[escher] Add a PointerTextView class

escher/Makefile

@@ -41,6 +41,7 @@ objs += $(addprefix escher/src/,\
   message_tree.o\
   modal_view_controller.o\
   palette.o\
+  pointer_text_view.o\
   responder.o\
   run_loop.o\
   scroll_view.o\

escher/include/escher.h

@@ -45,6 +45,7 @@
 #include <escher/metric.h>
 #include <escher/modal_view_controller.h>
 #include <escher/palette.h>
+#include <escher/pointer_text_view.h>
 #include <escher/responder.h>
 #include <escher/scroll_view.h>
 #include <escher/scroll_view_data_source.h>

escher/include/escher/pointer_text_view.h

@@ -0,0 +1,18 @@
+#ifndef ESCHER_POINTER_TEXT_VIEW_H
+#define ESCHER_POINTER_TEXT_VIEW_H
+
+#include <escher/text_view.h>
+#include <escher/i18n.h>
+
+class PointerTextView : public TextView {
+public:
+  PointerTextView(KDText::FontSize size = KDText::FontSize::Large, const char * text = nullptr, float horizontalAlignment = 0.0f, float verticalAlignment = 0.0f,
+    KDColor textColor = KDColorBlack, KDColor backgroundColor = KDColorWhite);
+  const char * text() const override { return m_text; }
+  void setText(const char * text) override;
+  KDSize minimalSizeForOptimalDisplay() const override;
+private:
+  const char * m_text;
+};
+
+#endif

escher/src/pointer_text_view.cpp

@@ -0,0 +1,20 @@
+#include <escher/pointer_text_view.h>
+#include <assert.h>
+
+PointerTextView::PointerTextView(KDText::FontSize size, const char * text, float horizontalAlignment, float verticalAlignment,
+    KDColor textColor, KDColor backgroundColor) :
+  TextView(size, horizontalAlignment, verticalAlignment, textColor, backgroundColor),
+  m_text(text)
+{
+}
+
+void PointerTextView::setText(const char * text) {
+  if (text != m_text) {
+    m_text = text;
+    markRectAsDirty(bounds());
+  }
+}
+
+KDSize PointerTextView::minimalSizeForOptimalDisplay() const  {
+  return KDText::stringSize(text(), m_fontSize);
+}