From 26754a3230f5c47ce07dc1f99f1e7c5ecaf81234 Mon Sep 17 00:00:00 2001
From: Gabriel Ozouf <gabriel.ozouf@numworks.com>
Date: Tue, 6 Oct 2020 11:57:45 +0200
Subject: [PATCH] [graph] Force same grid unit on orthonormal graphs

Change-Id: I2abca9eb1c4a14057323ee97e1044715f89620ff
---
 apps/shared/curve_view_range.h               |  3 ++-
 apps/shared/interactive_curve_view_range.cpp | 16 ++++++++++++++++
 apps/shared/interactive_curve_view_range.h   |  4 ++++
 3 files changed, 22 insertions(+), 1 deletion(-)

diff --git a/apps/shared/curve_view_range.h b/apps/shared/curve_view_range.h
index caa1d9ab0..ae31a94f2 100644
--- a/apps/shared/curve_view_range.h
+++ b/apps/shared/curve_view_range.h
@@ -27,9 +27,10 @@ public:
   }
   constexpr static float k_maxNumberOfXGridUnits = 18.0f;
   constexpr static float k_maxNumberOfYGridUnits = 13.0f;
-private:
+protected:
   constexpr static float k_minNumberOfXGridUnits = 7.0f;
   constexpr static float k_minNumberOfYGridUnits = 5.0f;
+private:
   /* 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/interactive_curve_view_range.cpp b/apps/shared/interactive_curve_view_range.cpp
index 46d347127..86953bc04 100644
--- a/apps/shared/interactive_curve_view_range.cpp
+++ b/apps/shared/interactive_curve_view_range.cpp
@@ -33,6 +33,22 @@ void InteractiveCurveViewRange::setYMax(float yMax) {
   MemoizedCurveViewRange::protectedSetYMax(yMax, k_lowerMaxFloat, k_upperMaxFloat);
 }
 
+float InteractiveCurveViewRange::yGridUnit() const {
+  float res = MemoizedCurveViewRange::yGridUnit();
+  if (m_zoomNormalize) {
+    /* When m_zoomNormalize is active, both xGridUnit and yGridUnit will be the
+     * same. To declutter the X axis, we try a unit twice as large. We check
+     * that it allows enough graduations on the Y axis, but if the standard
+     * unit would lead to too many graduations on the X axis, we force the
+     * larger unit anyways. */
+    float numberOfUnits = (yMax() - yMin()) / res;
+    if (numberOfUnits > k_maxNumberOfXGridUnits || numberOfUnits / 2.f > k_minNumberOfYGridUnits) {
+      return 2 * res;
+    }
+  }
+  return res;
+}
+
 void InteractiveCurveViewRange::zoom(float ratio, float x, float y) {
   float xMi = xMin();
   float xMa = xMax();
diff --git a/apps/shared/interactive_curve_view_range.h b/apps/shared/interactive_curve_view_range.h
index 4b1c389bd..5ba3ba3a6 100644
--- a/apps/shared/interactive_curve_view_range.h
+++ b/apps/shared/interactive_curve_view_range.h
@@ -26,6 +26,10 @@ public:
   bool zoomNormalize() const { return m_zoomNormalize; }
   void setZoomNormalize(bool v) { m_zoomNormalize = v; }
 
+  // MemoizedCurveViewRange
+  float xGridUnit() const override { return m_zoomNormalize ? yGridUnit() : MemoizedCurveViewRange::xGridUnit(); }
+  float yGridUnit() const override;
+
   // CurveViewWindow
   void setXMin(float f) override;
   void setXMax(float f) override;