Add selection cursor guide to make it easier to do selections

Closes #47.
mitchcurtis · Mar 31, 2018 · cf60fb5 · cf60fb5
1 parent b987497
commit cf60fb5
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Showing 2 changed files with 41 additions and 0 deletions.
diff --git a/app/imagecanvas.cpp b/app/imagecanvas.cpp
@@ -859,6 +859,9 @@ void ImageCanvas::drawPane(QPainter *painter, const CanvasPane &pane, int paneIn
         }
     }
 
+    if (shouldDrawSelectionCursorGuide())
+        drawSelectionCursorGuide(painter, pane, paneIndex);
+
     painter->restore();
 }
 
@@ -906,6 +909,34 @@ void ImageCanvas::drawGuide(QPainter *painter, const CanvasPane &pane, int paneI
     painter->restore();
 }
 
+void ImageCanvas::drawSelectionCursorGuide(QPainter *painter, const CanvasPane &pane, int paneIndex)
+{
+    painter->save();
+
+    QPen pen;
+    pen.setColor(Qt::gray);
+    pen.setStyle(Qt::DotLine);
+    painter->setPen(pen);
+
+    // Draw the vertical cursor selection guide.
+    painter->save();
+
+    int guidePosition = mCursorSceneX;
+    qreal zoomedGuidePosition = (guidePosition * pane.integerZoomLevel()) + (painter->pen().widthF() / 2.0);
+    painter->translate(0, -pane.offset().y());
+    painter->drawLine(QLineF(zoomedGuidePosition, 0, zoomedGuidePosition, height()));
+
+    painter->restore();
+
+    // Draw the horizontal cursor selection guide.
+    guidePosition = mCursorSceneY;
+    zoomedGuidePosition = (guidePosition * pane.integerZoomLevel()) + (painter->pen().widthF() / 2.0);
+    painter->translate(-pane.offset().x(), 0);
+    painter->drawLine(QLineF(0, zoomedGuidePosition, paneWidth(paneIndex), zoomedGuidePosition));
+
+    painter->restore();
+}
+
 int ImageCanvas::paneWidth(int index) const
 {
     return index == 0 ? mFirstPane.size() * width() : width() - mFirstPane.size() * width();
@@ -1316,6 +1347,11 @@ bool ImageCanvas::shouldDrawSelectionPreviewImage() const
     return mMovingSelection || mHasMovedSelection || mIsSelectionFromPaste;
 }
 
+bool ImageCanvas::shouldDrawSelectionCursorGuide() const
+{
+    return mTool == SelectionTool && !mHasSelection;
+}
+
 void ImageCanvas::confirmPasteSelection()
 {
     paintImageOntoPortionOfImage(mSelectionAreaBeforeFirstMove, mSelectionContents);
@@ -1793,6 +1829,9 @@ void ImageCanvas::updateCursorPos(const QPoint &eventPos)
         // ShaderSourceEffect to pick the colour instead
         setCursorPixelColour(contentImage().pixelColor(cursorScenePos));
     }
+
+    if (shouldDrawSelectionCursorGuide())
+        update();
 }
 
 void ImageCanvas::onLoadedChanged()

diff --git a/app/imagecanvas.h b/app/imagecanvas.h
@@ -322,6 +322,7 @@ protected slots:
     void drawPane(QPainter *painter, const CanvasPane &pane, int paneIndex);
     void drawLine(QPainter *painter) const;
     void drawGuide(QPainter *painter, const CanvasPane &pane, int paneIndex, const Guide &guide, int guideIndex);
+    void drawSelectionCursorGuide(QPainter *painter, const CanvasPane &pane, int paneIndex);
     int paneWidth(int index) const;
     void centrePanes(bool respectSceneCentred = true);
     enum ResetPaneSizePolicy {
@@ -364,6 +365,7 @@ protected slots:
     void setMovingSelection(bool movingSelection);
     bool cursorOverSelection() const;
     bool shouldDrawSelectionPreviewImage() const;
+    bool shouldDrawSelectionCursorGuide() const;
     void confirmPasteSelection();
     void setSelectionFromPaste(bool isSelectionFromPaste);