Android: window clipping working fl_rectf.

This code is not very beautiful, but the resulting class should be
easy to use. A range-based loop can be used to find all relevant
clipping rectangles for a drawing call.

git-svn-id: file:///fltk/svn/fltk/branches/branch-1.4@12754 ea41ed52-d2ee-0310-a9c1-e6b18d33e121

3 files changed, 241 insertions, 47 deletions

diff --git a/src/drivers/Android/Fl_Android_Graphics_Driver.H b/src/drivers/Android/Fl_Android_Graphics_Driver.H
index af106785d..e20f02a19 100644
--- a/src/drivers/Android/Fl_Android_Graphics_Driver.H
+++ b/src/drivers/Android/Fl_Android_Graphics_Driver.H
@@ -80,6 +80,7 @@ private:
   Fl_Rect_Region&  operator = (const Fl_Rect_Region& other);
 };
 
+
 /**
  * The Fl_Complex_Region represents a clipping region of any shape.
  *
@@ -98,32 +99,65 @@ private:
  */
 class Fl_Complex_Region : public Fl_Rect_Region
 {
+  class Iterator {
+  public:
+    Iterator(Fl_Complex_Region *r);
+    bool operator!= (const Iterator& other) const;
+    const Iterator& operator++ ();
+    Fl_Complex_Region *operator* () const;
+    Fl_Complex_Region *pRegion;
+  };
+
+  class Overlapping {
+    class OverlappingIterator {
+    public:
+      OverlappingIterator(Overlapping *ov);
+      bool operator!= (const OverlappingIterator& other) const;
+      const OverlappingIterator& operator++ ();
+      Overlapping *operator* () const;
+      Overlapping *pOv;
+    };
+  public:
+    Overlapping(Fl_Complex_Region *rgn, Fl_Rect_Region &rect);
+    OverlappingIterator begin();
+    OverlappingIterator end();
+    Fl_Rect_Region &clipped_rect();
+    bool intersects();
+    bool find_intersecting();
+    bool find_next();
+    Fl_Complex_Region *pRegion;
+    Fl_Rect_Region pOriginalRect;
+    Fl_Rect_Region pClippedRect;
+  };
+
 public:
   Fl_Complex_Region();
   Fl_Complex_Region(const Fl_Rect_Region&);
   virtual ~Fl_Complex_Region() override;
+
   virtual void set(const Fl_Rect_Region &r) override;
   void set(const Fl_Complex_Region &r);
+  Fl_Complex_Region *subregion() const { return pSubregion; }
+  Fl_Complex_Region *next() const { return pNext; }
+  Fl_Complex_Region *parent() const { return pParent; }
+  char is_simple() const { return pSubregion==0; }
+  char is_complex() const { return pSubregion!=0; }
+
   virtual int intersect_with(const Fl_Rect_Region &r) override;
   int subtract(const Fl_Rect_Region &r);
 
-  //  virtual void set(int x, int y, int w, int h);
-//  virtual void set(Fl_Rect_Region*);
-//  void subtract(Fl_Rect_Region*);
-//  void intersect(Fl_Rect_Region*);
-//  void clone(Fl_Complex_Region*);
-  char is_simple() const { return pSubregion==0; }
-  char is_complex() const { return pSubregion!=0; }
+  virtual void print(const char*) const override;
 
-  Fl_Complex_Region *subregion() const { return pSubregion; }
-  Fl_Complex_Region *next() const { return pNext; }
+  Iterator begin();
+  Iterator end();
 
-  Fl_Complex_Region *add_subregion();
+  Overlapping overlapping(Fl_Rect_Region &r);
 
-  virtual void print(const char*) const override;
 protected:
   void print_data(int indent) const;
   int subtract_smaller_region(const Fl_Rect_Region &r);
+  Fl_Complex_Region *add_subregion();
+
   Fl_Complex_Region *pSubregion = 0L;
   Fl_Complex_Region *pParent = 0L;
   Fl_Complex_Region *pNext = 0L;
diff --git a/src/drivers/Android/Fl_Android_Graphics_Driver.cxx b/src/drivers/Android/Fl_Android_Graphics_Driver.cxx
index 554d72e84..aa2bcd937 100644
--- a/src/drivers/Android/Fl_Android_Graphics_Driver.cxx
+++ b/src/drivers/Android/Fl_Android_Graphics_Driver.cxx
@@ -97,15 +97,46 @@ static uint16_t make565(Fl_Color crgba)
 
 void Fl_Android_Graphics_Driver::rectf_unscaled(float x, float y, float w, float h)
 {
-  // FIXME: r must be a complex region, like pClippingRegion.
+#if 1
 
