[escher] create class expression view

Change-Id: I16ddd22318ad120d736ad7f10bb2800a13c2b005

escher/Makefile

@@ -6,6 +6,7 @@ objs += $(addprefix escher/src/,\
   button.o\
   container.o\
   header_view_controller.o\
+  expression_view.o\
   image_view.o\
   invocation.o\
   input_view_controller.o\

escher/include/escher.h

@@ -6,6 +6,7 @@
 #include <escher/button.h>
 #include <escher/container.h>
 #include <escher/header_view_controller.h>
+#include <escher/expression_view.h>
 #include <escher/image.h>
 #include <escher/image_view.h>
 #include <escher/input_view_controller.h>

escher/include/escher/expression_view.h

@@ -0,0 +1,28 @@
+#ifndef ESCHER_EXPRESSION_VIEW_H
+#define ESCHER_EXPRESSION_VIEW_H
+
+#include <escher/view.h>
+#include <kandinsky/color.h>
+#include <poincare/expression_layout.h>
+
+/* This class does not handle the expression layout as the size of the layout is
+ * needed to compute the size of table cells hosting the expression. As the size
+ * of this cell is determined before we set the expression in the expression
+ * view, we cannot use minimalSizeForOptimalDisplay to assess the required
+ * size. */
+
+class ExpressionView : public View {
+public:
+  ExpressionView();
+  void setExpression(ExpressionLayout * expressionLayout);
+  void drawRect(KDContext * ctx, KDRect rect) const override;
+  void setBackgroundColor(KDColor backgroundColor);
+  void setTextColor(KDColor textColor);
+  KDSize minimalSizeForOptimalDisplay() override;
+private:
+  ExpressionLayout * m_expressionLayout;
+  KDColor m_textColor;
+  KDColor m_backgroundColor;
+};
+
+#endif

escher/src/expression_view.cpp

@@ -0,0 +1,37 @@
+#include <escher/expression_view.h>
+
+ExpressionView::ExpressionView() :
+  m_expressionLayout(nullptr),
+  m_textColor(KDColorBlack),
+  m_backgroundColor(KDColorWhite)
+{
+}
+
+void ExpressionView::setExpression(ExpressionLayout * expressionLayout) {
+  m_expressionLayout = expressionLayout;
+}
+
+void ExpressionView::setBackgroundColor(KDColor backgroundColor) {
+  m_backgroundColor = backgroundColor;
+}
+
+void ExpressionView::setTextColor(KDColor textColor) {
+  m_textColor = textColor;
+}
+
+KDSize ExpressionView::minimalSizeForOptimalDisplay() {
+  if (m_expressionLayout ==  nullptr) {
+    return KDSizeZero;
+  }
+  return m_expressionLayout->size();
+}
+
+void ExpressionView::drawRect(KDContext * ctx, KDRect rect) const {
+  ctx->fillRect(rect, m_backgroundColor);
+  if (m_expressionLayout != nullptr) {
+    //Position the origin of expression
+    KDSize expressionSize = m_expressionLayout->size();
+    KDPoint origin(0, 0.5f*(m_frame.height() - expressionSize.height()));
+    m_expressionLayout->draw(ctx, origin, m_textColor, m_backgroundColor);
+  }
+}