[img-editor] Added wheel zoom and middle-button panning for scene items.

Telegram/SourceFiles/editor/editor_paint.cpp

@@ -36,6 +36,9 @@ constexpr auto kMinCanvasZoom = 1.;
 constexpr auto kMaxCanvasZoom = 8.;
 constexpr auto kCanvasZoomStep = 1.15;
 constexpr auto kZoomEpsilon = 0.0001;
+constexpr auto kMinItemZoom = 0.1;
+constexpr auto kMaxItemZoom = 10.;
+constexpr auto kCanvasZoomStepFine = 1.015;
 
 std::shared_ptr<Scene> EnsureScene(
 		PhotoModifications &mods,
@@ -55,13 +58,15 @@ Paint::Paint(
 	PhotoModifications &modifications,
 	const QSize &imageSize,
 	std::shared_ptr<Controllers> controllers,
-	Fn<QImage(QRect)> blurSource)
+	Fn<QImage(QRect)> blurSource,
+	bool fixedCrop)
 : RpWidget(parent)
 , _controllers(controllers)
 , _scene(EnsureScene(modifications, imageSize))
 , _view(base::make_unique_q<QGraphicsView>(_scene.get(), this))
 , _viewport(_view->viewport())
-, _imageSize(imageSize) {
+, _imageSize(imageSize)
+, _fixedCrop(fixedCrop) {
 	Expects(modifications.paint != nullptr);
 
 	_scene->setBlurSource(std::move(blurSource));
@@ -165,6 +170,51 @@ Paint::Paint(
 
 }
 
+bool Paint::zoomSceneItems(float64 wheelDelta, bool fine) {
+	if (!wheelDelta) {
+		return false;
+	}
+	const auto step = wheelDelta
+		/ float64(QWheelEvent::DefaultDeltasPerStep);
+	const auto base = fine ? kCanvasZoomStepFine : kCanvasZoomStep;
+	const auto factor = std::pow(base, step);
+	const auto center = rect::center(_scene->sceneRect());
+	auto applied = false;
+	for (const auto &item : _scene->items()) {
+		const auto raw = item.get();
+		const auto oldScale = raw->scale();
+		const auto newScale = std::clamp(
+			oldScale * factor,
+			kMinItemZoom,
+			kMaxItemZoom);
+		if (std::abs(newScale - oldScale) < kZoomEpsilon) {
+			continue;
+		}
+		const auto ratio = newScale / oldScale;
+		raw->setScale(newScale);
+		const auto pos = raw->pos();
+		raw->setPos(center + (pos - center) * ratio);
+		applied = true;
+	}
+	return applied;
+}
+
+void Paint::panSceneItems(QPointF sceneDelta) {
+	if (sceneDelta.isNull()) {
+		return;
+	}
+	for (const auto &item : _scene->items()) {
+		item->setPos(item->pos() + sceneDelta);
+	}
+}
+
+QPointF Paint::mapWidgetDeltaToScene(QPoint delta) const {
+	if (!_view) {
+		return QPointF(delta);
+	}
+	return _view->mapToScene(delta) - _view->mapToScene(QPoint());
+}
+
 Paint::~Paint() {
 	if (_viewport) {
 		_viewport->removeEventFilter(this);
@@ -393,6 +443,12 @@ bool Paint::eventFilter(QObject *obj, QEvent *e) {
 			return true;
 		}
 
+		if (_fixedCrop) {
+			zoomSceneItems(
+				delta,
+				wheel->modifiers().testFlag(Qt::ShiftModifier));
+			return true;
+		}
 		const auto step = delta / float64(QWheelEvent::DefaultDeltasPerStep);
 		const auto factor = std::pow(kCanvasZoomStep, step);
 		const auto newZoom = std::clamp(
@@ -421,7 +477,8 @@ bool Paint::eventFilter(QObject *obj, QEvent *e) {
 		const auto mouse = static_cast<QMouseEvent*>(e);
 		if (mouse->button() == Qt::MiddleButton) {
 			_pan = {
-				.active = (_transform.userZoom > kMinCanvasZoom),
+				.active = (_fixedCrop
+					|| _transform.userZoom > kMinCanvasZoom),
 				.point = mouse->pos(),
 			};
 			if (_pan.active) {
@@ -436,7 +493,9 @@ bool Paint::eventFilter(QObject *obj, QEvent *e) {
 			const auto delta = point - _pan.point;
 			_pan.point = point;
 
-			if (_transform.userZoom > kMinCanvasZoom) {
+			if (_fixedCrop) {
+				panSceneItems(mapWidgetDeltaToScene(delta));
+			} else if (_transform.userZoom > kMinCanvasZoom) {
 				view->horizontalScrollBar()->setValue(
 					view->horizontalScrollBar()->value() - delta.x());
 				view->verticalScrollBar()->setValue(

