Add customizable drag & drop callback (GLFW)

Author: merlinND

include/polyscope/options.h

@@ -5,6 +5,7 @@
 #include <functional>
 #include <string>
 #include <tuple>
+#include <vector>
 
 #include "imgui.h"
 
@@ -141,6 +142,9 @@ extern std::function<void()> configureImGuiStyleCallback;
 // assign your own function to create custom styles. If this callback is null, default fonts will be used.
 extern std::function<std::tuple<ImFontAtlas*, ImFont*, ImFont*>()> prepareImGuiFontsCallback;
 
+// A callback function which will be invoked when a file is dropped on the Polyscope window. No action is taken by default.
+extern std::function<void(const std::vector<std::string>&)> filesDroppedCallback;
+
 // === Backend and low-level options
 
 // When using the EGL backend, which device to try to initialize with

src/options.cpp

@@ -66,6 +66,7 @@ bool renderScene = true;
 bool openImGuiWindowForUserCallback = true;
 std::function<void()> configureImGuiStyleCallback = configureImGuiStyle;
 std::function<std::tuple<ImFontAtlas*, ImFont*, ImFont*>()> prepareImGuiFontsCallback = prepareImGuiFonts;
+std::function<void(const std::vector<std::string>&)> filesDroppedCallback = nullptr;
 
 // Backend and low-level options
 int eglDeviceIndex = -1; // means "try all of them"

src/render/opengl/gl_engine_glfw.cpp

@@ -80,8 +80,21 @@ void GLEngineGLFW::initialize() {
 
   setWindowResizable(view::windowResizable);
 
-// === Initialize openGL
-// Load openGL functions (using GLAD)
+  // Drag & drop support
+  glfwSetDropCallback(mainWindow, [](GLFWwindow* window, int path_count, const char* paths[]) {
+    if (!options::filesDroppedCallback)
+      return;
+
+    std::vector<std::string> pathsVec(path_count);
+    for (int i = 0; i < path_count; i++) {
+      pathsVec[i] = paths[i];
+    }
+    options::filesDroppedCallback(pathsVec);
+  });
+
+
+  // === Initialize openGL
+  // Load openGL functions (using GLAD)
 #ifndef __APPLE__
   if (!gladLoadGL()) {
     exception("ERROR: Failed to load openGL using GLAD");