Ladybird/WebView: Notify LibWeb whenever the viewport is scrolled

Author: https://github.com/awesomekling
Commit: 345faff586
Pull-request: https://github.com/SerenityOS/serenity/pull/16583
Reviewed-by: https://github.com/ADKaster
Reviewed-by: https://github.com/linusg

Ladybird/WebView.cpp

@@ -363,6 +363,13 @@ WebView::WebView()
 
     verticalScrollBar()->setSingleStep(24);
     horizontalScrollBar()->setSingleStep(24);
+
+    QObject::connect(verticalScrollBar(), &QScrollBar::valueChanged, [this](int) {
+        update_viewport_rect();
+    });
+    QObject::connect(horizontalScrollBar(), &QScrollBar::valueChanged, [this](int) {
+        update_viewport_rect();
+    });
 }
 
 WebView::~WebView()
@@ -648,8 +655,14 @@ void WebView::paintEvent(QPaintEvent* event)
 
 void WebView::resizeEvent(QResizeEvent* event)
 {
-    auto scaled_width = int(event->size().width() / m_inverse_pixel_scaling_ratio);
-    auto scaled_height = int(event->size().height() / m_inverse_pixel_scaling_ratio);
+    QAbstractScrollArea::resizeEvent(event);
+    update_viewport_rect();
+}
+
+void WebView::update_viewport_rect()
+{
+    auto scaled_width = int(size().width() / m_inverse_pixel_scaling_ratio);
+    auto scaled_height = int(size().height() / m_inverse_pixel_scaling_ratio);
     Gfx::IntRect rect(horizontalScrollBar()->value(), verticalScrollBar()->value(), scaled_width, scaled_height);
     m_page_client->set_viewport_rect(rect);
 }

Ladybird/WebView.h

@@ -57,6 +57,8 @@ signals:
     void favicon_changed(QIcon);
 
 private:
+    void update_viewport_rect();
+
     OwnPtr<HeadlessBrowserPageClient> m_page_client;
 
     qreal m_inverse_pixel_scaling_ratio { 1.0 };