menu/background_*: vertices are only recalculated if the size changed

The size of the parent component is cached by the backgrounds and the
vertices to draw the backgrounds are only calculated again, if the
size of the parent component changed.

4 files changed, 66 insertions, 20 deletions

diff --git a/src/menu/background_color.cpp b/src/menu/background_color.cpp
index f55763b7..031ffe26 100644
--- a/src/menu/background_color.cpp
+++ b/src/menu/background_color.cpp
@@ -28,26 +28,33 @@
 namespace usdx
 {
 	BackgroundColor::BackgroundColor(const DrawableControl &control)
-		: Background(control), color(0,0,0)
+		: Background(control), color(0,0,0), size(0, 0)
 	{
 	}
 
 	BackgroundColor::BackgroundColor(const DrawableControl &control,
 									 const RgbColor &color) :
-		Background(control), color(color)
+		Background(control), color(color), size(0, 0)
 	{
 	}
 
-	void BackgroundColor::draw()
+	void BackgroundColor::updateVertices() {
+		vertices[0] = 0;
+		vertices[1] = get_parent().get_height();
+		vertices[2] = get_parent().get_width();
+		vertices[3] = get_parent().get_height();
+		vertices[4] = get_parent().get_width();
+		vertices[5] = 0;
+		vertices[6] = 0;
+		vertices[7] = 0;
+	}
+
+	void BackgroundColor::draw(void)
 	{
-		this->vertices[0] = 0;
-		this->vertices[1] = get_parent().get_height();
-		this->vertices[2] = get_parent().get_width();
-		this->vertices[3] = get_parent().get_height();
-		this->vertices[4] = get_parent().get_width();
-		this->vertices[5] = 0;
-		this->vertices[6] = 0;
-		this->vertices[7] = 0;
+		if (size != get_parent().get_size()) {
+			this->updateVertices();
+			size = get_parent().get_size();
+		}
 
 		glEnableClientState(GL_VERTEX_ARRAY);
 		glEnableClientState(GL_COLOR_ARRAY);
diff --git a/src/menu/background_color.hpp b/src/menu/background_color.hpp
index 7913fe30..4ba040cb 100644
--- a/src/menu/background_color.hpp
+++ b/src/menu/background_color.hpp
@@ -29,6 +29,7 @@
 
 #include "background.hpp"
 #include "utils/rgb_color.hpp"
+#include "utils/dimension.hpp"
 
 namespace usdx
 {
@@ -37,6 +38,19 @@ namespace usdx
 	private:
 		GLint vertices[8];
 		RgbColor color;
+
+		/**
+		 * Cache for the size of the parent component, to be able to detect
+		 * changes.
+		 */
+		Dimension<int> size;
+
+		/**
+		 * Update the vertices for drawing the background, if the size if the
+		 * parent component changes.
+		 */
+		void updateVertices();
+
 	protected:
 		void draw(void);
 
diff --git a/src/menu/background_image.cpp b/src/menu/background_image.cpp
index bb398304..451587f7 100644
--- a/src/menu/background_image.cpp
+++ b/src/menu/background_image.cpp
@@ -30,7 +30,7 @@ namespace usdx
 {
 	BackgroundImage::BackgroundImage(const DrawableControl &control,
 									 boost::filesystem::wpath filename) :
-		Background(control)
+		Background(control), texture(NULL), size(0,0)
 	{
 		texture = new Disposer<Texture>(new Texture(filename));
 	}
@@ -42,18 +42,24 @@ namespace usdx
 			texture = NULL;
 		}
 	}
+
+	void BackgroundImage::updateVertices() {
+		vertices[0] = 0;
+		vertices[1] = get_parent().get_height();
+		vertices[2] = get_parent().get_width();
+		vertices[3] = get_parent().get_height();
+		vertices[4] = get_parent().get_width();
+		vertices[5] = 0;
+		vertices[6] = 0;
+		vertices[7] = 0;
 	}
 
 	void BackgroundImage::draw(void)
 	{
-		this->vertices[0] = 0;
-		this->vertices[1] = get_parent().get_height();
-		this->vertices[2] = get_parent().get_width();
-		this->vertices[3] = get_parent().get_height();
-		this->vertices[4] = get_parent().get_width();
-		this->vertices[5] = 0;
-		this->vertices[6] = 0;
-		this->vertices[7] = 0;
+		if (size != get_parent().get_size()) {
+			this->updateVertices();
+			size = get_parent().get_size();
+		}
 
 		Activator<Texture> t(texture->get());
 
diff --git a/src/menu/background_image.hpp b/src/menu/background_image.hpp
index 23b1a68e..8b28a2e3 100644
--- a/src/menu/background_image.hpp
+++ b/src/menu/background_image.hpp
@@ -31,6 +31,7 @@
 #include "background.hpp"
 #include "texture.hpp"
 #include "utils/disposer.hpp"
+#include "utils/dimension.hpp"
 
 namespace usdx
 {
@@ -46,8 +47,26 @@ namespace usdx
 		 */
 		Disposer<Texture>* texture;
 
+		/**
+		 * Vertices to draw the background rectangle filled with the
+		 * texture. Cached until size of the parent component changes.
+		 *
+		 * @see updateVertices()
+		 */
 		GLint vertices[8];
 
+		/**
+		 * Cache for the size of the parent component, to be able to detect
+		 * changes.
+		 */
+		Dimension<int> size;
+
+		/**
+		 * Update the vertices for drawing the background, if the size if the
+		 * parent component changes.
+		 */
+		void updateVertices();
+
 	protected:
 		void draw(void);