Drag adjustment of fill and magic wand tolerance

Similar to how the magic wand tool works in GIMP, clicking and dragging
left and right will temporarily adjust the tolerance and show a preview
of the effect thereof.

Note that this is not how the fill tool works in GIMP, that just seems
to have bogus behavior there when you drag it.

Implements #1327.

ChangeLog

@@ -51,6 +51,7 @@ Unreleased Version 2.2.2-pre
  * Fix: The Delete Empty Annotations can now be undone without undoing what happened before it as well.
  * Feature: Empty annotations are now automatically deleted when you deselect them, to avoid the common clutter of stray empty annotations across the canvas. If you really did want an empty annotation, you can hit undo and it will return.
  * Server Feature: Setting a minimum protocol version of dp:4.24.0 now tells clients that they're using a Drawpile version too old for this server, rather than leaving them sitting at a session list where they can join no sessions.
+ * Feature: Allow clicking and dragging the fill and magic wand tools to adjust the tolerance.
 
 2024-08-09 Version 2.2.2-beta.3
  * Fix: Use more accurate timers for performance profiles if the platform supports it.

src/desktop/toolwidgets/fillsettings.cpp

@@ -141,7 +141,7 @@ QWidget *FillSettings::createUiWidget(QWidget *parent)
 		&FillSettings::updateSettings);
 	connect(
 		m_ui->tolerance, QOverload<int>::of(&QSpinBox::valueChanged), this,
-		&FillSettings::updateSettings);
+		&FillSettings::updateTolerance);
 	connect(
 		m_ui->size, QOverload<int>::of(&QSpinBox::valueChanged), this,
 		&FillSettings::updateSettings);
@@ -195,6 +195,10 @@ QWidget *FillSettings::createUiWidget(QWidget *parent)
 		&FillSettings::setButtonState);
 	setButtonState(false, false);
 
+	connect(
+		controller(), &ToolController::floodFillDragChanged, this,
+		&FillSettings::setDragState);
+
 	QWidget *disabledWidget = new QWidget;
 	QVBoxLayout *disabledLayout = new QVBoxLayout(disabledWidget);
 
@@ -259,7 +263,8 @@ void FillSettings::pushSettings()
 		static_cast<FloodFill *>(controller()->getTool(Tool::FLOODFILL));
 	int size = m_ui->size->value();
 	tool->setParameters(
-		m_ui->tolerance->value() / qreal(m_ui->tolerance->maximum()),
+		m_toleranceBeforeDrag < 0 ? m_ui->tolerance->value()
+								  : m_toleranceBeforeDrag,
 		m_ui->expandShrink->effectiveValue(), m_ui->expandShrink->kernel(),
 		m_ui->feather->value(), isSizeUnlimited(size) ? -1 : size,
 		m_ui->opacity->value() / 100.0, m_ui->gap->value(),
@@ -410,6 +415,13 @@ void FillSettings::stepAdjust1(bool increase)
 	}
 }
 
+void FillSettings::updateTolerance()
+{
+	if(m_toleranceBeforeDrag < 0) {
+		updateSettings();
+	}
+}
+
 void FillSettings::updateSettings()
 {
 	if(!m_updating) {
@@ -481,6 +493,19 @@ void FillSettings::setButtonState(bool running, bool pending)
 	m_ui->cancelButton->setEnabled(running || pending);
 }
 
+void FillSettings::setDragState(bool dragging, int tolerance)
+{
+	if(dragging) {
+		if(m_toleranceBeforeDrag < 0) {
+			m_toleranceBeforeDrag = m_ui->tolerance->value();
+		}
+		m_ui->tolerance->setValue(tolerance);
+	} else if(m_toleranceBeforeDrag >= 0) {
+		m_ui->tolerance->setValue(m_toleranceBeforeDrag);
+		m_toleranceBeforeDrag = -1;
+	}
+}
+
 void FillSettings::updateWidgets()
 {
 	if(m_stack) {

src/desktop/toolwidgets/fillsettings.h

@@ -62,6 +62,7 @@ public slots:
 	QWidget *createUiWidget(QWidget *parent) override;
 
 private:
+	void updateTolerance();
 	void updateSettings();
 
 	void updateSize();
@@ -72,6 +73,7 @@ public slots:
 	void selectBlendMode(int blendMode);
 
 	void setButtonState(bool running, bool pending);
+	void setDragState(bool dragging, int tolerance);
 	void updateWidgets();
 
 	QWidget *m_headerWidget = nullptr;
@@ -84,6 +86,7 @@ public slots:
 	QButtonGroup *m_areaGroup = nullptr;
 	int m_previousMode;
 	int m_previousEraseMode;
+	int m_toleranceBeforeDrag = -1;
 	qreal m_quickAdjust1 = 0.0;
 	bool m_featureAccess = true;
 	bool m_haveSelection = false;

