问题[qt](coding)

我想放大 QGraphicsView，以便鼠标下的场景位置保持在鼠标下。以下代码实现了这一点：

from PySide6.QtCore import QPoint
from PySide6.QtWidgets import QGraphicsView, QGraphicsScene, QApplication
import math

class MyGraphicsView(QGraphicsView):
    def wheelEvent(self, event):
        self.setTransformationAnchor(self.ViewportAnchor.AnchorUnderMouse)
        self.setResizeAnchor(self.ViewportAnchor.AnchorUnderMouse)
        if event.angleDelta().y() > 0:
            self.scale(1.1, 1.1)
        elif event.angleDelta().y() < 0:
            self.scale(1 / 1.1, 1 / 1.1)
        self.setTransformationAnchor(self.ViewportAnchor.NoAnchor)
        self.setResizeAnchor(self.ViewportAnchor.NoAnchor)


class MyTestScene(QGraphicsScene):
    def drawBackground(self, painter, rect, PySide6_QtCore_QRectF=None, PySide6_QtCore_QRect=None):
        left = int(math.floor(rect.left()))
        top = int(math.floor(rect.top()))
        right = int(math.ceil(rect.right()))
        bottom = int(math.ceil(rect.bottom()))
        first_left = left - (left % 100)
        first_top = top - (top % 100)

        for x in range(first_left, right + 1, 100):
            for y in range(first_top, bottom + 1, 100):
                painter.drawEllipse(QPoint(x, y), 2.5, 2.5)
                painter.drawText(x, y, f"{x},{y}")


if __name__ == '__main__':
    app = QApplication([])
    scene = MyTestScene()
    scene.setSceneRect(-2000, -2000, 4000, 4000)
    view = MyGraphicsView()
    view.setScene(scene)
    view.setGeometry(100, 100, 900, 600)
    view.setVisible(True)
    # view.setInteractive(False)
    app.exec()

此代码存在以下问题：

• 如果用户在第一次尝试使用滚轮缩放之前单击了视图（并且该视图是“交互式的”），则一切都会按预期工作。
• 如果不是，在第一个滚轮事件中，场景会“跳跃”（除了正确缩放之外，还会平移），以便 (0, 0) 位于鼠标下方。此后，一切都按预期运行。
• 如果视图设置为“非交互式”，场景就会“跳跃”，使得每次滚轮事件发生时 (0, 0) 都位于鼠标下方。

有人能解释一下这种行为吗？我遗漏了什么吗？或者这是 Qt 中的一个错误？

我尝试在 python 3.12.4 下使用 PySide 6.7.2，并在 python 3.13.1 下使用 PySide 6.8.1（均在 Windows 上），结果相同。

我使用QPainterdrawPixmap() 绘制了一幅图像，结果如下图B所示。

然后，我在 Windows 提供的图像查看器程序中打开同一张图片，并将其放大得更小，如下图A所示。

明显B比A大，但是没有A清晰，B有明显的混叠。

我尝试了setRenderHint(QPainter::Antialiasing)一下setRenderHint(QPainter::SmoothPixmapTransform)，有一定的效果，但不足以解决问题。

我尝试了不同的方式来显示同一幅图像（OpenGL、webEngine、QPainter.drawPixmap、graphicsView），结果各不相同，但它们的质量都低于 Windows 内置图像查看器。

我不认为这是图像清晰度的问题。当我使用 drawPixmap() 绘制图像并调用 QPainter 的 scale() 方法将其放大时，我可以看到图像的细节。

有人知道如何在 Qt 中绘制与内置 Windows 软件清晰度相同的图像吗？即使我缩小图像，我也想避免混叠问题。

- 编辑 -

最小可重现演示：

// canvaswidget.h
#ifndef CANVASWIDGET_H
#define CANVASWIDGET_H

#include <QWidget>

class CanvasWidget : public QWidget
{
    Q_OBJECT
public:
    explicit CanvasWidget(QImage img, QWidget *parent = nullptr);
    void zoomIn();
    void zoomOut();

signals:

protected:
    QSize sizeHint();
    void paintEvent(QPaintEvent *event) override;
    void wheelEvent(QWheelEvent *event) override;

private:
    qreal scale;
    QPixmap pixmap;
};

