Slightly optimized mouse painting in photo editor.

Telegram/SourceFiles/editor/editor_paint.cpp

@@ -63,6 +63,11 @@ Paint::Paint(
 		clearRedoList();
 	}, lifetime());
 
+	_scene->addsItem(
+	) | rpl::start_with_next([=] {
+		updateUndoState();
+	}, lifetime());
+
 	// Undo / Redo.
 	controllers->undoController->performRequestChanges(
 	) | rpl::start_with_next([=](const Undo &command) {

Telegram/SourceFiles/editor/scene.cpp

@@ -11,93 +11,75 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "editor/scene_item_line.h"
 #include "ui/rp_widget.h"
 
-#include <QGraphicsSceneMouseEvent>
-#include <QGraphicsSceneMouseEvent>
 #include <QGraphicsSceneMouseEvent>
 
 namespace Editor {
+namespace {
+
+bool SkipMouseEvent(not_null<QGraphicsSceneMouseEvent*> event) {
+	return event->isAccepted() || (event->button() == Qt::RightButton);
+}
+
+} // namespace
 
 Scene::Scene(const QRectF &rect)
 : QGraphicsScene(rect)
 , _canvas(new ItemCanvas) {
-	clearPath();
-
 	QGraphicsScene::addItem(_canvas);
+	_canvas->clearPixmap();
 
-	_canvas->paintRequest(
-	) | rpl::start_with_next([=](not_null<QPainter*> p) {
-		p->fillRect(sceneRect(), Qt::transparent);
-
-		p->setPen(QPen(_brushData.color, _brushData.size));
-		p->drawPath(_path);
+	_canvas->grabContentRequests(
+	) | rpl::start_with_next([=](ItemCanvas::Content &&content) {
+		const auto item = new ItemLine(std::move(content.pixmap));
+		item->setPos(content.position);
+		addItem(item);
+		_canvas->setZValue(++_lastLineZ);
 	}, _lifetime);
 }
 
 void Scene::addItem(not_null<NumberedItem*> item) {
 	item->setNumber(_itemNumber++);
 	QGraphicsScene::addItem(item);
+	_addsItem.fire({});
 }
 
 void Scene::mousePressEvent(QGraphicsSceneMouseEvent *event) {
 	QGraphicsScene::mousePressEvent(event);
-	if (event->isAccepted() || (event->button() == Qt::RightButton)) {
+	if (SkipMouseEvent(event)) {
 		return;
 	}
+	_canvas->handleMousePressEvent(event);
 	_mousePresses.fire({});
-	_path.moveTo(event->scenePos());
-	_drawing = true;
 }
 
 void Scene::mouseReleaseEvent(QGraphicsSceneMouseEvent *event) {
 	QGraphicsScene::mouseReleaseEvent(event);
-	if (event->isAccepted() || (event->button() == Qt::RightButton)) {
+	if (SkipMouseEvent(event)) {
 		return;
 	}
-	_path.lineTo(event->scenePos());
-	addLineItem();
-	_drawing = false;
+	_canvas->handleMouseReleaseEvent(event);
 }
 
 void Scene::mouseMoveEvent(QGraphicsSceneMouseEvent *event) {
 	QGraphicsScene::mouseMoveEvent(event);
-	if (event->isAccepted()
-		|| (event->button() == Qt::RightButton)
-		|| !_drawing) {
+	if (SkipMouseEvent(event)) {
 		return;
 	}
-	const auto scenePos = event->scenePos();
-	_path.lineTo(scenePos);
-	_path.moveTo(scenePos);
-	_canvas->update();
-}
-
-void Scene::addLineItem() {
-	if (_path.capacity() < 3) {
-		return;
-	}
-	addItem(new ItemLine(
-		_path,
-		sceneRect().size().toSize() * cIntRetinaFactor(),
-		_brushData.color,
-		_brushData.size));
-	_canvas->setZValue(++_lastLineZ);
-	clearPath();
+	_canvas->handleMouseMoveEvent(event);
 }
 
 void Scene::applyBrush(const QColor &color, float size) {
-	_brushData.color = color;
-	_brushData.size = size;
-}
-
-void Scene::clearPath() {
-	_path = QPainterPath();
-	_path.setFillRule(Qt::WindingFill);
+	_canvas->applyBrush(color, size);
 }
 
 rpl::producer<> Scene::mousePresses() const {
 	return _mousePresses.events();
 }
 
