qt Qgis二次开发-QgsMapTool地图交互工具详解

1.简介

QgsMapTool地图工具是用于操作地图画布的用户交互式工具。例如，地图平移和缩放功能被实现为地图工具。

QgsMapTool是抽象基类，以下是类的继承关系：

QgsMapToolEdit：用于编辑矢量几何图形的映射工具的基类 QgsMapToolEmitPoint：一个地图工具，当单击地图时，它只是发出一个点。将一个槽连接到它的canvasClicked()信号将允许您为传入点实现自定义行为。QgsMapToolExtent：地图画布上绘制矩形发出一个范围。QgsMapToolIdentify ：用于识别图层特征的映射工具。QgsMapToolPan：用于平移地图的地图工具。QgsMapToolZoom ：用于放大/缩小地图的地图工具。

2.常用接口

virtual void canvasDoubleClickEvent (QgsMapMouseEvent *e)重写鼠标双击事件virtual void canvasMoveEvent (QgsMapMouseEvent *e)重写鼠标移动事件virtual void canvasPressEvent (QgsMapMouseEvent *e)重写鼠标按下事件virtual void canvasReleaseEvent (QgsMapMouseEvent *e)重写鼠标抬起事件virtual void setCursor (const QCursor &cursor)设置光标QgsPointXY toMapCoordinates (QPoint point)将点从屏幕坐标转换为地图坐标。

3.示例

示例1：画布移动、放大、缩小

源码：

#pragma once

#include

#include "ui_GisCtrl.h"

#include

class GisCtrl : public QMainWindow

{

Q_OBJECT

public:

GisCtrl(QWidget *parent = Q_NULLPTR);

private:

Ui::GisCtrlClass ui;

private slots:

void slotXyCoordinates(const QgsPointXY &p);

void slotMove();

void slotZoomIn();

void slotZoomOut();

private:

QgsMapCanvas *m_mapCanvas = nullptr;

QList m_layers;

QgsMapToolPan *m_toolPan = nullptr; // 新建移动工具

QgsMapToolZoom *m_toolZoomIn = nullptr;//放大

QgsMapToolZoom *m_toolZoomOut = nullptr;//缩小

QActionGroup *m_actionGroup = nullptr;

};

#include "GisCtrl.h"

#include

#pragma execution_character_set("utf-8")

GisCtrl::GisCtrl(QWidget *parent)

: QMainWindow(parent)

{

ui.setupUi(this);

//创建画布

m_mapCanvas = new QgsMapCanvas(this);

QString url = "F:/arcgis/TMS.xml";

m_mapCanvas->setCanvasColor(QColor(255, 255, 255));

//加载瓦片地图

QgsRasterLayer *layer = new QgsRasterLayer(url);

if (!layer->isValid())

{

qDebug() << "load map faild";

}

m_layers.append(layer);

// 新建移动工具

m_toolPan = new QgsMapToolPan(m_mapCanvas);

m_mapCanvas->setExtent(layer->extent());

m_mapCanvas->enableAntiAliasing(true);

m_mapCanvas->setLayers(m_layers);

m_mapCanvas->setMapTool(m_toolPan);

m_toolZoomIn = new QgsMapToolZoom(m_mapCanvas, false);

m_toolZoomOut = new QgsMapToolZoom(m_mapCanvas, true);

m_actionGroup = new QActionGroup(this);

m_actionGroup->addAction(ui.actionMove);

m_actionGroup->addAction(ui.actionZoomIn);

m_actionGroup->addAction(ui.actionZoomOut);

m_actionGroup->setExclusive(true);

connect(m_mapCanvas, &QgsMapCanvas::xyCoordinates, this, &GisCtrl::slotXyCoordinates);

connect(ui.actionMove, &QAction::triggered, this, &GisCtrl::slotMove);

connect(ui.actionZoomIn, &QAction::triggered, this, &GisCtrl::slotZoomIn);

connect(ui.actionZoomOut, &QAction::triggered, this, &GisCtrl::slotZoomOut);

setCentralWidget(m_mapCanvas);

ui.actionMove->setChecked(true);

ui.actionLineManager->setVisible(false);

ui.actionLayer->setVisible(false);

ui.actionSelect->setVisible(false);

ui.actionItem->setVisible(false);

