QGis 載入的圖層包括向量圖層和柵格圖層，向量圖層中通常有點、線、面三種常用的圖層。載入後的圖層顯示的風格各異，但是我們可以對他們的不同的風格進行設定使其看起來很好看。
看一下設定的效果：

點圖層

線圖層

面圖層

1.點圖層設定關鍵程式碼：
獲取點圖層的各種屬性：

    QgsSingleSymbolRendererV2* render = (QgsSingleSymbolRendererV2*)pointVectorLayer->rendererV2();
    QgsMarkerSymbolV2* markSym = (QgsMarkerSymbolV2*)render->symbol();

    QgsSymbolLayerV2List symList = markSym->symbolLayers();
    QgsSvgMarkerSymbolLayerV2* svgMarker = (QgsSvgMarkerSymbolLayerV2*)symList.at(0
 
);
    svgPath = svgMarker->path();//SVG路徑
    double size = svgMarker->size();//SVG大小

    double minScale = pointVectorLayer->minimumScale();//最小顯示比例
    double maxScale = pointVectorLayer->maximumScale();//最大顯示比例

    QgsPalLayerSettings layerSetting = QgsPalLayerSettings::fromLayer(pointVectorLayer);
    bool
 
 bShowLabel = layerSetting.enabled;//是否顯示標籤
    fontColor = layerSetting.textColor;//字型顏色
    int fontSize = layerSetting.textFont.pointSize();//字型大小

    bool bBufferShow = layerSetting.bufferDraw;//輪廓顯示
    bufColor = layerSetting.bufferColor;//輪廓顏色

    bool bShadowShow = layerSetting.shadowDraw;//陰影顯示
    int
 
 shadowAngle = layerSetting.shadowOffsetAngle;//陰影角度
    int shadowDis = layerSetting.shadowOffsetDist;//陰影距離

設定點圖層的屬性：

//SVG
    QgsSvgMarkerSymbolLayerV2* svgMarker = new QgsSvgMarkerSymbolLayerV2(svgPath);
    QgsSymbolLayerV2List symList;
    symList.append(svgMarker);
    QgsMarkerSymbolV2* markSym = new QgsMarkerSymbolV2(symList);
    QgsSingleSymbolRendererV2* symRenderer = new QgsSingleSymbolRendererV2(markSym);

    pointVectorLayer->setRendererV2(symRenderer);
    svgMarker->setSize(svgSize); //設定svg大小

    //設定標註
    QgsPalLayerSettings layerSetting;
    layerSetting.enabled = bShowLable;//顯示標註  

    layerSetting.fieldName = pointVectorLayer->pendingFields()[1].name();
    layerSetting.centroidWhole = true; //設定位置參考的中心點
    //設定字型
    layerSetting.textColor = fontColor;
    QFont font("Times", fontSize);
    font.setBold(true);
    layerSetting.textFont = font;

    //設定輪廓
    layerSetting.bufferDraw = bShowBuf;
    layerSetting.bufferColor = bufColor;
    layerSetting.bufferSize = 1;
    layerSetting.bufferTransp = 0.5;

    //設定陰影
    layerSetting.shadowDraw = bShowShadow;
    layerSetting.shadowOffsetAngle = shadowAngle;
    layerSetting.shadowOffsetDist = shadowDis;

    layerSetting.writeToLayer(pointVectorLayer);

    DrawManager::getInstance()->getMainCanvas()->refresh();

2.線圖層的關鍵程式碼：
獲取線圖層的各種屬性：

    QgsSingleSymbolRendererV2* symRenderer = (QgsSingleSymbolRendererV2*)(lineVectorLayer->rendererV2());
    QgsLineSymbolV2* lineSymbol = (QgsLineSymbolV2*)symRenderer->symbol();
    lineColor = lineSymbol->color();//線顏色
    double lineWidth = lineSymbol->width();//線寬

設定線圖層的各種屬性：

    QgsSingleSymbolRendererV2* symRenderer = (QgsSingleSymbolRendererV2*)(lineVectorLayer->rendererV2());
    QgsLineSymbolV2* lineSymbol = (QgsLineSymbolV2*)symRenderer->symbol();
    lineSymbol->setColor(lineColor);
    lineSymbol->setWidth(lineWidth);

    DrawManager::getInstance()->getMainCanvas()->refresh();

3.面圖層的關鍵程式碼：
獲取面圖層的屬性：

    QgsSingleSymbolRendererV2* symRenderer = (QgsSingleSymbolRendererV2*)(polygonVectorLayer->rendererV2());
    QgsFillSymbolV2* fillSymbol = (QgsFillSymbolV2*)symRenderer->symbol();
    fillColor = fillSymbol->color();//填充顏色
    double alpha = fillSymbol->alpha();//透明度

設定面圖層的屬性：

    QgsSingleSymbolRendererV2* symRenderer = (QgsSingleSymbolRendererV2*)(polygonVectorLayer->rendererV2());
    QgsFillSymbolV2* fillSymbol = (QgsFillSymbolV2*)symRenderer->symbol();
    fillSymbol->setColor(fillColor);
    fillSymbol->setAlpha((double)alpha/100);