[shared] Create helper functions for ranges

These functions are used to test the full algorithm used to compute
ranges.

Change-Id: I48069e245aa6e879f66aecc29709fc6f992f5220

apps/shared/function_graph_controller.cpp

@@ -154,27 +154,8 @@ int FunctionGraphController::numberOfCurves() const {
 }
 
 void FunctionGraphController::interestingRanges(InteractiveCurveViewRange * range) {
-  Poincare::Context * context = textFieldDelegateApp()->localContext();
-  constexpr int maxLength = 10;
-  float xMins[maxLength], xMaxs[maxLength], yMins[maxLength], yMaxs[maxLength];
-  int length = functionStore()->numberOfActiveFunctions();
-
   float ratio = InteractiveCurveViewRange::NormalYXRatio() / (1 + cursorTopMarginRatio() + cursorBottomMarginRatio());
-
-  for (int i = 0; i < length; i++) {
-    ExpiringPointer<Function> f = functionStore()->modelForRecord(functionStore()->activeRecordAtIndex(i));
-    f->rangeForDisplay(xMins + i, xMaxs + i, yMins + i, yMaxs + i, ratio, context);
-  }
-
-  float xMin, xMax, yMin, yMax;
-  Poincare::Zoom::CombineRanges(length, xMins, xMaxs, &xMin, &xMax);
-  Poincare::Zoom::CombineRanges(length, yMins, yMaxs, &yMin, &yMax);
-  Poincare::Zoom::SanitizeRange(&xMin, &xMax, &yMin, &yMax, range->NormalYXRatio());
-
-  range->setXMin(xMin);
-  range->setXMax(xMax);
-  range->setYMin(yMin);
-  range->setYMax(yMax);
+  InterestingRangesHelper(range, textFieldDelegateApp()->localContext(), functionStore(), ratio);
 }
 
 }

apps/shared/interactive_curve_view_controller.cpp

@@ -41,32 +41,7 @@ InteractiveCurveViewController::InteractiveCurveViewController(Responder * paren
 }
 
 float InteractiveCurveViewController::addMargin(float y, float range, bool isVertical, bool isMin) {
-  /* The provided min or max range limit y is altered by adding a margin.
-   * In pixels, the view's height occupied by the vertical range is equal to
-   *   viewHeight - topMargin - bottomMargin.
-   * Hence one pixel must correspond to
-   *   range / (viewHeight - topMargin - bottomMargin).
-   * Finally, adding topMargin pixels of margin, say at the top, comes down
-   * to adding
-   *   range * topMargin / (viewHeight - topMargin - bottomMargin)
-   * which is equal to
-   *   range * topMarginRatio / ( 1 - topMarginRatio - bottomMarginRatio)
-   * where
-   *   topMarginRation = topMargin / viewHeight
-   *   bottomMarginRatio = bottomMargin / viewHeight.
-   * The same goes horizontally.
-   */
-  float topMarginRatio = isVertical ? cursorTopMarginRatio() : cursorRightMarginRatio();
-  float bottomMarginRatio = isVertical ? cursorBottomMarginRatio() : cursorLeftMarginRatio();
-  assert(topMarginRatio + bottomMarginRatio < 1); // Assertion so that the formula is correct
-  float ratioDenominator = 1 - bottomMarginRatio - topMarginRatio;
-  float ratio = isMin ? -bottomMarginRatio : topMarginRatio;
-  /* We want to add slightly more than the required margin, so that
-   * InteractiveCurveViewRange::panToMakePointVisible does not think a point is
-   * invisible due to precision problems when checking if it is outside the
-   * required margin. This is why we add a 1.05f factor. */
-  ratio = 1.05f * ratio / ratioDenominator;
-  return y + ratio * range;
+  return AddMarginHelper(y, range, isVertical, isMin, cursorTopMarginRatio(), cursorBottomMarginRatio(), cursorLeftMarginRatio(), cursorRightMarginRatio());
 }
 