   Fl_Rect_Region r(x, y, w, h);
-#if 0
-  if (r.intersect_with(pClippingRegion)) {
-    rectf_unclipped(r.x(), r.y(), r.w(), r.h());
+  for (const auto &it: pClippingRegion.overlapping(r)) {
+#if 1
+    Fl_Rect_Region s(it->clipped_rect());
+    rectf_unclipped(s.x(), s.y(), s.w(), s.h());
+#else
+    if (it->is_simple()) {
+      Fl_Rect_Region r(x, y, w, h);
+      if (r.intersect_with(*it)) {
+        rectf_unclipped(r.x(), r.y(), r.w(), r.h());
+      }
+    }
+#endif
+  }
+
+#elif 0
+
+  // This is elegant code, but it is not efficient. It walks the entire tree
+  // and checks for intersetion, even if the parent region indicated that there
+  // is no intersection.
+  //
+  // Maybe we can add a parameter somewhere so that the iterator runs the tree
+  // based on a give rectangle.
+
+  for (const auto &it: pClippingRegion) {
+    // TODO: if region is complex, but doesn't intersect, can we somehow manipulate the iterator?
+    if (it->is_simple()) {
+      Fl_Rect_Region r(x, y, w, h);
+      if (r.intersect_with(*it)) {
+        rectf_unclipped(r.x(), r.y(), r.w(), r.h());
+      }
+    }
   }
-#else // proof of concept
-  // FIXME: write iterator over tree
+
+#else
+
+  // This code is massiv and ugly and has the same problem in that it does not
+  // optimize the number of tests for intersections.
 
   r.print("---- fl_rectf");
   pClippingRegion.print("clip to");
@@ -134,36 +165,8 @@ void Fl_Android_Graphics_Driver::rectf_unscaled(float x, float y, float w, float
       }
     }
   }
-#endif
-
-
 
-
-
-  // TODO: create a complex region by intersecting r with the pClippingRegion
-  // TODO: walk the region and draw all rectangles
-
-  /*
-   * rectf(x, y, w, h) {
-   *   rectf(complex_window_region, drawing_rect(x, y, w, h))
-   * }
-   *
-   * rectf( complexRgn, drawRgn) {
-   *   // B: start of iterator
-   *     if (intersect(rect_of_complexRgn, drawRgn) {
-   *       if (complexRgn->is_complex() {
-   *         rectf(complexRgn->subregion, drawRect);
-   *       } else {
-   *         rawRect = intersection(rect_of_complexRgn, drawRgn);
-   *         rawDrawRect(rawRect);
-   *       }
-   *     }
-   *     // A: recursion
-   *     if (complexRgn->next)
-   *       rectf(complexRgn->next, drawRgn);
-   *   // B: end of iterator
-   * }
-   */
+#endif
 }
 
 void Fl_Android_Graphics_Driver::rectf_unclipped(float x, float y, float w, float h)
diff --git a/src/drivers/Android/Fl_Android_Graphics_Driver_region.cxx b/src/drivers/Android/Fl_Android_Graphics_Driver_region.cxx
index 95e4ccd9a..1763a8d0f 100644
--- a/src/drivers/Android/Fl_Android_Graphics_Driver_region.cxx
+++ b/src/drivers/Android/Fl_Android_Graphics_Driver_region.cxx
@@ -156,7 +156,7 @@ void Fl_Rect_Region::print(const char *label) const
   Fl_Android_Application::log_i("Rect l:%d t:%d r:%d b:%d", left(), top(), right(), bottom());
 }
 
-// -----------------------------------------------------------------------------
+// =============================================================================
 
 /**
  * Create an empty complex region.
@@ -330,12 +330,169 @@ int Fl_Complex_Region::subtract_smaller_region(const Fl_Rect_Region &r)
 Fl_Complex_Region *Fl_Complex_Region::add_subregion()
 {
   Fl_Complex_Region *r = new Fl_Complex_Region();
+  r->pParent = this;
   r->pNext = pSubregion;
   pSubregion = r;
   return r;
 }
 
