From 8572f4953c393b92a74f531f2e5a02d372608b1a Mon Sep 17 00:00:00 2001
From: Gabriel Ozouf <gabriel.ozouf@numworks.com>
Date: Tue, 13 Oct 2020 11:15:57 +0200
Subject: [PATCH] [poincare/zoom] Method CombineRanges

The logic behind combining several ranges will be handled by the Zoom
class directly.

Change-Id: I4de3f020d94b9bc1a21953b0c416158c65beb606
---
 poincare/include/poincare/zoom.h |  2 ++
 poincare/src/zoom.cpp            | 22 +++++++++++++++++++---
 2 files changed, 21 insertions(+), 3 deletions(-)

diff --git a/poincare/include/poincare/zoom.h b/poincare/include/poincare/zoom.h
index ff375415c..2c0b7b891 100644
--- a/poincare/include/poincare/zoom.h
+++ b/poincare/include/poincare/zoom.h
@@ -23,6 +23,8 @@ public:
   static void RangeWithRatioForDisplay(ValueAtAbscissa evaluation, float yxRatio, float * xMin, float * xMax, float * yMin, float * yMax, Context * context, const void * auxiliary);
   static void FullRange(ValueAtAbscissa evaluation, float tMin, float tMax, float tStep, float * fMin, float * fMax, Context * context, const void * auxiliary);
 
+  static void CombineRanges(int length, const float * mins, const float * maxs, float * minRes, float * maxRes);
+
   /* If shrink is false, the range will be set to ratio by increasing the size
    * of the smallest axis. If it is true, the longest axis will be reduced.*/
   static void SetToRatio(float yxRatio, float * xMin, float * xMax, float * yMin, float * yMax, bool shrink = false);
diff --git a/poincare/src/zoom.cpp b/poincare/src/zoom.cpp
index f20a596ba..b7004baa4 100644
--- a/poincare/src/zoom.cpp
+++ b/poincare/src/zoom.cpp
@@ -204,6 +204,25 @@ void Zoom::RefinedYRangeForDisplay(ValueAtAbscissa evaluation, float xMin, float
   }
 }
 
+void Zoom::CombineRanges(int length, const float * mins, const float * maxs, float * minRes, float * maxRes) {
+  ValueAtAbscissa evaluation = [](float x, Context * context, const void * auxiliary) {
+    int index = std::round(x);
+    return static_cast<const float *>(auxiliary)[index];
+  };
+  FullRange(evaluation, 0, length - 1, 1, minRes, maxRes, nullptr, mins);
+  float min, max;
+  FullRange(evaluation, 0, length - 1, 1, &min, &max, nullptr, maxs);
+  if (min < *minRes) {
+    *minRes = min;
+  }
+  if (max > *maxRes) {
+    *maxRes = max;
+  }
+  if (*minRes == *maxRes) {
+    RangeFromSingleValue(*minRes, minRes, maxRes);
+  }
+}
+
 void Zoom::SetToRatio(float yxRatio, float * xMin, float * xMax, float * yMin, float * yMax, bool shrink) {
   float currentRatio = (*yMax - *yMin) / (*xMax - *xMin);
 
@@ -276,9 +295,6 @@ void Zoom::FullRange(ValueAtAbscissa evaluation, float tMin, float tMax, float t
     }
     t += tStep;
   }
-  if (*fMin == *fMax) {
-    RangeFromSingleValue(*fMin, fMin, fMax);
-  }
 }
 
 void Zoom::RangeFromSingleValue(float value, float * boundMin, float * boundMax) {