Telegram/SourceFiles/editor/editor_paint.h

@@ -29,7 +29,8 @@ public:
 		PhotoModifications &modifications,
 		const QSize &imageSize,
 		std::shared_ptr<Controllers> controllers,
-		Fn<QImage(QRect)> blurSource);
+		Fn<QImage(QRect)> blurSource,
+		bool fixedCrop = false);
 	~Paint() override;
 
 	[[nodiscard]] std::shared_ptr<Scene> saveScene() const;
@@ -55,6 +56,10 @@ public:
 	void paintImage(QPainter &p, const QPixmap &image) const;
 	void resetView();
 
+	bool zoomSceneItems(float64 wheelDelta, bool fine = false);
+	void panSceneItems(QPointF sceneDelta);
+	[[nodiscard]] QPointF mapWidgetDeltaToScene(QPoint delta) const;
+
 private:
 	bool eventFilter(QObject *obj, QEvent *e) override;
 	void updateViewGeometry();
@@ -74,6 +79,7 @@ private:
 	const base::unique_qptr<QGraphicsView> _view;
 	QPointer<QWidget> _viewport;
 	const QSize _imageSize;
+	const bool _fixedCrop = false;
 	QRect _imageGeometry;
 	QRect _outerGeometry;
 

Telegram/SourceFiles/editor/photo_editor_content.cpp

@@ -13,6 +13,9 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "media/view/media_view_pip.h"
 #include "storage/storage_media_prepare.h"
 
+#include <QtGui/QMouseEvent>
+#include <QtGui/QWheelEvent>
+
 namespace Editor {
 
 using Media::View::FlipSizeByRotation;
@@ -26,6 +29,7 @@ PhotoEditorContent::PhotoEditorContent(
 	EditorData data)
 : RpWidget(parent)
 , _photoSize(photo->size())
+, _fixedCrop(data.fixedCrop)
 , _paint(base::make_unique_q<Paint>(
 	this,
 	modifications,
@@ -42,7 +46,8 @@ PhotoEditorContent::PhotoEditorContent(
 		auto result = img.copy(pixelRect.intersected(img.rect()));
 		result.setDevicePixelRatio(dpr);
 		return result;
-	}))
+	},
+	data.fixedCrop))
 , _crop(base::make_unique_q<Crop>(
 	this,
 	modifications,
@@ -110,6 +115,47 @@ PhotoEditorContent::PhotoEditorContent(
 	}, lifetime());
 
 	setupDragArea();
+
+	if (_fixedCrop) {
+		const auto pan = _crop->lifetime().make_state<
+			std::optional<QPoint>
+		>();
+		_crop->events(
+		) | rpl::on_next([=](not_null<QEvent*> e) {
+			const auto type = e->type();
+			if (type == QEvent::Wheel) {
+				const auto wheel = static_cast<QWheelEvent*>(e.get());
+				_paint->zoomSceneItems(
+					wheel->angleDelta().y(),
+					wheel->modifiers().testFlag(Qt::ShiftModifier));
+				e->accept();
+			} else if (type == QEvent::MouseButtonPress) {
+				const auto mouse = static_cast<QMouseEvent*>(e.get());
+				if (mouse->button() == Qt::MiddleButton) {
+					*pan = mouse->pos();
+					_crop->setCursor(Qt::ClosedHandCursor);
+					e->accept();
+				}
+			} else if (type == QEvent::MouseMove) {
+				if (pan->has_value()) {
+					const auto mouse = static_cast<QMouseEvent*>(e.get());
+					const auto point = mouse->pos();
+					const auto delta = point - **pan;
+					*pan = point;
+					_paint->panSceneItems(
+						_paint->mapWidgetDeltaToScene(delta));
+					e->accept();
+				}
+			} else if (type == QEvent::MouseButtonRelease) {
+				const auto mouse = static_cast<QMouseEvent*>(e.get());
+				if (mouse->button() == Qt::MiddleButton && pan->has_value()) {
+					pan->reset();
+					_crop->unsetCursor();
+					e->accept();
+				}
+			}
+		}, _crop->lifetime());
+	}
 }
 
 void PhotoEditorContent::applyModifications(

Telegram/SourceFiles/editor/photo_editor_content.h

@@ -54,6 +54,7 @@ public:
 private:
 
 	const QSize _photoSize;
+	const bool _fixedCrop = false;
 	const base::unique_qptr<Paint> _paint;
 	const base::unique_qptr<Crop> _crop;
 	const std::shared_ptr<Image> _photo;