I'm designing an application for Android right now and am not sure how to proceed.
I want to be able to support everything from a medium-density screen to and extra-extra-high-density screen. google suggests creating a separate resource for each density screen, using a resource folder structure like below:
res/layout/my_layout.xml // layout for normal screen size ("default") res/layout-large/my_layout.xml // layout for large screen size res/layout-xlarge/my_layout.xml // layout for extra-large screen size res/layout-xlarge-land/my_layout.xml // layout for extra-large in landscape orientation res/drawable-mdpi/graphic.png // bitmap for medium-density res/drawable-hdpi/graphic.png // bitmap for high-density res/drawable-xhdpi/graphic.png // bitmap for extra-high-density res/drawable-xxhdpi/graphic.png // bitmap for extra-extra-high-density res/mipmap-mdpi/my_icon.png // launcher icon for medium-density res/mipmap-hdpi/my_icon.png // launcher icon for high-density res/mipmap-xhdpi/my_icon.png // launcher icon for extra-high-density res/mipmap-xxhdpi/my_icon.png // launcher icon for extra-extra-high-density res/mipmap-xxxhdpi/my_icon.png // launcher icon for extra-extra-extra-high-density
Here are descriptions that define the terms for each density resource
Screen Size small Resources for small size screens. normal Resources for normal size screens. (This is the baseline size.) large Resources for large size screens. xlarge Resources for extra-large size screens.
The pixel density is also quantifiable as below:
Density ldpi Resources for low-density (ldpi) screens (~120dpi). mdpi Resources for medium-density (mdpi) screens (~160dpi). (This is the baseline density.) hdpi Resources for high-density (hdpi) screens (~240dpi). xhdpi Resources for extra-high-density (xhdpi) screens (~320dpi). xxhdpi Resources for extra-extra-high-density (xxhdpi) screens (~480dpi). xxxhdpi Resources for extra-extra-extra-high-density (xxxhdpi) uses (~640dpi). Use this for the launcher icon only, see note above. nodpi Resources for all densities. These are density-independent resources. The system does not scale resources tagged with this qualifier, regardless of the current screen's density. tvdpi Resources for screens somewhere between mdpi and hdpi; approximately 213dpi. This is not considered a "primary" density group. It is mostly intended for televisions and most apps shouldn't need it—providing mdpi and hdpi resources is sufficient for most apps and the system will scale them as appropriate. If you find it necessary to provide tvdpi resources, you should size them at a factor of 1.33*mdpi. For example, a 100px x 100px image for mdpi screens should be 133px x 133px for tvdpi. Orientation land Resources for screens in the landscape orientation (wide aspect ratio). port Resources for screens in the portrait orientation (tall aspect ratio). Aspect ratio long Resources for screens that have a significantly taller or wider aspect ratio (when in portrait or landscape orientation, respectively) than the baseline screen configuration. notlong Resources for use screens that have an aspect ratio that is similar to the baseline screen configuration.
They also give details for the ratio for exporting screen sizes here:
To create alternative bitmap drawables for different densities, you should follow the 3:4:6:8:12:16 scaling ratio between the six generalized densities. For example, if you have a bitmap drawable that's 48x48 pixels for medium-density screens, all the different sizes should be:
36x36 (0.75x) for low-density 48x48 (1.0x baseline) for medium-density 72x72 (1.5x) for high-density 96x96 (2.0x) for extra-high-density 144x144 (3.0x) for extra-extra-high-density 192x192 (4.0x) for extra-extra-extra-high-density (launcher icon only; see note above)
So for my case, I'm currently creating graphics that either take up full-screen or ~1/2 screen. I've created vector images In Illustrator using a Surface Pro 3 (pixel density 216.33). I believe that PNG-24 is the recommended format; please correct me if I'm wrong. How should I export to support to support each screen?