implement android import, update android project and build for release

android/src/main/cpp/main.cpp

@@ -29,6 +29,7 @@
 #include "asset.h"
 #include "keymap.h"
 #include "main.h"
+#include "com_omixlab_panopainter_MainActivity.h"
 
 typedef void (*GLDEBUGPROC)(GLenum source,
     GLenum type,
@@ -51,6 +52,12 @@ typedef void (*fnDebugMessageCallback)(GLDEBUGPROC callback, const void* userPar
 EGLDisplay g_display = EGL_NO_DISPLAY;
 EGLContext g_context = EGL_NO_CONTEXT;
 
+jint JNI_OnLoad(JavaVM* vm, void* /*reserved*/)
+{
+    LOG("JNI_OnLoad");
+    return JNI_VERSION_1_6;
+}
+
 std::string utf8chr(int cp)
 {
     char c[5]={ 0x00,0x00,0x00,0x00,0x00 };
@@ -226,6 +233,100 @@ void displayKeyboard(android_app* mApplication, bool pShow)
     lJavaVM->DetachCurrentThread();
 }
 
+/*
+ * Class:     com_omixlab_panopainter_MainActivity
+ * Method:    pickFileCallback
+ * Signature: (Ljava/lang/String;)V
+ */
+std::function<void(std::string)> pick_file_callback;
+std::function<void()> pick_file_callback_context;
+extern "C"
+{
+JNIEXPORT void JNICALL Java_com_omixlab_panopainter_MainActivity_pickFileCallback(JNIEnv *env, jobject, jstring path)
+{
+    const char* path_utf = env->GetStringUTFChars(path, nullptr);
+    std::string file_path = path_utf; // create a copy
+    env->ReleaseStringUTFChars(path, path_utf);
+
+    LOG("received %s", file_path.c_str());
+    pick_file_callback_context = [file_path]
+    {
+        if (pick_file_callback)
+        {
+            LOG("callback");
+            pick_file_callback(file_path);
+            pick_file_callback = nullptr;
+        }
+    };
+}
+}
+
+void pick_file(android_app* mApplication, std::function<void(std::string)> callback)
+{
+    // Attaches the current thread to the JVM.
+    jint lResult;
+    jint lFlags = 0;
+
+    JavaVM* lJavaVM = mApplication->activity->vm;
+    JNIEnv* lJNIEnv = mApplication->activity->env;
+
+    JavaVMAttachArgs lJavaVMAttachArgs;
+    lJavaVMAttachArgs.version = JNI_VERSION_1_6;
+    lJavaVMAttachArgs.name = "NativeThread";
+    lJavaVMAttachArgs.group = NULL;
+
+    lResult=lJavaVM->AttachCurrentThread(&lJNIEnv, &lJavaVMAttachArgs);
+    if (lResult == JNI_ERR)
+    {
+        return;
+    }
+
+    pick_file_callback = callback;
+
+    // Retrieves NativeActivity.
+    jobject lNativeActivity = mApplication->activity->clazz;
+    jclass ClassNativeActivity = lJNIEnv->GetObjectClass(lNativeActivity);
+
+    jmethodID MethodPickFile = lJNIEnv->GetMethodID(ClassNativeActivity, "pickFile", "()V");
+    lJNIEnv->CallVoidMethod(lNativeActivity, MethodPickFile);
+
+    // Finished with the JVM.
+    lJavaVM->DetachCurrentThread();
+}
+
+
+float get_display_density(android_app* mApplication)
+{
+    // Attaches the current thread to the JVM.
+    jint lResult;
+    jint lFlags = 0;
+
+    JavaVM* lJavaVM = mApplication->activity->vm;
+    JNIEnv* lJNIEnv = mApplication->activity->env;
+
+    JavaVMAttachArgs lJavaVMAttachArgs;
+    lJavaVMAttachArgs.version = JNI_VERSION_1_6;
+    lJavaVMAttachArgs.name = "NativeThread";
+    lJavaVMAttachArgs.group = NULL;
+
+    lResult=lJavaVM->AttachCurrentThread(&lJNIEnv, &lJavaVMAttachArgs);
+    if (lResult == JNI_ERR)
+    {
+        return 1;
+    }
+
+    // Retrieves NativeActivity.
+    jobject lNativeActivity = mApplication->activity->clazz;
+    jclass ClassNativeActivity = lJNIEnv->GetObjectClass(lNativeActivity);
+
+    jmethodID MethodPickFile = lJNIEnv->GetMethodID(ClassNativeActivity, "getDensity", "()F");
+    float density = lJNIEnv->CallFloatMethod(lNativeActivity, MethodPickFile);
+
+    // Finished with the JVM.
+    lJavaVM->DetachCurrentThread();
+    return density;
+}
+
 /**
  * Initialize an EGL context for the current display.
  */
@@ -376,12 +477,17 @@ static int engine_init_display(struct engine* engine) {
     engine->height = h;
     engine->state.angle = 0;
 
+    float density = get_display_density(engine->app);
+    LOG("density %f", density);
+    App::I.zoom = density / 1.5;
+
     g_display = display;
     g_context = context;
 
     if (resuming_context)
     {
         LOG("RESUME APP");
+        App::I.and_app = engine->app;
         return 0;
     }
 
@@ -855,11 +961,12 @@ void android_main(struct android_app* state) {
         }
 
         //if (engine.animating)
+        if (engine.display != EGL_NO_DISPLAY)
         {
-            // Done with events; draw next animation frame.
-            engine.state.angle += .01f;
-            if (engine.state.angle > 1) {
-                engine.state.angle = 0;
+            if (pick_file_callback_context)
+            {
+                pick_file_callback_context();
+                pick_file_callback_context = nullptr;
             }
 
             // Drawing is throttled to the screen update rate, so there