qelectrotech-source-mirror/sources/qetgraphicsitem/diagramimageitem.h

/*
	Copyright 2006-2026 The QElectroTech Team
	This file is part of QElectroTech.

	QElectroTech is free software: you can redistribute it and/or modify
	it under the terms of the GNU General Public License as published by
	the Free Software Foundation, either version 2 of the License, or
	(at your option) any later version.

	QElectroTech is distributed in the hope that it will be useful,
	but WITHOUT ANY WARRANTY; without even the implied warranty of
	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
	GNU General Public License for more details.

	You should have received a copy of the GNU General Public License
	along with QElectroTech.  If not, see <http://www.gnu.org/licenses/>.
*/
#ifndef DIAGRAM_IMAGE_ITEM_H
#define DIAGRAM_IMAGE_ITEM_H

#include "qetgraphicsitem.h"
#include "shapetransform.h"
#include "../ui/imagetransparentcolordialog.h"

#include <QColor>
#include <QFont>
#include <QList>
#include <QUuid>
#include <QStyleOptionGraphicsItem>
#include <QVector>

class QDomElement;
class QDomDocument;
class QGraphicsSceneContextMenuEvent;
class QetGraphicsHandlerItem;

/**
	This class represents a selectable, movable and editable image on a
	diagram.
	@see QGraphicsItem::GraphicsItemFlags
*/
class DiagramImageItem : public QetGraphicsItem {
	Q_OBJECT
	Q_PROPERTY(QPixmap pixmap READ pixmap WRITE setPixmap NOTIFY pixmapChanged)
	Q_PROPERTY(qreal scaleFactorX READ scaleFactorX WRITE setScaleFactorX NOTIFY transformChanged)
	Q_PROPERTY(qreal scaleFactorY READ scaleFactorY WRITE setScaleFactorY NOTIFY transformChanged)
	Q_PROPERTY(qreal rotationAngle READ rotationAngle WRITE setRotationAngle NOTIFY transformChanged)
	Q_PROPERTY(qreal skewX READ skewX WRITE setSkewX NOTIFY transformChanged)
	Q_PROPERTY(qreal skewY READ skewY WRITE setSkewY NOTIFY transformChanged)
	Q_PROPERTY(QPointF pivot READ pivot WRITE setPivot NOTIFY transformChanged)
	Q_PROPERTY(QString label READ label WRITE setLabel NOTIFY labelChanged)
	// The picture's source -- original, crop rectangle, transparent
	// colours -- as one value. The displayed pixmap is computed from it,
	// so every edit of it (crop, colour key, mirror, replace) is one
	// undo step on this property alone.
	Q_PROPERTY(QVariant imageSource READ imageSourceVariant WRITE setImageSourceVariant)
	Q_PROPERTY(bool adaptToDarkTheme READ adaptToDarkTheme WRITE setAdaptToDarkTheme NOTIFY adaptToDarkThemeChanged)
	// A second, deliberately non-compensating property on the SAME
	// underlying value -- setPivot() (above) intentionally adjusts
	// pos() to keep the image visually in place, which is exactly
	// wrong for crop()'s own undo chain: crop() already computes the
	// correct final pos() itself (accounting for the crop, not just
	// the pivot move) and pushes it as its own separate "pos" command,
	// so a chained "pivot" step going through the compensating setter
	// would silently overwrite that already-correct pos() a second
	// time. rawPivot exists solely for that one caller.
	Q_PROPERTY(QPointF rawPivot READ pivot WRITE setPivotRaw NOTIFY transformChanged)
	// Whether the pivot was placed by hand: a hand-placed pivot is saved
	// and kept through a resize. Changes in the same undo step as the
	// pivot itself, so that Ctrl+Z restores both.
	Q_PROPERTY(bool pivotIsCustom READ pivotIsCustom WRITE setPivotIsCustom)

	// constructors, destructor
	public:
	DiagramImageItem(QetGraphicsItem * = nullptr);
	DiagramImageItem(const QPixmap &pixmap, QetGraphicsItem * = nullptr);
	~DiagramImageItem() override;

	struct ImageSource
	{
		QPixmap base;
		QRect crop;
		QList<ImageTransparentColorDialog::PickedColor> colors;
	};
	ImageSource imageSource() const { return {m_base_pixmap, m_crop_rect, m_transparent_colors}; }
	void setImageSource(const ImageSource &source);
	QVariant imageSourceVariant() const;
	void setImageSourceVariant(const QVariant &source);
	QRect cropRect() const { return m_crop_rect; }
	bool applyCrop(const QRect &cropRect);
	
	// attributes
	public:
	enum { Type = UserType + 1007 };