src/desktop/toolwidgets/selectionsettings.cpp

@@ -137,8 +137,7 @@ void SelectionSettings::pushSettings()
 	int size = m_sizeSlider->value();
 	selectionParams.size = isSizeUnlimited(size) ? -1 : size;
 	selectionParams.opacity = m_opacitySlider->value() / 100.0;
-	selectionParams.tolerance =
-		m_toleranceSlider->value() / qreal(m_toleranceSlider->maximum());
+	selectionParams.tolerance = m_toleranceSlider->value();
 	selectionParams.expansion = m_expandShrink->effectiveValue();
 	selectionParams.featherRadius = m_featherSlider->value();
 	selectionParams.gap = m_closeGapsSlider->value();
@@ -268,7 +267,7 @@ QWidget *SelectionSettings::createUiWidget(QWidget *parent)
 	m_toleranceSlider->setBlockUpdateSignalOnDrag(true);
 	connect(
 		m_toleranceSlider, QOverload<int>::of(&KisSliderSpinBox::valueChanged),
-		this, &SelectionSettings::pushSettings);
+		this, &SelectionSettings::updateTolerance);
 	magicWandLayout->addRow(m_toleranceSlider);
 
 	m_expandShrink = new widgets::ExpandShrinkSpinner;
@@ -420,6 +419,10 @@ QWidget *SelectionSettings::createUiWidget(QWidget *parent)
 
 	setActiveTool(tools::Tool::SELECTION);
 	updateSize(m_sizeSlider->value());
+	connect(
+		controller(), &ToolController::magicWandDragChanged, this,
+		&SelectionSettings::setDragState);
+
 	return widget;
 }
 
@@ -433,6 +436,13 @@ void SelectionSettings::updateSize(int size)
 	emit pixelSizeChanged(calculatePixelSize(size, unlimited));
 }
 
+void SelectionSettings::updateTolerance()
+{
+	if(m_toleranceBeforeDrag < 0) {
+		pushSettings();
+	}
+}
+
 bool SelectionSettings::isSizeUnlimited(int size)
 {
 	return size >= props::size.max;
@@ -443,4 +453,17 @@ int SelectionSettings::calculatePixelSize(int size, bool unlimited)
 	return unlimited ? 0 : size * 2 + 1;
 }
 
+void SelectionSettings::setDragState(bool dragging, int tolerance)
+{
+	if(dragging) {
+		if(m_toleranceBeforeDrag < 0) {
+			m_toleranceBeforeDrag = m_toleranceSlider->value();
+		}
+		m_toleranceSlider->setValue(tolerance);
+	} else if(m_toleranceBeforeDrag >= 0) {
+		m_toleranceSlider->setValue(m_toleranceBeforeDrag);
+		m_toleranceBeforeDrag = -1;
+	}
+}
+
 }

src/desktop/toolwidgets/selectionsettings.h

@@ -60,9 +60,12 @@ public slots:
 	enum Area { Continuous, Similar };
 
 	void updateSize(int size);
+	void updateTolerance();
 	static bool isSizeUnlimited(int size);
 	static int calculatePixelSize(int size, bool unlimited);
 
+	void setDragState(bool dragging, int tolerance);
+
 	QWidget *m_headerWidget = nullptr;
 	QButtonGroup *m_headerGroup = nullptr;
 	QWidget *m_selectionContainer = nullptr;
@@ -77,6 +80,7 @@ public slots:
 	QButtonGroup *m_sourceGroup = nullptr;
 	QButtonGroup *m_areaGroup = nullptr;
 	QPushButton *m_startTransformButton = nullptr;
+	int m_toleranceBeforeDrag = -1;
 	bool m_isMagicWand = false;
 };
 

src/libclient/tools/clickdetector.h

@@ -10,7 +10,11 @@
 
 namespace tools {
 
+class DragDetector;
+
 class ClickDetector final {
+	friend class DragDetector;
+
 public:
 	void begin(const QPointF &viewPos, DeviceType deviceType)
 	{
@@ -43,8 +47,8 @@ class ClickDetector final {
 		m_clicks = 0;
 	}
 
-	bool isClick() { return m_clicks != 0; }
-	int clicks() { return m_clicks; }
+	bool isClick() const { return m_clicks != 0; }
+	int clicks() const { return m_clicks; }
 
 private:
 	static constexpr int CLICK_TIME = 150;
@@ -56,7 +60,7 @@ class ClickDetector final {
 			QGuiApplication::styleHints()->mouseDoubleClickInterval());
 	}
 
-	qreal getClickDistance(DeviceType deviceType)
+	static qreal getClickDistance(DeviceType deviceType)
 	{
 		int distance;
 		switch(deviceType) {
@@ -84,6 +88,34 @@ class ClickDetector final {
 	unsigned int m_clicks = 0;
 };
 
+class DragDetector final {
+public:
+	void begin(const QPointF &viewPos, DeviceType deviceType)
+	{
+		m_clickDistance = ClickDetector::getClickDistance(deviceType);
+		m_timer.setRemainingTime(ClickDetector::CLICK_TIME);
+		m_startViewPos = viewPos;
+		m_dragThresholdHit = false;
+	}
+
+	void motion(const QPointF &viewPos)
+	{
+		if(!m_dragThresholdHit && !m_timer.hasExpired()) {
+			if(QLineF(m_startViewPos, viewPos).length() > m_clickDistance) {
+				m_dragThresholdHit = true;
+			}
+		}
+	}
+
+	bool isDrag() const { return m_dragThresholdHit || m_timer.hasExpired(); }
+
+private:
+	QDeadlineTimer m_timer;
+	qreal m_clickDistance = 0.0;
+	QPointF m_startViewPos;
+	bool m_dragThresholdHit = false;
+};
+
 }
 
 #endif