+rpl::producer<> Scene::addsItem() const {
+	return _addsItem.events();
+}
+
 std::vector<QGraphicsItem*> Scene::items(Qt::SortOrder order) const {
 	using Item = QGraphicsItem;
 	auto rawItems = QGraphicsScene::items();

Telegram/SourceFiles/editor/scene.h

@@ -11,8 +11,6 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 
 #include <QGraphicsScene>
 
-class QGraphicsSceneMouseEvent;
-class QGraphicsSceneMouseEvent;
 class QGraphicsSceneMouseEvent;
 
 namespace Ui {
@@ -33,6 +31,7 @@ public:
 	[[nodiscard]] std::vector<QGraphicsItem*> items(
 		Qt::SortOrder order = Qt::DescendingOrder) const;
 	void addItem(not_null<NumberedItem*> item);
+	[[nodiscard]] rpl::producer<> addsItem() const;
 	[[nodiscard]] rpl::producer<> mousePresses() const;
 
 protected:
@@ -40,24 +39,13 @@ protected:
 	void mouseReleaseEvent(QGraphicsSceneMouseEvent *event) override;
 	void mouseMoveEvent(QGraphicsSceneMouseEvent *event) override;
 private:
-	void clearPath();
-	void addLineItem();
-
 	const not_null<ItemCanvas*> _canvas;
 
-	QPainterPath _path;
-	bool _drawing = false;
-
 	float64 _lastLineZ = 0.;
-
 	int _itemNumber = 0;
 
-	struct {
-		float size = 1.;
-		QColor color;
-	} _brushData;
-
 	rpl::event_stream<> _mousePresses;
+	rpl::event_stream<> _addsItem;
 	rpl::lifetime _lifetime;
 
 };

Telegram/SourceFiles/editor/scene_item_canvas.cpp

@@ -8,32 +8,197 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "editor/scene_item_canvas.h"
 
 #include <QGraphicsScene>
+#include <QGraphicsSceneMouseEvent>
 
 namespace Editor {
+namespace {
+
+QRectF NormalizedRect(const QPointF& p1, const QPointF& p2) {
+	return QRectF(
+		std::min(p1.x(), p2.x()),
+		std::min(p1.y(), p2.y()),
+		std::abs(p2.x() - p1.x()) + 1,
+		std::abs(p2.y() - p1.y()) + 1);
+}
+
+std::vector<QPointF> InterpolatedPoints(
+		const QPointF &startPoint,
+		const QPointF &endPoint) {
+	std::vector<QPointF> points;
+
+	const auto x1 = startPoint.x();
+	const auto y1 = startPoint.y();
+	const auto x2 = endPoint.x();
+	const auto y2 = endPoint.y();
+
+	// Difference of x and y values.
+	const auto dx = x2 - x1;
+	const auto dy = y2 - y1;
+
+	// Absolute values of differences.
+	const auto ix = std::abs(dx);
+	const auto iy = std::abs(dy);
+
+	// Larger of the x and y differences.
+	const auto inc = ix > iy ? ix : iy;
+
+	// Plot location.
+	auto plotx = x1;
+	auto ploty = y1;
+
+	auto x = 0;
+	auto y = 0;
+
+	points.push_back(QPointF(plotx, ploty));
+
+	for (auto i = 0; i <= inc; i++) {
+		const auto xInc = x > inc;
+		const auto yInc = y > inc;
+
+		x += ix;
+		y += iy;
+
+		if (xInc) {
+			x -= inc;
+			plotx += 1 * ((dx < 0) ? -1 : 1);
+		}
+
+		if (yInc) {
+			y -= inc;
+			ploty += 1 * ((dy < 0) ? -1 : 1);
+		}
+
+		if (xInc || yInc) {
+			points.push_back(QPointF(plotx, ploty));
+		}
+	}
+	return points;
+}
+
+} // namespace
 
