Add undo and redo functionality to imglab (davisking#606) (davisking#3143)

Implemented Ctrl+Z and Ctrl+Y/Ctrl+Shift+Z shortcuts in imglab to undo and redo bounding box modifications. Added equality operators to box struct and limited maximum state history to 10 to avoid large memory footprints.

Author: gzbykyasin

dlib/data_io/image_dataset_metadata.h

@@ -93,6 +93,27 @@ namespace dlib
                 ensures
                     - returns true if label metadata is present and false otherwise.
             !*/
+
+            bool operator==(const box& rhs) const
+            {
+                return rect == rhs.rect &&
+                       parts == rhs.parts &&
+                       label == rhs.label &&
+                       difficult == rhs.difficult &&
+                       truncated == rhs.truncated &&
+                       occluded == rhs.occluded &&
+                       ignore == rhs.ignore &&
+                       pose == rhs.pose &&
+                       detection_score == rhs.detection_score &&
+                       angle == rhs.angle &&
+                       gender == rhs.gender &&
+                       age == rhs.age;
+            }
+
+            bool operator!=(const box& rhs) const
+            {
+                return !(*this == rhs);
+            }
         };
 
     // ------------------------------------------------------------------------------------

tools/imglab/src/metadata_editor.cpp

@@ -21,6 +21,11 @@ extern const char* VERSION;
 
 // ----------------------------------------------------------------------------------------
 
+std::vector<dlib::image_display::overlay_rect> get_overlays (
+    const dlib::image_dataset_metadata::image& data,
+    color_mapper& string_to_color 
+);
+
 metadata_editor::
 metadata_editor(
     const std::string& filename_,
@@ -390,6 +395,25 @@ on_keydown (
             select_image(image_pos);
         }
 
+        if ((key == 'z' || key == 'Z') && (state&base_window::KBD_MOD_CONTROL) && !overlay_label.has_input_focus())
+        {
+            if (state&base_window::KBD_MOD_SHIFT)
+            {
+                perform_redo();
+            }
+            else
+            {
+                perform_undo();
+            }
+            return;
+        }
+
+        if ((key == 'y' || key == 'Y') && (state&base_window::KBD_MOD_CONTROL) && !overlay_label.has_input_focus())
+        {
+            perform_redo();
+            return;
+        }
+
         // Make 'w' and 's' act like KEY_UP and KEY_DOWN
         if ((key == 'w' || key == 'W') && !overlay_label.has_input_focus())
         {
@@ -532,6 +556,12 @@ load_image(
     if (idx >= metadata.images.size())
         return;
 
+    if (image_pos != idx)
+    {
+        undo_history.clear();
+        redo_history.clear();
+    }
+
     image_pos = idx; 
 
     array2d<rgb_pixel> img;
@@ -556,6 +586,40 @@ load_image(
 
 // ----------------------------------------------------------------------------------------
 
+void metadata_editor::
+perform_undo()
+{
+    if (!undo_history.empty())
+    {
+        redo_history.push_back(metadata.images[image_pos].boxes);
+        if (redo_history.size() > MAX_UNDO_HISTORY) redo_history.erase(redo_history.begin());
+
+        metadata.images[image_pos].boxes = undo_history.back();
+        undo_history.pop_back();
+        display.clear_overlay();
+        display.add_overlay(get_overlays(metadata.images[image_pos], string_to_color));
+    }
+}
+
+// ----------------------------------------------------------------------------------------
+
+void metadata_editor::
+perform_redo()
+{
+    if (!redo_history.empty())
+    {
+        undo_history.push_back(metadata.images[image_pos].boxes);
+        if (undo_history.size() > MAX_UNDO_HISTORY) undo_history.erase(undo_history.begin());
+
+        metadata.images[image_pos].boxes = redo_history.back();
+        redo_history.pop_back();
+        display.clear_overlay();
+        display.add_overlay(get_overlays(metadata.images[image_pos], string_to_color));
+    }
+}
+
+// ----------------------------------------------------------------------------------------
+
 void metadata_editor::
 load_image_and_set_size(
     unsigned long idx
@@ -564,6 +628,12 @@ load_image_and_set_size(
     if (idx >= metadata.images.size())
         return;
 
+    if (image_pos != idx)
+    {
+        undo_history.clear();
+        redo_history.clear();
+    }
+
     image_pos = idx; 
 
     array2d<rgb_pixel> img;
@@ -616,6 +686,7 @@ on_overlay_rects_changed(
         const std::vector<image_display::overlay_rect>& rects = display.get_overlay_rects();
 
         std::vector<box>& boxes = metadata.images[image_pos].boxes;
+        std::vector<box> old_boxes = boxes;
 
         boxes.clear();
         for (unsigned long i = 0; i < rects.size(); ++i)
@@ -627,6 +698,14 @@ on_overlay_rects_changed(
             temp.ignore = rects[i].crossed_out;
             boxes.push_back(temp);
         }
+
+        if (old_boxes != boxes)
+        {
+            undo_history.push_back(old_boxes);
+            if (undo_history.size() > MAX_UNDO_HISTORY)
+                undo_history.erase(undo_history.begin());
+            redo_history.clear();
+        }
     }
 }
 

tools/imglab/src/metadata_editor.h

@@ -7,6 +7,7 @@
 #include <dlib/data_io.h>
 #include <dlib/pixel.h>
 #include <map>
+#include <vector>
 
 // ----------------------------------------------------------------------------------------
 
@@ -69,6 +70,8 @@ class metadata_editor : public dlib::drawable_window
     );
 
 private:
+    void perform_undo();
+    void perform_redo();
 
     void file_save();
     void file_save_as();
@@ -96,6 +99,10 @@ class metadata_editor : public dlib::drawable_window
     std::string filename;
     dlib::image_dataset_metadata::dataset metadata;
 
+    std::vector<std::vector<dlib::image_dataset_metadata::box>> undo_history;
+    std::vector<std::vector<dlib::image_dataset_metadata::box>> redo_history;
+    static constexpr size_t MAX_UNDO_HISTORY = 10;
+
     dlib::menu_bar mbar;
     dlib::list_box lb_images;
     unsigned long image_pos;