From f2fce3cc0fd022f6a06721c9042b9099efcfde4d Mon Sep 17 00:00:00 2001
From: letsfindaway <me@letsfindaway.de>
Date: Sun, 28 Feb 2021 10:27:21 +0100
Subject: [PATCH] detect and handle change of stylusTool while device pressed

- Basically simulate a device release with the previous tool and a
device press with the new tool to correctly terminate the previous
action.
- Hide the eraser when switching to another tool.
---
 src/board/UBDrawingController.cpp |  3 ++-
 src/board/UBDrawingController.h   |  2 +-
 src/domain/UBGraphicsScene.cpp    | 32 +++++++++++++++++++++++++------
 src/domain/UBGraphicsScene.h      |  4 +++-
 4 files changed, 32 insertions(+), 9 deletions(-)

diff --git a/src/board/UBDrawingController.cpp b/src/board/UBDrawingController.cpp
index 0af87fbd..279e2ca4 100644
--- a/src/board/UBDrawingController.cpp
+++ b/src/board/UBDrawingController.cpp
@@ -120,6 +120,7 @@ void UBDrawingController::setStylusTool(int tool)
             emit colorIndexChanged(UBSettings::settings()->markerColorIndex());
         }
 
+        UBStylusTool::Enum previousTool = mStylusTool;
         mStylusTool = (UBStylusTool::Enum)tool;
 
 
@@ -148,7 +149,7 @@ void UBDrawingController::setStylusTool(int tool)
         else if (mStylusTool == UBStylusTool::Capture)
             UBApplication::mainWindow->actionCapture->setChecked(true);
 
-        emit stylusToolChanged(tool);
+        emit stylusToolChanged(tool, previousTool);
         if (mStylusTool != UBStylusTool::Selector)
             emit colorPaletteChanged();
     }
diff --git a/src/board/UBDrawingController.h b/src/board/UBDrawingController.h
index e40c156f..6b163117 100644
--- a/src/board/UBDrawingController.h
+++ b/src/board/UBDrawingController.h
@@ -82,7 +82,7 @@ class UBDrawingController : public QObject
         void setEraserWidthIndex(int index);
 
     signals:
-        void stylusToolChanged(int tool);
+        void stylusToolChanged(int tool, int previousTool = -1);
         void colorPaletteChanged();
 
         void lineWidthIndexChanged(int index);
diff --git a/src/domain/UBGraphicsScene.cpp b/src/domain/UBGraphicsScene.cpp
index 44b14418..b264c1cb 100644
--- a/src/domain/UBGraphicsScene.cpp
+++ b/src/domain/UBGraphicsScene.cpp
@@ -362,6 +362,7 @@ UBGraphicsScene::UBGraphicsScene(UBDocumentProxy* parent, bool enableUndoRedoSta
 //    Just for debug. Do not delete please
 //    connect(this, SIGNAL(selectionChanged()), this, SLOT(selectionChangedProcessing()));
     connect(UBApplication::undoStack.data(), SIGNAL(indexChanged(int)), this, SLOT(updateSelectionFrameWrapper(int)));
+    connect(UBDrawingController::drawingController(), SIGNAL(stylusToolChanged(int,int)), this, SLOT(stylusToolChanged(int,int)));
 }
 
 UBGraphicsScene::~UBGraphicsScene()
@@ -615,10 +616,13 @@ bool UBGraphicsScene::inputDeviceMove(const QPointF& scenePos, const qreal& pres
                         mTempPolygon = NULL;
                     }
 
-                    QPointF lastDrawnPoint = mCurrentStroke->points().last().first;
+                    if (!mCurrentStroke->points().empty())
+                    {
+                        QPointF lastDrawnPoint = mCurrentStroke->points().last().first;
 
-                    mTempPolygon = lineToPolygonItem(QLineF(lastDrawnPoint, scenePos), mPreviousWidth, width);
-                    addItem(mTempPolygon);
+                        mTempPolygon = lineToPolygonItem(QLineF(lastDrawnPoint, scenePos), mPreviousWidth, width);
+                        addItem(mTempPolygon);
+                    }
                 }
             }
         }
@@ -641,7 +645,7 @@ bool UBGraphicsScene::inputDeviceMove(const QPointF& scenePos, const qreal& pres
     return accepted;
 }
 
-bool UBGraphicsScene::inputDeviceRelease()
+bool UBGraphicsScene::inputDeviceRelease(int tool)
 {
     bool accepted = false;
 
@@ -651,10 +655,15 @@ bool UBGraphicsScene::inputDeviceRelease()
         accepted = true;
     }
 
-    UBStylusTool::Enum currentTool = (UBStylusTool::Enum)UBDrawingController::drawingController()->stylusTool();
+    if (tool < 0)
+    {
+        tool = UBDrawingController::drawingController()->stylusTool();
+    }
+
+    UBStylusTool::Enum currentTool = (UBStylusTool::Enum)tool;
 
     if (currentTool == UBStylusTool::Eraser)
-        redrawEraser(false);
+        hideEraser();
 
 
     UBDrawingController *dc = UBDrawingController::drawingController();
@@ -2355,6 +2364,17 @@ void UBGraphicsScene::resizedMagnifier(qreal newPercent)
     }
 }
 
+void UBGraphicsScene::stylusToolChanged(int tool, int previousTool)
+{
+    if (mInputDeviceIsPressed && tool != previousTool)
+    {
+        // tool was changed while input device is pressed
+        // simulate release and press to terminate pervious strokes
+        inputDeviceRelease(previousTool);
+        inputDevicePress(mPreviousPoint);
+    }
+}
+
 void UBGraphicsScene::addCompass(QPointF center)
 {
     UBGraphicsCompass* compass = new UBGraphicsCompass(); // mem : owned and destroyed by the scene
diff --git a/src/domain/UBGraphicsScene.h b/src/domain/UBGraphicsScene.h
index 4040af7e..ab637756 100644
--- a/src/domain/UBGraphicsScene.h
+++ b/src/domain/UBGraphicsScene.h
@@ -141,7 +141,7 @@ class UBGraphicsScene: public UBCoreGraphicsScene, public UBItem
 
         bool inputDevicePress(const QPointF& scenePos, const qreal& pressure = 1.0);
         bool inputDeviceMove(const QPointF& scenePos, const qreal& pressure = 1.0);
-        bool inputDeviceRelease();
+        bool inputDeviceRelease(int tool = -1);
 
         void leaveEvent (QEvent* event);
 
@@ -381,6 +381,8 @@ public slots:
         void changeMagnifierMode(int mode);
         void resizedMagnifier(qreal newPercent);
 
+        void stylusToolChanged(int tool, int previousTool);
+
     protected:
 
         UBGraphicsPolygonItem* lineToPolygonItem(const QLineF& pLine, const qreal& pWidth);