1 files changed, 45 insertions(+), 0 deletions(-)

M src/main.c

@@ 57,6 57,11 @@ int main(void) {
     bool pos_updated = true;
     char debug_text[256] = "";
 
+    bool is_dragging = false;
+    float drag_start_x, drag_start_y;
+    double drag_start_x_min, drag_start_x_max;
+    double drag_start_y_min, drag_start_y_max;
+
     while (running) {
         while (SDL_PollEvent(&e)) {
             if (e.type == SDL_EVENT_QUIT) {


@@ 84,6 89,16 @@ int main(void) {
                 pos_updated = true;
             }
             if (e.type == SDL_EVENT_MOUSE_BUTTON_DOWN) {
+                if (e.button.button == SDL_BUTTON_LEFT) {
+                    is_dragging = true;
+                    drag_start_x = (float)e.button.x;
+                    drag_start_y = (float)e.button.y;
+                    // store current view
+                    drag_start_x_min = position.x_min;
+                    drag_start_x_max = position.x_max;
+                    drag_start_y_min = position.y_min;
+                    drag_start_y_max = position.y_max;
+                }
                 float mx, my;
                 SDL_GetMouseState(&mx, &my);
                 int ix = (int)floor(mx);


@@ 92,6 107,36 @@ int main(void) {
                 snprintf(debug_text, sizeof(debug_text), "x: %d  y: %d  iterations: %d", ix, iy,
                          iter);
             }
+
+            if (e.type == SDL_EVENT_MOUSE_MOTION) {
+                if (is_dragging) {
+                    float mx = (float)e.motion.x;
+                    float my = (float)e.motion.y;
+
+                    double dx = mx - drag_start_x;
+                    double dy = my - drag_start_y;
+
+                    double view_width = drag_start_x_max - drag_start_x_min;
+                    double view_height = drag_start_y_max - drag_start_y_min;
+
+                    // Pan: shift the view opposite to mouse movement
+                    double x_shift = dx * view_width / (WINDOW_WIDTH - 1);
+                    double y_shift = dy * view_height / (WINDOW_HEIGHT - 1);
+
+                    position.x_min = drag_start_x_min - x_shift;
+                    position.x_max = drag_start_x_max - x_shift;
+                    position.y_min = drag_start_y_min - y_shift;
+                    position.y_max = drag_start_y_max - y_shift;
+
+                    pos_updated = true;
+                }
+            }
+
+            if (e.type == SDL_EVENT_MOUSE_BUTTON_UP) {
+                if (e.button.button == SDL_BUTTON_LEFT) {
+                    is_dragging = false;
+                }
+            }
         }
         if (pos_updated) {
             calculate_points(&position);