From 4233f197d3a479b8252004fe9fb2bfebfad52905 Mon Sep 17 00:00:00 2001
From: Gabriel Ozouf <gabriel.ozouf@numworks.com>
Date: Thu, 12 Nov 2020 14:43:17 +0100
Subject: [PATCH] [shared] Keep graph units when using navigation

When using the Navigate menu on graphs, the grid units are computed
using the normal graph's range, so that the units won't change.

Change-Id: I8ff8853868e5c90319619a6271d6a7d87ae82ab0
---
 apps/shared/curve_view_range.h                              | 3 ++-
 apps/shared/function_zoom_and_pan_curve_view_controller.cpp | 5 ++++-
 apps/shared/interactive_curve_view_range.h                  | 5 +++++
 3 files changed, 11 insertions(+), 2 deletions(-)

diff --git a/apps/shared/curve_view_range.h b/apps/shared/curve_view_range.h
index 40c0709bb..5867ab566 100644
--- a/apps/shared/curve_view_range.h
+++ b/apps/shared/curve_view_range.h
@@ -24,7 +24,7 @@ public:
     return computeGridUnit(k_minNumberOfXGridUnits, k_maxNumberOfXGridUnits, xMax() - xMin());
   }
   virtual float yGridUnit() const {
-    return computeGridUnit(k_minNumberOfYGridUnits, k_maxNumberOfYGridUnits, yMax() - yMin());
+    return computeGridUnit(k_minNumberOfYGridUnits, k_maxNumberOfYGridUnits, yMax() - yMin() + offscreenYAxis());
   }
   constexpr static float k_maxNumberOfXGridUnits = 18.0f;
   constexpr static float k_maxNumberOfYGridUnits = 13.0f;
@@ -32,6 +32,7 @@ protected:
   constexpr static float k_minNumberOfXGridUnits = 7.0f;
   constexpr static float k_minNumberOfYGridUnits = 5.0f;
 private:
+  virtual float offscreenYAxis() const { return 0.f; }
   /* The grid units is constrained to be a number of type: k*10^n with k = 1,2 or 5
    * and n a relative integer. The choice of x and y grid units depend on the
    * grid range.*/
diff --git a/apps/shared/function_zoom_and_pan_curve_view_controller.cpp b/apps/shared/function_zoom_and_pan_curve_view_controller.cpp
index cd1edbf60..72fb708ed 100644
--- a/apps/shared/function_zoom_and_pan_curve_view_controller.cpp
+++ b/apps/shared/function_zoom_and_pan_curve_view_controller.cpp
@@ -37,9 +37,12 @@ void FunctionZoomAndPanCurveViewController::adaptCurveRange(bool viewWillAppear)
   float currentRange = m_interactiveRange->yMax() - m_interactiveRange->yMin();
   float newYMin = 0;
   if (viewWillAppear) {
-    newYMin = currentYMin + ((float)ContentView::k_legendHeight)/((float)k_standardViewHeight)*currentRange;
+    float rangeOffscreen = ((float)ContentView::k_legendHeight)/((float)k_standardViewHeight)*currentRange;
+    newYMin = currentYMin + rangeOffscreen;
+    m_interactiveRange->setOffscreenYAxis(rangeOffscreen);
   } else {
     newYMin = m_interactiveRange->yMax() - currentRange*((float)k_standardViewHeight)/(((float)k_standardViewHeight)-((float)ContentView::k_legendHeight));
+    m_interactiveRange->setOffscreenYAxis(0.f);
   }
   m_interactiveRange->setYMin(newYMin);
   m_contentView.curveView()->reload();
diff --git a/apps/shared/interactive_curve_view_range.h b/apps/shared/interactive_curve_view_range.h
index a44169986..ced28f46d 100644
--- a/apps/shared/interactive_curve_view_range.h
+++ b/apps/shared/interactive_curve_view_range.h
@@ -46,6 +46,8 @@ public:
   void setYMin(float f) override;
   void setYMax(float f) override;
 
+  void setOffscreenYAxis(float f) { m_offscreenYAxis = f; }
+
   // Window
   void zoom(float ratio, float x, float y);
   void panWithVector(float x, float y);
@@ -77,6 +79,9 @@ protected:
   constexpr static float NormalizedYHalfRange(float unit) {  return 3.06f * unit; }
   InteractiveCurveViewRangeDelegate * m_delegate;
 private:
+  float offscreenYAxis() const override { return m_offscreenYAxis; }
+
+  float m_offscreenYAxis;
   bool m_zoomAuto;
   bool m_zoomNormalize;
 };