Add pan tool

To allow moving the canvas around without having to hold down a key or
needing a middle click button on the pen.

Implements #1217.

ChangeLog

@@ -35,6 +35,7 @@ Unreleased Version 2.2.2-pre
  * Feature: Don't require restarting the application when changing kinetic scrolling settings.
  * Fix: Change default canvas size to 2000x2000, because 800x600 is a bit outdated. Thanks MorrowShore for for contributing.
  * Feature: Don't require restarting the application to switch between desktop and small screen mode. There's also a "dynamic" option now, which will change the mode based on the size of the window, enabled by default on Android and in the browser.
+ * Feature: Pan or "hand" tool. Lets you move the canvas around by clicking. Thanks DeeJii for suggesting.
 
 2024-02-25 Version 2.2.2-beta.1
  * Server Feature: Allow adding a message when kicking someone through the admin API.

src/desktop/CMakeLists.txt

@@ -252,6 +252,8 @@ target_sources(drawpile PRIVATE
 	toolwidgets/inspectorsettings.h
 	toolwidgets/lasersettings.cpp
 	toolwidgets/lasersettings.h
+	toolwidgets/pansettings.cpp
+	toolwidgets/pansettings.h
 	toolwidgets/selectionsettings.cpp
 	toolwidgets/selectionsettings.h
 	toolwidgets/toolsettings.cpp

src/desktop/docks/toolsettingsdock.cpp

@@ -9,6 +9,7 @@
 #include "desktop/toolwidgets/fillsettings.h"
 #include "desktop/toolwidgets/inspectorsettings.h"
 #include "desktop/toolwidgets/lasersettings.h"
+#include "desktop/toolwidgets/pansettings.h"
 #include "desktop/toolwidgets/selectionsettings.h"
 #include "desktop/toolwidgets/zoomsettings.h"
 #include "libclient/tools/toolcontroller.h"
@@ -112,6 +113,9 @@ struct ToolSettings::Private {
 		pages[tools::Tool::POLYGONSELECTION] = {
 			sel, "selection", QIcon::fromTheme("edit-select-lasso"),
 			QApplication::tr("Selection (Free-Form)")};
+		pages[tools::Tool::PAN] = {
+			QSharedPointer<tools::ToolSettings>(new tools::PanSettings(ctrl)),
+			"pan", QIcon::fromTheme("hand"), QApplication::tr("Pan")};
 		pages[tools::Tool::ZOOM] = {
 			QSharedPointer<tools::ToolSettings>(new tools::ZoomSettings(ctrl)),
 			"zoom", QIcon::fromTheme("edit-find"), QApplication::tr("Zoom")};
@@ -310,6 +314,12 @@ tools::LaserPointerSettings *ToolSettings::laserPointerSettings()
 		getToolSettingsPage(tools::Tool::LASERPOINTER));
 }
 
+tools::PanSettings *ToolSettings::panSettings()
+{
+	return static_cast<tools::PanSettings *>(
+		getToolSettingsPage(tools::Tool::PAN));
+}
+
 tools::SelectionSettings *ToolSettings::selectionSettings()
 {
 	return static_cast<tools::SelectionSettings *>(

src/desktop/docks/toolsettingsdock.h

@@ -13,6 +13,7 @@ class ColorPickerSettings;
 class FillSettings;
 class InspectorSettings;
 class LaserPointerSettings;
+class PanSettings;
 class SelectionSettings;
 class ToolController;
 class ToolSettings;
@@ -52,6 +53,7 @@ class ToolSettings final : public DockBase {
 	tools::FillSettings *fillSettings();
 	tools::InspectorSettings *inspectorSettings();
 	tools::LaserPointerSettings *laserPointerSettings();
+	tools::PanSettings *panSettings();
 	tools::SelectionSettings *selectionSettings();
 	tools::ZoomSettings *zoomSettings();
 

