core/region: add per-corner radius support

changelog/next.md

@@ -28,6 +28,7 @@ set shell id.
 - Added vulkan support to screencopy.
 - Added generic WindowManager interface implementing ext-workspace.
 - Added ext-background-effect window blur support.
+- Added per-corner radius support to Region.
 
 ## Other Changes
 

src/core/region.cpp

@@ -1,4 +1,5 @@
 #include "region.hpp"
+#include <algorithm>
 #include <cmath>
 
 #include <qobject.h>
@@ -18,6 +19,11 @@ PendingRegion::PendingRegion(QObject* parent): QObject(parent) {
 	QObject::connect(this, &PendingRegion::yChanged, this, &PendingRegion::changed);
 	QObject::connect(this, &PendingRegion::widthChanged, this, &PendingRegion::changed);
 	QObject::connect(this, &PendingRegion::heightChanged, this, &PendingRegion::changed);
+	QObject::connect(this, &PendingRegion::radiusChanged, this, &PendingRegion::changed);
+	QObject::connect(this, &PendingRegion::topLeftRadiusChanged, this, &PendingRegion::changed);
+	QObject::connect(this, &PendingRegion::topRightRadiusChanged, this, &PendingRegion::changed);
+	QObject::connect(this, &PendingRegion::bottomLeftRadiusChanged, this, &PendingRegion::changed);
+	QObject::connect(this, &PendingRegion::bottomRightRadiusChanged, this, &PendingRegion::changed);
 	QObject::connect(this, &PendingRegion::childrenChanged, this, &PendingRegion::changed);
 }
 
@@ -45,6 +51,79 @@ void PendingRegion::onItemDestroyed() { this->mItem = nullptr; }
 
 void PendingRegion::onChildDestroyed() { this->mRegions.removeAll(this->sender()); }
 
+qint32 PendingRegion::radius() const { return this->mRadius; }
+
+void PendingRegion::setRadius(qint32 radius) {
+	if (radius == this->mRadius) return;
+	this->mRadius = radius;
+	emit this->radiusChanged();
+
+	if (!(this->mCornerOverrides & TopLeft)) emit this->topLeftRadiusChanged();
+	if (!(this->mCornerOverrides & TopRight)) emit this->topRightRadiusChanged();
+	if (!(this->mCornerOverrides & BottomLeft)) emit this->bottomLeftRadiusChanged();
+	if (!(this->mCornerOverrides & BottomRight)) emit this->bottomRightRadiusChanged();
+}
+
+qint32 PendingRegion::topLeftRadius() const {
+	return (this->mCornerOverrides & TopLeft) ? this->mTopLeftRadius : this->mRadius;
+}
+
+void PendingRegion::setTopLeftRadius(qint32 radius) {
+	this->mTopLeftRadius = radius;
+	this->mCornerOverrides |= TopLeft;
+	emit this->topLeftRadiusChanged();
+}
+
+void PendingRegion::resetTopLeftRadius() {
+	this->mCornerOverrides &= ~TopLeft;
+	emit this->topLeftRadiusChanged();
+}
+
+qint32 PendingRegion::topRightRadius() const {
+	return (this->mCornerOverrides & TopRight) ? this->mTopRightRadius : this->mRadius;
+}
+
+void PendingRegion::setTopRightRadius(qint32 radius) {
+	this->mTopRightRadius = radius;
+	this->mCornerOverrides |= TopRight;
+	emit this->topRightRadiusChanged();
+}
+
+void PendingRegion::resetTopRightRadius() {
+	this->mCornerOverrides &= ~TopRight;
+	emit this->topRightRadiusChanged();
+}
+
+qint32 PendingRegion::bottomLeftRadius() const {
+	return (this->mCornerOverrides & BottomLeft) ? this->mBottomLeftRadius : this->mRadius;
+}
+
+void PendingRegion::setBottomLeftRadius(qint32 radius) {
+	this->mBottomLeftRadius = radius;
+	this->mCornerOverrides |= BottomLeft;
+	emit this->bottomLeftRadiusChanged();
+}
+
+void PendingRegion::resetBottomLeftRadius() {
+	this->mCornerOverrides &= ~BottomLeft;
+	emit this->bottomLeftRadiusChanged();
+}
+
+qint32 PendingRegion::bottomRightRadius() const {
+	return (this->mCornerOverrides & BottomRight) ? this->mBottomRightRadius : this->mRadius;
+}
+
+void PendingRegion::setBottomRightRadius(qint32 radius) {
+	this->mBottomRightRadius = radius;
+	this->mCornerOverrides |= BottomRight;
+	emit this->bottomRightRadiusChanged();
+}
+
+void PendingRegion::resetBottomRightRadius() {
+	this->mCornerOverrides &= ~BottomRight;
+	emit this->bottomRightRadiusChanged();
+}
+
 QQmlListProperty<PendingRegion> PendingRegion::regions() {
 	return QQmlListProperty<PendingRegion>(
 	    this,
@@ -90,6 +169,60 @@ QRegion PendingRegion::build() const {
 		region = QRegion(this->mX, this->mY, this->mWidth, this->mHeight, type);
 	}
 
