#include "metawndo.h"
#include <math.h>

int ZoomRect ( grafPort *srcPort, grafPort *desPort, rect *srcRect, rect * desRect);

int ZoomRect ( grafPort *srcPort, grafPort *desPort, rect *srcRect, rect * desRect)
{
	float ratioX = 0.0;
	float ratioY = 0.0;
	rect padRect;
	int srcOffX, srcOffY; // Offset of srcRect from (0,0).
	int desOffX, desOffY; // Offset of desRect from (0,0).
	int count;
	int srcX, srcY;
	int desX, desY;
	int srcXsize, srcYsize;
	int desXsize, desYsize;
	int color;
	int step = 0;
	float errStep;
	float errTerm = 0.0;
	int (*GetPixelPrim)(int, int, grafMap *);

	GetPixelPrim = srcPort->portMap->prGetPx;
	srcXsize = srcRect->Xmax - srcRect->Xmin;
	srcYsize = srcRect->Ymax - srcRect->Ymin;
	desXsize = desRect->Xmax - desRect->Xmin;
	desYsize = desRect->Ymax - desRect->Ymin;

	ratioX =  (float)srcXsize / (float)desXsize;
	ratioY =  (float)srcYsize / (float)desYsize;

	if (ratioX < 1.0)
		{
		step = (float)(desXsize / srcXsize);
		errStep = ((desXsize % srcXsize) / (float)desXsize) * step;
		}


	//  Test for empty ratio's or 1:1
	if ((ratioX == 0.0) || (ratioY == 0.0))
		return False;
	if ((ratioX == 1.0) && (ratioY == 1.0))
		{
		CopyBlit (srcPort, desPort, srcRect, desRect);
		return True;
		}
	// The main loop.
	// Scan each destination line, and match it to a source raster.
	SetPort (desPort);
   PenSize (0,0);

	for (desY = desRect->Ymin; desY < desRect->Ymax; desY++)
		{
		errTerm = 0.0;
		srcY = (desY * ratioY) + srcRect->Ymin;
		for (desX = desRect->Xmin; desX < desRect->Xmax;)
			{
			srcX = (desX * ratioX) + srcRect->Xmin ;
			color = GetPixelPrim (srcX, srcY, srcPort->portMap);
			PenColor (color);
			// This gets used when you're Zooming up.
			if (step)
				{
            /*
				for (count = 0; count < step; count++)
					{
					SetPixel (desX, desY);
					desX++;
					}

				SetPixel (desX, desY);
            */

            MoveTo (desX, desY);
            LineTo (desX + step, desY);

				errTerm += errStep;
				if (errTerm >= 1.0)
					{
					desX++;
					SetPixel (desX, desY);
					errTerm -= 1.0;
					}
				}
			// If you're Zooming down, use this one.
			else
				{
				SetPixel (desX, desY);
				desX++;
				}
			}
		}
	return True;
}