added aspect ratio options

android/app/src/main/cpp/xemu_android.cpp

@@ -693,6 +693,8 @@ static bool WriteConfigToml(const std::string& config_path,
   return true;
 }
 
+extern "C" void xemu_android_set_display_mode_setting(int mode);
+
 static SetupFiles SyncSetupFiles() {
   SetupFiles out{};
   JNIEnv* env = GetEnv();
@@ -800,6 +802,9 @@ static SetupFiles SyncSetupFiles() {
   }
   out.audio_driver = GetPrefString(env, activity, "setting_audio_driver");
 
+  int displayMode = GetPrefInt(env, activity, "setting_display_mode", 0);
+  xemu_android_set_display_mode_setting(displayMode);
+
   out.config_path = base + "/xemu.toml";
   WriteConfigToml(out.config_path, out.mcpx, out.flash, out.hdd, out.dvd, out.eeprom, emuSettings);
   LogInfoFmt("SyncSetupFiles: config %s", out.config_path.c_str());

android/app/src/main/java/com/izzy2lost/x1box/SettingsActivity.kt

@@ -20,6 +20,7 @@ class SettingsActivity : AppCompatActivity() {
     val btn1x             = findViewById<MaterialButton>(R.id.btn_scale_1x)
     val btn2x             = findViewById<MaterialButton>(R.id.btn_scale_2x)
     val btn3x             = findViewById<MaterialButton>(R.id.btn_scale_3x)
+    val toggleDisplayMode = findViewById<MaterialButtonToggleGroup>(R.id.toggle_display_mode)
     val toggleThread      = findViewById<MaterialButtonToggleGroup>(R.id.toggle_tcg_thread)
     val btnMulti          = findViewById<MaterialButton>(R.id.btn_thread_multi)
     val btnSingle         = findViewById<MaterialButton>(R.id.btn_thread_single)
@@ -38,6 +39,13 @@ class SettingsActivity : AppCompatActivity() {
       else -> toggleScale.check(R.id.btn_scale_1x)
     }
 
+    val displayMode = prefs.getInt("setting_display_mode", 0)
+    when (displayMode) {
+      1    -> toggleDisplayMode.check(R.id.btn_display_4_3)
+      2    -> toggleDisplayMode.check(R.id.btn_display_16_9)
+      else -> toggleDisplayMode.check(R.id.btn_display_stretch)
+    }
+
     val tcgThread = prefs.getString("setting_tcg_thread", "multi") ?: "multi"
     if (tcgThread == "single") {
       toggleThread.check(R.id.btn_thread_single)
@@ -58,6 +66,11 @@ class SettingsActivity : AppCompatActivity() {
     }
 
     btnSave.setOnClickListener {
+      val selectedDisplayMode = when (toggleDisplayMode.checkedButtonId) {
+        R.id.btn_display_4_3  -> 1
+        R.id.btn_display_16_9 -> 2
+        else                   -> 0
+      }
       val selectedScale = when (toggleScale.checkedButtonId) {
         R.id.btn_scale_2x -> 2
         R.id.btn_scale_3x -> 3
@@ -74,6 +87,7 @@ class SettingsActivity : AppCompatActivity() {
       }
 
       prefs.edit()
+        .putInt("setting_display_mode", selectedDisplayMode)
         .putInt("setting_surface_scale", selectedScale)
         .putString("setting_tcg_thread", selectedThread)
         .putBoolean("setting_use_dsp", switchDsp.isChecked)