}

void GisCtrl::slotXyCoordinates(const QgsPointXY &p)

{

QString str = QString("经度= %1，纬度=%2").arg(QString::number(p.x(), 'f', 6)).arg(QString::number(p.y(), 'f', 6));

this->statusBar()->showMessage(str);

}

void GisCtrl::slotMove()

{

m_mapCanvas->setMapTool(m_toolPan);

}

void GisCtrl::slotZoomIn()

{

m_mapCanvas->setMapTool(m_toolZoomIn);

}

void GisCtrl::slotZoomOut()

{

m_mapCanvas->setMapTool(m_toolZoomOut);

}

示例2：鼠标点击画矩形。

自定义一个地图交互工具继承QgsMapToolIdentify

源码：

#pragma once

#include

class QgsMapToolSelectFeatures : public QgsMapToolIdentify

{

Q_OBJECT

public:

QgsMapToolSelectFeatures(QgsMapCanvas *mapCanvas);

protected:

//重写鼠标移动

void canvasMoveEvent(QgsMapMouseEvent *e) override;

//重写鼠标按下

void canvasPressEvent(QgsMapMouseEvent *e) override;

void initRubberBand();

private:

// 是否正在选择

bool mSelectionActive = false;

QScopedPointer mSelectionRubberBand;

QColor mFillColor = QColor(255, 255, 0, 63);

QColor mStrokeColor = QColor(255, 255, 0, 100);

QPoint mInitDragPos;

};

//cpp

#include "QgsMapToolSelectFeatures.h"

#include "QgsMapToolIdentify.h"

QgsMapToolSelectFeatures::QgsMapToolSelectFeatures(QgsMapCanvas *mapCanvas)

: QgsMapToolIdentify(mapCanvas)

{

}

void QgsMapToolSelectFeatures::canvasMoveEvent(QgsMapMouseEvent * e)

{

if (e->buttons() != Qt::LeftButton)

return;

QRect rect;

if (!mSelectionActive)

{

mSelectionActive = true;

rect = QRect(e->pos(), e->pos());

}

else

{

rect = QRect(e->pos(), mInitDragPos);

}

if (mSelectionRubberBand)

mSelectionRubberBand->setToCanvasRectangle(rect);

}

void QgsMapToolSelectFeatures::canvasPressEvent(QgsMapMouseEvent * e)

{

if (!mSelectionRubberBand)

initRubberBand();

mInitDragPos = e->pos();

}

void QgsMapToolSelectFeatures::initRubberBand()

{

mSelectionRubberBand.reset(new QgsRubberBand(mCanvas, QgsWkbTypes::PolygonGeometry));

mSelectionRubberBand->setFillColor(mFillColor);

mSelectionRubberBand->setStrokeColor(mStrokeColor);

}

使用

QgsMapToolSelectFeatures *m_tool = new QgsMapToolSelectFeatures(m_mapCanvas);

m_mapCanvas->setMapTool(m_tool);

示例3：右键弹出菜单标注地点。

#pragma once

#include

class QgsRubberBand;

class QgsAnnotationPointTextItem;

class QgsMapToolAddItem : public QgsMapToolIdentify

{

Q_OBJECT

public:

QgsMapToolAddItem(QgsMapCanvas *mapCanvas);

typedef struct _mark

{

QgsRubberBand *rubberBand; //svg图标item

QgsGeometry geo; //区域

QgsAnnotationPointTextItem *text;//字体

QgsAnnotationLayer *layer;

}Mark;

protected:

//重写鼠标按下

void canvasPressEvent(QgsMapMouseEvent *e) override;

private slots:

void slotAdd();

void slotDel();

void slotShowScale(double scale);

void slotZoomLastStatusChanged(bool);

private:

