Rename Framebuffer to Canvas (issue #263). Move error reporting code.

Error reporting now resides in Graphics::newCanvas() instead of the
previous location wrap_newFramebuffer(). Changed error text for
"Error in implementation" to point to a possible fix.

src/modules/graphics/opengl/Canvas.h

@@ -0,0 +1,76 @@
+#ifndef LOVE_GRAPHICS_CANVAS_H
+#define LOVE_GRAPHICS_CANVAS_H
+
+#include <graphics/Drawable.h>
+#include <graphics/Volatile.h>
+#include <graphics/Image.h>
+#include <graphics/Color.h>
+#include <image/Image.h>
+#include <image/ImageData.h>
+#include <common/math.h>
+#include "GLee.h"
+
+namespace love
+{
+namespace graphics
+{
+namespace opengl
+{
+	class Canvas : public Drawable, public Volatile
+	{
+	public:
+		Canvas(int width, int height);
+		virtual ~Canvas();
+
+		static bool isSupported();
+
+		unsigned int getStatus() const { return status; }
+
+		static Canvas* current;
+		static void bindDefaultCanvas();
+
+		void startGrab();
+		void stopGrab();
+
+		void clear(const Color& c);
+
+		virtual void draw(float x, float y, float angle, float sx, float sy, float ox, float oy, float kx, float ky) const;
+		love::image::ImageData * getImageData(love::image::Image * image);
+
+		void setFilter(const Image::Filter &f);
+		Image::Filter getFilter() const;
+
+		void setWrap(const Image::Wrap &w);
+		Image::Wrap getWrap() const;
+
+		int getWidth();
+		int getHeight();
+
+		bool loadVolatile();
+		void unloadVolatile();
+
+	private:
+		friend class PixelEffect;
+		GLuint getTextureName() const { return img; }
+
+		GLsizei width;
+		GLsizei height;
+		GLuint fbo;
+		GLuint depthbuffer;
+		GLuint img;
+
+		vertex vertices[4];
+
+		GLenum status;
+
+		struct {
+			Image::Filter filter;
+			Image::Wrap wrap;
+		} settings;
+	};
+
+} // opengl
+} // graphics
+} // love
+
+#endif // LOVE_GRAPHICS_CANVAS_H