[apps] Graph: when setting default range of a function, take

into account the potential periodicity

apps/graph/graph/graph_controller.cpp

@@ -39,6 +39,19 @@ void GraphController::setDisplayDerivativeInBanner(bool displayDerivative) {
   m_displayDerivativeInBanner = displayDerivative;
 }
 
+float GraphController::interestingXRange() {
+  float characteristicRange = 0.0f;
+  TextFieldDelegateApp * myApp = (TextFieldDelegateApp *)app();
+  for (int i = 0; i < functionStore()->numberOfActiveFunctions(); i++) {
+    Function * f = functionStore()->activeFunctionAtIndex(i);
+    float fRange = f->expression(myApp->localContext())->characteristicXRange(*(myApp->localContext()));
+    if (!std::isnan(fRange)) {
+      characteristicRange = fRange > characteristicRange ? fRange : characteristicRange;
+    }
+  }
+  return (characteristicRange > 0.0f ? 1.6f*characteristicRange : 10.0f);
+}
+
 void GraphController::selectFunctionWithCursor(int functionIndex) {
   FunctionGraphController::selectFunctionWithCursor(functionIndex);
   CartesianFunction * f = m_functionStore->activeFunctionAtIndex(indexFunctionSelectedByCursor());

apps/graph/graph/graph_controller.h

@@ -20,6 +20,7 @@ public:
   void viewWillAppear() override;
   bool displayDerivativeInBanner() const;
   void setDisplayDerivativeInBanner(bool displayDerivative);
+  float interestingXRange() override;
 private:
   void selectFunctionWithCursor(int functionIndex) override;
   BannerView * bannerView() override;

apps/sequence/graph/curve_view_range.cpp

@@ -75,7 +75,8 @@ void CurveViewRange::setTrigonometric() {
 }
 
 void CurveViewRange::setDefault() {
-  m_xMax = 10.0f;
+  assert(m_delegate);
+  m_xMax = m_delegate->interestingXRange();
   m_xMin = -k_displayLeftMarginRatio*m_xMax;
   m_xGridUnit = computeGridUnit(Axis::X, m_xMin, m_xMax);
   setYAuto(true);

apps/shared/interactive_curve_view_range.cpp

@@ -167,8 +167,9 @@ void InteractiveCurveViewRange::setTrigonometric() {
 }
 
 void InteractiveCurveViewRange::setDefault() {
-  m_xMax = 10.0f;
-  MemoizedCurveViewRange::setXMin(-10.0f);
+  assert(m_delegate);
+  m_xMax = m_delegate->interestingXRange();
+  MemoizedCurveViewRange::setXMin(-m_xMax);
   setYAuto(true);
 }
 

apps/shared/interactive_curve_view_range_delegate.cpp

@@ -48,4 +48,8 @@ bool InteractiveCurveViewRangeDelegate::didChangeRange(InteractiveCurveViewRange
   return true;
 }
 
+float InteractiveCurveViewRangeDelegate::interestingXRange() {
+  return 10.0f;
+}
+
 }

apps/shared/interactive_curve_view_range_delegate.h

@@ -8,6 +8,7 @@ class InteractiveCurveViewRange;
 class InteractiveCurveViewRangeDelegate {
 public:
   bool didChangeRange(InteractiveCurveViewRange * interactiveCurveViewRange);
+  virtual float interestingXRange();
 protected:
   struct Range {
     float min;