如何捕捉QGraphicsTextItem网格？

Question

如何捕捉QGraphicsTextItem网格？

BPL*_*BPL 6 python pyqt python-3.x pyqt5

让这个小片段:

import sys
from PyQt5 import QtWidgets
from PyQt5 import QtCore
from PyQt5 import QtGui
from PyQt5.QtWidgets import QMenu
from PyQt5.QtGui import QKeySequence
from PyQt5.QtCore import Qt
from PyQt5.QtGui import QCursor
from PyQt5.QtWidgets import QGraphicsObject
from PyQt5.QtCore import QRectF
from PyQt5.QtGui import QBrush
from PyQt5.QtCore import QPoint
from PyQt5.QtGui import QLinearGradient
from PyQt5.QtGui import QColor
from PyQt5.QtGui import QPen
from PyQt5.QtGui import QPainter
from PyQt5.QtWidgets import QGraphicsTextItem
from PyQt5.QtWidgets import QGraphicsItem


def create_action(parent, text, slot=None,
                  shortcut=None, shortcuts=None, shortcut_context=None,
                  icon=None, tooltip=None,
                  checkable=False, checked=False):
    action = QtWidgets.QAction(text, parent)

    if icon is not None:
        action.setIcon(QIcon(':/%s.png' % icon))
    if shortcut is not None:
        action.setShortcut(shortcut)
    if shortcuts is not None:
        action.setShortcuts(shortcuts)
    if shortcut_context is not None:
        action.setShortcutContext(shortcut_context)
    if tooltip is not None:
        action.setToolTip(tooltip)
        action.setStatusTip(tooltip)
    if checkable:
        action.setCheckable(True)
    if checked:
        action.setChecked(True)
    if slot is not None:
        action.triggered.connect(slot)

    return action


class Settings():

    WIDTH = 20
    HEIGHT = 15
    NUM_BLOCKS_X = 32
    NUM_BLOCKS_Y = 16


class CI(QGraphicsTextItem):

    def __init__(self, text, pos):
        QGraphicsTextItem.__init__(self)

        self.content = text
        self.setPlainText(text)

        self.setPos(pos)
        self.setTextInteractionFlags(Qt.TextEditorInteraction)
        self.setDefaultTextColor(Qt.black)
        self.setFlags(
            self.flags() | QGraphicsItem.ItemIsMovable | QGraphicsItem.ItemIsSelectable)
        self.setZValue(-1)

    def paint(self, painter, option, widget):
        painter.save()
        painter.setBrush(QBrush(Qt.white))
        painter.drawRect(self.boundingRect())
        painter.restore()

        super().paint(painter, option, widget)

    def keyPressEvent(self, event):
        super().keyPressEvent(event)
        self.content = self.toPlainText()

    def focusInEvent(self, event):
        self.scene().writing_comment = True
        # self.setPlainText(self.content)
        # print("Focusinevent")

    def focusOutEvent(self, event):
        self.scene().writing_comment = False
        # self.setHtml(self.content)
        # print("FocusOutevent")

    def contextMenuEvent(self, scme):
        super().contextMenuEvent(scme)


class QS(QtWidgets.QGraphicsScene):

    def __init__(self, *args, **kwargs):
        super().__init__(*args, **kwargs)

        width = Settings.NUM_BLOCKS_X * Settings.WIDTH
        height = Settings.NUM_BLOCKS_Y * Settings.HEIGHT
        self.setSceneRect(0, 0, width, height)
        self.setItemIndexMethod(QtWidgets.QGraphicsScene.NoIndex)

        pos = QPoint(
            5 * Settings.WIDTH,
            2 * Settings.HEIGHT
        )
        content = """<!DOCTYPE html>
<html>
<body>

<h1>This is heading 1</h1>
<h2>This is heading 2</h2>
<h3>This is heading 3</h3>
<h4>This is heading 4</h4>
<h5>This is heading 5</h5>
<h6>This is heading 6</h6>

