移动端界面大小设置：默认 600 逻辑高，系统选项可选 600/700/800

Android 上 40250 界面原先固定按 800 逻辑像素高排版，弹窗文字在手机上只有约 1 mm 高。
- UIScaleMode.h + host ui_scale.cpp：逻辑高度来自保存的设置（默认 600），ui_height.cfg 保存，下次启动生效；
  桌面可用 MT_UI_HEIGHT 测试
- app.GetUIHeight/GetAppliedUIHeight/SetUIHeight
- mt_uiscale PORT 模块：系统选项对话框加高一行，"界面大小 大/中/小"，修改后聊天提示重启生效

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

src/host/CMakeLists.txt

@@ -25,6 +25,7 @@ set(MT_NATIVE_RENDER_SOURCES
     vulkan_window.cpp
     sdl_window.cpp
     ui_batches.cpp
+    ui_scale.cpp
     vk_device.cpp
     vk_frame.cpp
     vk_pipelines.cpp

src/host/live_client.cpp

@@ -8,6 +8,7 @@
 #include "native_audio.h"
 #include "perf_log.h"
 #include "texture_decode.h"
+#include "ui_scale.h"
 #include "vulkan_window.h"
 
 #include "platform/MilesLib/AudioCommands.h"
@@ -452,6 +453,7 @@ int run_live_client(
     };
     while ((frames == 0 || completed < frames) && renderer.poll(true) && PythonBoot::IsAppLooping()) {
         apply_policy();
+        save_ui_height_if_changed();
         double pace_ms = 0.0;
         if (cap_period.count()) {
             // Fixed cadence: a late frame starts the next one at once, a frame more than one period

src/host/sdl_window.cpp

@@ -3,6 +3,7 @@
 
 #include "input_keymap.h"
 #include "texture_decode.h"
+#include "ui_scale.h"
 
 #ifdef MT_NATIVE_HAS_LIVE_CLIENT
 #include "platform/ScriptLib/PythonBoot.h"
@@ -141,20 +142,17 @@ void VulkanWindow::request_screenshot(std::string path, std::uint64_t frame) {
 std::uint32_t VulkanWindow::logical_width() const {
     int w = 0, h = 0;
     if (window_) SDL_GetWindowSize(window_, &w, &h);
-#ifdef __ANDROID__
-    // Keep the 40250 UI at the same height as the macOS 1280x800 window,
-    // while retaining the device aspect ratio on wider phone displays.
-    if (w > 0 && h > 0) return std::max(1, int(std::lround(double(w) * 800.0 / h)));
-#endif
+    // The UI size setting (ui_scale.h; always on Android, MT_UI_HEIGHT on the desktop) fixes the logical
+    // height and keeps the device aspect ratio on wider phone displays.
+    if (const int ui_h = mt_host::ui_height(); ui_h > 0 && w > 0 && h > 0)
+        return std::max(1, int(std::lround(double(w) * ui_h / h)));
     return w > 0 ? static_cast<std::uint32_t>(w) : extent_.width;
 }
 
 std::uint32_t VulkanWindow::logical_height() const {
     int w = 0, h = 0;
     if (window_) SDL_GetWindowSize(window_, &w, &h);
-#ifdef __ANDROID__
-    if (w > 0 && h > 0) return 800;
-#endif
+    if (const int ui_h = mt_host::ui_height(); ui_h > 0 && w > 0 && h > 0) return std::uint32_t(ui_h);
     return h > 0 ? static_cast<std::uint32_t>(h) : extent_.height;
 }
 

src/host/ui_scale.cpp

@@ -0,0 +1,58 @@
+#include "ui_scale.h"
+
+#include "platform/EterBase/UIScaleMode.h"
+
+#include <SDL3/SDL.h>
+
+#include <cstdlib>
+#include <fstream>
+#include <string>
+
+namespace mt_host {
+namespace {
+
+std::string settings_path() {
+    std::string dir;
+    if (char* pref = SDL_GetPrefPath("metin2port", "client")) {
+        dir = pref;
+        SDL_free(pref);
+    }
+    return dir + "ui_height.cfg";
+}
+
+int g_saved = 0;
+
+} // namespace
+
+int ui_height() {
+    static const int height = [] {
+        int saved = 0;
+#ifdef __ANDROID__
+        saved = MtUIScale::c_iDefaultHeight;
+        if (std::ifstream in{settings_path()}; in) {
+            int value = 0;
+            if (in >> value && MtUIScale::IsValid(value)) saved = value;
+        }
+#endif
+        int applied = saved;
+        if (const char* env = std::getenv("MT_UI_HEIGHT"); env && *env) {
+            const int value = std::atoi(env);
+            if (MtUIScale::IsValid(value)) applied = saved = value;
+        }
+        g_saved = saved;
+        MtUIScale::Applied().store(applied);
+        MtUIScale::Chosen().store(saved);
+        return applied;
+    }();
+    return height;
+}
+
+void save_ui_height_if_changed() {
+    const int chosen = MtUIScale::Chosen().load(std::memory_order_relaxed);
+    if (!chosen || chosen == g_saved) return;
+    g_saved = chosen;
+    std::ofstream out{settings_path(), std::ios::trunc};
+    out << chosen << '\n';
+}
+
+} // namespace mt_host

src/host/ui_scale.h

@@ -0,0 +1,13 @@
+#pragma once
+
+namespace mt_host {
+
+// The logical UI height (platform/EterBase/UIScaleMode.h): the saved setting on Android, MT_UI_HEIGHT on
+// the desktop (a test override that also shows the option), 0 when the window's own size is the UI size.
+// Loaded on first use, which needs SDL initialised.
+int ui_height();
+
+// Writes the player's choice from the system option dialog when it differs from the saved one.
+void save_ui_height_if_changed();
+
+} // namespace mt_host