#endif // CANVASWIDGET_H

// canvaswidget.cpp
#include "canvaswidget.h"
#include <QWheelEvent>
#include <QPainter>
#include <QPixmap>

CanvasWidget::CanvasWidget(QImage img, QWidget *parent)
    : QWidget{parent}, scale(1.0)
{
    // make sure high resolution source
    pixmap = QPixmap::fromImage(img.scaled(img.size() * 10, Qt::KeepAspectRatio, Qt::SmoothTransformation));
}

void CanvasWidget::zoomIn() {
    scale = fmin(scale + 0.1, 10);
    update();
}

void CanvasWidget::zoomOut() {
    scale = fmax(scale - 0.1, 0.1);
    update();
}

void CanvasWidget::paintEvent(QPaintEvent *event) {
    if(!pixmap) {
        return QWidget::paintEvent(event);
    }
    QPainter p(this);

    p.setRenderHint(QPainter::Antialiasing);
    p.setRenderHint(QPainter::SmoothPixmapTransform);
    p.drawPixmap(0,0,width() * scale,height() * scale, pixmap); // draw image
}

void CanvasWidget::wheelEvent(QWheelEvent *event)
{

    if(event->modifiers() == Qt::ControlModifier) {
        QPointF delta = event->angleDelta();
        int v_delta = delta.y();
        if(v_delta > 0) {
            zoomIn();
        } else {
            zoomOut();
        }
        update();
        adjustSize();
    } else {
        QWidget::wheelEvent(event);
    }
}
QSize CanvasWidget::sizeHint()
{
    return QSize(800,800);
}

下图左侧为本次演示的结果，右侧为Windows内置的图像查看器。

--- 编辑 2 ---

这是我在演示中使用的图像，它的格式是 PNG QImage::Format_ARGB32，大小是QSize(1541, 1188) 25KB

我正在 QPdfView 中显示 pdf 文档，并且需要在几页上的某些区域上绘制覆盖层。

我已经设法绘制了覆盖层，但我需要一些帮助来调整滚动时其位置的调整方式。

代码如下：

from PySide6.QtCore import QRectF
from PySide6.QtGui import QPainter, QColor
from PySide6.QtPdfWidgets import QPdfView
from PySide6.QtCore import Qt
from PySide6.QtPdf import QPdfDocument

class CustomPdfView(QPdfView):  
    def __init__(self, parent=None):
        super().__init__(parent)
        
        # Placeholder areas
        self.highlights: dict[int, list[QRectF]] = {
            i : [QRectF(150.0, 150.0, 300.0, 300.0)] for i in range(200)
            }

    def paintEvent(self, event):
        super().paintEvent(event)

        if self.document().status() == QPdfDocument.Status.Ready:

            current_page_number = self.pageNavigator().currentPage()

            if current_page_number in self.highlights.keys():
                painter = QPainter(self.viewport())
                painter.setRenderHint(QPainter.RenderHint.Antialiasing)
                painter.setBrush(QColor(255, 255, 0, 100))
                painter.setPen(Qt.PenStyle.NoPen)

                total_pages = self.document().pageCount()
                current_page_size = self.document().pagePointSize(current_page_number)
                viewport_size = self.viewport().size()
                
                scroll_bar = self.verticalScrollBar()
                max_scroll = scroll_bar.maximum()
                
                scroll_per_page = max_scroll / total_pages
                scroll_calculated = scroll_per_page * current_page_number
                
                for rect in self.highlights[current_page_number]:

                    h_diff = scroll_bar.value() - scroll_calculated
                    
                    scaled_rect = QRectF(
                        (rect.x() / current_page_size.width()) * viewport_size.width(),
                        rect.y() - h_diff,
                        (rect.width() / current_page_size.width()) * viewport_size.width(),
                        rect.height()
                    )
                    painter.drawRect(scaled_rect)

                painter.end()

在最好的情况下，我想知道当前页面在视口中呈现了多少像素，因此 h_diff 变为 page_height - 可见像素

我有下面列出的 QML 组件。我遇到的问题是，当我使用捏合区域缩放矩形时（我希望发生这种情况），该矩形的子文本也会被缩放（我不希望发生这种情况）。

是什么导致文本缩放？鉴于Text的scale属性已明确设置为1.0以及font.pointSize，我完全不明白文本为何会发生变化。

如何创建可扩展组件的文本，而文本本身不进行缩放？

QML代码：

import QtQuick 2

Rectangle {
    id: page
    width: 1000; height: 1000
    color: "black"

