Escher: Add a ScrollViewIndicator

Change-Id: Ie619c16c9f784c3456a33de3ce21e25fae952ffc

escher/src/scroll_view_indicator.cpp

@@ -0,0 +1,55 @@
+#include <escher/scroll_view_indicator.h>
+extern "C" {
+#include <assert.h>
+}
+
+constexpr KDColor k_backgroundColor = 0x00;
+constexpr KDColor k_indicatorColor = 0x30;
+
+ScrollViewIndicator::ScrollViewIndicator(ScrollViewIndicator::Direction direction) :
+  ChildlessView(),
+  m_direction(direction),
+  m_start(0),
+  m_end(0)
+{
+}
+
+void ScrollViewIndicator::drawRect(KDRect rect) const {
+  KDFillRect(bounds(), k_backgroundColor);
+  KDRect indicatorFrame;
+  if (m_direction == Direction::Horizontal) {
+  indicatorFrame.x = m_start*bounds().width;
+  indicatorFrame.y = 0;
+  indicatorFrame.width = (m_end-m_start)*bounds().width;
+  indicatorFrame.height = bounds().height;
+  } else {
+    assert(m_direction == Direction::Vertical);
+    indicatorFrame.x = 0;
+    indicatorFrame.y = m_start*bounds().height;
+    indicatorFrame.width = bounds().width;
+    indicatorFrame.height = (m_end-m_start)*bounds().height;
+  }
+  KDFillRect(indicatorFrame, k_indicatorColor);
+}
+
+void ScrollViewIndicator::setStart(float start) {
+  m_start = start;
+  redraw();
+}
+
+void ScrollViewIndicator::setEnd(float end) {
+  m_end = end;
+  redraw();
+}
+
+#if ESCHER_VIEW_LOGGING
+const char * ScrollViewIndicator::className() const {
+  return "ScrollViewIndicator";
+}
+
+void ScrollViewIndicator::logAttributes(std::ostream &os) const {
+  View::logAttributes(os);
+  os << " start=\"" << m_start << "\"";
+  os << " end=\"" << m_end << "\"";
+}
+#endif