Get the right pixel density on Android

ports/libsimpleservo/src/api.rs

@@ -101,6 +101,7 @@ pub fn init(
     callbacks: Box<HostTrait>,
     width: u32,
     height: u32,
+    density: f32,
 ) -> Result<(), &'static str> {
     resources::set(Box::new(ResourceReader(readfile)));
 
@@ -136,6 +137,7 @@ pub fn init(
         host_callbacks: callbacks,
         width: Cell::new(width),
         height: Cell::new(height),
+        density,
         waker,
     });
 
@@ -419,6 +421,7 @@ struct ServoCallbacks {
     host_callbacks: Box<HostTrait>,
     width: Cell<u32>,
     height: Cell<u32>,
+    density: f32,
 }
 
 impl WindowMethods for ServoCallbacks {
@@ -460,7 +463,7 @@ impl WindowMethods for ServoCallbacks {
             window: (size, TypedPoint2D::new(0, 0)),
             screen: size,
             screen_avail: size,
-            hidpi_factor: TypedScale::new(2.0),
+            hidpi_factor: TypedScale::new(self.density),
         }
     }
 }

ports/libsimpleservo/src/capi.rs

@@ -55,7 +55,8 @@ fn init(
     readfile: extern fn(*const c_char) -> *const c_char,
     callbacks: CHostCallbacks,
     width: u32,
-    height: u32) {
+    height: u32,
+    density: f32) {
     let args = unsafe { CStr::from_ptr(args) };
     let args = args.to_str().expect("Can't read string").to_string();
 
@@ -75,6 +76,7 @@ fn init(
         callbacks,
         width,
         height,
+        density,
     ).unwrap();
 }
 
@@ -87,9 +89,10 @@ pub extern "C" fn init_with_egl(
     readfile: extern fn(*const c_char) -> *const c_char,
     callbacks: CHostCallbacks,
     width: u32,
-    height: u32) {
+    height: u32,
+    density: f32) {
     let gl = gl_glue::egl::init().unwrap();
-    init(gl, args, url, wakeup, readfile, callbacks, width, height)
+    init(gl, args, url, wakeup, readfile, callbacks, width, height, density)
 }
 
 #[cfg(any(target_os = "linux", target_os = "windows", target_os = "macos"))]
@@ -101,9 +104,10 @@ pub extern "C" fn init_with_gl(
     readfile: extern fn(*const c_char) -> *const c_char,
     callbacks: CHostCallbacks,
     width: u32,
-    height: u32) {
+    height: u32,
+    density: f32) {
     let gl = gl_glue::gl::init().unwrap();
-    init(gl, args, url, wakeup, readfile, callbacks, width, height)
+    init(gl, args, url, wakeup, readfile, callbacks, width, height, density)
 }
 
 #[no_mangle]

ports/libsimpleservo/src/jniapi.rs

@@ -54,6 +54,7 @@ pub fn Java_com_mozilla_servoview_JNIServo_init(
     callbacks_obj: JObject,
     width: jint,
     height: jint,
+    density: jfloat,
     log: jboolean,
 ) {
     if log == JNI_TRUE {
@@ -102,7 +103,8 @@ pub fn Java_com_mozilla_servoview_JNIServo_init(
             readfile,
             callbacks,
             width as u32,
-            height as u32)
+            height as u32,
+            density as f32)
     }).or_else(|err| {
         env.throw(("java/lang/Exception", err))
     }).unwrap();

support/android/apk/servoview/src/main/java/com/mozilla/servoview/JNIServo.java

@@ -24,7 +24,8 @@ public class JNIServo {
                             String url,
                             String logstr,
                             Callbacks callbacks,
-                            int width, int height, boolean log);
+                            int width, int height, float density,
+                            boolean log);
 
     public native void setBatchMode(boolean mode);
 

support/android/apk/servoview/src/main/java/com/mozilla/servoview/Servo.java

@@ -27,7 +27,7 @@ public class Servo {
             String args,
             String url,
             String logstr,
-            int width, int height, boolean log) {
+            int width, int height, float density, boolean log) {
 
         mRunCallback = runCallback;
 
@@ -36,7 +36,7 @@ public class Servo {
         Callbacks cbs = new Callbacks(client, gfxcb);
 
         mRunCallback.inGLThread(() -> {
-            mJNI.init(activity, args, url, logstr, cbs, width, height, log);
+            mJNI.init(activity, args, url, logstr, cbs, width, height, density, log);
         });
     }
 

support/android/apk/servoview/src/main/java/com/mozilla/servoview/ServoSurface.java

@@ -206,7 +206,7 @@ public class ServoSurface {
             inUIThread(() -> {
               final boolean showLogs = true;
               String uri = mInitialUri == null ? null : mInitialUri;
-              mServo = new Servo(this, surface, mClient, mActivity, mServoArgs, uri, mServoLog, mWidth, mHeight, showLogs);
+              mServo = new Servo(this, surface, mClient, mActivity, mServoArgs, uri, mServoLog, mWidth, mHeight, 1, showLogs);
             });
 
             Looper.loop();

support/android/apk/servoview/src/main/java/com/mozilla/servoview/ServoView.java

@@ -11,6 +11,7 @@ import android.net.Uri;
 import android.opengl.GLES31;
 import android.opengl.GLSurfaceView;
 import android.util.AttributeSet;
+import android.util.DisplayMetrics;
 import android.util.Log;
 import android.view.Choreographer;
 import android.view.GestureDetector;
@@ -139,9 +140,13 @@ public class ServoView extends GLSurfaceView
         final boolean showLogs = true;
         int width = getWidth();
         int height = getHeight();
+        DisplayMetrics metrics = new DisplayMetrics();
+        mActivity.getWindowManager().getDefaultDisplay().getMetrics(metrics);
+        float density = metrics.density;
+
         inGLThread(() -> {
             String uri = mInitialUri == null ? null : mInitialUri.toString();
-            mServo = new Servo(this, this, mClient, mActivity, mServoArgs, uri, mServoLog, width, height, showLogs);
+            mServo = new Servo(this, this, mClient, mActivity, mServoArgs, uri, mServoLog, width, height, density, showLogs);
         });
     }