diff --git a/src/api/system.c b/src/api/system.c
index 99180ad8..be5fdea5 100644
--- a/src/api/system.c
+++ b/src/api/system.c
@@ -109,9 +109,11 @@ top:
 
     case SDL_WINDOWEVENT:
       if (e.window.event == SDL_WINDOWEVENT_RESIZED) {
+        int w = e.window.data1, h = e.window.data2;
+        ren_resize(w, h);
         lua_pushstring(L, "resized");
-        lua_pushnumber(L, e.window.data1);
-        lua_pushnumber(L, e.window.data2);
+        lua_pushnumber(L, w);
+        lua_pushnumber(L, h);
         return 3;
       } else if (e.window.event == SDL_WINDOWEVENT_EXPOSED) {
         rencache_invalidate();
diff --git a/src/main.c b/src/main.c
index 98dd6eb3..43652fbc 100644
--- a/src/main.c
+++ b/src/main.c
@@ -125,9 +125,6 @@ int main(int argc, char **argv) {
   window = SDL_CreateWindow(
     "", SDL_WINDOWPOS_UNDEFINED, SDL_WINDOWPOS_UNDEFINED, dm.w * 0.8, dm.h * 0.8,
     SDL_WINDOW_RESIZABLE | SDL_WINDOW_ALLOW_HIGHDPI | SDL_WINDOW_HIDDEN);
-
-  fprintf(stderr, "New window: %p\n", window); fflush(stderr);
-
   init_window_icon();
   ren_init(window);
 
@@ -203,7 +200,7 @@ init_lua:
   }
 
   lua_close(L);
-  SDL_DestroyWindow(window);
+  ren_free_window_resources();
 
   return EXIT_SUCCESS;
 }
diff --git a/src/renderer.c b/src/renderer.c
index da406c20..145e3f47 100644
--- a/src/renderer.c
+++ b/src/renderer.c
@@ -66,26 +66,17 @@ static const char* utf8_to_codepoint(const char *p, unsigned *dst) {
 }
 
 
-static SDL_Surface *get_window_surface(SDL_Window *this_window) {
-  int w, h;
-  // fprintf(stderr, "get_window_surface: %p\n", this_window); fflush(stderr);
-  SDL_GL_GetDrawableSize(this_window, &w, &h);
-  // FIXME: check for errors ?
-  if (window_surface && w == window_w && h == window_h) {
-    fprintf(stderr, "get_window_surface: return current surface: %p\n", window_surface); fflush(stderr);
-    return window_surface;
-  }
+static void init_window_surface() {
   if (window_surface) {
-    fprintf(stderr, "going to free: %p\n", window_surface); fflush(stderr);
     SDL_FreeSurface(window_surface);
   }
-  window_surface = SDL_CreateRGBSurfaceWithFormat(0, w, h, 24, SDL_PIXELFORMAT_BGR24);
+  SDL_GL_GetDrawableSize(window, &window_w, &window_h);
+  window_surface = SDL_CreateRGBSurfaceWithFormat(0, window_w, window_h, 32, SDL_PIXELFORMAT_BGRA32);
+  ren_set_clip_rect( (RenRect) { 0, 0, window_w, window_h } );
+}
 
-  fprintf(stderr, "NEW surface: %p, size: %d %d\n", window_surface, w, h); fflush(stderr);
-
-  window_w = w;
-  window_h = h;
 
+static SDL_Surface *get_window_surface() {
   return window_surface;
 }
 
@@ -120,44 +111,56 @@ void ren_cp_replace_add(CPReplaceTable *rep_table, const char *src, const char *
   rep_table->size = table_size + 1;
 }
 
+void ren_free_window_resources() {
+  SDL_DestroyWindow(window);
+  SDL_DestroyRenderer(window_renderer);
+  SDL_DestroyTexture(window_texture);
+  window = NULL;
+  window_renderer = NULL;
+}
+
+static void setup_renderer(int w, int h) {
+  /* Note that w and h here should always be in pixels and obtained from
+     a call to SDL_GL_GetDrawableSize(). */
+  if (window_renderer) {
+    SDL_DestroyRenderer(window_renderer);
+    SDL_DestroyTexture(window_texture);
+  }
+  window_renderer = SDL_CreateRenderer(window, -1, 0);
+  // May be we could use: SDL_CreateTextureFromSurface(sdlRenderer, mySurface);
+  window_texture = SDL_CreateTexture(window_renderer, SDL_PIXELFORMAT_BGRA32, SDL_TEXTUREACCESS_STREAMING, w, h);
+}
 
 void ren_init(SDL_Window *win) {
   assert(win);
   window = win;
-  SDL_Surface *surf = get_window_surface(window); //SDL_GetWindowSurface(window);
-  fprintf(stderr, "New surface %p\n", surf); fflush(stderr);
-  ren_set_clip_rect( (RenRect) { 0, 0, surf->w, surf->h } );
+  init_window_surface();
+}
+
+
+void ren_resize(int w, int h) {
+  int new_w, new_h;
+  SDL_GL_GetDrawableSize(window, &new_w, &new_h);
+  /* Note that (w, h) may differ from (new_w, new_h) on retina displays. */
+  if (new_w != window_h || new_h != window_h) {
+    init_window_surface();
+    setup_renderer(new_w, new_h);
+  }
 }
 
 
 void ren_update_rects(RenRect *rects, int count) {
-#if 0
-  SDL_UpdateWindowSurfaceRects(window, (SDL_Rect*) rects, count);
-#endif
-  fprintf(stderr, "ren_update_rects\n"); fflush(stderr);
   static bool initial_frame = true;
   if (initial_frame) {
+    int w, h;
     SDL_ShowWindow(window);
+    SDL_GL_GetDrawableSize(window, &w, &h);
+    setup_renderer(w, h);
     initial_frame = false;
   }
 
