much improved paint and reflow scheduling

src/Box.cpp

@@ -95,4 +95,28 @@ double Box::clamp_for_dimension(Direction direction, double value) {
     }
 }
 
+Box Box::united(const Box &other) {
+    if (is_null()) {
+        return other;
+    }
+    if (other.is_null()) {
+        return *this;
+    }
+
+    Box rect;
+    rect.set_left(std::min(left(), other.left()));
+    rect.set_top(std::min(top(), other.top()));
+    rect.set_right(std::max(right(), other.right()));
+    rect.set_bottom(std::max(bottom(), other.bottom()));
+    return rect;
+}
+
+bool Box::is_null() const {
+    return !(m_x && m_y && m_width && m_height);
+}
+
+std::string Box::debug() {
+    return "Box(" + std::to_string(m_x) + ", " + std::to_string(m_y) + ", " + std::to_string(m_width) + ", " + std::to_string(m_height) + ")";
+}
+
 }

src/Box.hpp

@@ -1,6 +1,7 @@
 #pragma once
 
 #include "Point.hpp"
+#include <string>
 
 namespace Raven {
 
@@ -51,6 +52,11 @@ public:
     double min_height() const { return m_min_height; }
     double max_width() const { return m_max_width; }
     double max_height() const { return m_max_height; }
+    double top() const { return y(); }
+    double bottom() const { return y() + height() - 1; }
+    double left() const { return x(); }
+    double right() const { return x() + width() - 1; }
+    bool is_null() const;
     double dimension_at(Direction direction) { return direction == Direction::Horizontal ? width() : height(); }
     double max_dimension_at(Direction direction) { return direction == Direction::Horizontal ? max_width() : max_height(); }
     double min_dimension_at(Direction direction) { return direction == Direction::Horizontal ? min_width() : min_height(); }
@@ -60,6 +66,10 @@ public:
     void set_y(double y) { m_y = y; }
     void set_width(double width);
     void set_height(double height);
+    void set_top(double top) { set_y(top); }
+    void set_bottom(double bottom) { set_height(bottom - y() + 1); }
+    void set_right(double right) { set_width(right - x() + 1); }
+    void set_left(double left) { set_x(left); }
 
     void set_max_width(double max_width) { m_max_width = max_width; set_width(m_width); }
     void set_max_height(double max_height) { m_max_height = max_height; set_height(m_height); }
@@ -73,6 +83,9 @@ public:
     bool contains_box(const Box &other) const;
 
     Box offset(double x, double y);
+    Box united(const Box &other);
+
+    std::string debug();
 };
 
 }

src/Widget.cpp

@@ -192,18 +192,18 @@ void Widget::handle_repaint_rect(RepaintRectEvent &event) {
 }
 
 void Widget::handle_relayout_subtree(RelayoutSubtreeEvent &event) {
-    on_layout(); // hack
+    on_layout();
 
     m_window_relative = compute_window_relative();
 
-    for (auto child : m_children) {
-        child->dispatch_event(event);
-    }
-
     if (m_layout) {
         m_layout->run();
     }
 
+    for (auto child : m_children) {
+        child->dispatch_event(event);
+    }
+
     on_after_layout();
 }
 

src/Window.cpp

@@ -76,9 +76,10 @@ bool Window::dispatch_to_main_widget(Event &event) {
 }
 
 void Window::repaint(Box geometry) {
-    m_did_repaint_during_batch = true;
-    if (m_batches)
+    if (m_batches) {
+        m_invalidated_area = m_invalidated_area.united(geometry);
         return;
+    }
 
     auto event = RepaintRectEvent(true, geometry);
     dispatch_to_main_widget(event);
@@ -116,7 +117,6 @@ void Window::reflow() {
 }
 
 void Window::start_batch() {
-    //INFO << "New batch started. Current count: " << m_batches << std::endl;
     m_batches++;
 }
 
@@ -127,7 +127,6 @@ void Window::end_batch() {
     // we are only interested in performing batch operations for the last batch
     if (m_batches > 1) {
         m_batches--;
-        //INFO << "Consumed batch. Current count: " << m_batches << std::endl;
         return;
     }
 
@@ -135,17 +134,17 @@ void Window::end_batch() {
 
     if (m_did_relayout_during_batch) {
         reflow();
-    } else if (m_did_repaint_during_batch) {
-        repaint();
+    } else if (!m_invalidated_area.is_null()) {
+        repaint(m_invalidated_area);
     }
 
     m_did_relayout_during_batch = false;
-    m_did_repaint_during_batch = false;
-    INFO << "Performed all batch actions." << std::endl;
+    m_invalidated_area = {0, 0, 0, 0};
 }
 
 void Window::run(bool block) {
     XEvent e;
+    bool is_loop_batch_started = false;
 
     for (;;) {
         if (block || XPending(m_x_display))
@@ -153,10 +152,13 @@ void Window::run(bool block) {
         else
             break;
 
+        if (!is_loop_batch_started) {
+            start_batch();
+            is_loop_batch_started = true;
+        }
         switch (e.type) {
             case MapNotify: {
                 INFO << "[X11 EVENT] MapNotify" << std::endl;
-                end_batch();
                 break;
             }
             case ConfigureNotify: {
@@ -210,14 +212,16 @@ void Window::run(bool block) {
             }
         }
 
-        if (XPending(m_x_display) == 0 && !m_microtasks.empty()) {
-            start_batch();
+        if (XPending(m_x_display) == 0) {
             while (!m_microtasks.empty()) {
                 auto callback = m_microtasks.front();
                 callback();
                 m_microtasks.pop();
             }
-            end_batch();
+            if (is_loop_batch_started) {
+                end_batch();
+                is_loop_batch_started = false;
+            }
         }
     }
 }

src/Window.hpp

@@ -59,8 +59,8 @@ private:
     Box m_rect { 0, 0, 800, 600 };
     Painter m_painter {};
     Cairo::RefPtr<Cairo::XlibSurface> m_xlib_surface { nullptr };
-    int m_batches { 1 };
-    bool m_did_repaint_during_batch { false };
+    int m_batches { 0 };
+    Box m_invalidated_area {0, 0, 0, 0};
     bool m_did_relayout_during_batch { false };
     std::queue<std::function<void()>> m_microtasks;
 

src/main.cpp

@@ -21,6 +21,7 @@
 int main() {
     Raven::Window window {};
     window.spawn_window();
+    window.start_batch();
 
     auto main_widget = window.set_main_widget<Raven::Widget>();
     auto main_widget_layout = main_widget->set_layout<Raven::BoxLayout>(Raven::Direction::Horizontal);
@@ -66,6 +67,7 @@ int main() {
     }
     list_view->elements_updated();
 
+    window.end_batch();
     window.run(true);
     return 0;
 }