Add support for loading custom label fonts in imglab (#2733)

tools/imglab/src/main.cpp

@@ -21,7 +21,7 @@
 #include <dlib/dir_nav.h>
 
 
-const char* VERSION = "1.19";
+const char* VERSION = "1.20";
 
 
 
@@ -599,6 +599,7 @@ int main(int argc, char** argv)
 
         parser.add_option("h","Displays this information.");
         parser.add_option("v","Display version.");
+        parser.add_option("font", "Set the label font in the GUI.", 1);
 
         parser.set_group_name("Creating XML files");
         parser.add_option("c","Create an XML file named <arg> listing a set of images.",1);
@@ -672,6 +673,8 @@ int main(int argc, char** argv)
 
         parser.parse(argc, argv);
 
+        const std::string font_path = get_option(parser, "font", "");
+
         const char* singles[] = {"h","c","r","l","files","convert","parts","rmdiff", "rmtrunc", "rmdupes", "seed", "shuffle", "split", "add", 
                                  "flip-basic", "flip", "rotate", "tile", "size", "cluster", "resample", "min-object-size", "rmempty",
                                  "crop-size", "cropped-object-size", "rmlabel", "rm-other-labels", "rm-if-overlaps", "sort-num-objects", 
@@ -1263,7 +1266,7 @@ int main(int argc, char** argv)
 
         if (parser.number_of_arguments() == 1)
         {
-            metadata_editor editor(parser[0]);
+            metadata_editor editor(parser[0], font_path);
             if (parser.option("parts"))
             {
                 std::vector<string> parts = split(parser.option("parts").argument());

tools/imglab/src/metadata_editor.cpp

@@ -23,7 +23,8 @@ extern const char* VERSION;
 
 metadata_editor::
 metadata_editor(
-    const std::string& filename_
+    const std::string& filename_,
+    const std::string& font_path
 ) : 
     mbar(*this),
     lb_images(*this),
@@ -36,6 +37,26 @@ metadata_editor(
 {
     file metadata_file(filename_);
     filename = metadata_file.full_name();
+
+    // Set the custom label fonts
+    if (!font_path.empty())
+    {
+        const auto custom_font = std::make_shared<dlib::bdf_font>();
+        std::ifstream fin(font_path);
+        if (fin.good())
+        {
+            custom_font->read_bdf_file(fin, 0xFFFF);
+            custom_font->adjust_metrics();
+            font = std::move(custom_font);
+        }
+        else
+        {
+            std::cerr << "WARNING: could not open file '" + font_path + "', using default font\n.";
+        }
+    }
+    display.set_main_font(font);
+    overlay_label.set_main_font(font);
+
     // Make our current directory be the one that contains the metadata file.  We 
     // do this because that file might contain relative paths to the image files
     // we are supposed to be loading.

tools/imglab/src/metadata_editor.h

@@ -58,7 +58,8 @@ class metadata_editor : public dlib::drawable_window
 {
 public:
     metadata_editor(
-        const std::string& filename_
+        const std::string& filename_,
+        const std::string& font_path = ""
     );
 
     ~metadata_editor();
@@ -107,6 +108,8 @@ private:
     time_t last_keyboard_jump_pos_update;
     bool display_equialized_image = false;
     color_mapper string_to_color;
+
+    std::shared_ptr<dlib::font> font = dlib::default_font::get_font();
 };
 
 // ----------------------------------------------------------------------------------------