 
+// -----------------------------------------------------------------------------
+
+Fl_Complex_Region::Iterator Fl_Complex_Region::begin()
+{
+  return Iterator(this);
+}
+
+
+Fl_Complex_Region::Iterator Fl_Complex_Region::end()
+{
+  return Iterator(0L);
+}
+
+
+Fl_Complex_Region::Iterator::Iterator(Fl_Complex_Region *r) :
+        pRegion(r)
+{
+}
+
+
+bool Fl_Complex_Region::Iterator::operator!=(const Iterator &other) const
+{
+  return pRegion != other.pRegion;
+}
+
+
+const Fl_Complex_Region::Iterator &Fl_Complex_Region::Iterator::operator++()
+{
+  if (pRegion->subregion()) {
+    pRegion = pRegion->subregion();
+  } else if (pRegion->next()) {
+    pRegion = pRegion->next();
+  } else {
+    pRegion = pRegion->parent();
+  }
+  return *this;
+}
+
+
+Fl_Complex_Region *Fl_Complex_Region::Iterator::operator*() const
+{
+  return pRegion;
+}
+
+// -----------------------------------------------------------------------------
+
+Fl_Complex_Region::Overlapping Fl_Complex_Region::overlapping(Fl_Rect_Region &r)
+{
+  return Overlapping(this, r);
+}
+
+
+Fl_Complex_Region::Overlapping::Overlapping(Fl_Complex_Region *rgn,
+                                            Fl_Rect_Region &rect) :
+        pRegion(rgn),
+        pOriginalRect(rect),
+        pClippedRect(rect)
+{
+}
+
+
+Fl_Complex_Region::Overlapping::OverlappingIterator Fl_Complex_Region::Overlapping::begin()
+{
+  find_intersecting();
+  return OverlappingIterator(this);
+}
+
+
+Fl_Complex_Region::Overlapping::OverlappingIterator Fl_Complex_Region::Overlapping::end()
+{
+  return OverlappingIterator(0L);
+}
+
+
+Fl_Rect_Region &Fl_Complex_Region::Overlapping::clipped_rect()
+{
+  return pClippedRect;
+}
+
+
+bool Fl_Complex_Region::Overlapping::intersects()
+{
+  return (pClippedRect.intersect_with(*pRegion) != EMPTY);
+}
+
+
+bool Fl_Complex_Region::Overlapping::find_intersecting()
+{
+  for (;;) {
+    if (!pRegion) return false;
+    pClippedRect.set(pOriginalRect);
+    pRegion->print("find intersetion");
+    pClippedRect.print("with");
+    pOriginalRect.print("with");
+    if (intersects()) {
+      if (!pRegion->subregion()) {
+        return true;
+      } else {
+        pRegion = pRegion->subregion();
+      }
+    } else {
+      find_next();
+    }
+  }
+}
+
+
+bool Fl_Complex_Region::Overlapping::find_next()
+{
+  if (pRegion->subregion()) {
+    pRegion = pRegion->subregion();
+  } else if (pRegion->next()) {
+    pRegion = pRegion->next();
+  } else {
+    pRegion = pRegion->parent(); // can be NULL
+  }
+  return (pRegion != 0L);
+}
+
+// -----------------------------------------------------------------------------
+
+
+Fl_Complex_Region::Overlapping::OverlappingIterator::OverlappingIterator(
+        Overlapping *ov) :
+        pOv(ov)
+{
+}
+
+
+bool Fl_Complex_Region::Overlapping::OverlappingIterator::operator!=(
+        const OverlappingIterator &other) const
+{
+  auto thisRegion = pOv ? pOv->pRegion : nullptr;
+  auto otherRegion = other.pOv ? other.pOv->pRegion : nullptr;
+  return thisRegion != otherRegion;
+}
+
+
+const Fl_Complex_Region::Overlapping::OverlappingIterator &
+Fl_Complex_Region::Overlapping::OverlappingIterator::operator++()
+{
+  pOv->find_next();
+  if (pOv->pRegion)
+    pOv->find_intersecting();
+  return *this;
+}
+
+
+Fl_Complex_Region::Overlapping *
+Fl_Complex_Region::Overlapping::OverlappingIterator::operator*() const
+{
+  return pOv;
+}
+
+// =============================================================================
+
 #if 0
 
 void Fl_Complex_Region::set(int x, int y, int w, int h)