diff --git a/assets/map_tiles.png b/assets/map_tiles.png
index f342d63..56e5c51 100644
Binary files a/assets/map_tiles.png and b/assets/map_tiles.png differ
diff --git a/tools/icongen.cpp b/tools/icongen.cpp
index 919a76e..7bee6ab 100644
--- a/tools/icongen.cpp
+++ b/tools/icongen.cpp
@@ -10,6 +10,8 @@
 
 namespace fs = std::filesystem;
 constexpr const int TILE_COUNT=10;
+constexpr const sf::Color DEFAULT_COLOR{255, 255, 255, 255};
+constexpr const size_t DEFAULT_DIM=128;
 
 using namespace shiterator;
 
@@ -23,19 +25,17 @@ struct MapTileBuilder {
   unsigned int $font_size = 20;
   sf::Glyph $glyph;
   sf::Font $font{FONT_FILE_NAME};
+  std::shared_ptr<sf::RenderTexture> $render = nullptr;
   sf::Vector2u $size;
   sf::Vector2u $image_size;
-  sf::RenderTexture $render;
   sf::RenderTexture $temp_render;
 
   MapTileBuilder(size_t x, size_t y) :
     $size(x, y),
     $image_size($size.x * TILE_COUNT, $size.y * TILE_COUNT),
-    $render($image_size),
     $temp_render($size)
   {
     $font.setSmooth(false);
-    $render.setSmooth(false);
   }
 
   void best_size(wchar_t for_char) {
@@ -56,25 +56,29 @@ struct MapTileBuilder {
   }
 
   void save_image(std::string icon_path) {
+    dbc::check($render != nullptr, "You have to call run() first.");
     fs::path out_path{icon_path};
 
     if(fs::exists(out_path)) {
       fs::remove(out_path);
     }
 
-    sf::Image out_img = $render.getTexture().copyToImage();
+    sf::Image out_img = $render->getTexture().copyToImage();
 
     bool worked = out_img.saveToFile(out_path);
     dbc::check(worked, "Failed to write screenshot.png");
   }
 
+  void run(MapGrid& map, unsigned int width, unsigned int height, BoolGrid& centered) {
+    sf::Vector2u crop{$size.x * width, $size.y * height};
+    $render = std::make_shared<sf::RenderTexture>(crop);
 
-  void run(MapGrid& map, BoolGrid& centered) {
+    $render->setSmooth(false);
     sf::Vector2f cell_pos{0.0f,0.0f};
 
     for(each_row_t<MapGrid> it{map}; it.next();) {
-      // skip empty slots
-      if(map[it.y][it.x] == 0) continue;
+      // a 0 slot means we're done
+      if(map[it.y][it.x] == 0) break;
       cell_pos.x = it.x * $size.x;
       cell_pos.y = it.y * $size.y;
       bool is_centered = centered[it.y][it.x];
@@ -97,7 +101,6 @@ struct MapTileBuilder {
       dbc::check(int($size.x - t_size.x) > 0, "font too big on x");
       dbc::check(int($size.y - t_size.y) > 0, "font too big on y");
 
-
       if(is_centered) {
         sf::Vector2f center{
           (float($size.x) - float(t_size.x)) / 2.0f,
@@ -112,12 +115,12 @@ struct MapTileBuilder {
         sprite.setPosition(cell_pos);
       }
 
-      sprite.setColor({0, 0, 0, 255});
+      sprite.setColor(DEFAULT_COLOR);
 
-      $render.draw(sprite);
+      $render->draw(sprite);
     }
 
-    $render.display();
+    $render->display();
   }
 };
 
@@ -159,8 +162,8 @@ int main() {
   load_config(map, centered, true, it, "./assets/devices.json", component_display);
   load_config(map, centered, true, it, "./assets/enemies.json", component_display);
 
-  MapTileBuilder builder(32, 32);
-  builder.run(map, centered);
+  MapTileBuilder builder(DEFAULT_DIM, DEFAULT_DIM);
+  builder.run(map, it.width, it.y, centered);
 
   builder.save_image("./assets/map_tiles.png");
   return 0;