[python] Matplotlib: handle 'auto' range computation

python/port/mod/matplotlib/plot_store.cpp

@@ -4,6 +4,7 @@ namespace Matplotlib {
 
 PlotStore::PlotStore() : Shared::InteractiveCurveViewRange(),
   m_axesRequested(true),
+  m_axesAuto(true),
   m_gridRequested(false)
 {
   flush();
@@ -14,6 +15,9 @@ void PlotStore::flush() {
   m_segments = mp_obj_new_list(0, nullptr);
   m_rects = mp_obj_new_list(0, nullptr);
   m_labels = mp_obj_new_list(0, nullptr);
+  m_axesRequested = true;
+  m_axesAuto = true;
+  m_gridRequested = false;
 }
 
 // Iterators
@@ -133,4 +137,61 @@ void PlotStore::addLabel(mp_obj_t x, mp_obj_t y, mp_obj_t string) {
   mp_obj_list_append(m_labels, tuple);
 }
 
+// Axes
+
+static inline float minFloat(float x, float y) { return x < y ? x : y; }
+static inline float maxFloat(float x, float y) { return x > y ? x : y; }
+
+void updateRange(float * xMin, float * xMax, float * yMin, float * yMax, float x, float y) {
+  if (!std::isnan(x) && !std::isinf(x) && !std::isnan(y) && !std::isinf(y)) {
+    *xMin = minFloat(*xMin, x);
+    *xMax = maxFloat(*xMax, x);
+    *yMin = minFloat(*yMin, y);
+    *yMax = maxFloat(*yMax, y);
+  }
+}
+
+void checkPositiveRangeAndAddMargin(float * min, float * max) {
+  if (*min > *max) {
+    *min = - Shared::Range1D::k_default;
+    *max = Shared::Range1D::k_default;
+    return;
+  }
+  // Add margins
+  float margin = (*max - *min)/10.0f;
+  *min -= margin;
+  *max += margin;
+}
+
+void PlotStore::initRange() {
+  if (m_axesAuto) {
+    float xMin = FLT_MAX;
+    float xMax = -FLT_MAX;
+    float yMin = FLT_MAX;
+    float yMax = -FLT_MAX;
+    for (PlotStore::Dot dot : dots()) {
+      updateRange(&xMin, &xMax, &yMin, &yMax, dot.x(), dot.y());
+    }
+    for (PlotStore::Label label : labels()) {
+      updateRange(&xMin, &xMax, &yMin, &yMax, label.x(), label.y());
+    }
+    for (PlotStore::Segment segment : segments()) {
+      updateRange(&xMin, &xMax, &yMin, &yMax, segment.xStart(), segment.yStart());
+      updateRange(&xMin, &xMax, &yMin, &yMax, segment.xEnd(), segment.yEnd());
+    }
+    for (PlotStore::Rect rectangle : rects()) {
+      float x = rectangle.x();
+      float y = rectangle.y();
+      updateRange(&xMin, &xMax, &yMin, &yMax, x, y);
+      updateRange(&xMin, &xMax, &yMin, &yMax, x + rectangle.width(), y + rectangle.height());
+    }
+    checkPositiveRangeAndAddMargin(&xMin, &xMax);
+    checkPositiveRangeAndAddMargin(&yMin, &yMax);
+    setXMin(xMin);
+    setXMax(xMax);
+    setYMin(yMin);
+    setYMax(yMax);
+  }
+}
+
 }

python/port/mod/matplotlib/plot_store.h

@@ -121,6 +121,7 @@ public:
 
   void setAxesRequested(bool b) { m_axesRequested = b; }
   bool axesRequested() const { return m_axesRequested; }
+  void initRange();
 
   void setGridRequested(bool b) { m_gridRequested = b; }
   bool gridRequested() const { return m_gridRequested; }
@@ -130,6 +131,7 @@ private:
   mp_obj_t m_segments; // List of (x, y, dx, dy, style, color)
   mp_obj_t m_rects; // List of (x, y, w, h, color)
   bool m_axesRequested;
+  bool m_axesAuto;
   bool m_gridRequested;
 };