让我们开发一个非常好用的卷帘工具
目录
版权声明：未经作者允许不得转载，此插件不得用于商业用途。
目录
开发环境
- QGIS 3.2
- python（QGIS自带）
插件开发
关于QGIS中使用python开发插件的方法，自行查看官方文档（https://docs.qgis.org/testing/en/docs/pyqgis_developer_cookbook/plugins.html）
__init__.py
from .map_swipe_plugin import MapSwipePlugin
def classFactory(iface):
return MapSwipePlugin(iface)
map_swipe_plugin.py
import os
from PyQt5.QtGui import QIcon
from PyQt5.QtWidgets import QWidget, QHBoxLayout, QComboBox, QPushButton
from qgis.core import QgsProject
from qgis.gui import QgsMapToolPan
from .map_swipe_tool import MapSwipeTool
plugin_path = os.path.dirname(__file__)
class MapSwipePlugin:
def __init__(self, iface):
self.iface = iface
self.canvas = iface.mapCanvas()
# 图层变化信号
QgsProject.instance().layerTreeRoot().layerOrderChanged.connect(self.combobox_add_items)
def initGui(self):
self.menu = self.title = "卷帘工具"
self._create_widget()
self.tool = MapSwipeTool(plugin_path, self.combobox, self.iface)
self.tool.deactivated.connect(self.tool_deactivated)
self.widget_action = self.iface.addToolBarWidget(self.widget)
def unload(self):
self.canvas.setMapTool(QgsMapToolPan(self.iface.mapCanvas()))
self.iface.removeToolBarIcon(self.widget_action)
del self.widget_action
def run(self):
if self.canvas.mapTool() != self.tool:
self.prevTool = self.canvas.mapTool()
self.canvas.setMapTool(self.tool)
else:
self.canvas.setMapTool(self.prevTool)
if self.pushbutton.isChecked() and self.combobox.isHidden():
self.combobox.show()
self.combobox_add_items()
else:
self.combobox.hide()
def _create_widget(self):
icon = QIcon(os.path.join(plugin_path, 'icon.png'))
# 新建widget
self.widget = QWidget(self.iface.mainWindow())
self.hlayout = QHBoxLayout(self.widget)
self.hlayout.setContentsMargins(0, 0, 0, 0)
self.pushbutton = QPushButton(icon, '', self.widget)
self.pushbutton.setCheckable(True)
self.pushbutton.setFlat(True)
self.combobox = QComboBox(self.widget)
self.hlayout.addWidget(self.pushbutton)
self.hlayout.addWidget(self.combobox)
self.combobox.hide()
self.combobox_add_items()
self.pushbutton.clicked.connect(self.run)
def combobox_add_items(self):
self.combobox.clear()
layers = QgsProject.instance().layerTreeRoot().layerOrder()
self.combobox.addItems([layer.name() for layer in layers])
def tool_deactivated(self):
'''tool非激活状态'''
self.pushbutton.setChecked(False)
self.combobox.hide()
map_swipe_tool.py
import os
from PyQt5.QtCore import Qt, QPoint
from PyQt5.QtGui import QCursor, QPixmap
from qgis.gui import QgsMapTool
from qgis.core import QgsProject, QgsMapSettings, QgsMapRendererParallelJob
from .swipe_map import SwipeMap
class MapSwipeTool(QgsMapTool):
def __init__(self, plugin_path, combobox, iface):
super(MapSwipeTool, self).__init__(iface.mapCanvas())
self.combobox = combobox
self.map_canvas = iface.mapCanvas()
self.view = iface.layerTreeView()
self.swipe = SwipeMap(self.map_canvas)
self.hasSwipe = None
self.start_point = QPoint()
self.cursorSV = QCursor(QPixmap(os.path.join(plugin_path, 'images/split_v.png')))
self.cursorSH = QCursor(QPixmap(os.path.join(plugin_path, 'images/split_h.png')))
self.cursorUP = QCursor(QPixmap(os.path.join(plugin_path, 'images/up.png')))
self.cursorDOWN = QCursor(QPixmap(os.path.join(plugin_path, 'images/down.png')))
self.cursorLEFT = QCursor(QPixmap(os.path.join(plugin_path, 'images/left.png')))
self.cursorRIGHT = QCursor(QPixmap(os.path.join(plugin_path, 'images/right.png')))
def activate(self):
self.map_canvas.setCursor(QCursor(Qt.CrossCursor))
