Very nice.

I suspect DelegateRecycler doesn't do grid, otherwise this could have been an option?

What the original code was trying to do was distribute the whitespace among cells, right now if you resize to be 5.8 columns wide we want to spread that out, not have a gap on the white.

You're right on the fonts resizing though.
This is also a fix:

• fontSizeMode: Text.Fit

+ fontSizeMode: Text.VerticalFit

Though given we have a fixed grid size, maybe we could just set a pixelSize in here. That'd be even faster.

I used Loader as I didn't want loading glyphs to block scrollbar responsiveness. GridView reuses delegates, but I don't think it's the MouseArea + Label constructor that's slow. I think it's the "rendering the emoji glyph" in the GUI draw that is the root cause.

The cell spacing code re-renders the glyph (which is a slow process), which is why I removed it. Though I guess we can use anchor.centerIn:

MouseArea {
	id: mouse
	width: emojiView.cellWidth
	height: emojiView.cellHeight

	Label {
		anchor.centerIn: mouse
		width: emojiView.desiredSize
		height: emojiView.desiredSize
	}
}

... to keep the cell spacing if that's a requirement.

Using fontSizeMode: Qt.VerticalFit would make emoji's overflow horizontally. Various "hand + skin tone" emoji's that don't yet have a custom emoji are 2x wider than they are tall.

Right, maybe we can find a better way of doing this. Or just delaying resizing of the Label since it's indeed the slow part.

Here's an alternative https://phabricator.kde.org/D27346