File chooser navigation

src/gui/ScrollablePage.cpp

@@ -1,16 +1,21 @@
 #include "../../include/gui/ScrollablePage.hpp"
+#include "../../include/gui/Utils.hpp"
 
 #include <mglpp/window/Window.hpp>
+#include <mglpp/window/Event.hpp>
+//#include <mglpp/graphics/Rectangle.hpp>
 
 namespace gsr {
+    static const int scroll_speed = 80;
+    static const double scroll_update_speed = 10.0;
+
     ScrollablePage::ScrollablePage(mgl::vec2f size) : size(size) {}
 
     bool ScrollablePage::on_event(mgl::Event &event, mgl::Window &window, mgl::vec2f offset) {
         if(!visible)
             return true;
 
-        const mgl::vec2f draw_pos = position + offset;
-        offset = draw_pos;
+        offset = position + offset + mgl::vec2f(0.0f, scroll_y);
         Widget *selected_widget = selected_child_widget;
 
         if(selected_widget) {
@@ -19,21 +24,34 @@ namespace gsr {
         }
 
         // Process widgets by visibility (backwards)
-        return widgets.for_each_reverse([selected_widget, &window, &event, offset](std::unique_ptr<Widget> &widget) {
+        const bool continue_events = widgets.for_each_reverse([selected_widget, &window, &event, offset](std::unique_ptr<Widget> &widget) {
             if(widget.get() != selected_widget) {
                 if(!widget->on_event(event, window, offset))
                     return false;
             }
             return true;
         });
+
+        if(!continue_events)
+            return false;
+
+        if(event.type == mgl::Event::MouseWheelScrolled) {
+            const double scroll = event.mouse_wheel_scroll.delta * scroll_speed;
+            scroll_target_y += scroll;
+            return false;
+        }
+
+        return true;
     }
 
     void ScrollablePage::draw(mgl::Window &window, mgl::vec2f offset) {
-        if(!visible)
+        if(!visible || widgets.empty()) {
+            reset_scroll();
             return;
+        }
 
-        const mgl::vec2f draw_pos = position + offset;
-        offset = draw_pos;
+        offset = position + offset;
+        const mgl::vec2f page_scroll_start = offset;
 
         mgl_scissor prev_scissor;
         mgl_window_get_scissor(window.internal_window(), &prev_scissor);
@@ -46,16 +64,67 @@ namespace gsr {
         mgl_window_set_scissor(window.internal_window(), &new_scissor);
 
         Widget *selected_widget = selected_child_widget;
+        offset.y += scroll_y;
 
+        double child_top = 999999.0;
+        double child_bottom = 0.0;
         for(size_t i = 0; i < widgets.size(); ++i) {
             auto &widget = widgets[i];
-            if(widget.get() != selected_widget)
+            if(widget.get() != selected_widget) {
                 widget->draw(window, offset);
+
+                // TODO: Create a widget function to get the render area instead, which each widget should set (position + offset as start, and position + offset + size as end), this has to be done in the widgets to ensure that recursive rendering has correct position.
+                // TODO: Do these calls before drawing, so that scroll limits can be set before drawing to prevent scrolling from overflowing for 1 frame.
+                // To make that possible move inner_size calculation in FileChooserBody to the get_inner_size function.
+                // That calculation can be done without looping folders.
+                const mgl::vec2f widget_pos = widget->get_position() + offset;
+                const mgl::vec2f widget_inner_size = widget->get_inner_size();
+
+                child_top = std::min(child_top, (double)widget_pos.y);
+                child_bottom = std::max(child_bottom, (double)widget_pos.y + (double)widget_inner_size.y);
+            }
         }
 
-        if(selected_widget)
+        if(selected_widget) {
             selected_widget->draw(window, offset);
 
+            const mgl::vec2f widget_pos = selected_widget->get_position() + offset;
+            const mgl::vec2f widget_inner_size = selected_widget->get_inner_size();
+
+            child_top = std::min(child_top, (double)widget_pos.y);
+            child_bottom = std::max(child_bottom, (double)widget_pos.y + (double)widget_inner_size.y);
+        }
+
+        const double child_height = child_bottom - child_top;
+
+        // Debug output
+        // mgl::Rectangle bottom(mgl::vec2f(size.x, 5.0f));
+        // bottom.set_color(mgl::Color(255, 0, 0, 255));
+        // bottom.set_position(mgl::vec2f(offset.x, child_bottom));
+        // window.draw(bottom);
+
+        // mgl::Rectangle bottom_d(mgl::vec2f(size.x, 5.0f));
+        // bottom_d.set_color(mgl::Color(0, 255, 0, 255));
+        // bottom_d.set_position(mgl::vec2f(offset.x, page_scroll_start.y + size.y - 5));
+        // window.draw(bottom_d);
+
+        // Scroll animation
+        const double scroll_diff = scroll_target_y - scroll_y;
+        if(std::abs(scroll_diff) < 0.1) {
+            scroll_y = scroll_target_y;
+        } else {
+            const double frame_scroll_speed = std::min(1.0, get_frame_delta_seconds() * scroll_update_speed);
+            scroll_y += (scroll_diff * frame_scroll_speed);
+        }
+
+        // Top and bottom limit
+        const double child_draw_overflow = (page_scroll_start.y + size.y) - child_bottom;
+        if(scroll_y > 0.001 || child_height < size.y) {
+            scroll_target_y = 0;
+        } else if(child_draw_overflow > 0.001) {
+            scroll_target_y = scroll_y + child_draw_overflow;
+        }
+
         mgl_window_set_scissor(window.internal_window(), &prev_scissor);
     }
 
@@ -73,4 +142,9 @@ namespace gsr {
     void ScrollablePage::add_widget(std::unique_ptr<Widget> widget) {
         widgets.push_back(std::move(widget));
     }
+
+    void ScrollablePage::reset_scroll() {
+        scroll_y = 0;
+        scroll_target_y = 0;
+    }
 }