	// A deliberately smaller, image-specific set than QetShapeItem's own
	// HandleMode/HandleRole: images have no path/polygon/arc concepts at
	// all, so reusing those enums directly would pull in a great deal of
	// irrelevant baggage for no benefit. RotateSkew's math (rotate,
	// skew, and their shared scaleAndShearOffset()/scaleOnlyOffset()
	// helpers) mirrors QetShapeItem's own identical formulas -- adapted
	// to this class's own, simpler 4-corner/4-edge/1-pivot handle set,
	// not shared code, since the two classes' broader handle roles
	// differ too much (no path/polygon/arc concepts here) for sharing
	// the dispatcher itself to be worth an indirect abstraction.
	enum class HandleMode { Size, RotateSkew };
	enum class HandleRole { Resize, Rotate, SkewEdge, Pivot };
	
	// methods
	public:
	/**
		Enable the use of qgraphicsitem_cast to safely cast a QGraphicsItem into a
		DiagramImageItem
		@return the QGraphicsItem type
	*/
	int type() const override { return Type; }
	
	virtual bool fromXml(const QDomElement &);
	virtual QDomElement toXml(QDomDocument &) const;
	QUuid uuid() const {return m_uuid;}
	void setUuid(const QUuid &uuid) {m_uuid = uuid; emit uuidChanged();}
	void newUuid() {setUuid(QUuid::createUuid());}	//create new uuid for this item
	QRectF imageRect() const;
	void editProperty() override;
	void setPixmap(const QPixmap &pixmap);
	QPixmap pixmap() const { return pixmap_; }
	bool pivotIsCustom() const { return m_pivotIsCustom; }
	void setPivotIsCustom(bool custom) { m_pivotIsCustom = custom; }
	QRectF boundingRect() const override;
	QString name() const override;

	/// DXF export: replay this item's paint() on an arbitrary QPainter
	/// (e.g. one targeting DxfPaintDevice). paint() itself stays
	/// protected, as it should for the normal
	/// QGraphicsScene/QGraphicsView paint contract - this is a
	/// deliberate, narrow escape hatch for exporters, not a general
	/// relaxation of that contract. Matches CrossRefItem::paintForExport()
	/// exactly, for the identical reason.
	void paintForExport(QPainter *painter)
	{
		QStyleOptionGraphicsItem option;
		paint(painter, &option, nullptr);
	}

	qreal scaleFactorX() const { return m_transform.scaleX; }
	qreal scaleFactorY() const { return m_transform.scaleY; }
	void setScaleFactorX(qreal factor);
	void setScaleFactorY(qreal factor);
	qreal rotationAngle() const { return m_transform.rotation; }
	void setRotationAngle(qreal angle);
	qreal skewX() const { return m_transform.skewX; }
	void setSkewX(qreal skew);
	qreal skewY() const { return m_transform.skewY; }
	void setSkewY(qreal skew);
	QPointF pivot() const { return m_transform.pivot; }
	void setPivot(const QPointF &pivot);
	void setPivotRaw(const QPointF &pivot);
	QString label() const { return m_label; }
	void setLabel(const QString &label);
	bool adaptToDarkTheme() const { return m_adapt_to_dark_theme; }
	void setAdaptToDarkTheme(bool adapt);

	signals:
	void pixmapChanged();
	void transformChanged();
	void uuidChanged();
	void labelChanged();
	void adaptToDarkThemeChanged();

	protected:
	void paint(QPainter *, const QStyleOptionGraphicsItem *, QWidget *) override;
	void contextMenuEvent(QGraphicsSceneContextMenuEvent *event) override;
	void mousePressEvent(QGraphicsSceneMouseEvent *event) override;
	void hoverEnterEvent(QGraphicsSceneHoverEvent *event) override;
	void hoverLeaveEvent(QGraphicsSceneHoverEvent *event) override;
	bool sceneEventFilter(QGraphicsItem *watched, QEvent *event) override;
	void keyPressEvent(QKeyEvent *event) override;
	QVariant itemChange(GraphicsItemChange change, const QVariant &value) override;

	private:
	void replaceImage();
	void mirror(bool horizontal);
	void setTransparentColor();
	void crop();
	void pushImageSourceChange(const QString &text, const ImageSource &oldSource, const ImageSource &newSource);
	void restoreAspectRatio();
	void saveImageAs();
	void saveOriginalImageAs();
	void saveImagePixmapAs(const QPixmap &pixmap, const QString &dialogTitle, bool hasTransparency);
	static bool writeRasterAsSvg(const QPixmap &pixmap, const QString &path);
	static const QByteArray &encodedPng(const QPixmap &pixmap, QByteArray &cache, qint64 &cacheKey);
	static QPixmap computeDisplayPixmap(const QPixmap &base, const QRect &cropRect, const QList<ImageTransparentColorDialog::PickedColor> &colors);

