Bug 602322 - Implement GetDPI on Android. r=mwu, a=blocking-fennec

embedding/android/GeckoAppShell.java

@@ -549,4 +549,9 @@ class GeckoAppShell
         notificationManager.cancel(notificationID);
     }
 
+    public static int getDpi() {
+         DisplayMetrics metrics = new DisplayMetrics();
+         GeckoApp.mAppContext.getWindowManager().getDefaultDisplay().getMetrics(metrics);
+         return metrics.densityDpi;
+    }
 }

widget/src/android/AndroidBridge.cpp

@@ -113,6 +113,7 @@ AndroidBridge::Init(JNIEnv *jEnv,
     jSetClipboardText = (jmethodID) jEnv->GetStaticMethodID(jGeckoAppShellClass, "setClipboardText", "(Ljava/lang/String;)V");
     jShowAlertNotification = (jmethodID) jEnv->GetStaticMethodID(jGeckoAppShellClass, "showAlertNotification", "(Ljava/lang/String;Ljava/lang/String;Ljava/lang/String;Ljava/lang/String;Ljava/lang/String;)V");
     jAlertsProgressListener_OnProgress = (jmethodID) jEnv->GetStaticMethodID(jGeckoAppShellClass, "alertsProgressListener_OnProgress", "(Ljava/lang/String;JJLjava/lang/String;)V");
+    jGetDpi = (jmethodID) jEnv->GetStaticMethodID(jGeckoAppShellClass, "getDpi", "()I");
 
 
     jEGLContextClass = (jclass) jEnv->NewGlobalRef(jEnv->FindClass("javax/microedition/khronos/egl/EGLContext"));
@@ -477,6 +478,12 @@ AndroidBridge::AlertsProgressListener_OnProgress(const nsAString& aAlertName,
                                   jstrName, aProgress, aProgressMax, jstrText);
 }
 
+int
+AndroidBridge::GetDPI()
+{
+    return (int) mJNIEnv->CallStaticIntMethod(mGeckoAppShellClass, jGetDpi);
+}
+
 void
 AndroidBridge::SetSurfaceView(jobject obj)
 {

widget/src/android/AndroidBridge.h

@@ -158,6 +158,8 @@ public:
                                            PRInt64 aProgressMax,
                                            const nsAString& aAlertText);
 
+    int GetDPI();
+
     struct AutoLocalJNIFrame {
         AutoLocalJNIFrame(int nEntries = 128) : mEntries(nEntries) {
             AndroidBridge::Bridge()->JNI()->PushLocalFrame(mEntries);
@@ -219,7 +221,7 @@ protected:
     jmethodID jSetClipboardText;
     jmethodID jShowAlertNotification;
     jmethodID jAlertsProgressListener_OnProgress;
-    jmethodID jShowFilePicker;
+    jmethodID jGetDpi;
 
     // stuff we need for CallEglCreateWindowSurface
     jclass jEGLSurfaceImplClass;

widget/src/android/nsWindow.cpp

@@ -270,6 +270,14 @@ nsWindow::GetParent()
     return mParent;
 }
 
+float
+nsWindow::GetDPI()
+{
+    if (AndroidBridge::Bridge())
+        return AndroidBridge::Bridge()->GetDPI();
+    return 160.0f;
+}
+
 NS_IMETHODIMP
 nsWindow::Show(PRBool aState)
 {

widget/src/android/nsWindow.h

@@ -93,6 +93,7 @@ public:
     NS_IMETHOD ConfigureChildren(const nsTArray<nsIWidget::Configuration>&);
     NS_IMETHOD SetParent(nsIWidget* aNewParent);
     virtual nsIWidget *GetParent(void);
+    virtual float GetDPI();
     NS_IMETHOD Show(PRBool aState);
     NS_IMETHOD SetModal(PRBool aModal);
     NS_IMETHOD IsVisible(PRBool & aState);