    Rectangle {
        id: image_boundary
        color: "green"
        width: 200
        height: 100
        x: (parent.width/2)-(image_boundary.width/2)
        y: (parent.height/2)-(image_boundary.height/2)

        onScaleChanged: {
            console.log("Scale changed:", scale)
        }

        PinchArea {
            anchors.fill: image_boundary
            property real initialScale: 1.0
            property real scale: 1.0
            id: pinch_area

            onPinchStarted: {
                initialScale = scale
            }

            onPinchUpdated: function(pinch) {
                scale = initialScale * pinch.scale
                console.log(scale)
                parent.scale = scale
            }
        }
        Text {
            text: "mumble mumble"
            font.pointSize: 10
            scale: 1.0
            color: "yellow"
            anchors.left: parent.right
        }
    }
}

我可以使用以下 Python 代码（使用 PySide6）运行它：

import sys
from pathlib import Path
from PySide6.QtQuick import QQuickView
from PySide6.QtCore import QUrl
from PySide6.QtGui import QGuiApplication


if __name__ == '__main__':

    #Set up the application window
    app = QGuiApplication(sys.argv)
    view = QQuickView()
    view.setResizeMode(QQuickView.SizeRootObjectToView)

    #Load the QML file
    qml_file = Path(__file__).parent / "test_qml_file.qml"
    view.setSource(QUrl.fromLocalFile(qml_file.resolve()))

    #Show the window
    if view.status() == QQuickView.Error:
        sys.exit(-1)
    view.show()

    #execute and cleanup
    app.exec()
    del view

我正在研究解码类似 HDLC 的协议，并从网上找到的一些代码开始（https://github.com/jarkko-hautakorpi/Arduhdlc）。以下代码是摘录，重点介绍我遇到的问题。它读取 QByteArray（来自串行），然后丢弃初始和最终帧边界字节，管理转义序列并检查 CRC

#include <QCoreApplication>
#include <QDebug>
#include "hdlc_qt.h"

#define FRAME_BOUNDARY_OCTET 0x7E
#define CONTROL_ESCAPE_OCTET 0x7D
#define INVERT_OCTET 0x20
QByteArray receive_frame_buffer;
quint16 frame_position;
quint16 frame_checksum;
bool escape_character;


bool hdlcFrameCRC_check(int frame_index);

void charReceiver(QByteArray dataArray)
{

    quint8 data = 0;
    qDebug() << "Received:\t"<<dataArray.toHex();
    for(QByteArray::iterator it = dataArray.begin(); it != dataArray.end(); it++) {
        data = (*it);
        //qDebug ("data: %x",data);
        /* Start flag or end flag */
        if(data == FRAME_BOUNDARY_OCTET) {

            qDebug("FRAME_BOUNDARY_OCTET: %x",data);
            qDebug() << "frame_position:"<<frame_position;
            if(escape_character == true) {
                escape_character = false;
            }
            /* Do CRC check if frame is valid */

            else if(  (frame_position >= 2) && (hdlcFrameCRC_check(frame_position)) )  {
                /* Call user defined function to handle HDLC frame */
                qDebug() << "ValidFrame"<<receive_frame_buffer.toHex();

            }
            qDebug() << "frame_buffer:\t"<<receive_frame_buffer.toHex();
            /* Reset all for next frame */
            frame_position = 0;
            frame_checksum = 0;
            receive_frame_buffer.clear();
            continue;

        }

        if(escape_character) {
            escape_character = false;
            data ^= INVERT_OCTET;
        } else if(data == CONTROL_ESCAPE_OCTET) {
            escape_character = true;
            continue;
        }
        //receive_frame_buffer[frame_position] = data;
        receive_frame_buffer.append(data); //changed to avoid compiler warning

        // qDebug ("rx_framebuf[%d] = %x",frame_position,receive_frame_buffer.at(frame_position));

        frame_position++;