src/desktop/mainwindow.cpp

@@ -4370,6 +4370,7 @@ void MainWindow::setupActions()
 	QAction *lasertool = makeAction("toollaser", tr("&Laser Pointer")).icon("cursor-arrow").statusTip(tr("Point out things on the canvas")).shortcut("L").checkable();
 	QAction *selectiontool = makeAction("toolselectrect", tr("&Select (Rectangular)")).icon("select-rectangular").statusTip(tr("Select area for copying")).shortcut("S").checkable();
 	QAction *lassotool = makeAction("toolselectpolygon", tr("&Select (Free-Form)")).icon("edit-select-lasso").statusTip(tr("Select a free-form area for copying")).shortcut("D").checkable();
+	QAction *pantool = makeAction("toolpan", tr("Pan")).icon("hand").statusTip(tr("Pan canvas view")).shortcut("P").checkable();
 	QAction *zoomtool = makeAction("toolzoom", tr("Zoom")).icon("edit-find").statusTip(tr("Zoom the canvas view")).shortcut("Z").checkable();
 	QAction *inspectortool = makeAction("toolinspector", tr("Inspector")).icon("help-whatsthis").statusTip(tr("Find out who did it")).shortcut("Ctrl+I").checkable();
 
@@ -4385,6 +4386,7 @@ void MainWindow::setupActions()
 	m_drawingtools->addAction(lasertool);
 	m_drawingtools->addAction(selectiontool);
 	m_drawingtools->addAction(lassotool);
+	m_drawingtools->addAction(pantool);
 	m_drawingtools->addAction(zoomtool);
 	m_drawingtools->addAction(inspectortool);
 

src/desktop/scene/scenewrapper.cpp

@@ -250,6 +250,9 @@ void SceneWrapper::connectDocument(Document *doc)
 	connect(
 		toolCtrl, &tools::ToolController::busyStateChanged, m_view,
 		&CanvasView::setBusy);
+	connect(
+		toolCtrl, &tools::ToolController::panRequested, m_view,
+		&CanvasView::scrollBy);
 	connect(
 		toolCtrl, &tools::ToolController::zoomRequested, m_view,
 		&CanvasView::zoomTo);

src/desktop/toolwidgets/pansettings.cpp

@@ -0,0 +1,23 @@
+// SPDX-License-Identifier: GPL-3.0-or-later
+#include "desktop/toolwidgets/pansettings.h"
+#include "desktop/widgets/groupedtoolbutton.h"
+#include <QButtonGroup>
+#include <QPushButton>
+#include <QVBoxLayout>
+#include <QWidget>
+
+namespace tools {
+
+PanSettings::PanSettings(ToolController *ctrl, QObject *parent)
+	: ToolSettings(ctrl, parent)
+{
+}
+
+QWidget *PanSettings::createUiWidget(QWidget *parent)
+{
+	QWidget *widget = new QWidget(parent);
+	// The pan tool has no settings.
+	return widget;
+}
+
+}

src/desktop/toolwidgets/pansettings.h

@@ -0,0 +1,32 @@
+// SPDX-License-Identifier: GPL-3.0-or-later
+#ifndef DESKTOP_TOOLWIDGETS_PANSETTINGS_H
+#define DESKTOP_TOOLWIDGETS_PANSETTINGS_H
+#include "desktop/toolwidgets/toolsettings.h"
+
+class QAction;
+
+namespace widgets {
+class GroupedToolButton;
+}
+
+namespace tools {
+
+class PanSettings final : public ToolSettings {
+	Q_OBJECT
+public:
+	PanSettings(ToolController *ctrl, QObject *parent = nullptr);
+
+	QString toolType() const override { return QStringLiteral("pan"); }
+
+	void setForeground(const QColor &color) override { Q_UNUSED(color); }
+
+	int getSize() const override { return 0; }
+	bool getSubpixelMode() const override { return false; }
+
+protected:
+	QWidget *createUiWidget(QWidget *parent) override;
+};
+
+}
+
+#endif

src/desktop/view/viewwrapper.cpp

@@ -8,6 +8,7 @@
 #include "desktop/toolwidgets/annotationsettings.h"
 #include "desktop/toolwidgets/brushsettings.h"
 #include "desktop/toolwidgets/lasersettings.h"
+#include "desktop/toolwidgets/pansettings.h"
 #include "desktop/toolwidgets/selectionsettings.h"
 #include "desktop/toolwidgets/zoomsettings.h"
 #include "desktop/view/canvascontroller.h"
@@ -248,6 +249,9 @@ void ViewWrapper::connectDocument(Document *doc)
 	connect(
 		toolCtrl, &tools::ToolController::busyStateChanged, m_controller,
 		&CanvasController::setBusy);
+	connect(
+		toolCtrl, &tools::ToolController::panRequested, m_controller,
+		&CanvasController::scrollBy);
 	connect(
 		toolCtrl, &tools::ToolController::zoomRequested, m_controller,
 		&CanvasController::zoomTo);

