AdaptiveRasterizer.cpp

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#include "EdgeDetection/AdaptiveRasterizer.h"

#include "EdgeDetection/OwnedImage.h"

namespace EdgeDetection
{
        Image* AdaptiveRasterizer::Rasterize(Rasterizable* object, int width, int height)
        {
                if (object == 0) throw "The parameter 'object' cannot be NULL.";
                if (width < 0) throw "The parameter 'threshold' was out of range.";
                if (height < 0) throw "The parameter 'threshold' was out of range.";
        
                OwnedImage* image = new OwnedImage(width, height);

                Rectangle region = object->GetRegion();

                double pixelWidth = region.GetWidth() / width;
                double pixelHeight = region.GetHeight() / height;

                for (int y = 0; y < height; y++)
                        for (int x = 0; x < width; x++)
                        {
                                double left = region.GetLeft() + (x + 0) * pixelWidth;
                                double right = region.GetLeft() + (x + 1) * pixelWidth;
                                double top = region.GetTop() + (y + 0) * pixelHeight;
                                double bottom = region.GetTop() + (y + 1) * pixelHeight;

                                double value = GetValue(object, Rectangle(left, right, top, bottom));                   

                                image->Set(x, y, value);
                        }

                return image;
        }

        double AdaptiveRasterizer::GetValue(Rasterizable* object, Rectangle rectangle)
        {
                if (object->CanCalculateIntegral(rectangle)) return object->CalculateIntegral(rectangle);
                if (rectangle.GetArea() < threshold) return object->EstimateIntegral(rectangle);

                Rectangle leftTop = Rectangle(rectangle.GetLeft(), rectangle.GetCenter().GetX(), rectangle.GetTop(), rectangle.GetCenter().GetY());
                Rectangle rightTop = Rectangle(rectangle.GetCenter().GetX(), rectangle.GetRight(), rectangle.GetTop(), rectangle.GetCenter().GetY());
                Rectangle leftBottom = Rectangle(rectangle.GetLeft(), rectangle.GetCenter().GetX(), rectangle.GetCenter().GetY(), rectangle.GetBottom());
                Rectangle rightBottom = Rectangle(rectangle.GetCenter().GetX(), rectangle.GetRight(), rectangle.GetCenter().GetY(), rectangle.GetBottom());

                return GetValue(object, leftTop) + GetValue(object, rightTop) + GetValue(object, leftBottom) + GetValue(object, rightBottom);
        }
};