zoomout.cpp

在vc环境下

#include "StdAfx.h"
#include ".\zoomout.h"

//////////////////////////////////////////////////////////////////////////
//CZoomout

STDMETHODIMP CZoomout::OnMouseDown(LONG Button, LONG Shift, LONG X, LONG Y)
{
	if (MouseDown(X,Y))
	{
		GetFocusMapActiveView(&m_cpActiveView);
		ToFocusMapPoint(X,Y, &m_cpStartPoint);
	}

	return S_OK;
}

STDMETHODIMP CZoomout::OnMouseMove(LONG Button, LONG Shift, LONG X, LONG Y)
{

	if (CMapToolBase::IsMouseDown() && (m_cpStartPoint!=0))
	{
		if (m_cpEnvelopeFeedback==0)
		{
			// Start the feedback if its not previously started
			m_cpEnvelopeFeedback.CreateInstance(CLSID_NewEnvelopeFeedback);
			IScreenDisplayPtr cpScreenDisplay;
			m_cpActiveView->get_ScreenDisplay(&cpScreenDisplay);

			m_cpEnvelopeFeedback->putref_Display(cpScreenDisplay);
			m_cpEnvelopeFeedback->Start(m_cpStartPoint);
		}

		// Update the feedback to the new point
		IPointPtr cpPoint;
		ToFocusMapPoint(X,Y, &cpPoint);
		m_cpEnvelopeFeedback->MoveTo(cpPoint);
	}

	return S_OK;

}

STDMETHODIMP CZoomout::OnMouseUp(LONG Button, LONG Shift, LONG X, LONG Y)
{
	if (CMapToolBase::IsMouseDown() && (m_cpStartPoint!=0))
	{
		IEnvelopePtr cpEnvelope;

		if (m_cpEnvelopeFeedback == 0)
		{
			// It was just a click, so zoomout by a fixed amount
			m_cpActiveView->get_Extent(&cpEnvelope);
			cpEnvelope->Expand( 2, 2, VARIANT_TRUE);
			cpEnvelope->CenterAt(m_cpStartPoint);
		}
		else
		{
			m_cpEnvelopeFeedback->Stop(&cpEnvelope);
			DOUBLE efWidth,efHeight, efXMin, efYMin;
			cpEnvelope->get_Width(&efWidth);
			cpEnvelope->get_Height(&efHeight);
			cpEnvelope->get_XMin(&efXMin);
			cpEnvelope->get_YMin(&efYMin);
			if (efWidth!=0 && efHeight!=0)
			{
				DOUBLE avWidth, avHeight, avXMin, avYMin;
				IEnvelopePtr cpAvEnvelope;
				m_cpActiveView->get_Extent(&cpAvEnvelope);
				cpAvEnvelope->get_Width(&avWidth);
				cpAvEnvelope->get_Height(&avHeight);
				cpAvEnvelope->get_XMin(&avXMin);
				cpAvEnvelope->get_YMin(&avYMin);

				// The plan is to transform the active view extent into the tracked extent
				// and thus expand the new active view
				DOUBLE newWidth = avWidth * (avWidth / efWidth);
				DOUBLE newHeight = avHeight * (avHeight / efHeight);
				DOUBLE newXMin = avXMin - ((efXMin - avXMin) * (avWidth / efWidth));
				DOUBLE newYMin = avYMin - ((efYMin - avYMin) * (avHeight / efHeight));

				cpEnvelope->PutCoords(newXMin, newYMin, newXMin + newWidth, newYMin + newHeight);
			}
			else
			{
				cpEnvelope = 0;
			}
		}
		if (cpEnvelope!=0)
		{
			m_cpActiveView->put_Extent(cpEnvelope);
			m_cpActiveView->Refresh();
		}
	}

	Reset();

	return S_OK;
}

STDMETHODIMP CZoomout::OnKeyDown(LONG keyCode, LONG Shift)
{
	if (keyCode == VK_ESCAPE)
		Reset();

	return S_OK;
}



STDMETHODIMP CZoomout::Refresh(OLE_HANDLE hDC)
{
	if (m_cpEnvelopeFeedback!=0)
		m_cpEnvelopeFeedback->Refresh(hDC);

	return S_OK;
}

void CZoomout::Reset()
{
	// clear out temp variables release mouse capture in base class
	m_cpActiveView = 0;
	m_cpStartPoint = 0;
	if (m_cpEnvelopeFeedback)
	{
		IEnvelopePtr cpEnvelope;
		m_cpEnvelopeFeedback->Stop(&cpEnvelope);
	}

	m_cpEnvelopeFeedback = 0;

	CMapToolBase::MouseUp();
}