</body>
</html>
"""
        self.addItem(CI(content, pos))


class QV(QtWidgets.QGraphicsView):

    def __init__(self, *args, **kwargs):
        super().__init__(*args, **kwargs)

        self.view_menu = QMenu(self)
        self.create_actions()

    def create_actions(self):
        act = create_action(self.view_menu, "Zoom in",
                            slot=self.on_zoom_in,
                            shortcut=QKeySequence("+"), shortcut_context=Qt.WidgetShortcut)
        self.view_menu.addAction(act)

        act = create_action(self.view_menu, "Zoom out",
                            slot=self.on_zoom_out,
                            shortcut=QKeySequence("-"), shortcut_context=Qt.WidgetShortcut)
        self.view_menu.addAction(act)
        self.addActions(self.view_menu.actions())

    def on_zoom_in(self):
        if not self.scene():
            return

        self.scale(1.5, 1.5)

    def on_zoom_out(self):
        if not self.scene():
            return

        self.scale(1.0 / 1.5, 1.0 / 1.5)

    def drawBackground(self, painter, rect):
        painter.setRenderHint(QPainter.Antialiasing, True)

        gr = rect.toRect()
        start_x = gr.left() + Settings.WIDTH - (gr.left() % Settings.WIDTH)
        start_y = gr.top() + Settings.HEIGHT - (gr.top() % Settings.HEIGHT)
        painter.save()

        for index, x in enumerate(range(start_x, gr.right(), Settings.WIDTH)):
            if index == Settings.NUM_BLOCKS_X:
                painter.setPen(QtGui.QColor(255, 70, 80).lighter(90))
                painter.setOpacity(0.7)
            else:
                painter.setPen(QtGui.QColor(60, 70, 80).lighter(90))
                painter.setOpacity(0.7)

            painter.drawLine(x, gr.top(), x, gr.bottom())

        for index, y in enumerate(range(start_y, gr.bottom(), Settings.HEIGHT)):
            if index == Settings.NUM_BLOCKS_Y:
                painter.setPen(QtGui.QColor(255, 70, 80).lighter(90))
                painter.setOpacity(0.7)
            else:
                painter.setPen(QtGui.QColor(60, 70, 80).lighter(90))
                painter.setOpacity(0.7)

            painter.drawLine(gr.left(), y, gr.right(), y)

        painter.restore()

        super().drawBackground(painter, rect)


if __name__ == '__main__':
    app = QtWidgets.QApplication(sys.argv)

    a = QS()
    b = QV()
    b.setScene(a)
    print(b.mapToScene(b.rect()))
    b.show()
    sys.exit(app.exec_())

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如果我们运行它,我们会看到它正在创建一个带有网格和QGraphicsTextItem的小场景,如下所示:

我想弄清楚的是如何在每次移动或调整大小时将QGraphicsTextItem捕捉到网格交叉点上(当我写一些文本时),我该如何保证？这是一张小图片,可以更好地解释我想要的东西:

Answer 1

a_m*_*_67 5

要设置QGraphicsTextItem您可以覆盖的新宽度和高度boundingRect()，setPos()您可以使用任何适当的事件，MouseReleaseEvent或者MouseMoveEvent例如，从最后一个计算下一个左上角的网格交点pos()：

class CI(QGraphicsTextItem):

    def __init__(self, text, pos):
        QGraphicsTextItem.__init__(self)

        self.content = text
        self.setPlainText(text)

        self.setPos(pos)
        self.setTextInteractionFlags(Qt.TextEditorInteraction)
        self.setDefaultTextColor(Qt.black)
        self.setFlags(
            self.flags() | QGraphicsItem.ItemIsMovable | QGraphicsItem.ItemIsSelectable)
        self.setZValue(-1)

    def boundingRect(self):     
        # get the original width and height of boundingrect
        br = QGraphicsTextItem.boundingRect(self)
        brw = br.width()
        brh = br.height()
        # new width and height in "blocks"
        wblocks = int(brw/Settings.WIDTH) + 1
        hblocks = int(brh/Settings.HEIGHT) + 1
        w = wblocks*Settings.WIDTH
        h = hblocks*Settings.HEIGHT
        return QtCore.QRectF(0, 0, w, h)

