android: populate dpi_scale from DisplayMetrics.density#647
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Upstream miniquad leaves dpi_scale at its 1.0 default on Android. As a result, macroquad's screen_width() / mouse_position() (which divide by dpi_scale to return density-independent units) return physical-pixel values instead of dp — so the same code that lays out UI correctly on macOS Retina has to special-case Android. This change queries the activity's Resources.getDisplayMetrics().density via JNI when init_with_activity sets up NativeDisplayData and again on every SurfaceChanged. With dpi_scale set, callers get consistent dp units across iOS / Android / macOS / Windows. query_display_density() is fail-soft — every nullable JNI lookup falls back to 1.0, matching upstream's behaviour for apps that don't yet expect a non-1 dpi_scale on Android.
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Summary
Upstream leaves
NativeDisplayData::dpi_scaleat1.0on Android. macroquad'sscreen_width()/mouse_position()divide bydpi_scaleto return density-independent units, so the same code that returns dp on a Retina Mac returns physical pixels on Android — UI laid out in dp lands at the wrong screen position, and apps have to special-case Android to compensate.This populates
dpi_scalefromResources.getDisplayMetrics().density(mdpi = 1.0, xhdpi = 2.0, etc.) via JNI:init_with_activitywhenNativeDisplayDatais first constructedSurfaceChanged(covers device density changes the OS may push at runtime)query_display_density()is fail-soft — every nullable JNI lookup falls back to1.0, preserving upstream behaviour for apps that don't expect a non-1dpi_scaleon Android.Test plan
density = 2.625):screen_width()now reports ≈ 411 dp instead of ≈ 1080 px; touch coords land on dp-positioned UI without per-platform conversion.cargo check --target aarch64-linux-androidclean (no new warnings).