Density (from dip to pixel)

I design my UI with Density-independent pixel as units of measurement.

I have same icons 18x18 dip. What 开发者_如何学运维should be the phisical dimension of the png icons for ldpi, mdpi and hdpi? I try 9x9, 12x12 and 18x18 but the emulator enlarge them.

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Try this answer. Dips are equivalent to pixels at 160 dpi. Anything else, just scale it.