self._connect()
self.hasSwipe = False
self.setLayersSwipe()
def canvasPressEvent(self, e):
self.hasSwipe = True
direction = None
w, h = self.map_canvas.width(), self.map_canvas.height()
if 0.25 * w < e.x() < 0.75 * w and e.y() < 0.5 * h:
direction = 0 # '⬇'
self.swipe.isVertical = False
if 0.25 * w < e.x() < 0.75 * w and e.y() > 0.5 * h:
direction = 1 # '⬆'
self.swipe.isVertical = False
if e.x() < 0.25 * w:
direction = 2 # '➡'
self.swipe.isVertical = True
if e.x() > 0.75 * w:
direction = 3 # '⬅'
self.swipe.isVertical = True
self.swipe.set_direction(direction)
self.map_canvas.setCursor(self.cursorSH if self.swipe.isVertical else self.cursorSV)
self.swipe.set_img_extent(e.x(), e.y())
def canvasReleaseEvent(self, e):
self.hasSwipe = False
self.canvasMoveEvent(e)
# 鼠标释放后，移除绘制的线
self.swipe.set_img_extent(-9999, -9999)
def canvasMoveEvent(self, e):
if self.hasSwipe:
self.swipe.set_img_extent(e.x(), e.y())
else:
# 设置当前cursor
w, h = self.map_canvas.width(), self.map_canvas.height()
if e.x() < 0.25 * w:
self.canvas().setCursor(self.cursorRIGHT)
if e.x() > 0.75 * w:
self.canvas().setCursor(self.cursorLEFT)
if 0.25 * w < e.x() < 0.75 * w and e.y() < 0.5 * h:
self.canvas().setCursor(self.cursorDOWN)
if 0.25 * w < e.x() < 0.75 * w and e.y() > 0.5 * h:
self.canvas().setCursor(self.cursorUP)
def _connect(self, isConnect=True):
signal_slot = (
{'signal': self.map_canvas.mapCanvasRefreshed, 'slot': self.setMap},
{'signal': self.combobox.currentIndexChanged, 'slot': self.setLayersSwipe},
{'signal': QgsProject.instance().removeAll, 'slot': self.disable}
)
if isConnect:
for item in signal_slot:
item['signal'].connect(item['slot'])
else:
for item in signal_slot:
item['signal'].disconnect(item['slot'])
def setLayersSwipe(self, ):
current_layer = QgsProject.instance().mapLayersByName(self.combobox.currentText())
if len(current_layer) == 0:
return
layers = QgsProject.instance().layerTreeRoot().layerOrder()
layer_list = []
for layer in layers:
if layer.id() == current_layer[0].id():
continue
layer_list.append(layer)
self.swipe.clear()
self.swipe.setLayersId(layer_list)
self.setMap()
def disable(self):
self.swipe.clear()
self.hasSwipe = False
def deactivate(self):
self.deactivated.emit()
self.swipe.clear()
self._connect(False)
def setMap(self):
def finished():
self.swipe.setContent(job.renderedImage(), self.map_canvas.extent())
if len(self.swipe.layers) == 0:
return
settings = QgsMapSettings(self.map_canvas.mapSettings())
settings.setLayers(self.swipe.layers)
job = QgsMapRendererParallelJob(settings)
job.start()
job.finished.connect(finished)
job.waitForFinished()
MapSwipeTool继承了QgsMapTool类，重新实现了activate、deactivate、canvasPressEvent、canvasReleaseEvent、canvasMoveEvent方法，还用到了QgsMapRendererParallelJob类，QgsMapRendererParallelJob是QGIS提供的并行绘图类，不做详解，下面对重新实现的方法详细说明:
active
工具激活后执行此函数
deactivate
工具非激活状态执行此函数
canvasPressEvent
def canvasPressEvent(self, e):
self.hasSwipe = True
direction = None
w, h = self.map_canvas.width(), self.map_canvas.height()
if 0.25 * w < e.x() < 0.75 * w and e.y() < 0.5 * h:
direction = 0 # '⬇'
self.swipe.isVertical = False
if 0.25 * w < e.x() < 0.75 * w and e.y() > 0.5 * h:
direction = 1 # '⬆'
self.swipe.isVertical = False
if e.x() < 0.25 * w:
direction = 2 # '➡'
self.swipe.isVertical = True
if e.x() > 0.75 * w:
direction = 3 # '⬅'
self.swipe.isVertical = True
self.swipe.set_direction(direction)
self.map_canvas.setCursor(self.cursorSH if self.swipe.isVertical else self.cursorSV)