	void toggleHandleMode();
	HandleMode nextHandleMode() const;
	static QString handleModeLabel(HandleMode mode);
	void updateModeHint();
	void refreshInteractionHints();
	QString currentModeStatusHint() const;
	void rebuildHandles();
	void repositionHandles();
	void clearHandles();
	void resetPivotToBoundingRectCenter();
	void handlerMousePressEvent(int index, Qt::KeyboardModifiers mods);
	void handlerMouseMoveEvent(int index, QGraphicsSceneMouseEvent *event);
	void handlerMouseReleaseEvent(int index);
	void cancelHandleDrag();
	void endHandleDrag();
	void dragResize(int index, const QPointF &localPos, Qt::KeyboardModifiers mods);
	void dragRotateHandle(int cornerIndex, const QPointF &scenePos, Qt::KeyboardModifiers mods);
	void dragSkewHandle(int edgeIndex, const QPointF &scenePos, Qt::KeyboardModifiers mods);
	void dragPivot(const QPointF &localPos);
	QPointF scaleOnlyOffset(const QPointF &localPoint) const;
	QPointF scaleAndShearOffset(const QPointF &localPoint) const;
	QPointF handlePosition(int index) const;
	static QPointF cornerPosition(int cornerIndex, qreal w, qreal h);
	static QPointF edgeMidpointPosition(int edgeIndex, qreal w, qreal h);
	static QColor colorForHandleRole(HandleRole role);
	static QString hintForHandleRole(HandleRole role);
	void showStatusHint(const QString &text) const;
	void clearStatusHint() const;
	QRectF labelRect() const;
	void updateLabelScale();

	protected:
	QUuid m_uuid = QUuid::createUuid();
	QPixmap pixmap_;
	// The true, pristine original -- never itself cropped or colour-
	// keyed. pixmap_ (the displayed result) is always re-derived from
	// this plus m_crop_rect and m_transparent_colors (each colour
	// carrying its own tolerance), via computeDisplayPixmap(). Without
	// keeping this separate, re-opening either the crop or
	// transparency dialog after using the other would show an
	// already-modified image as if it were the source -- areas already
	// cropped away or coloured out would be gone for good, with no way
	// to recover or adjust them, only start over. Updated by whatever
	// genuinely replaces or reorients the image's actual content
	// (construction, replaceImage(), and mirror(), which also mirrors
	// m_crop_rect to keep referring to the same region of the
	// now-flipped base) -- never by crop() or setTransparentColor()
	// themselves, which only ever change which subset of this base is
	// shown.
	QPixmap m_base_pixmap;
	QRect m_crop_rect;   // relative to m_base_pixmap; equals m_base_pixmap.rect() when nothing has been cropped
	QList<ImageTransparentColorDialog::PickedColor> m_transparent_colors;
	// PNG bytes of pixmap_ and m_base_pixmap as last written, reused by
	// toXml() while the pixmap's cacheKey() still matches. PNG encoding
	// is the bulk of the time a save spends on a picture, and redoing it
	// on every save, autosave and copy of an unchanged picture is pure
	// waste. Filled from the file itself on load, so even the first save
	// encodes nothing.
	mutable QByteArray m_png_cache;
	mutable qint64 m_png_cache_key = 0;
	mutable QByteArray m_base_png_cache;
	mutable qint64 m_base_png_cache_key = 0;

	// Independent scaleX/scaleY here is the actual point of this whole
	// member: QGraphicsItem::scale() is a single, uniform float, which
	// is exactly why an image could never break its own aspect ratio
	// before this. skewX/skewY exist in the struct but are never
	// written by anything below -- deliberately deferred, not an
	// oversight (see the .cpp for why).
	ShapeTransform m_transform;
	bool m_pivotIsCustom = false;
	HandleMode m_handleMode = HandleMode::Size;
	QVector<QetGraphicsHandlerItem *> m_handler_vector;
	QVector<HandleRole> m_handleRoles;
	int m_vector_index = -1;
	QPointF m_original_pos;   // scene position at the start of a resize/rotate/pivot drag, for Escape-to-cancel
	bool m_drag_cancelled = false;   // Escape pressed: ignore the rest of this mouse gesture
	ShapeTransform m_original_transform;
	bool m_original_pivotIsCustom = false;
	bool m_deferHandleReposition = false;   // see setPivot()'s comment
	// Optional caption drawn centred under the picture (issue #349).
	// Empty by default, and then neither saved nor painted, so a picture
	// without one costs exactly what it did before.
	QString m_label;
	bool m_adapt_to_dark_theme = false;
	QFont m_label_font;
	QSizeF m_label_size;   // in scene units, measured once in setLabel()
	QPointF m_label_scale{1.0, 1.0};   // scale the label rect was last computed for -- see updateLabelScale()
	bool m_resizeCenterAnchored = false;   // decided once, at press time -- see handlerMousePressEvent()'s comment for why, mirroring the identical fix already made for shape creation
};
Q_DECLARE_METATYPE(DiagramImageItem::ImageSource)

#endif