+	if (this->mShape == RegionShape::Rect && !region.isEmpty()) {
+		auto tl = std::max(this->topLeftRadius(), 0);
+		auto tr = std::max(this->topRightRadius(), 0);
+		auto bl = std::max(this->bottomLeftRadius(), 0);
+		auto br = std::max(this->bottomRightRadius(), 0);
+
+		if (tl > 0 || tr > 0 || bl > 0 || br > 0) {
+			auto rect = region.boundingRect();
+			auto x = rect.x();
+			auto y = rect.y();
+			auto w = rect.width();
+			auto h = rect.height();
+
+			// Normalize so adjacent corners don't exceed their shared edge.
+			// Each corner is scaled by the tightest constraint of its two edges.
+			auto topScale = tl + tr > w ? static_cast<double>(w) / (tl + tr) : 1.0;
+			auto bottomScale = bl + br > w ? static_cast<double>(w) / (bl + br) : 1.0;
+			auto leftScale = tl + bl > h ? static_cast<double>(h) / (tl + bl) : 1.0;
+			auto rightScale = tr + br > h ? static_cast<double>(h) / (tr + br) : 1.0;
+
+			tl = static_cast<qint32>(tl * std::min(topScale, leftScale));
+			tr = static_cast<qint32>(tr * std::min(topScale, rightScale));
+			bl = static_cast<qint32>(bl * std::min(bottomScale, leftScale));
+			br = static_cast<qint32>(br * std::min(bottomScale, rightScale));
+
+			// Unlock each corner: subtract (cornerBox - quarterEllipse) from the
+			// full rect. Each corner only modifies pixels inside its own box,
+			// so no diagonal overlap is possible.
+			if (tl > 0) {
+				auto box = QRegion(x, y, tl, tl);
+				auto ellipse = QRegion(x, y, tl * 2, tl * 2, QRegion::Ellipse);
+				region -= box - (ellipse & box);
+			}
+
+			if (tr > 0) {
+				auto box = QRegion(x + w - tr, y, tr, tr);
+				auto ellipse = QRegion(x + w - tr * 2, y, tr * 2, tr * 2, QRegion::Ellipse);
+				region -= box - (ellipse & box);
+			}
+
+			if (bl > 0) {
+				auto box = QRegion(x, y + h - bl, bl, bl);
+				auto ellipse = QRegion(x, y + h - bl * 2, bl * 2, bl * 2, QRegion::Ellipse);
+				region -= box - (ellipse & box);
+			}
+
+			if (br > 0) {
+				auto box = QRegion(x + w - br, y + h - br, br, br);
+				auto ellipse = QRegion(x + w - br * 2, y + h - br * 2, br * 2, br * 2, QRegion::Ellipse);
+				region -= box - (ellipse & box);
+			}
+		}
+	}
+
 	for (const auto& childRegion: this->mRegions) {
 		region = childRegion->applyTo(region);
 	}