self.swipe.set_img_extent(e.x(), e.y())
画布的鼠标按压事件，将画布分为四个部分，获得卷帘的方向，然后设置鼠标光标，具体实现方式自行脑补，原理如下图：
canvasReleaseEvent
def canvasReleaseEvent(self, e):
self.hasSwipe = False
self.canvasMoveEvent(e)
# 鼠标释放后，移除绘制的线
self.swipe.set_img_extent(-9999, -9999)
画布的鼠标释放事件，鼠标释放后要把绘制的线移出画布
self.swipe.set_img_extent(-9999, -9999)
canvasMoveEvent
def canvasMoveEvent(self, e):
if self.hasSwipe:
self.swipe.set_img_extent(e.x(), e.y())
else:
# 设置当前cursor
w, h = self.map_canvas.width(), self.map_canvas.height()
if e.x() < 0.25 * w:
self.canvas().setCursor(self.cursorRIGHT)
if e.x() > 0.75 * w:
self.canvas().setCursor(self.cursorLEFT)
if 0.25 * w < e.x() < 0.75 * w and e.y() < 0.5 * h:
self.canvas().setCursor(self.cursorDOWN)
if 0.25 * w < e.x() < 0.75 * w and e.y() > 0.5 * h:
self.canvas().setCursor(self.cursorUP)
画布的鼠标移动事件，当使用卷帘时，获得鼠标的位置（e.x(),e.y()），当不使用卷帘时，根据鼠标的位置设置鼠标的光标形状，原理与canvasPressEvent相同
swipe_map.py
from PyQt5.QtCore import QRectF, QPointF, Qt
from PyQt5.QtGui import QPen, QColor
from qgis.gui import QgsMapCanvasItem
class SwipeMap(QgsMapCanvasItem):
def __init__(self, canvas):
super(SwipeMap, self).__init__(canvas)
self.length = 0
self.isVertical = True
self.layers = []
self.is_paint = False
def setContent(self, image, rect):
self.copyimage = image
self.setRect(rect)
def clear(self):
del self.layers[:]
self.is_paint = False
def setLayersId(self, layers):
del self.layers[:]
for item in layers:
self.layers.append(item)
def set_direction(self, direction):
# 0:'⬇', 1:'⬆', 2:'➡', 3:'⬅'
if direction == 0:
self.direction = 0
elif direction == 1:
self.direction = 1
elif direction == 2:
self.direction = 2
else:
self.direction = 3
self.startx, self.starty, self.endx, self.endy = 0, 0, self.boundingRect().width(), self.boundingRect().height()
def set_img_extent(self, x, y):
self.x = x
self.y = y
if self.direction == 0: # 0:'⬇'
self.endy = y
elif self.direction == 1: # 1:'⬆'
self.starty = y
elif self.direction == 2: # 2:'➡'
self.endx = x
else: # 3:'⬅'
self.startx = x
self.is_paint = True
self.update()
def paint(self, painter, *args):
if len(self.layers) == 0 or self.is_paint == False:
return
w = self.boundingRect().width()
h = self.boundingRect().height()
pen = QPen(Qt.DashDotDotLine)
pen.setColor(QColor(18, 150, 219))
pen.setWidth(4)
if self.isVertical:
painter.setPen(pen)
painter.drawLine(QPointF(self.x, 0), QPointF(self.x, h))
else:
painter.setPen(pen)
painter.drawLine(QPointF(0, self.y), QPointF(w, self.y))
image = self.copyimage.copy(self.startx, self.starty, self.endx, self.endy)
painter.drawImage(QRectF(self.startx, self.starty, self.endx, self.endy), image)
此模块为绘制地图模块，首先获得绘制地图的范围
self.startx, self.starty, self.endx, self.endy = 0, 0, self.boundingRect().width(), self.boundingRect().height()
然后重写绘制函数paint
def paint(self, painter, *args):
if len(self.layers) == 0 or self.is_paint == False:
return
w = self.boundingRect().width()
h = self.boundingRect().height()
pen = QPen(Qt.DashDotDotLine)
pen.setColor(QColor(18, 150, 219))
pen.setWidth(4)
if self.isVertical:
painter.setPen(pen)
painter.drawLine(QPointF(self.x, 0), QPointF(self.x, h))
else:
painter.setPen(pen)
painter.drawLine(QPointF(0, self.y), QPointF(w, self.y))
image = self.copyimage.copy(self.startx, self.starty, self.endx, self.endy)
painter.drawImage(QRectF(self.startx, self.starty, self.endx, self.endy), image)
实现结果
参考链接：https://plugins.qgis.org/plugins/mapswipetool_plugin/
转载自：https://blog.csdn.net/this_is_id/article/details/82907585