// 是否正在选择

bool mSelectionActive = false;

QMenu *m_menu = nullptr;

QAction *m_add = nullptr;

QAction *m_del = nullptr;

QgsMapCanvas *m_canvas;

QList m_lstMark;

};

#include "QgsMapToolAddItem.h"

#include "QgsMapToolIdentify.h"

#include "qgsapplication.h"

#include "qgsvectorlayer.h"

#include

#include "BaseFunc.h"

#include

#pragma execution_character_set("utf-8")

extern bool g_is3857crs;

extern QList g_layers;

static QgsPointXY g_point;

static int g_index = -1;

QgsMapToolAddItem::QgsMapToolAddItem(QgsMapCanvas *mapCanvas)

: QgsMapToolIdentify(mapCanvas)

, m_canvas(mapCanvas)

{

this->setCursor(Qt::CrossCursor);

m_menu = new QMenu();

m_add = m_menu->addAction(QIcon(QPixmap(":/GisCtrl/image/add.png")),"添加");

m_del = m_menu->addAction(QIcon(QPixmap(":/GisCtrl/image/del.png")),"删除");

connect(m_add, &QAction::triggered, this, &QgsMapToolAddItem::slotAdd);

connect(m_del, &QAction::triggered, this, &QgsMapToolAddItem::slotDel);

connect(mapCanvas, &QgsMapCanvas::zoomLastStatusChanged,

this, &QgsMapToolAddItem::slotZoomLastStatusChanged);

}

void QgsMapToolAddItem::canvasPressEvent(QgsMapMouseEvent * e)

{

if (e->buttons() == Qt::RightButton)

{

g_point = e->mapPoint();

bool isHaveItem = false;

const QgsMapToPixel *mtransform = m_canvas->getCoordinateTransform();

for (int i = 0; i < m_lstMark.size(); i++)

{

Mark item = m_lstMark.at(i);

QgsVector qgsVector;

QgsPointXY p2 = item.geo.asPoint();

QgsPointXY curPoint = mtransform->transform(g_point.x(), g_point.y());

QgsPointXY itemPoint = mtransform->transform(p2.x(), p2.y());

qgsVector = curPoint - itemPoint;

if ((-10 < qgsVector.x() && qgsVector.x() < 15) &&

(-10 < qgsVector.y() && qgsVector.y() < 15))

{

isHaveItem = true;

g_index = i;

break;

}

if (!isHaveItem)

g_index = -1;

QPoint point = e->pos();

point.setY(point.y() + 80);

m_del->setVisible(isHaveItem);

m_menu->exec(point);

}

else

{

m_menu->hide();

}

void QgsMapToolAddItem::slotAdd()

{

//添加点

QgsRubberBand *rb = new QgsRubberBand(m_canvas, QgsWkbTypes::PointGeometry);

//rb->setOpacity(0.8);

rb->setIcon(QgsRubberBand::IconType::ICON_SVG); //设置图标类型

rb->setIconSize(5); //设置图标尺寸

rb->setSvgIcon(":/GisCtrl/image/water.svg", QPoint(-16, -16)); //设置图标文件路径和偏移

QgsGeometry geo = QgsGeometry::fromPointXY(g_point); //经纬度

rb->addGeometry(geo); //绘制

//添加文字

QgsCoordinateTransformContext coordinateTransformContext;

//先构造出一个能加注记的图层

QgsAnnotationLayer *textLayer = new QgsAnnotationLayer("annotationLayer",

QgsAnnotationLayer::LayerOptions(coordinateTransformContext));

double lon = 0, lat = 0;

BaseFunc::WebMercatorToWGS84(g_point.x(), g_point.y(), &lon, &lat);

//构造时传入地理坐标，有必要后期改成鼠标事件点击来创建QgsAnnotationMarkerItem

const QgsMapToPixel *mtransform = m_canvas->getCoordinateTransform();

