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Telegram/SourceFiles/editor/scene/scene_item_canvas.h

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+/*
+This file is part of Telegram Desktop,
+the official desktop application for the Telegram messaging service.
+
+For license and copyright information please follow this link:
+https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
+*/
+#pragma once
+
+#include "ui/painter.h"
+
+#include <QGraphicsItem>
+
+class QGraphicsSceneMouseEvent;
+
+namespace Editor {
+
+class ItemCanvas : public QGraphicsItem {
+public:
+	struct Content {
+		QPixmap pixmap;
+		QPointF position;
+	};
+
+	ItemCanvas();
+	~ItemCanvas();
+
+	void applyBrush(const QColor &color, float size);
+	void clearPixmap();
+	void cancelDrawing();
+	void updateZoom(float64 zoom);
+
+	QRectF boundingRect() const override;
+	void paint(
+		QPainter *p,
+		const QStyleOptionGraphicsItem *option,
+		QWidget *widget) override;
+
+	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 *,
+		Qt::ItemSelectionMode) const override;
+
+	bool collidesWithPath(
+		const QPainterPath &,
+		Qt::ItemSelectionMode) const override;
+private:
+	struct StrokePoint {
+		QPointF pos;
+		float64 pressure = 1.0;
+		int64 time = 0;
+	};
+
+	void computeContentRect(const QPointF &p);
+	void addStrokePoint(const QPointF &point, int64 time);
+	void drawIncrementalStroke();
+	std::vector<StrokePoint> smoothStroke(
+		const std::vector<StrokePoint> &points) const;
+	void renderSegment(
+		const std::vector<StrokePoint> &points,
+		int startIdx);
+
+	bool _drawing = false;
+	std::vector<StrokePoint> _currentStroke;
+	int _lastRenderedIndex = 0;
+	float64 _zoom = 1.0;
+	int64 _lastPointTime = 0;
+
+	std::unique_ptr<PainterHighQualityEnabler> _hq;
+	std::unique_ptr<Painter> _p;
+
+	QRectF _rectToUpdate;
+	QRectF _contentRect;
+	QMarginsF _brushMargins;
+
+	QPointF _lastPoint;
+
+	QPixmap _pixmap;
+	QPainterPath _currentPath;
+
+	struct {
+		float size = 1.;
+		QColor color;
+	} _brushData;
+
+	rpl::event_stream<Content> _grabContentRequests;
+
+};
+
+} // namespace Editor