Allow any window to be bounds-checked (#4802)

Co-authored-by: Rasmus Karlsson <rasmus.karlsson@pajlada.com>

src/util/WidgetHelpers.cpp

@@ -0,0 +1,82 @@
+#include "util/WidgetHelpers.hpp"
+
+#include <QCursor>
+#include <QGuiApplication>
+#include <QPoint>
+#include <QScreen>
+#include <QWidget>
+
+namespace {
+
+/// Move the `window` into the `screen` geometry if it's not already in there.
+void moveWithinScreen(QWidget *window, QScreen *screen, QPoint point)
+{
+    if (screen == nullptr)
+    {
+        screen = QGuiApplication::primaryScreen();
+    }
+
+    const QRect bounds = screen->availableGeometry();
+
+    bool stickRight = false;
+    bool stickBottom = false;
+
+    const auto w = window->frameGeometry().width();
+    const auto h = window->frameGeometry().height();
+
+    if (point.x() < bounds.left())
+    {
+        point.setX(bounds.left());
+    }
+    if (point.y() < bounds.top())
+    {
+        point.setY(bounds.top());
+    }
+    if (point.x() + w > bounds.right())
+    {
+        stickRight = true;
+        point.setX(bounds.right() - w);
+    }
+    if (point.y() + h > bounds.bottom())
+    {
+        stickBottom = true;
+        point.setY(bounds.bottom() - h);
+    }
+
+    if (stickRight && stickBottom)
+    {
+        const QPoint globalCursorPos = QCursor::pos();
+        point.setY(globalCursorPos.y() - window->height() - 16);
+    }
+
+    window->move(point);
+}
+
+}  // namespace
+
+namespace chatterino::widgets {
+
+void moveWindowTo(QWidget *window, QPoint position, BoundsChecking mode)
+{
+    switch (mode)
+    {
+        case BoundsChecking::Off: {
+            window->move(position);
+        }
+        break;
+
+        case BoundsChecking::CursorPosition: {
+            moveWithinScreen(window, QGuiApplication::screenAt(QCursor::pos()),
+                             position);
+        }
+        break;
+
+        case BoundsChecking::DesiredPosition: {
+            moveWithinScreen(window, QGuiApplication::screenAt(position),
+                             position);
+        }
+        break;
+    }
+}
+
+}  // namespace chatterino::widgets

src/util/WidgetHelpers.hpp

@@ -0,0 +1,29 @@
+#pragma once
+
+class QWidget;
+class QPoint;
+class QScreen;
+
+namespace chatterino::widgets {
+
+enum class BoundsChecking {
+    /// Don't do any bounds checking (equivalent to `QWidget::move`).
+    Off,
+
+    /// Attempt to keep the window within bounds of the screen the cursor is on.
+    CursorPosition,
+
+    /// Attempt to keep the window within bounds of the screen the desired position is on.
+    DesiredPosition,
+};
+
+/// Moves the `window` to the (global) `position`
+/// while doing bounds-checking according to `mode` to ensure the window stays on one screen.
+///
+/// @param window The window to move.
+/// @param position The global position to move the window to.
+/// @param mode The desired bounds checking.
+void moveWindowTo(QWidget *window, QPoint position,
+                  BoundsChecking mode = BoundsChecking::DesiredPosition);
+
+}  // namespace chatterino::widgets