GIS內核-編寫自定義圖層並完成繪製業務

需求問題:

多個影像文件圖層,和其對應的幾何範圍,需要一起顯示,GIS內核只設計了基本的單個影像和單個地物類繪製的圖層,請參見前面  

GIS內核-加載tif 影像文件圖層,以及GsFeatureLayer.

封裝一個自定義的圖層至少要繼承GsLayer 類,並且至少實現基本的基類 虛函數接口.下面是我封裝的一個直接擼代碼,頭文件定義:

class  GsCoustomRasterLayer :public GsLayer
{
public:
	GsCoustomRasterLayer();
	~GsCoustomRasterLayer();


private:
	GsVector<GsRasterLayerPtr> m_Lys;
	GsFeatureLayerPtr m_ptrfcsLayer;
	GsString m_ClipGeometryField;
	virtual bool InnerDraw(GsDisplay* pDisplay, GsTrackCancel* pCancel, GsDrawPhase eDrawPhase);
	//根據特定規則找到每個影像圖層對應的數據集裁切幾何的對象
	GsGeometry* FindGeometry(const char *strLyrName);
public:
	// 通過 GsLayer 繼承
	virtual GsBox Extent(GsSpatialReference * pTargetSR = 0) override;


	virtual bool HasSelection() override;


	virtual GsSmarterPtr<GsLayer> Clone() override;


	void AddRasterLayer(GsRasterLayer *pLayer);
	void RemoveRasterLayer(const char * strLyrName);
	void ClearLayers();
	GsVector<GsRasterLayerPtr >* RasterLayers();
	GsFeatureLayer* FeatureLayer();
	void FeatureLayer(GsFeatureLayer* pFeaLyr);
};
GS_SMARTER_PTR(GsCoustomRasterLayer);

cpp文件實現:

GsCoustomRasterLayer::GsCoustomRasterLayer()
{
}

GsCoustomRasterLayer::~GsCoustomRasterLayer()
{
}

bool GsCoustomRasterLayer::InnerDraw(GsDisplay * pDisplay, GsTrackCancel * pCancel, GsDrawPhase eDrawPhase)
{
	std::vector<GsRasterLayerPtr >::iterator it = m_Lys.begin();
	for (; it != m_Lys.end(); it++)
	{
		
		GsGeometryPtr pGeo = FindGeometry((*it)->Name().c_str());
		(*it)->ClipGeometry(pGeo);
		(*it)->Draw(pDisplay, pCancel, eDrawPhase);
	}
	m_ptrfcsLayer->Draw(pDisplay, pCancel, eDrawPhase);
	return false;
}

GsGeometry * GsCoustomRasterLayer::FindGeometry(const char * strLyrName)
{
	return nullptr;
}

GsBox GsCoustomRasterLayer::Extent(GsSpatialReference * pTargetSR)
{
	std::vector<GsRasterLayerPtr >::iterator it = m_Lys.begin();
	GsBox boxret;
	for (; it != m_Lys.end(); it++)
	{
		GsBox box = (*it)->Extent();
		if (box.IsValid())
			boxret.Union(box);
	}
	
	return boxret;
}

bool GsCoustomRasterLayer::HasSelection()
{
	return false;
}

GsSmarterPtr<GsLayer> GsCoustomRasterLayer::Clone()
{
	std::vector<GsRasterLayerPtr >::iterator it = m_Lys.begin();
	GsCoustomRasterLayerPtr ptrColne = new GsCoustomRasterLayer();
	for (; it != m_Lys.end(); it++)
		ptrColne->RasterLayers()->push_back((*it)->Clone());
	GsFeatureLayerPtr pLyr = m_ptrfcsLayer->Clone();
	ptrColne->FeatureLayer(pLyr);

	//基礎屬性
	GsLayerPtr pLayer = ptrColne;
	pLayer->Name(Name().c_str());
	pLayer->Visible(Visible());
	pLayer->AliasName(AliasName().c_str());
	pLayer->MinScale(MinScale());
	pLayer->MaxScale(MaxScale());
	pLayer->ReferenceScale(ReferenceScale());
	pLayer->Tag(Tag());

	return ptrColne;
}

void  GsCoustomRasterLayer::AddRasterLayer(GsRasterLayer * pLayer)
{
	m_Lys.push_back(pLayer);
}

void GsCoustomRasterLayer::RemoveRasterLayer(const char * strLyrName)
{
	std::vector<GsRasterLayerPtr >::iterator it = m_Lys.begin();
	for (; it != m_Lys.end(); it++)
	{
		if (GsCRT::_stricmp((*it)->Name().c_str(), strLyrName))
		{
			m_Lys.erase(it);
			break;
		}
	}
}

void GsCoustomRasterLayer::ClearLayers()
{
	m_Lys.clear();
}

GsVector<GsRasterLayerPtr>* GsCoustomRasterLayer::RasterLayers()
{
	return &m_Lys;
}

GsFeatureLayer * GsCoustomRasterLayer::FeatureLayer()
{
	return m_ptrfcsLayer.p;
}

void GsCoustomRasterLayer::FeatureLayer(GsFeatureLayer * pFeaLyr)
{
	m_ptrfcsLayer = pFeaLyr;
}

這個圖層的使用 就是填充兩個 GsVector<GsRasterLayerPtr> m_Lys和 GsFeatureLayerPtr m_ptrfcsLayer; 其中有個Clipgeometry  對象 這個需要根據業務自身去定義,目前這裏接口定義好的位根據名稱去FetureLayer內部找Geometry .