diff --git a/main.cpp b/main.cpp
index 227bb1b..fde7b85 100644
--- a/main.cpp
+++ b/main.cpp
@@ -52,6 +52,9 @@ void POBWindow::initializeGL() {
 }
 
 void POBWindow::resizeGL(int w, int h) {
+    float ratio = pobwindow->devicePixelRatio();
+    scaleWidth = w * ratio;
+    scaleHeight = h * ratio;
     width = w;
     height = h;
 }
@@ -596,7 +599,12 @@ static int l_SetDrawLayer(lua_State* L)
 }
 
 void ViewportCmd::execute() {
-    glViewport(x, pobwindow->height - y - h, w, h);
+    float ratio = pobwindow->devicePixelRatio();
+    int new_x = x * ratio;
+    int new_y = (pobwindow->height - h - y) * ratio;
+    int new_w = w * ratio;
+    int new_h = h * ratio;
+    glViewport(new_x, new_y, new_w, new_h);
     glMatrixMode(GL_PROJECTION);
     glLoadIdentity();
     glOrtho(0, (float)w, (float)h, 0, -9999, 9999);
@@ -607,15 +615,25 @@ void ViewportCmd::execute() {
 static int l_SetViewport(lua_State* L)
 {
     int n = lua_gettop(L);
+    int x = 0;
+    int y = 0;
+    int w = 0;
+    int h = 0;
+    float ratio = pobwindow->devicePixelRatio();
     if (n) {
         pobwindow->LAssert(L, n >= 4, "Usage: SetViewport([x, y, width, height])");
         for (int i = 1; i <= 4; i++) {
             pobwindow->LAssert(L, lua_isnumber(L, i), "SetViewport() argument %d: expected number, got %t", i, i);
         }
-        pobwindow->AppendCmd(std::make_unique<ViewportCmd>((int)lua_tointeger(L, 1), (int)lua_tointeger(L, 2), (int)lua_tointeger(L, 3), (int)lua_tointeger(L, 4)));
+        x = lua_tointeger(L, 1);
+        y = lua_tointeger(L, 2);
+        w = lua_tointeger(L, 3);
+        h = lua_tointeger(L, 4);
     } else {
-        pobwindow->AppendCmd(std::make_unique<ViewportCmd>(0, 0, pobwindow->width, pobwindow->height));
+      w = pobwindow->width;
+      h = pobwindow->height;
     }
+    pobwindow->AppendCmd(std::make_unique<ViewportCmd>(x, y, w, h));
     return 0;
 }
 
@@ -802,7 +820,7 @@ DrawStringCmd::DrawStringCmd(float X, float Y, int Align, int Size, int Font, co
             break;
         case 0:
         default:
-            fontName = "Bitstream Vera Mono";
+            fontName = "Bitstream Vera Sans Mono";
             break;
         }
         QFont font(fontName);
@@ -877,10 +895,13 @@ static int l_DrawString(lua_State* L)
     pobwindow->LAssert(L, lua_isstring(L, 6), "DrawString() argument 6: expected string, got %t", 6);
     static const char* alignMap[6] = { "LEFT", "CENTER", "RIGHT", "CENTER_X", "RIGHT_X", nullptr };
     static const char* fontMap[4] = { "FIXED", "VAR", "VAR BOLD", nullptr };
-    pobwindow->AppendCmd(std::make_unique<DrawStringCmd>(
-        (float)lua_tonumber(L, 1), (float)lua_tonumber(L, 2), luaL_checkoption(L, 3, "LEFT", alignMap), 
-        (int)lua_tointeger(L, 4), luaL_checkoption(L, 5, "FIXED", fontMap), lua_tostring(L, 6)
-                                                  ));
+    int left = (float)lua_tonumber(L, 1);
+    int top = (float)lua_tonumber(L, 2);
+    char align = luaL_checkoption(L, 3, "LEFT", alignMap);
+    int height = (int)lua_tointeger(L, 4);
+    char font = luaL_checkoption(L, 5, "FIXED", fontMap);
+    const char* text = lua_tostring(L, 6);
+    pobwindow->AppendCmd(std::make_unique<DrawStringCmd>(left, top, align, height, font, text));
     return 0;
 }
 
@@ -901,7 +922,7 @@ static int l_DrawStringWidth(lua_State* L)
         fontName = "Liberation Sans Bold";
         fontKey = "2";
     } else {
-        fontName = "Bitstream Vera Mono";
+        fontName = "Bitstream Vera Sans Mono";
     }
     QString text(lua_tostring(L, 3));
 
@@ -937,7 +958,7 @@ static int l_DrawStringCursorIndex(lua_State* L)
     } else if (fontName == "VAR BOLD") {
         fontName = "Liberation Sans Bold";
     } else {
-        fontName = "Bitstream Vera Mono";
+        fontName = "Bitstream Vera Sans Mono";
     }
     QString text(lua_tostring(L, 3));
 
@@ -1746,7 +1767,7 @@ int main(int argc, char **argv)
     if (result != 0) {
         lua_error(L);
     }
-    pobwindow->resize(800, 600);
+    pobwindow->resize(1024, 768);
     pobwindow->show();
     QFontDatabase::addApplicationFont("VeraMono.ttf");
     QFontDatabase::addApplicationFont("LiberationSans-Regular.ttf");
diff --git a/pobwindow.hpp b/pobwindow.hpp
index e4fc4e4..f276271 100644
--- a/pobwindow.hpp
+++ b/pobwindow.hpp
@@ -5,6 +5,7 @@
 #include <QPainter>
 #include <QTimer>
 #include <memory>
+#include <QScreen>
 
 #include "main.h"
 #include "subscript.hpp"
@@ -61,6 +62,8 @@ class POBWindow : public QOpenGLWindow {
     void wheelEvent(QWheelEvent *event);
     void keyPressEvent(QKeyEvent *event);
     void keyReleaseEvent(QKeyEvent *event);
+    int scaleWidth;
+    int scaleHeight;
 
     void LAssert(lua_State* L, int cond, const char* fmt, ...);
     int IsUserData(lua_State* L, int index, const char* metaName);