From b05041dbd07d3ab2559fa3dcc0ae411a35d81490 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?L=C3=A9a=20Saviot?= <lea.saviot@numworks.com>
Date: Mon, 2 Sep 2019 15:45:21 +0200
Subject: [PATCH] [apps/shared] Add display margin on top of / below constant
 curve

---
 apps/shared/interactive_curve_view_range_delegate.cpp | 6 ++++++
 apps/shared/memoized_curve_view_range.h               | 2 +-
 2 files changed, 7 insertions(+), 1 deletion(-)

diff --git a/apps/shared/interactive_curve_view_range_delegate.cpp b/apps/shared/interactive_curve_view_range_delegate.cpp
index 0c78f3dc2..1f61f1e5d 100644
--- a/apps/shared/interactive_curve_view_range_delegate.cpp
+++ b/apps/shared/interactive_curve_view_range_delegate.cpp
@@ -22,6 +22,12 @@ bool InteractiveCurveViewRangeDelegate::didChangeRange(InteractiveCurveViewRange
   if (interactiveCurveViewRange->yMin() == addMargin(min, range, true) && interactiveCurveViewRange->yMax() == addMargin(max, range, false)) {
     return false;
   }
+  if (min == max) {
+    // Add same margin on top of / below the curve, to center it on the screen
+    float step = max != 0.0f ? 2.0f * interactiveCurveViewRange->defaultRangeLengthFor(max) : 1.0f;
+    min = min - step;
+    max = max + step;
+  }
   if (min == FLT_MAX && max == -FLT_MAX) {
     min = -1.0f;
     max = 1.0f;
diff --git a/apps/shared/memoized_curve_view_range.h b/apps/shared/memoized_curve_view_range.h
index e3a78998b..3b5ff15f9 100644
--- a/apps/shared/memoized_curve_view_range.h
+++ b/apps/shared/memoized_curve_view_range.h
@@ -19,9 +19,9 @@ public:
   virtual void setXMax(float f);
   virtual void setYMin(float f);
   virtual void setYMax(float f);
+  float defaultRangeLengthFor(float position) const;
 
 protected:
-  float defaultRangeLengthFor(float position) const;
   // Window bounds of the data
   float m_xMin;
   float m_xMax;