From 345faff5866343d9be59971cd6101fd8ecea2e67 Mon Sep 17 00:00:00 2001
From: Andreas Kling <kling@serenityos.org>
Date: Sat, 17 Sep 2022 17:31:18 +0200
Subject: [PATCH] Ladybird/WebView: Notify LibWeb whenever the viewport is
 scrolled

---
 Ladybird/WebView.cpp | 17 +++++++++++++++--
 Ladybird/WebView.h   |  2 ++
 2 files changed, 17 insertions(+), 2 deletions(-)

diff --git a/Ladybird/WebView.cpp b/Ladybird/WebView.cpp
index 36a30b9a72..ac4048fb2b 100644
--- a/Ladybird/WebView.cpp
+++ b/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);
 }
diff --git a/Ladybird/WebView.h b/Ladybird/WebView.h
index 2af499be19..52cc45bfb3 100644
--- a/Ladybird/WebView.h
+++ b/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 };