    def mouseReleaseEvent(self, event):                         
        # QGraphicsItem.mouseReleaseEvent(self, event)
        QGraphicsTextItem.mouseReleaseEvent(self, event)
        self.setGridIntersection(self.pos())

    def mouseMoveEvent(self, event):
        QGraphicsTextItem.mouseMoveEvent(self, event)
        self.setGridIntersection(self.pos())

    def setGridIntersection(self, pos):
        # get the next grid intersection top left of items top-left corner
        grid_x = int(pos.x()/Settings.WIDTH)                        
        grid_y = int(pos.y()/Settings.HEIGHT)
        self.setPos(grid_x*Settings.WIDTH, grid_y*Settings.HEIGHT)

    def paint(self, painter, option, widget):
        painter.save()
        painter.setBrush(QBrush(Qt.white))
        painter.drawRect(self.boundingRect())
        painter.restore()

        super().paint(painter, option, widget)

    def keyPressEvent(self, event):
        super().keyPressEvent(event)
        self.content = self.toPlainText()

    def focusInEvent(self, event):
        self.scene().writing_comment = True
        # self.setPlainText(self.content)
        # print("Focusinevent")

    def focusOutEvent(self, event):
        self.scene().writing_comment = False
        # self.setHtml(self.content)
        # print("FocusOutevent")

    def contextMenuEvent(self, scme):
        super().contextMenuEvent(scme)

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17 年 2 月 1 日编辑：上述解决方案仅适用于单选，单选和多选均可使用：

class CI(QGraphicsTextItem):

    def __init__(self, text, pos):
        QGraphicsTextItem.__init__(self)

        self.content = text
        self.setPlainText(text)

        self.setPos(pos)
        self.setTextInteractionFlags(Qt.TextEditorInteraction)
        self.setDefaultTextColor(Qt.black)
        self.setFlags(
            self.flags() | QGraphicsItem.ItemIsMovable | QGraphicsItem.ItemIsSelectable)
        self.setZValue(-1)
        self.setAcceptDrops(True)

    def boundingRect(self):
        # get the original width and height of boundingrect
        br = QGraphicsTextItem.boundingRect(self)
        brw = br.width()
        brh = br.height()
        # new width and height in "blocks"
        wblocks = int(brw / Settings.WIDTH) + 1
        hblocks = int(brh / Settings.HEIGHT) + 1
        w = wblocks * Settings.WIDTH
        h = hblocks * Settings.HEIGHT
        return QtCore.QRectF(0, 0, w, h)

    def setGridIntersection(self, pos):
        # get the next grid intersection top left of items top-left corner
        grid_x = int(pos.x() / Settings.WIDTH)
        grid_y = int(pos.y() / Settings.HEIGHT)
        self.setPos(grid_x * Settings.WIDTH, grid_y * Settings.HEIGHT)

    def paint(self, painter, option, widget):
        painter.save()
        painter.setBrush(QBrush(Qt.white))
        painter.drawRect(self.boundingRect())
        painter.restore()

        super().paint(painter, option, widget)

    def keyPressEvent(self, event):
        super().keyPressEvent(event)
        self.content = self.toPlainText()

    def focusInEvent(self, event):
        self.scene().writing_comment = True
        # self.setPlainText(self.content)
        # print("Focusinevent")

    def focusOutEvent(self, event):
        self.scene().writing_comment = False
        # self.setHtml(self.content)
        # print("FocusOutevent")

    def contextMenuEvent(self, scme):
        super().contextMenuEvent(scme)

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并在 QS 类中添加：

    def mouseMoveEvent(self, event):
        QtWidgets.QGraphicsScene.mouseMoveEvent(self, event)
        for i in self.selectedItems():
            if type(i) == CI:
                i.setGridIntersection(i.pos())

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