 ItemCanvas::ItemCanvas() {
 	setAcceptedMouseButtons(0);
 }
 
+void ItemCanvas::clearPixmap() {
+	_hq = nullptr;
+	_p = nullptr;
+
+	_pixmap = QPixmap(
+		(scene()->sceneRect().size() * cIntRetinaFactor()).toSize());
+	_pixmap.setDevicePixelRatio(cRetinaFactor());
+	_pixmap.fill(Qt::transparent);
+
+	_p = std::make_unique<Painter>(&_pixmap);
+	_hq = std::make_unique<PainterHighQualityEnabler>(*_p);
+	_p->setPen(Qt::NoPen);
+	_p->setBrush(_brushData.color);
+}
+
+void ItemCanvas::applyBrush(const QColor &color, float size) {
+	_brushData.color = color;
+	_brushData.size = size;
+	_p->setBrush(color);
+	_brushMargins = QMarginsF(size, size, size, size) / 2.;
+}
+
 QRectF ItemCanvas::boundingRect() const {
 	return scene()->sceneRect();
 }
 
+void ItemCanvas::computeContentRect(const QPointF &p) {
+	if (!scene()) {
+		return;
+	}
+	const auto sceneSize = scene()->sceneRect().size();
+	_contentRect = QRectF(
+		QPointF(
+			std::clamp(p.x() - _brushMargins.left(), 0., _contentRect.x()),
+			std::clamp(p.y() - _brushMargins.top(), 0., _contentRect.y())
+		),
+		QPointF(
+			std::clamp(
+				p.x() + _brushMargins.right(),
+				_contentRect.x() + _contentRect.width(),
+				sceneSize.width()),
+			std::clamp(
+				p.y() + _brushMargins.bottom(),
+				_contentRect.y() + _contentRect.height(),
+				sceneSize.height())
+		));
+}
+
+void ItemCanvas::drawLine(
+		const QPointF &currentPoint,
+		const QPointF &lastPoint) {
+	const auto halfBrushSize = _brushData.size / 2.;
+	const auto points = InterpolatedPoints(lastPoint, currentPoint);
+
+	_rectToUpdate |= NormalizedRect(currentPoint, lastPoint) + _brushMargins;
+
+	for (const auto &point : points) {
+		_p->drawEllipse(point, halfBrushSize, halfBrushSize);
+	}
+}
+
+void ItemCanvas::handleMousePressEvent(
+		not_null<QGraphicsSceneMouseEvent*> e) {
+	_lastPoint = e->scenePos();
+	_contentRect = QRectF(_lastPoint, _lastPoint);
+	_drawing = true;
+}
+
+void ItemCanvas::handleMouseMoveEvent(
+		not_null<QGraphicsSceneMouseEvent*> e) {
+	if (!_drawing) {
+		return;
+	}
+	const auto scenePos = e->scenePos();
+	drawLine(scenePos, _lastPoint);
+	update(_rectToUpdate);
+	computeContentRect(scenePos);
+	_lastPoint = scenePos;
+}
+
+void ItemCanvas::handleMouseReleaseEvent(
+		not_null<QGraphicsSceneMouseEvent*> e) {
+	if (!_drawing) {
+		return;
+	}
+	_drawing = false;
+
+	const auto scaledContentRect = QRectF(
+		_contentRect.x() * cRetinaFactor(),
+		_contentRect.y() * cRetinaFactor(),
+		_contentRect.width() * cRetinaFactor(),
+		_contentRect.height() * cRetinaFactor());
+
+	_grabContentRequests.fire({
+		.pixmap = _pixmap.copy(scaledContentRect.toRect()),
+		.position = _contentRect.topLeft(),
+	});
+	clearPixmap();
+	update();
+}
+
 void ItemCanvas::paint(
 		QPainter *p,
 		const QStyleOptionGraphicsItem *,
 		QWidget *) {
-	_paintRequest.fire_copy(p);
+	p->fillRect(_rectToUpdate, Qt::transparent);
+	p->drawPixmap(0, 0, _pixmap);
+	_rectToUpdate = QRectF();
+}
+
+rpl::producer<ItemCanvas::Content> ItemCanvas::grabContentRequests() const {
+	return _grabContentRequests.events();
 }
 
 int ItemCanvas::type() const {
 	return Type;
 }
 
-rpl::producer<not_null<QPainter*>> ItemCanvas::paintRequest() const {
-	return _paintRequest.events();
-}
-
 bool ItemCanvas::collidesWithItem(
 		const QGraphicsItem *,
 		Qt::ItemSelectionMode) const {
@@ -46,4 +211,9 @@ bool ItemCanvas::collidesWithPath(
 	return false;
 }
 