        /* If we don't ever receive valid frame,
         * buffer will keep growing bigger and bigger.
         * Hard coded max size limit and then reset
         */
        if(frame_position >= 2048)
        {
            receive_frame_buffer.clear();
            frame_position = 0;
            frame_checksum = 0;
        }
    }
}

bool hdlcFrameCRC_check(int frame_index)
{
    /* frame = ...[CRC-LO] [CRC-HI] */
    quint16 crc_received = 0;
    crc_received = receive_frame_buffer[frame_index-1]; // msb
    crc_received = crc_received << 8;
    crc_received |= receive_frame_buffer[frame_index-2]; // lsb
    quint16 crc_calculated = qChecksum((const char*)receive_frame_buffer.constData(), frame_index-2);
    //crc_calculated = crc_calculated^0xFFFF;

    qDebug("CRC received:%x",crc_received);
    qDebug("CRC calculated:%x",crc_calculated);

    if(crc_received == crc_calculated) {
        return true;
    } else {
        return false;
    }
}

int main(int argc, char *argv[])
{
    QCoreApplication a(argc, argv);


    QByteArray test1 = QByteArray("\x7E\x08\x1A\x00\x00\x07\x2B\x08\x00\x08\x16\x00\x00\x08\x8E\x07\xF7\x22\x20\x7E",20);
    QByteArray test2 = QByteArray("\x7e\x08\x22\x00\x00\x07\x28\x08\x08\x08\x10\x00\x05\x08\x95\x07\xff\xf6\x41\x7e",20);
    QByteArray test3 = QByteArray("\x7e\x08\x22\x00\x00\x07\x21\x08\x09\x08\x10\x00\x07\x08\x8f\x08\x00\xe7\x89\x7e",20);
    QByteArray test4 = QByteArray("\x7e\x08\x0e\x00\x00\x07\x2f\x08\x07\x08\x1b\x00\x00\x08\x93\x07\xf8\x9a\xb1\x7e",20);
    QByteArray test5 = QByteArray("\x7e\x08\x27\x00\x00\x07\x27\x08\x0a\x08\x10\x00\x05\x08\x93\x07\xfd\x18\x53\x7e",20);

    QVector<QByteArray> test;
    test.push_back(test1);
    test.push_back(test2);
    test.push_back(test3);
    test.push_back(test4);
    test.push_back(test5);

    for(int i = 0; i < test.size();++i) {
        qDebug()<<"-------------------------------------------------------";
        qDebug()<<"Test #" << i+1<< ":\t "<< test[i].toHex();
        charReceiver(test[i]);

    }
    return a.exec();
}

我准备了一些测试，分别命名为 test1、...、test5，并发现它在 CRC 验证步骤中失败。问题是，在某些测试中，传递给方法的 CRC 序列是初始序列中不存在的序列。对于 test1，CRC 序列（“\x22\x20”）正确传递，而在 test2 中，方法接收的是“\xff\xf6”，而不是“\xf6\x41”，对于 test3 和 test4 也是如此，而 test5 是正确的。您有什么可能的解释和补救措施吗？

我为 QTreeView 创建了一个自定义模型。显示问题的完整最小代码如下。如果我向根节点添加一个新节点，通过单击“添加级别 1”，它就会显示。但是，如果我通过单击“添加级别 2”将新节点添加到第二级别，则它不会显示。仅当我折叠父节点然后再次展开它时，该节点才会显示。我的哪一部分MyTreeModel出了问题？

我添加了 QT 标签，即使我的代码是 PySide6，因为错误可能在于我对 QAbstractItemModel 方法的理解，这不是 Python 或 PySide 特有的东西。

完整代码

from __future__ import annotations
from typing import Optional

from PySide6.QtCore import QAbstractItemModel, QModelIndex
from PySide6.QtGui import Qt
from PySide6.QtWidgets import QApplication, QMainWindow, QWidget, QVBoxLayout, QPushButton, QHBoxLayout, QTreeView


class TreeNode:
    def __init__(self, name: str, parent_node):
        self.name = name
        self.parent_node = parent_node
        self.children: list[TreeNode] = []

    def get_child_by_name(self, name) -> Optional[TreeNode]:
        for child in self.children:
            if child.name == name:
                return child

        return None


class MyTreeModel(QAbstractItemModel):
    def __init__(self):
        super().__init__()
        self.root_node = TreeNode("root", None)

    def headerData(self, section, orientation, role=Qt.DisplayRole):
        if orientation == Qt.Horizontal and role == Qt.DisplayRole:
            return "Name"

