Implement GridLayout

4 files changed, 172 insertions, 10 deletions

diff --git a/plugingui/layout.cc b/plugingui/layout.cc
index 7e3c6e8..551611c 100644
--- a/plugingui/layout.cc
+++ b/plugingui/layout.cc
@@ -233,4 +233,119 @@ void HBoxLayout::setVAlignment(VAlignment alignment)
 	align = alignment;
 }
 
+//
+// GridLayout
+//
+
+GridLayout::GridLayout(LayoutItem* parent, std::size_t number_of_columns,
+    std::size_t number_of_rows)
+    : BoxLayout(parent)
+    , number_of_columns(number_of_columns)
+    , number_of_rows(number_of_rows)
+{
+}
+
+void GridLayout::removeItem(LayoutItem* item)
+{
+	Layout::removeItem(item);
+
+	// manually remove from grid_ranges as remove_if doesn't work on an
+	// unordered_map
+	for(auto it = grid_ranges.begin(); it != grid_ranges.end(); ++it)
+	{
+		if(it->first == item)
+		{
+			it = grid_ranges.erase(it);
+		}
+		else
+		{
+			++it;
+		}
+	}
+}
+
+void GridLayout::layout()
+{
+	if(grid_ranges.empty())
+	{
+		return;
+	}
+
+	// Calculate cell sizes
+	auto cell_size = calculateCellSize();
+
+	for(auto const& pair : grid_ranges)
+	{
+		auto& item = *pair.first;
+		auto const& range = pair.second;
+
+		moveAndResize(item, range, cell_size);
+	}
+}
+
+void GridLayout::setPosition(LayoutItem* item, GridRange const& range)
+{
+	grid_ranges[item] = range;
+}
+
+auto GridLayout::calculateCellSize() const -> CellSize
+{
+	auto empty_width = (number_of_columns - 1) * spacing;
+	auto available_width = parent->width();
+	auto empty_height = (number_of_rows - 1) * spacing;
+	auto available_height = parent->height();
+
+	CellSize cell_size;
+	if(available_width > empty_width && available_height > empty_height)
+	{
+		cell_size.width = (available_width - empty_width) / number_of_columns;
+		cell_size.height = (available_height - empty_height) / number_of_rows;
+	}
+	else
+	{
+		cell_size.width = 0;
+		cell_size.height = 0;
+	}
+
+	return cell_size;
+}
+
+void GridLayout::moveAndResize(
+    LayoutItem& item, GridRange const& range, CellSize cell_size) const
+{
+	std::size_t x = range.column_begin * (cell_size.width + spacing);
+	std::size_t y = range.row_begin * (cell_size.height + spacing);
+
+	std::size_t column_count = (range.column_end - range.column_begin);
+	std::size_t row_count = (range.row_end - range.row_begin);
+	std::size_t width = column_count * (cell_size.width + spacing) - spacing;
+	std::size_t height = row_count * (cell_size.height + spacing) - spacing;
+
+	if(resizeChildren)
+	{
+		item.move(x, y);
+
+		if(cell_size.width * cell_size.height != 0)
+		{
+			item.resize(width, height);
+		}
+		else
+		{
+			item.resize(0, 0);
+		}
+	}
+	else
+	{
+		if(item.width() <= width && item.height() <= height)
+		{
+			item.move(x + (width - item.width()) / 2,
+			    y + (height - item.height()) / 2);
+		}
+		else
+		{
+			item.move(x, y);
+		}
+	}
+}
+
 } // GUI::
diff --git a/plugingui/layout.h b/plugingui/layout.h
index 37a7d6d..763f616 100644
--- a/plugingui/layout.h
+++ b/plugingui/layout.h
@@ -28,6 +28,7 @@
 
 #include <cstdlib>
 #include <list>
+#include <unordered_map>
 
 #include <notifier.h>
 
@@ -56,8 +57,7 @@ private:
 };
 
 //! \brief Abtract Layout class.
-class Layout
-	: public Listener
+class Layout : public Listener
 {
 public:
 	Layout(LayoutItem* parent);
@@ -80,8 +80,7 @@ protected:
 };
 