-  int w, h;
-  SDL_GL_GetDrawableSize(window, &w, &h);
-
-  if (window_renderer && (w != window_w || h != window_h)) {
-    SDL_DestroyTexture(window_texture);
-    SDL_DestroyRenderer(window_renderer);
-    window_renderer = NULL;
-  }
-
-  if (!window_renderer) {
-    window_renderer = SDL_CreateRenderer(window, -1, 0);
-    // SDL_CreateTextureFromSurface(sdlRenderer, mySurface);
-    window_texture = SDL_CreateTexture(window_renderer, SDL_PIXELFORMAT_BGR24, SDL_TEXTUREACCESS_STREAMING, w, h);
-    fprintf(stderr, "got new renderer and texture: %p %p\n", window_renderer, window_texture); fflush(stderr);
-  }
   // FIXME: we ignore the rects here.
-  SDL_UpdateTexture(window_texture, NULL, window_surface->pixels, window_w * 3);
+  SDL_UpdateTexture(window_texture, NULL, window_surface->pixels, window_w * 4);
   SDL_RenderCopy(window_renderer, window_texture, NULL, NULL);
   SDL_RenderPresent(window_renderer);
 }
@@ -172,7 +175,7 @@ void ren_set_clip_rect(RenRect rect) {
 
 
 void ren_get_size(int *x, int *y) {
-  SDL_Surface *surf = get_window_surface(window); //SDL_GetWindowSurface(window);
+  SDL_Surface *surf = get_window_surface(window);
   *x = surf->w;
   *y = surf->h;
 }
@@ -331,9 +334,6 @@ void ren_draw_rect(RenRect rect, RenColor color) {
   x2 = x2 > clip.right  ? clip.right  : x2;
   y2 = y2 > clip.bottom ? clip.bottom : y2;
 
-  // fprintf(stderr, "ren_draw_rect: clipped rect: (%d, %d) (%d, %d)\n", x1, y1, x2, y2);
-
-  // SDL_Surface *surf = SDL_GetWindowSurface(window);
   SDL_Surface *surf = get_window_surface(window);
   RenColor *d = (RenColor*) surf->pixels;
   d += x1 + y1 * surf->w;
@@ -346,41 +346,6 @@ void ren_draw_rect(RenRect rect, RenColor color) {
   }
 }
 
-// FIXME: this function is never used
-#if 0
-void ren_draw_image(RenImage *image, RenRect *sub, int x, int y, RenColor color) {
-  if (color.a == 0) { return; }
-
-  int n;
-  if ((n = clip.left - x) > 0) { sub->width  -= n; sub->x += n; x += n; }
-  if ((n = clip.top  - y) > 0) { sub->height -= n; sub->y += n; x += n; }
-  if ((n = x + sub->width  - clip.right ) > 0) { sub->width  -= n; }
-  if ((n = y + sub->height - clip.bottom) > 0) { sub->height -= n; }
-
-  if (sub->width <= 0 || sub->height <= 0) {
-    return;
-  }
-
-  /* draw */
-  SDL_Surface *surf = get_window_surface(window); //SDL_GetWindowSurface(window);
-  RenColor *s = image->pixels;
-  RenColor *d = (RenColor*) surf->pixels;
-  s += sub->x + sub->y * image->width;
-  d += x + y * surf->w;
-  int sr = image->width - sub->width;
-  int dr = surf->w - sub->width;
-
-  for (int j = 0; j < sub->height; j++) {
-    for (int i = 0; i < sub->width; i++) {
-      *d = blend_pixel2(*d, *s, color);
-      d++;
-      s++;
-    }
-    d += dr;
-    s += sr;
-  }
-}
-#endif
 
 static int codepoint_replace(CPReplaceTable *rep_table, unsigned *codepoint) {
   for (int i = 0; i < rep_table->size; i++) {
@@ -399,7 +364,7 @@ void ren_draw_text_subpixel(RenFont *font, const char *text, int x_subpixel, int
 {
   const char *p = text;
   unsigned codepoint;
-  SDL_Surface *surf = get_window_surface(window); // SDL_GetWindowSurface(window);
+  SDL_Surface *surf = get_window_surface(window);
   const FR_Color color_fr = { .r = color.r, .g = color.g, .b = color.b };
   while (*p) {
     FR_Color color_rep;
diff --git a/src/renderer.h b/src/renderer.h
index 2b1f29d3..1ab82206 100644
--- a/src/renderer.h
+++ b/src/renderer.h
@@ -36,9 +36,11 @@ typedef struct CPReplaceTable CPReplaceTable;
 
 
 void ren_init(SDL_Window *win);
+void ren_resize(int w, int h);
 void ren_update_rects(RenRect *rects, int count);
 void ren_set_clip_rect(RenRect rect);
 void ren_get_size(int *x, int *y);
+void ren_free_window_resources();
 
 RenImage* ren_new_image(int width, int height);
 void ren_free_image(RenImage *image);
@@ -53,7 +55,6 @@ int ren_get_font_subpixel_scale(RenFont *font);
 int ren_font_subpixel_round(int width, int subpixel_scale, int orientation);
 
 void ren_draw_rect(RenRect rect, RenColor color);
-void ren_draw_image(RenImage *image, RenRect *sub, int x, int y, RenColor color);
 void ren_draw_text(RenFont *font, const char *text, int x, int y, RenColor color, CPReplaceTable *replacements, RenColor replace_color);
 void ren_draw_text_subpixel(RenFont *font, const char *text, int x_subpixel, int y, RenColor color, CPReplaceTable *replacements, RenColor replace_color);