src/libclient/CMakeLists.txt

@@ -131,6 +131,8 @@ target_sources(dpclient PRIVATE
 	tools/inspector.h
 	tools/laser.cpp
 	tools/laser.h
+	tools/pan.cpp
+	tools/pan.h
 	tools/selection.cpp
 	tools/selection.h
 	tools/shapetools.cpp

src/libclient/tools/pan.cpp

@@ -0,0 +1,48 @@
+// SPDX-License-Identifier: GPL-3.0-or-later
+#include "libclient/tools/pan.h"
+#include "libclient/tools/toolcontroller.h"
+#include <QCursor>
+#include <QPixmap>
+
+namespace tools {
+
+PanTool::PanTool(ToolController &owner)
+	: Tool(owner, PAN, QCursor(Qt::OpenHandCursor), true, false, true)
+{
+}
+
+void PanTool::begin(
+	const canvas::Point &point, bool right, float zoom, const QPointF &viewPos)
+{
+	Q_UNUSED(point);
+	Q_UNUSED(zoom);
+	if(!right) {
+		setCursor(Qt::ClosedHandCursor);
+		m_lastViewPos = viewPos;
+		m_panning = true;
+	}
+}
+
+void PanTool::motion(
+	const canvas::Point &point, bool constrain, bool center,
+	const QPointF &viewPos)
+{
+	Q_UNUSED(point);
+	Q_UNUSED(constrain);
+	Q_UNUSED(center);
+	if(m_panning) {
+		QPointF delta = m_lastViewPos - viewPos;
+		emit m_owner.panRequested(qRound(delta.x()), qRound(delta.y()));
+		m_lastViewPos = viewPos;
+	}
+}
+
+void PanTool::end()
+{
+	if(m_panning) {
+		setCursor(Qt::OpenHandCursor);
+		m_panning = false;
+	}
+}
+
+}

src/libclient/tools/pan.h

@@ -0,0 +1,30 @@
+// SPDX-License-Identifier: GPL-3.0-or-later
+#ifndef LIBCLIENT_TOOLS_PAN_H
+#define LIBCLIENT_TOOLS_PAN_H
+#include "libclient/tools/tool.h"
+#include <QPointF>
+
+namespace tools {
+
+class PanTool final : public Tool {
+public:
+	PanTool(ToolController &owner);
+
+	void begin(
+		const canvas::Point &point, bool right, float zoom,
+		const QPointF &viewPos) override;
+
+	void motion(
+		const canvas::Point &point, bool constrain, bool center,
+		const QPointF &viewPos) override;
+
+	void end() override;
+
+private:
+	QPointF m_lastViewPos;
+	bool m_panning = false;
+};
+
+}
+
+#endif

src/libclient/tools/tool.h

@@ -35,6 +35,7 @@ class Tool {
 		LASERPOINTER,
 		SELECTION,
 		POLYGONSELECTION,
+		PAN,
 		ZOOM,
 		INSPECTOR,
 		_LASTTOOL,

src/libclient/tools/toolcontroller.cpp

@@ -11,6 +11,7 @@
 #include "libclient/tools/freehand.h"
 #include "libclient/tools/inspector.h"
 #include "libclient/tools/laser.h"
+#include "libclient/tools/pan.h"
 #include "libclient/tools/selection.h"
 #include "libclient/tools/shapetools.h"
 #include "libclient/tools/zoom.h"
@@ -52,6 +53,7 @@ ToolController::ToolController(net::Client *client, QObject *parent)
 	registerTool(new LaserPointer(*this));
 	registerTool(new RectangleSelection(*this));
 	registerTool(new PolygonSelection(*this));
+	registerTool(new PanTool(*this));
 	registerTool(new ZoomTool(*this));
 	registerTool(new Inspector(*this));
 

src/libclient/tools/toolcontroller.h

@@ -182,6 +182,7 @@ public slots:
 	void actionCancelled();
 
 	void colorUsed(const QColor &color);
+	void panRequested(int x, int y);
 	void zoomRequested(const QRect &rect, int steps);
 
 	void busyStateChanged(bool busy);