    def rowCount(self, parentIndex):
        if not parentIndex.isValid():
            parentNode = self.root_node
        else:
            parentNode = parentIndex.internalPointer()

        return len(parentNode.children)

    def columnCount(self, parent):
        return 1

    def data(self, index, role):
        if not index.isValid():
            return None

        if role == Qt.DisplayRole:
            node: TreeNode = index.internalPointer()
            column = index.column()
            match column:
                case 0:
                    return node.name
                case _:
                    return None
        else:
            return None

    def parent(self, index):
        if not index.isValid():
            return QModelIndex()

        childNode: TreeNode = index.internalPointer()
        parentNode = childNode.parent_node

        if parentNode == self.root_node:
            return QModelIndex()

        row_within_parent = parentNode.children.index(childNode)

        return self.createIndex(row_within_parent, 0, parentNode);

    def index(self, row, column, parentIndex):
        if not self.hasIndex(row, column, parentIndex):
            return QModelIndex()

        if not parentIndex.isValid():
            parentNode = self.root_node
        else:
            parentNode = parentIndex.internalPointer()

        child_node = parentNode.children[row]
        if child_node:
            return self.createIndex(row, column, child_node)
        else:
            return QModelIndex()

    def set_data(self, data: []):
        self.beginResetModel()
        self.apply_data(data)
        self.endResetModel()

    def update_data(self, data: []):
        self.apply_data(data, True)

    def apply_data(self, data, notify=False):
        for item in data:
            parent_node = self.root_node;
            for part in item.split("/"):
                existing = parent_node.get_child_by_name(part)
                if existing:
                    parent_node = existing
                else:
                    if notify:
                        parent_index = self.get_index(parent_node)
                        count = len(parent_node.children)
                        self.beginInsertRows(parent_index, count, count)

                    new_node = TreeNode(part, parent_node)
                    parent_node.children.append(new_node)
                    parent_node = new_node

                    if notify:
                        self.endInsertRows()

    def get_index(self, node: TreeNode):
        if not node.parent_node:
            return QModelIndex()

        row = node.parent_node.children.index(node)
        return self.createIndex(row, 0, node.parent_node)


class MainWindow(QMainWindow):
    def __init__(self):
        super().__init__()
        self.resize(600, 400)

        button1 = QPushButton("Add Level 1")
        button1.clicked.connect(self.add1)
        button2 = QPushButton("Add Level 2")
        button2.clicked.connect(self.add2)

        row1 = QHBoxLayout()
        row1.setAlignment(Qt.AlignLeft)
        row1.addWidget(button1)
        row1.addWidget(button2)

        self.tree_view = QTreeView()

        layout = QVBoxLayout()
        layout.addLayout(row1)
        layout.addWidget(self.tree_view, stretch=1)

        self.central_widget = QWidget()
        self.central_widget.setLayout(layout)
        self.setCentralWidget(self.central_widget)

    def showEvent(self, event):
        data = ["mammals", "birds", "mammals/dog", "birds/eagle", "mammals/cat"]

        my_model = MyTreeModel()
        my_model.set_data(data)
        self.tree_view.setModel(my_model)
        self.tree_view.expandAll()

    def add1(self):
        data = ["reptiles"]
        m = self.tree_view.model()
        m.update_data(data)

    def add2(self):
        data = ["mammals/rat"]
        m = self.tree_view.model()
        m.update_data(data)


app = QApplication([])
win = MainWindow()
win.show()
app.exec()

在 Qt 5 中，假设有以下自定义小部件：

class QMeow final :
    public QWidget
{
public:
    explicit QMeow()
    {
        this->setSizePolicy(QSizePolicy::Expanding, QSizePolicy::Expanding);
        this->setFocusPolicy(Qt::StrongFocus);
    }

protected:
    void keyPressEvent(QKeyEvent * const event) override
    {
        _s = !_s;
        this->update();
        QWidget::keyPressEvent(event);
    }

    void paintEvent(QPaintEvent *) override
    {
        QPainter painter {this};

        painter.fillRect(this->rect(), QColor {_s ? "red" : "blue"});
    }

private:
    bool _s = false;
};

