From 37b9fed4c6b2878c814130cc11013ec918fb8ded Mon Sep 17 00:00:00 2001
From: Soeren Apel <soeren@apelpie.net>
Date: Thu, 7 Apr 2016 22:02:50 +0200
Subject: [PATCH] AnalogSignal: Implement vertical grid

---
 pv/view/analogsignal.cpp | 47 +++++++++++++++++++++++++++++++++++-----
 pv/view/analogsignal.hpp |  7 +++++-
 2 files changed, 47 insertions(+), 7 deletions(-)

diff --git a/pv/view/analogsignal.cpp b/pv/view/analogsignal.cpp
index 30cf5abf..b340de67 100644
--- a/pv/view/analogsignal.cpp
+++ b/pv/view/analogsignal.cpp
@@ -25,6 +25,8 @@
 #include <cstdlib>
 #include <limits>
 
+#include <QApplication>
+
 #include "analogsignal.hpp"
 #include "pv/data/analog.hpp"
 #include "pv/data/analogsegment.hpp"
@@ -43,8 +45,6 @@ using sigrok::Channel;
 namespace pv {
 namespace view {
 
-const int AnalogSignal::NominalHeight = 80;
-
 const QColor AnalogSignal::SignalColours[4] = {
 	QColor(0xC4, 0xA0, 0x00),	// Yellow
 	QColor(0x87, 0x20, 0x7A),	// Magenta
@@ -52,6 +52,9 @@ const QColor AnalogSignal::SignalColours[4] = {
 	QColor(0x4E, 0x9A, 0x06)	// Green
 };
 
+const QColor AnalogSignal::GridMajorColor = QColor(0xB0, 0xB0, 0xB0);
+const QColor AnalogSignal::GridMinorColor = QColor(0xD0, 0xD0, 0xD0);
+
 const float AnalogSignal::EnvelopeThreshold = 256.0f;
 
 AnalogSignal::AnalogSignal(
@@ -61,7 +64,9 @@ AnalogSignal::AnalogSignal(
 	Signal(session, channel),
 	data_(data),
 	scale_index_(0),
-	scale_index_drag_offset_(0)
+	scale_index_drag_offset_(0),
+	div_height_(3 * QFontMetrics(QApplication::font()).height()),
+	vdivs_(1)
 {
 	set_colour(SignalColours[channel_->index() % countof(SignalColours)]);
 }
@@ -78,20 +83,24 @@ shared_ptr<pv::data::Analog> AnalogSignal::analog_data() const
 
 std::pair<int, int> AnalogSignal::v_extents() const
 {
-	const int h = NominalHeight / 2;
+	const int h = vdivs_ * div_height_;
 	return make_pair(-h, h);
 }
 
 int AnalogSignal::scale_handle_offset() const
 {
+	const int h = vdivs_ * div_height_;
+
 	return ((scale_index_drag_offset_ - scale_index_) *
-		NominalHeight / 4) - NominalHeight / 2;
+		h / 4) - h / 2;
 }
 
 void AnalogSignal::scale_handle_dragged(int offset)
 {
+	const int h = vdivs_ * div_height_;
+
 	scale_index_ = scale_index_drag_offset_ -
-		(offset + NominalHeight / 2) / (NominalHeight / 4);
+		(offset + h / 2) / (h / 4);
 }
 
 void AnalogSignal::scale_handle_drag_release()
@@ -117,6 +126,8 @@ void AnalogSignal::paint_mid(QPainter &p, const ViewItemPaintParams &pp)
 	if (!channel_->enabled())
 		return;
 
+	paint_grid(p, y, pp.left(), pp.right());
+
 	const deque< shared_ptr<pv::data::AnalogSegment> > &segments =
 		data_->analog_segments();
 	if (segments.empty())
@@ -148,6 +159,30 @@ void AnalogSignal::paint_mid(QPainter &p, const ViewItemPaintParams &pp)
 			pixels_offset, samples_per_pixel);
 }
 
+void AnalogSignal::paint_grid(QPainter &p, int y, int left, int right)
+{
+	p.setPen(QPen(GridMajorColor, 0.5, Qt::DashLine));
+	for (int i = 1; i <= vdivs_; i++) {
+		const int dy = i * div_height_;
+		p.drawLine(QLineF(left, y - dy, right, y - dy));
+		p.drawLine(QLineF(left, y + dy, right, y + dy));
+	}
+
+	p.setPen(QPen(GridMinorColor, 0.5, Qt::DashLine));
+	for (int i = 0; i < vdivs_; i++) {
+		const int dy = i * div_height_;
+		const float dy25 = dy + (0.25 * div_height_);
+		const float dy50 = dy + (0.50 * div_height_);
+		const float dy75 = dy + (0.75 * div_height_);
+		p.drawLine(QLineF(left, y - dy25, right, y - dy25));
+		p.drawLine(QLineF(left, y + dy25, right, y + dy25));
+		p.drawLine(QLineF(left, y - dy50, right, y - dy50));
+		p.drawLine(QLineF(left, y + dy50, right, y + dy50));
+		p.drawLine(QLineF(left, y - dy75, right, y - dy75));
+		p.drawLine(QLineF(left, y + dy75, right, y + dy75));
+	}
+}
+
 void AnalogSignal::paint_trace(QPainter &p,
 	const shared_ptr<pv::data::AnalogSegment> &segment,
 	int y, int left, const int64_t start, const int64_t end,
diff --git a/pv/view/analogsignal.hpp b/pv/view/analogsignal.hpp
index 06867a55..dd2b31dc 100644
--- a/pv/view/analogsignal.hpp
+++ b/pv/view/analogsignal.hpp
@@ -37,8 +37,8 @@ namespace view {
 class AnalogSignal : public Signal
 {
 private:
-	static const int NominalHeight;
 	static const QColor SignalColours[4];
+	static const QColor GridMajorColor, GridMinorColor;
 
 	static const float EnvelopeThreshold;
 
@@ -90,6 +90,8 @@ public:
 	void paint_mid(QPainter &p, const ViewItemPaintParams &pp);
 
 private:
+	void paint_grid(QPainter &p, int y, int left, int right);
+
 	void paint_trace(QPainter &p,
 		const std::shared_ptr<pv::data::AnalogSegment> &segment,
 		int y, int left, const int64_t start, const int64_t end,
@@ -110,6 +112,9 @@ private:
 
 	int scale_index_;
 	int scale_index_drag_offset_;
+
+	int div_height_;
+	int vdivs_;  // divs per positive/negative side
 };
 
 } // namespace view
-- 
2.30.2