android/app/src/main/res/layout/activity_settings.xml

@@ -97,6 +97,49 @@
 
           </com.google.android.material.button.MaterialButtonToggleGroup>
 
+          <TextView
+            android:layout_width="match_parent"
+            android:layout_height="wrap_content"
+            android:layout_marginTop="16dp"
+            android:layout_marginBottom="6dp"
+            android:text="@string/settings_display_mode"
+            android:textAppearance="@style/TextAppearance.Material3.BodyMedium"
+            android:textColor="@color/xemu_text_muted" />
+
+          <com.google.android.material.button.MaterialButtonToggleGroup
+            android:id="@+id/toggle_display_mode"
+            android:layout_width="match_parent"
+            android:layout_height="wrap_content"
+            android:layout_marginBottom="16dp"
+            app:selectionRequired="true"
+            app:singleSelection="true">
+
+            <com.google.android.material.button.MaterialButton
+              android:id="@+id/btn_display_stretch"
+              style="?attr/materialButtonOutlinedStyle"
+              android:layout_width="0dp"
+              android:layout_height="wrap_content"
+              android:layout_weight="1"
+              android:text="@string/settings_display_mode_stretch" />
+
+            <com.google.android.material.button.MaterialButton
+              android:id="@+id/btn_display_4_3"
+              style="?attr/materialButtonOutlinedStyle"
+              android:layout_width="0dp"
+              android:layout_height="wrap_content"
+              android:layout_weight="1"
+              android:text="@string/settings_display_mode_4_3" />
+
+            <com.google.android.material.button.MaterialButton
+              android:id="@+id/btn_display_16_9"
+              style="?attr/materialButtonOutlinedStyle"
+              android:layout_width="0dp"
+              android:layout_height="wrap_content"
+              android:layout_weight="1"
+              android:text="@string/settings_display_mode_16_9" />
+
+          </com.google.android.material.button.MaterialButtonToggleGroup>
+
           <!-- ── PERFORMANCE ── -->
           <TextView
             android:layout_width="match_parent"

android/app/src/main/res/values/strings.xml

@@ -80,6 +80,11 @@
   <string name="settings_save">Save</string>
 
   <string name="settings_section_display">Display</string>
+  <string name="settings_display_mode">Aspect Ratio</string>
+  <string name="settings_display_mode_stretch">Stretch</string>
+  <string name="settings_display_mode_4_3">4:3</string>
+  <string name="settings_display_mode_16_9">16:9</string>
+
   <string name="settings_resolution_scale">Internal Resolution Scale</string>
   <string name="settings_resolution_scale_1x">1x (Native 480p)</string>
   <string name="settings_resolution_scale_2x">2x (960p)</string>

ui/xemu.c

@@ -137,6 +137,7 @@ static GLuint g_android_blit_vao;
 static GLuint g_android_blit_vbo;
 static GLint g_android_blit_tex_loc = -1;
 static GLint g_android_blit_flip_loc = -1;
+static int g_android_display_mode = 0; /* 0=stretch, 1=4:3, 2=16:9 */
 static GLuint g_android_cpu_tex = 0;
 static int g_android_cpu_tex_w = 0;
 static int g_android_cpu_tex_h = 0;
@@ -202,6 +203,11 @@ static GLuint android_gl_compile_shader(GLenum type, const char *src)
     return shader;
 }
 
+void xemu_android_set_display_mode_setting(int mode)
+{
+    g_android_display_mode = mode;
+}
+
 static bool android_blit_init(void)
 {
     if (g_android_blit_prog) {
@@ -291,8 +297,21 @@ static void android_blit_frame(GLuint tex, bool flip)
     if (w <= 0) w = 1;
     if (h <= 0) h = 1;
 
+    int vx = 0, vy = 0, vw = w, vh = h;
+    if (g_android_display_mode != 0) {
+        float target = (g_android_display_mode == 1) ? (4.0f / 3.0f) : (16.0f / 9.0f);
+        float screen = (float)w / (float)h;
+        if (screen > target) {
+            vw = (int)(h * target);
+            vx = (w - vw) / 2;
+        } else {
+            vh = (int)(w / target);
+            vy = (h - vh) / 2;
+        }
+    }
+
     glBindFramebuffer(GL_FRAMEBUFFER, 0);
-    glViewport(0, 0, w, h);
+    glViewport(vx, vy, vw, vh);
     glColorMask(GL_TRUE, GL_TRUE, GL_TRUE, GL_TRUE);
     glDisable(GL_BLEND);
     glDisable(GL_DEPTH_TEST);