zoomin.cpp

在vc环境下

#include "StdAfx.h"
#include ".\zoomin.h"

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

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

			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 CZoomin::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 zoomin by 50%
			m_cpActiveView->get_Extent(&cpEnvelope);
			cpEnvelope->Expand( 0.5, 0.5, VARIANT_TRUE);
			cpEnvelope->CenterAt(m_cpStartPoint);
		}
		else
			m_cpEnvelopeFeedback->Stop(&cpEnvelope);

		DOUBLE width,height;
		cpEnvelope->get_Width(&width);
		cpEnvelope->get_Height(&height);
		if (width!=0 && height!=0)
		{
			m_cpActiveView->put_Extent(cpEnvelope);
			m_cpActiveView->Refresh();
		}
	}

	// remove capture and release feedback objects
	Reset();

	return S_OK;
}


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

	return S_OK;
}


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

	return S_OK;
}




void CZoomin::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();
}