当按下任意键时，此小部件的实例会在红色和蓝色之间更改其背景颜色。

现在，让我们创建一个窗口并添加 aQLineEdit和 a ，并使用快捷键AQMeow设置操作：

QApplication app {argc, argv};
QWidget window;
QVBoxLayout layout {&window};

layout.addWidget(new QLineEdit);
layout.addWidget(new QMeow);

QAction action {"hello"};

action.setShortcut(Qt::Key_A);
window.addAction(&action);

window.show();
app.exec();

如果您尝试这样做，您会注意到：

• 当QLineEdit小部件获得焦点时，它会处理所有键，包括小写A，并将其添加到渲染的文本中。
• 当QMeow小部件获得焦点时，它会处理除小写A之外的所有键，这表明操作会处理它。

如何QMeow::keyPressEvent()调用任何键，包括操作快捷键，例如QLineEdit？

我尝试了QWidget::grabKeyboard()不同的焦点策略，但qlineedit.cpp没有成功。

我正在尝试在 Qt Creator 中创建一个新的 Qt Quick 应用程序。然而，每次我尝试构建该项目时，它甚至在执行任何操作之前都会立即失败。

/PATH/QMLTest/ds-subbuild/ds-populate-prefix/tmp/ds-populate-gitclone.cmake:39: error: Failed to clone repository:  
'https://code.qt.io/qt-labs/qtquickdesigner-components.git'  
:-1: error: ninja: build stopped: subcommand failed.  
/PATH/QMLTest/CMakeLists.txt:32: error: Build step for ds failed: 1

Call stack:  
  /PATH/QMLTest/CMakeLists.txt:32 (include)  
  /PATH/QMLTest/qmlcomponents:16 (FetchContent_Populate)  
  /opt/homebrew/Cellar/cmake/3.28.3/share/cmake/Modules/FetchContent.cmake:1819 (cmake_language)  
  /opt/homebrew/Cellar/cmake/3.28.3/share/cmake/Modules/FetchContent.cmake:1819:EVAL:2 (__FetchContent_directPopulate)  
  /opt/homebrew/Cellar/cmake/3.28.3/share/cmake/Modules/FetchContent.cmake:1679 (message)  
:-1: error: CMake process exited with exit code 1.  
:-1: error: CMake project configuration failed. No CMake configuration for build type "Debug" found.

克隆存储库似乎存在一些问题https://code.qt.io/qt-labs/qtquickdesigner-components.git，我什至无法使用浏览器访问它。我不知道该怎么做才能解决这个问题。如果您需要更多信息，请告诉我。

这是终端构建输出：

$ cmake -S '/PATH/FirstQML' -B /PATH/Qt/Builds/build-FirstQML-Qt_6_6_1_for_macOS-Debug
-- The CXX compiler identification is AppleClang 15.0.0.15000100
-- Detecting CXX compiler ABI info
-- Detecting CXX compiler ABI info - done
-- Check for working CXX compiler: /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/clang++ - skipped
-- Detecting CXX compile features
-- Detecting CXX compile features - done
Building designer components.
[1/9] Creating directories for 'ds-populate'
[1/9] Performing download step (git clone) for 'ds-populate'
Cloning into 'ds-src'...
fatal: unable to access 'https://code.qt.io/qt-labs/qtquickdesigner-components.git/': Failed to connect to code.qt.io port 443 after 75 ms: Couldn't connect to server
Cloning into 'ds-src'...
fatal: unable to access 'https://code.qt.io/qt-labs/qtquickdesigner-components.git/': Failed to connect to code.qt.io port 443 after 74 ms: Couldn't connect to server
Cloning into 'ds-src'...
fatal: unable to access 'https://code.qt.io/qt-labs/qtquickdesigner-components.git/': Failed to connect to code.qt.io port 443 after 73 ms: Couldn't connect to server
-- Had to git clone more than once: 3 times.
CMake Error at ds-subbuild/ds-populate-prefix/tmp/ds-populate-gitclone.cmake:39 (message):
  Failed to clone repository:
  'https://code.qt.io/qt-labs/qtquickdesigner-components.git'


