From bb8a28ade0f76259d3909d71b85096f0d8db59e5 Mon Sep 17 00:00:00 2001
From: Hugo Saint-Vignes <hugo.saint-vignes@numworks.com>
Date: Thu, 8 Oct 2020 18:22:58 +0200
Subject: [PATCH] [poincare/zoom] Simplify plot ranges after adding margins

Change-Id: If8904ca4e7d306376de785a125fe5fba168de718
---
 apps/regression/store.cpp                    |  7 ++++--
 apps/shared/interactive_curve_view_range.cpp | 24 ++++++++++++++++----
 apps/shared/interactive_curve_view_range.h   |  1 +
 3 files changed, 25 insertions(+), 7 deletions(-)

diff --git a/apps/regression/store.cpp b/apps/regression/store.cpp
index 33474812d..a794ef3c6 100644
--- a/apps/regression/store.cpp
+++ b/apps/regression/store.cpp
@@ -139,6 +139,8 @@ int Store::nextDot(int series, int direction, int dot) {
 /* Window */
 
 void Store::setDefault() {
+  setZoomNormalize(false);
+
   float xMin, xMax, yMin, yMax;
   float mins[k_numberOfSeries], maxs[k_numberOfSeries];
   for (int series = 0; series < k_numberOfSeries; series++) {
@@ -168,12 +170,13 @@ void Store::setDefault() {
   setXMax(xMax + k_displayHorizontalMarginRatio * range);
 
   range = yMax - yMin;
-  setYMin(m_delegate->addMargin(yMin, range, true, true));
-  setYMax(m_delegate->addMargin(yMax, range, true, false));
+  setYMin(roundLimit(m_delegate->addMargin(yMin, range, true, true ), range, true));
+  setYMax(roundLimit(m_delegate->addMargin(yMax, range, true, false), range, false));
 
   if (revertToOrthonormal) {
     normalize();
   }
+  setZoomAuto(true);
 }
 
 /* Series */
diff --git a/apps/shared/interactive_curve_view_range.cpp b/apps/shared/interactive_curve_view_range.cpp
index 20793e956..77126f4b0 100644
--- a/apps/shared/interactive_curve_view_range.cpp
+++ b/apps/shared/interactive_curve_view_range.cpp
@@ -3,6 +3,7 @@
 #include <cmath>
 #include <stddef.h>
 #include <assert.h>
+#include <poincare/ieee754.h>
 #include <poincare/preferences.h>
 #include <poincare/zoom.h>
 #include <algorithm>
@@ -39,6 +40,19 @@ void InteractiveCurveViewRange::setZoomNormalize(bool v) {
   }
 }
 
+float InteractiveCurveViewRange::roundLimit(float y, float range, bool isMin) {
+  /* Floor/ceil to a round number, with a precision depending on the range.
+   * A range within : | Will have a magnitude : | 3.14 would be floored to :
+   *    [100,1000]    |     10                  | 0
+   *    [10,100]      |     1                   | 3
+   *    [1,10]        |     0.1                 | 3.1                       */
+  float magnitude = std::pow(10.0f, Poincare::IEEE754<float>::exponentBase10(range) - 1.0f);
+  if (isMin) {
+    return magnitude * std::floor(y / magnitude);
+  }
+  return magnitude * std::ceil(y / magnitude);
+}
+
 void InteractiveCurveViewRange::setXMin(float xMin) {
   MemoizedCurveViewRange::protectedSetXMin(xMin, k_lowerMaxFloat, k_upperMaxFloat);
 }
@@ -141,14 +155,14 @@ void InteractiveCurveViewRange::setDefault() {
   m_delegate->interestingRanges(this);
   bool revertToNormalized = isOrthonormal(k_orthonormalTolerance);
 
-  // Add margins
+  // Add margins, then round limits.
   float xRange = xMax() - xMin();
   float yRange = yMax() - yMin();
-  m_xRange.setMin(m_delegate->addMargin(xMin(), xRange, false, true), k_lowerMaxFloat, k_upperMaxFloat);
+  m_xRange.setMin(roundLimit(m_delegate->addMargin(xMin(), xRange, false, true), xRange, true), k_lowerMaxFloat, k_upperMaxFloat);
   // Use MemoizedCurveViewRange::protectedSetXMax to update xGridUnit
-  MemoizedCurveViewRange::protectedSetXMax(m_delegate->addMargin(xMax(), xRange, false, false), k_lowerMaxFloat, k_upperMaxFloat);
-  m_yRange.setMin(m_delegate->addMargin(yMin(), yRange, true, true), k_lowerMaxFloat, k_upperMaxFloat);
-  MemoizedCurveViewRange::protectedSetYMax(m_delegate->addMargin(yMax(), yRange, true, false), k_lowerMaxFloat, k_upperMaxFloat);
+  MemoizedCurveViewRange::protectedSetXMax(roundLimit(m_delegate->addMargin(xMax(), xRange, false, false), xRange, false), k_lowerMaxFloat, k_upperMaxFloat);
+  m_yRange.setMin(roundLimit(m_delegate->addMargin(yMin(), yRange, true , true), yRange, true), k_lowerMaxFloat, k_upperMaxFloat);
+  MemoizedCurveViewRange::protectedSetYMax(roundLimit(m_delegate->addMargin(yMax(), yRange, true , false), yRange, false), k_lowerMaxFloat, k_upperMaxFloat);
 
   if (m_delegate->defaultRangeIsNormalized() || revertToNormalized) {
     // Normalize the axes, so that a polar circle is displayed as a circle
diff --git a/apps/shared/interactive_curve_view_range.h b/apps/shared/interactive_curve_view_range.h
index 9608f1bee..5e4607b29 100644
--- a/apps/shared/interactive_curve_view_range.h
+++ b/apps/shared/interactive_curve_view_range.h
@@ -32,6 +32,7 @@ public:
   void setZoomAuto(bool v);
   bool zoomNormalize() const { return m_zoomNormalize; }
   void setZoomNormalize(bool v);
+  float roundLimit(float y, float range, bool isMin);
 
   // MemoizedCurveViewRange
   float xGridUnit() const override { return m_zoomNormalize ? yGridUnit() : MemoizedCurveViewRange::xGridUnit(); }