+ItemCanvas::~ItemCanvas() {
+	_hq = nullptr;
+	_p = nullptr;
+}
+
 } // namespace Editor

Telegram/SourceFiles/editor/scene_item_canvas.h

@@ -9,13 +9,24 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 
 #include <QGraphicsItem>
 
+class QGraphicsSceneMouseEvent;
+
 namespace Editor {
 
 class ItemCanvas : public QGraphicsItem {
 public:
 	enum { Type = UserType + 6 };
 
+	struct Content {
+		QPixmap pixmap;
+		QPointF position;
+	};
+
 	ItemCanvas();
+	~ItemCanvas();
+
+	void applyBrush(const QColor &color, float size);
+	void clearPixmap();
 
 	QRectF boundingRect() const override;
 	void paint(
@@ -24,7 +35,12 @@ public:
 		QWidget *widget) override;
 	int type() const override;
 
-	[[nodiscard]] rpl::producer<not_null<QPainter*>> paintRequest() const;
+	void handleMousePressEvent(not_null<QGraphicsSceneMouseEvent*> event);
+	void handleMouseReleaseEvent(not_null<QGraphicsSceneMouseEvent*> event);
+	void handleMouseMoveEvent(not_null<QGraphicsSceneMouseEvent*> event);
+
+	[[nodiscard]] rpl::producer<Content> grabContentRequests() const;
+
 protected:
 	bool collidesWithItem(
 		const QGraphicsItem *,
@@ -34,7 +50,28 @@ protected:
 		const QPainterPath &,
 		Qt::ItemSelectionMode) const override;
 private:
-	rpl::event_stream<not_null<QPainter*>> _paintRequest;
+	void computeContentRect(const QPointF &p);
+	void drawLine(const QPointF &currentPoint, const QPointF &lastPoint);
+
+	bool _drawing = false;
+
+	std::unique_ptr<PainterHighQualityEnabler> _hq;
+	std::unique_ptr<Painter> _p;
+
+	QRectF _rectToUpdate;
+	QRectF _contentRect;
+	QMarginsF _brushMargins;
+
+	QPointF _lastPoint;
+
+	QPixmap _pixmap;
+
+	struct {
+		float size = 1.;
+		QColor color;
+	} _brushData;
+
+	rpl::event_stream<Content> _grabContentRequests;
 
 };
 

Telegram/SourceFiles/editor/scene_item_line.cpp

@@ -10,35 +10,14 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include <QGraphicsScene>
 
 namespace Editor {
-namespace {
 
-QPixmap PathToPixmap(
-		const QPainterPath &path,
-		const QSize &size,
-		const QColor &brushColor,
-		float brushSize) {
-	auto pixmap = QPixmap(size);
-	pixmap.setDevicePixelRatio(cRetinaFactor());
-	pixmap.fill(Qt::transparent);
-	Painter p(&pixmap);
-	p.setPen(QPen(brushColor, brushSize));
-	p.drawPath(path);
-	return pixmap;
-}
-
-} // namespace
-
-ItemLine::ItemLine(
-	const QPainterPath &path,
-	const QSize &size,
-	const QColor &brushColor,
-	float brushSize)
-: _pixmap(PathToPixmap(path, size, brushColor, brushSize)) {
-	Expects(path.capacity() > 0);
+ItemLine::ItemLine(const QPixmap &&pixmap)
+: _pixmap(std::move(pixmap))
+, _rect(QPointF(), _pixmap.size() / cRetinaFactor()) {
 }
 
 QRectF ItemLine::boundingRect() const {
-	return scene()->sceneRect();
+	return _rect;
 }
 
 void ItemLine::paint(

Telegram/SourceFiles/editor/scene_item_line.h

@@ -15,11 +15,7 @@ class ItemLine : public NumberedItem {
 public:
 	enum { Type = UserType + 5 };
 
-	ItemLine(
-		const QPainterPath &path,
-		const QSize &size,
-		const QColor &brushColor,
-		float brushSize);
+	ItemLine(const QPixmap &&pixmap);
 	QRectF boundingRect() const override;
 	void paint(
 		QPainter *p,
@@ -33,8 +29,8 @@ protected:
 		const QPainterPath &,
 		Qt::ItemSelectionMode) const override;
 private:
-	const QRectF _rect;
 	const QPixmap _pixmap;
+	const QRectF _rect;
 
 };