//转换到屏幕坐标

QgsPointXY offsetPoint = mtransform->transform(g_point.x(), g_point.y());

int yOffset = 25;

offsetPoint.setY(offsetPoint.y() + yOffset);

//转回去到地图坐标

offsetPoint = mtransform->toMapCoordinates(offsetPoint.x(), offsetPoint.y());

QString showText = QString("%1,%2").arg(QString::number(lon, 'f', 6)).arg(QString::number(lat, 'f', 6));

QgsAnnotationPointTextItem* textItem = new QgsAnnotationPointTextItem(showText, QgsPoint(offsetPoint.x(), offsetPoint.y()));

textItem->setAlignment(Qt::AlignHCenter);

QgsTextFormat format;

QFont font;

font.setBold(true);

font.setPointSize(13);

format.setFont(font);

format.setColor(QColor(Qt::yellow));

textItem->setFormat(format);

textLayer->addItem(textItem);//画布添加Item

Mark mark;

mark.rubberBand = rb;

mark.geo = geo;

mark.text = textItem;

mark.layer = textLayer;

m_lstMark.append(mark);

g_layers.push_front(textLayer);

m_canvas->setLayers(g_layers);

m_canvas->refresh();

}

void QgsMapToolAddItem::slotDel()

{

if (g_index < 0)

return;

Mark mark = m_lstMark.at(g_index);

g_layers.removeOne(mark.layer);

delete mark.layer;

mark.rubberBand->reset();

delete mark.rubberBand;

m_lstMark.removeAt(g_index);

m_canvas->setLayers(g_layers);

m_canvas->refresh();

}

void QgsMapToolAddItem::slotShowScale(double scale)

{

qDebug() << "scale = " << scale;

}

void QgsMapToolAddItem::slotZoomLastStatusChanged(bool)

{

for (int i = 0; i < m_lstMark.size(); i++)

{

QgsPointXY xy = m_lstMark.at(i).geo.asPoint();

const QgsMapToPixel *mtransform = m_canvas->getCoordinateTransform();

//转换到屏幕坐标

QgsPointXY offsetPoint = mtransform->transform(xy.x(), xy.y());

int yOffset = 25;

offsetPoint.setY(offsetPoint.y() + yOffset);

//转回去到地图坐标

offsetPoint = mtransform->toMapCoordinates(offsetPoint.x(), offsetPoint.y());

m_lstMark.at(i).text->setPoint(QgsPoint(offsetPoint.x(), offsetPoint.y()));

}

4.更多参考

Qgis二次开发-QgsAnnotationItem（添加文字、图片标注（支持svg、png、jpg等常用图片格式））_Mr.codeee的博客-CSDN博客

Qgis二次开发-QgsMapCanvas画布简介_Mr.codeee的博客-CSDN博客

Qgis二次开发-QgsRubberBand详解（画线、画多边形）_Mr.codeee的博客-CSDN博客

Qgis二次开发-QgsAnnotationItem（添加文字、图片标注（支持svg、png、jpg等常用图片格式））_Mr.codeee的博客-CSDN博客

评论可见，请评论后查看内容，谢谢！！！

您阅读本篇文章共花了：

金钥匙

qt Qgis二次开发-QgsMapTool地图交互工具详解

自然语言处理人工智能语言模型编程实践开发语言架构设计让交互更自然：基于语义理解的创新交互方式

javascript ajax 开发语言阶段四前后端交互

发表评论取消回复

金钥匙

qt Qgis二次开发-QgsMapTool地图交互工具详解

自然语言处理 人工智能 语言模型 编程实践 开发语言 架构设计 让交互更自然：基于语义理解的创新交互方式

javascript ajax 开发语言 阶段四 前后端交互

相关文章

发表评论取消回复

自然语言处理人工智能语言模型编程实践开发语言架构设计让交互更自然：基于语义理解的创新交互方式

javascript ajax 开发语言阶段四前后端交互