 //! \brief Abstract box layout
-class BoxLayout
-	: public Layout
+class BoxLayout : public Layout
 {
 public:
 	BoxLayout(LayoutItem* parent);
@@ -107,8 +106,7 @@ enum class HAlignment
 };
 
 //! \brief A Layout that lays out its elements vertically.
-class VBoxLayout
-	: public BoxLayout
+class VBoxLayout : public BoxLayout
 {
 public:
 	VBoxLayout(LayoutItem* parent);
@@ -130,8 +128,7 @@ enum class VAlignment
 };
 
 //! \brief A Layout that lays out its elements vertically.
-class HBoxLayout
-	: public BoxLayout
+class HBoxLayout : public BoxLayout
 {
 public:
 	HBoxLayout(LayoutItem* parent);
@@ -145,4 +142,51 @@ protected:
 	VAlignment align;
 };
 
+//! \brief A Layout class which places the items in a regular grid. An item can
+//! span multiple rows/columns.
+class GridLayout : public BoxLayout
+{
+public:
+	// The range is open, i.e. end is one past the last one.
+	struct GridRange
+	{
+		int column_begin;
+		int column_end;
+		int row_begin;
+		int row_end;
+	};
+
+	GridLayout(LayoutItem* parent, std::size_t number_of_columns,
+	    std::size_t number_of_rows);
+
+	virtual ~GridLayout()
+	{
+	}
+
+	// From Layout:
+	virtual void removeItem(LayoutItem* item);
+	virtual void layout();
+
+	void setPosition(LayoutItem* item, GridRange const& range);
+
+protected:
+	std::size_t number_of_columns;
+	std::size_t number_of_rows;
+
+	// Note: Yes, this is somewhat redundant to the LayoutItemList of the Layout
+	// class. However, this was the best idea I had such that I could still
+	// derive from Layout. If you find this ugly, feel free to fix it.
+	std::unordered_map<LayoutItem*, GridRange> grid_ranges;
+
+private:
+	struct CellSize {
+		std::size_t width;
+		std::size_t height;
+	};
+
+	CellSize calculateCellSize() const;
+	void moveAndResize(
+	    LayoutItem& item, GridRange const& range, CellSize cell_size) const;
+};
+
 } // GUI::
diff --git a/plugingui/maintab.cc b/plugingui/maintab.cc
index f450bc0..498660e 100644
--- a/plugingui/maintab.cc
+++ b/plugingui/maintab.cc
@@ -33,12 +33,15 @@ MainTab::MainTab(Widget* parent) : Widget(parent)
 {
 	layout.setSpacing(10);
 	layout.setResizeChildren(true);
-	layout.setHAlignment(GUI::HAlignment::center);
 
 	layout.addItem(&drumkit_frame);
 	layout.addItem(&status_frame);
 	layout.addItem(&humanizer_frame);
 	layout.addItem(&diskstreaming_frame);
+	layout.setPosition(&drumkit_frame, GridLayout::GridRange{0, 1, 0, 4});
+	layout.setPosition(&status_frame, GridLayout::GridRange{0, 1, 4, 7});
+	layout.setPosition(&humanizer_frame, GridLayout::GridRange{1, 2, 0, 3});
+	layout.setPosition(&diskstreaming_frame, GridLayout::GridRange{1, 2, 3, 5});
 
 	drumkit_frame.setTitle("Drumkit");
 	status_frame.setTitle("Status");
diff --git a/plugingui/maintab.h b/plugingui/maintab.h
index 1ab30d7..ac39daf 100644
--- a/plugingui/maintab.h
+++ b/plugingui/maintab.h
@@ -42,7 +42,7 @@ public:
 	MainTab(Widget* parent);
 
 private:
-	VBoxLayout layout{this};
+	GridLayout layout{this, 2, 9};
 
 	FrameWidget drumkit_frame{this, false};
 	FrameWidget status_frame{this, false};