where mdi:barley at least shows an actual ear of grain. mdi:nature and mdi:seed are generic enough that they would just add another lookalike to the tree group. So they stay out for now, but the list is a good reference if the API ever adds more allergens.

If you spot a group above where a different icon would read better, happy to hear it before 0.5.4 ships.

[zeus86]

for some trees (maybe ash, alder, elm, basically any tree that is sufficiently "round"), if found mdi:nature an interesting icon, because it looks like a tree with a perfectly round crown (and it is an additional icon for a generic tree...). I also found mdi:seed interesting, but i'm unsure where this would fit best