From 4eba9990f617cba59193c7df8e6359ea642ccb27 Mon Sep 17 00:00:00 2001
From: jaseg <git@jaseg.net>
Date: Sat, 8 Jun 2019 11:19:48 +0900
Subject: [PATCH] Trace view: Allow setting cursors via shift-drag

---
 pv/views/trace/view.cpp       | 37 +++++++++++++++++++++---------
 pv/views/trace/view.hpp       |  5 ++++
 pv/views/trace/viewwidget.cpp | 43 +++++++++++++++++++++++++----------
 pv/views/trace/viewwidget.hpp |  3 +++
 4 files changed, 65 insertions(+), 23 deletions(-)

diff --git a/pv/views/trace/view.cpp b/pv/views/trace/view.cpp
index 05e6da3e..2a4c4372 100644
--- a/pv/views/trace/view.cpp
+++ b/pv/views/trace/view.cpp
@@ -790,22 +790,37 @@ bool View::cursors_shown() const
 
 void View::show_cursors(bool show)
 {
-	show_cursors_ = show;
-	cursor_state_changed(show);
-	ruler_->update();
-	viewport_->update();
+    if (show_cursors_ != show) {
+        show_cursors_ = show;
+        cursor_state_changed(show);
+        ruler_->update();
+        viewport_->update();
+
+    } else {
+        show_cursors_ = show;
+    }
+}
+
+void View::set_cursors(pv::util::Timestamp& first, pv::util::Timestamp& second) {
+    assert(cursors);
+
+    cursors_->first()->set_time(first);
+    cursors_->second()->set_time(second);
+
+    ruler_->update();
+    viewport_->update();
 }
 
 void View::centre_cursors()
 {
-	if (cursors_) {
-		const double time_width = scale_ * viewport_->width();
-		cursors_->first()->set_time(offset_ + time_width * 0.4);
-		cursors_->second()->set_time(offset_ + time_width * 0.6);
+    assert(cursors);
 
-		ruler_->update();
-		viewport_->update();
-	}
+    const double time_width = scale_ * viewport_->width();
+    cursors_->first()->set_time(offset_ + time_width * 0.4);
+    cursors_->second()->set_time(offset_ + time_width * 0.6);
+
+    ruler_->update();
+    viewport_->update();
 }
 
 shared_ptr<CursorPair> View::cursors() const
diff --git a/pv/views/trace/view.hpp b/pv/views/trace/view.hpp
index e66f7d0e..8fdbc15d 100644
--- a/pv/views/trace/view.hpp
+++ b/pv/views/trace/view.hpp
@@ -278,6 +278,11 @@ public:
 	 */
 	void show_cursors(bool show = true);
 
+    /**
+     * Sets the cursors to the given offsets. You will still have to call show_cursors separately.
+     */
+    void set_cursors(pv::util::Timestamp& first, pv::util::Timestamp& second);
+
 	/**
 	 * Moves the cursors to a convenient position in the view.
 	 */
diff --git a/pv/views/trace/viewwidget.cpp b/pv/views/trace/viewwidget.cpp
index 46946a5c..e20be24f 100644
--- a/pv/views/trace/viewwidget.cpp
+++ b/pv/views/trace/viewwidget.cpp
@@ -253,7 +253,10 @@ void ViewWidget::mousePressEvent(QMouseEvent *event)
 	assert(event);
 
 	if (event->button() & Qt::LeftButton) {
+        if (event->modifiers() & Qt::ShiftModifier)
+            view_.show_cursors(false);
 		mouse_down_point_ = event->pos();
+		mouse_down_offset_ =  view_.offset() + event->pos().x() * view_.scale();
 		mouse_down_item_ = get_mouse_over_item(event->pos());
 		mouse_left_press_event(event);
 	}
@@ -285,22 +288,38 @@ void ViewWidget::mouseMoveEvent(QMouseEvent *event)
 	assert(event);
 	mouse_point_ = event->pos();
 
-	if (!event->buttons())
+	if (!event->buttons()) {
 		item_hover(get_mouse_over_item(event->pos()), event->pos());
-	else if (event->buttons() & Qt::LeftButton) {
-		if (!item_dragging_) {
-			if ((event->pos() - mouse_down_point_).manhattanLength() <
-				QApplication::startDragDistance())
-				return;
 
-			if (!accept_drag())
-				return;
+    } else if (event->buttons() & Qt::LeftButton) {
 
-			item_dragging_ = true;
-		}
+        if (event->modifiers() & Qt::ShiftModifier) { // Cursor drag 
+            pv::util::Timestamp current_offset =  view_.offset() + event->pos().x() * view_.scale();
+
+            // TODO: Is startDragDistance the right constant here?
+            if (qAbs(current_offset - mouse_down_offset_)/view_.scale() > QApplication::startDragDistance()) {
+                view_.show_cursors(true);
+                view_.set_cursors(mouse_down_offset_, current_offset);
+
+            } else {
+                view_.show_cursors(false);
+            }
+
+        } else {
+            if (!item_dragging_) {
+                if ((event->pos() - mouse_down_point_).manhattanLength() <
+                    QApplication::startDragDistance())
+                    return;
+
+                if (!accept_drag())
+                    return;
+
+                item_dragging_ = true;
+            }
 
-		// Do the drag
-		drag_items(event->pos() - mouse_down_point_);
+            // Do the drag
+            drag_items(event->pos() - mouse_down_point_);
+        }
 	}
 }
 
diff --git a/pv/views/trace/viewwidget.hpp b/pv/views/trace/viewwidget.hpp
index f4928e67..0e012560 100644
--- a/pv/views/trace/viewwidget.hpp
+++ b/pv/views/trace/viewwidget.hpp
@@ -25,6 +25,8 @@
 #include <QPoint>
 #include <QWidget>
 
+#include <pv/util.hpp>
+
 using std::shared_ptr;
 using std::vector;
 
@@ -143,6 +145,7 @@ protected:
 	pv::views::trace::View &view_;
 	QPoint mouse_point_;
 	QPoint mouse_down_point_;
+	pv::util::Timestamp mouse_down_offset_;
 	shared_ptr<ViewItem> mouse_down_item_;
 	bool item_dragging_;
 };
-- 
2.30.2