FAILED: ds-populate-prefix/src/ds-populate-stamp/ds-populate-download /PATH/Qt/Builds/build-FirstQML-Qt_6_6_1_for_macOS-Debug/_deps/ds-subbuild/ds-populate-prefix/src/ds-populate-stamp/ds-populate-download 
cd /PATH/Qt/Builds/build-FirstQML-Qt_6_6_1_for_macOS-Debug/_deps && /opt/homebrew/Cellar/cmake/3.28.3/bin/cmake -P /PATH/Qt/Builds/build-FirstQML-Qt_6_6_1_for_macOS-Debug/_deps/ds-subbuild/ds-populate-prefix/tmp/ds-populate-gitclone.cmake && /opt/homebrew/Cellar/cmake/3.28.3/bin/cmake -E touch /PATH/Qt/Builds/build-FirstQML-Qt_6_6_1_for_macOS-Debug/_deps/ds-subbuild/ds-populate-prefix/src/ds-populate-stamp/ds-populate-download
ninja: build stopped: subcommand failed.

CMake Error at /opt/homebrew/Cellar/cmake/3.28.3/share/cmake/Modules/FetchContent.cmake:1679 (message):
  Build step for ds failed: 1
Call Stack (most recent call first):
  /opt/homebrew/Cellar/cmake/3.28.3/share/cmake/Modules/FetchContent.cmake:1819:EVAL:2 (__FetchContent_directPopulate)
  /opt/homebrew/Cellar/cmake/3.28.3/share/cmake/Modules/FetchContent.cmake:1819 (cmake_language)
  qmlcomponents:16 (FetchContent_Populate)
  CMakeLists.txt:32 (include)


-- Configuring incomplete, errors occurred!

感谢任何有助于解决此问题的帮助或提示。提前致谢！

在此代码部分中，我创建了内部包含窗口和矩形的简单示例。我为矩形设置 x = 100 和 y = 100 内部坐标。当我将这些坐标映射到全局并得到不正确的结果时，坐标总是比实际坐标多 2 倍。例如，如果我将 x 和 y 设置为 50，则结果将为 50*2 = 100。为什么会出现错误？我该如何修复它？

    import QtQuick 2.15
    import QtQuick.Window 2.15
    
    Window {
        id: root
    
        width: 640; height: 480; visible: true;
        title: qsTr("Hello World")
        onXChanged: innerRect.globalChanged();
        onYChanged: innerRect.globalChanged()
        onWidthChanged: innerRect.globalChanged();
        onHeightChanged: innerRect.globalChanged()
    
        Rectangle {
            id: innerRect
    
            signal globalChanged()
            property point globalPoint
            onGlobalChanged: {
                innerRect.globalPoint = mapToGlobal(innerRect.x, innerRect.y)
            }
            color: "yellow"
            width: parent.width / 2; height: parent.height / 2
    
            x: 100; y: 100
    
            Text {
                id: xCoord
    
                anchors.left: parent.left;
                anchors.leftMargin: 20
                anchors.verticalCenter: parent.verticalCenter
                text: "Gx: " + innerRect.globalPoint.x + " Wx: " + root.x
            }
            Text {
                id: yCoord
    
                anchors.right: parent.right;
                anchors.rightMargin: 20
                anchors.verticalCenter: parent.verticalCenter
                text: "Gy: " + innerRect.globalPoint.y + " Wy: " + root.y
            }
        }
    }

我目前正在使用 Qt6 开发 GUI。我想使用样式表创建自定义垂直滑块。我希望滑块的底部（手柄正下方）具有不同的颜色，但是当我尝试操作滑块样式表的“添加页面”部分时，宽度不再恒定，如下所示：

我希望滑块的凹槽区域的宽度在手柄的顶部和下方保持不变。到目前为止，这是我的代码：

QSlider:vertical
{
  min-height: 100px;
  min-width: 20px;
  background: none;
}
QSlider::groove:vertical
{
  background: rgb(43, 43, 43); 
  border: 1px solid rgb(43, 43, 43); 
  border-radius: 2px;
  width: 4px;
  margin: 0px 17px;
}
QSlider::handle:vertical
{
  background: white;
  border: 1px solid white;
  border-radius: 3px;
  top: 14px;
  bottom: 14px;
  margin: -15px -7px;
  min-width: 30px;
  min-height: 30px;
}
QSlider::add-page:vertical
{
  background: white;
}

当我从样式表中删除添加页面部分时，滑块如下所示：

正如你所看到的，底部不再是白色的，但宽度现在看起来确实不错。