 void InteractiveCurveViewController::updateZoomButtons() {

apps/shared/interactive_curve_view_range_delegate.cpp

@@ -0,0 +1,58 @@
+#include "interactive_curve_view_range_delegate.h"
+#include "interactive_curve_view_range.h"
+#include "function_store.h"
+#include <poincare/zoom.h>
+
+namespace Shared {
+
+void InteractiveCurveViewRangeDelegate::InterestingRangesHelper(InteractiveCurveViewRange * range, Poincare::Context * context, FunctionStore * functionStore, float targetRatio) {
+  constexpr int maxLength = 10;
+  float xMins[maxLength], xMaxs[maxLength], yMins[maxLength], yMaxs[maxLength];
+  int length = functionStore->numberOfActiveFunctions();
+
+  for (int i = 0; i < length; i++) {
+    ExpiringPointer<Function> f = functionStore->modelForRecord(functionStore->activeRecordAtIndex(i));
+    f->rangeForDisplay(xMins + i, xMaxs + i, yMins + i, yMaxs + i, targetRatio, context);
+  }
+
+  float xMin, xMax, yMin, yMax;
+  Poincare::Zoom::CombineRanges(length, xMins, xMaxs, &xMin, &xMax);
+  Poincare::Zoom::CombineRanges(length, yMins, yMaxs, &yMin, &yMax);
+  Poincare::Zoom::SanitizeRange(&xMin, &xMax, &yMin, &yMax, range->NormalYXRatio());
+
+  range->setXMin(xMin);
+  range->setXMax(xMax);
+  range->setYMin(yMin);
+  range->setYMax(yMax);
+}
+
+float InteractiveCurveViewRangeDelegate::AddMarginHelper(float x, float range, bool isVertical, bool isMin, float top, float bottom, float left, float right) {
+  /* The provided min or max range limit y is altered by adding a margin.
+   * In pixels, the view's height occupied by the vertical range is equal to
+   *   viewHeight - topMargin - bottomMargin.
+   * Hence one pixel must correspond to
+   *   range / (viewHeight - topMargin - bottomMargin).
+   * Finally, adding topMargin pixels of margin, say at the top, comes down
+   * to adding
+   *   range * topMargin / (viewHeight - topMargin - bottomMargin)
+   * which is equal to
+   *   range * topMarginRatio / ( 1 - topMarginRatio - bottomMarginRatio)
+   * where
+   *   topMarginRation = topMargin / viewHeight
+   *   bottomMarginRatio = bottomMargin / viewHeight.
+   * The same goes horizontally.
+   */
+  float topMarginRatio = isVertical ? top : right;
+  float bottomMarginRatio = isVertical ? bottom : left;
+  assert(topMarginRatio + bottomMarginRatio < 1); // Assertion so that the formula is correct
+  float ratioDenominator = 1 - bottomMarginRatio - topMarginRatio;
+  float ratio = isMin ? -bottomMarginRatio : topMarginRatio;
+  /* We want to add slightly more than the required margin, so that
+   * InteractiveCurveViewRange::panToMakePointVisible does not think a point is
+   * invisible due to precision problems when checking if it is outside the
+   * required margin. This is why we add a 1.05f factor. */
+  ratio = 1.05f * ratio / ratioDenominator;
+  return x + ratio * range;
+}
+
+}

apps/shared/interactive_curve_view_range_delegate.h

@@ -1,15 +1,21 @@
 #ifndef SHARED_INTERACTIVE_CURVE_VIEW_DELEGATE_H
 #define SHARED_INTERACTIVE_CURVE_VIEW_DELEGATE_H
 
+#include <poincare/context.h>
 #include <assert.h>
 
 namespace Shared {
 
 class InteractiveCurveViewRange;
+class FunctionStore;
 
 class InteractiveCurveViewRangeDelegate {
 public:
   static constexpr float k_defaultXHalfRange = 10.0f;
+
+  static void InterestingRangesHelper(InteractiveCurveViewRange * range, Poincare::Context * context, FunctionStore * functionStore, float targetRatio);
+  static float AddMarginHelper(float x, float range, bool isVertical, bool isMin, float top, float bottom, float left, float right);
+
   virtual float interestingXMin() const { return -k_defaultXHalfRange; }
   virtual bool defaultRangeIsNormalized() const { return false; }
   virtual void interestingRanges(InteractiveCurveViewRange * range) { assert(false); }