src/core/region.hpp

@@ -66,6 +66,29 @@ class PendingRegion: public QObject {
 	Q_PROPERTY(qint32 width MEMBER mWidth NOTIFY widthChanged);
 	/// Defaults to 0. Does nothing if @@item is set.
 	Q_PROPERTY(qint32 height MEMBER mHeight NOTIFY heightChanged);
+	// clang-format off
+	/// Corner radius for rounded rectangles. Only applies when @@shape is `Rect`. Defaults to 0.
+	///
+	/// Acts as the default for @@topLeftRadius, @@topRightRadius, @@bottomLeftRadius,
+	/// and @@bottomRightRadius.
+	Q_PROPERTY(qint32 radius READ radius WRITE setRadius NOTIFY radiusChanged);
+	/// Top-left corner radius. Only applies when @@shape is `Rect`.
+	///
+	/// Defaults to @@radius, and may be reset by assigning `undefined`.
+	Q_PROPERTY(qint32 topLeftRadius READ topLeftRadius WRITE setTopLeftRadius RESET resetTopLeftRadius NOTIFY topLeftRadiusChanged);
+	/// Top-right corner radius. Only applies when @@shape is `Rect`.
+	///
+	/// Defaults to @@radius, and may be reset by assigning `undefined`.
+	Q_PROPERTY(qint32 topRightRadius READ topRightRadius WRITE setTopRightRadius RESET resetTopRightRadius NOTIFY topRightRadiusChanged);
+	/// Bottom-left corner radius. Only applies when @@shape is `Rect`.
+	///
+	/// Defaults to @@radius, and may be reset by assigning `undefined`.
+	Q_PROPERTY(qint32 bottomLeftRadius READ bottomLeftRadius WRITE setBottomLeftRadius RESET resetBottomLeftRadius NOTIFY bottomLeftRadiusChanged);
+	/// Bottom-right corner radius. Only applies when @@shape is `Rect`.
+	///
+	/// Defaults to @@radius, and may be reset by assigning `undefined`.
+	Q_PROPERTY(qint32 bottomRightRadius READ bottomRightRadius WRITE setBottomRightRadius RESET resetBottomRightRadius NOTIFY bottomRightRadiusChanged);
+	// clang-format on
 
 	/// Regions to apply on top of this region.
 	///
@@ -91,6 +114,25 @@ public:
 
 	void setItem(QQuickItem* item);
 
+	[[nodiscard]] qint32 radius() const;
+	void setRadius(qint32 radius);
+
+	[[nodiscard]] qint32 topLeftRadius() const;
+	void setTopLeftRadius(qint32 radius);
+	void resetTopLeftRadius();
+
+	[[nodiscard]] qint32 topRightRadius() const;
+	void setTopRightRadius(qint32 radius);
+	void resetTopRightRadius();
+
+	[[nodiscard]] qint32 bottomLeftRadius() const;
+	void setBottomLeftRadius(qint32 radius);
+	void resetBottomLeftRadius();
+
+	[[nodiscard]] qint32 bottomRightRadius() const;
+	void setBottomRightRadius(qint32 radius);
+	void resetBottomRightRadius();
+
 	QQmlListProperty<PendingRegion> regions();
 
 	[[nodiscard]] bool empty() const;
@@ -109,6 +151,11 @@ signals:
 	void yChanged();
 	void widthChanged();
 	void heightChanged();
+	void radiusChanged();
+	void topLeftRadiusChanged();
+	void topRightRadiusChanged();
+	void bottomLeftRadiusChanged();
+	void bottomRightRadiusChanged();
 	void childrenChanged();
 
 	/// Triggered when the region's geometry changes.
@@ -130,12 +177,25 @@ private:
 	static void
 	regionsReplace(QQmlListProperty<PendingRegion>* prop, qsizetype i, PendingRegion* region);
 
+	enum CornerOverride : quint8 {
+		TopLeft = 0b1,
+		TopRight = 0b10,
+		BottomLeft = 0b100,
+		BottomRight = 0b1000,
+	};
+
 	QQuickItem* mItem = nullptr;
 
 	qint32 mX = 0;
 	qint32 mY = 0;
 	qint32 mWidth = 0;
 	qint32 mHeight = 0;
+	qint32 mRadius = 0;
+	qint32 mTopLeftRadius = 0;
+	qint32 mTopRightRadius = 0;
+	qint32 mBottomLeftRadius = 0;
+	qint32 mBottomRightRadius = 0;
+	quint8 mCornerOverrides = 0;
 
 	QList<PendingRegion*> mRegions;
 };

src/wayland/background_effect/test/manual/background_effect.qml

@@ -38,10 +38,25 @@ FloatingWindow {
 			to: 1000
 			value: 100
 		}
+
+		component EdgeSlider: Slider {
+			from: -1
+			to: 1000
+			value: -1
+		}
+
+		EdgeSlider { id: topLeftSlider }
+		EdgeSlider { id: topRightSlider }
+		EdgeSlider { id: bottomLeftSlider }
+		EdgeSlider { id: bottomRightSlider }
 	}
 
 	BackgroundEffect.blurRegion: Region {
 		item: enableBox.checked ? root.contentItem : null
 		radius: radiusSlider.value == -1 ? undefined : radiusSlider.value
+		topLeftRadius: topLeftSlider.value == -1 ? undefined : topLeftSlider.value
+		topRightRadius: topRightSlider.value == -1 ? undefined : topRightSlider.value
+		bottomLeftRadius: bottomLeftSlider.value == -1 ? undefined : bottomLeftSlider.value
+		bottomRightRadius: bottomRightSlider.value == -1 ? undefined : bottomRightSlider.value
 	}
 }