在 PyQt5 界面中显示 PDF

在 PyQt5 界面中显示 PDF（使用 PyMuPDF）

以下是将 PyMuPDF 渲染的 PDF 页面显示在 PyQt5 界面中的完整实现方案：

1. 基础实现：使用 QLabel 显示 PDF 页面

import fitz
from PyQt5.QtWidgets import QApplication, QMainWindow, QLabel, QScrollArea, QVBoxLayout, QWidget
from PyQt5.QtGui import QPixmap, QImage
from PyQt5.QtCore import Qt

class PdfViewer(QMainWindow):
    def __init__(self):
        super().__init__()
        self.setWindowTitle("PDF 查看器 (PyMuPDF)")
        self.setGeometry(100, 100, 800, 600)
        
        # 主部件和布局
        central_widget = QWidget()
        self.setCentralWidget(central_widget)
        layout = QVBoxLayout(central_widget)
        
        # 创建滚动区域
        self.scroll_area = QScrollArea()
        self.scroll_area.setWidgetResizable(True)
        
        # 用于显示PDF的标签
        self.pdf_label = QLabel()
        self.pdf_label.setAlignment(Qt.AlignCenter)
        self.scroll_area.setWidget(self.pdf_label)
        
        layout.addWidget(self.scroll_area)
        
        # 加载PDF
        self.load_pdf("example.pdf")
    
    def load_pdf(self, file_path):
        # 打开PDF文档
        self.doc = fitz.open(file_path)
        self.current_page = 0
        
        # 显示第一页
        self.show_page(self.current_page)
    
    def show_page(self, page_num):
        # 加载指定页面
        page = self.doc.load_page(page_num)
        
        # 渲染为图像 (300 DPI高质量)
        zoom = 3.0  # 缩放因子 (3.0 = 300 DPI)
        mat = fitz.Matrix(zoom, zoom)
        pix = page.get_pixmap(matrix=mat, alpha=False)
        
        # 转换为Qt可用的图像格式
        img = QImage(
            pix.samples, 
            pix.width, 
            pix.height, 
            pix.stride, 
            QImage.Format_RGB888
        )
        
        # 显示在QLabel上
        self.pdf_label.setPixmap(QPixmap.fromImage(img))
        self.setWindowTitle(f"PDF 查看器 - 第 {page_num+1}/{self.doc.page_count} 页")

if __name__ == "__main__":
    app = QApplication([])
    viewer = PdfViewer()
    viewer.show()
    app.exec_()

2. 增强版：添加导航工具栏

from PyQt5.QtWidgets import (QApplication, QMainWindow, QLabel, QScrollArea, 
                            QVBoxLayout, QWidget, QToolBar, QAction, 
                            QSpinBox, Q***boBox)

class EnhancedPdfViewer(QMainWindow):
    def __init__(self):
        super().__init__()
        self.setup_ui()
        self.load_pdf("example.pdf")
    
    def setup_ui(self):
        self.setWindowTitle("PDF 查看器 (增强版)")
        self.setGeometry(100, 100, 1000, 800)
        
        # 主部件和布局
        central_widget = QWidget()
        self.setCentralWidget(central_widget)
        layout = QVBoxLayout(central_widget)
        
        # 创建工具栏
        self.setup_toolbar()
        
        # 创建滚动区域
        self.scroll_area = QScrollArea()
        self.scroll_area.setWidgetResizable(True)
        
        # PDF显示标签
        self.pdf_label = QLabel()
        self.pdf_label.setAlignment(Qt.AlignCenter)
        self.scroll_area.setWidget(self.pdf_label)
        
        layout.addWidget(self.scroll_area)
    
    def setup_toolbar(self):
        toolbar = QToolBar("PDF 控制")
        self.addToolBar(toolbar)
        
        # 上一页/下一页
        prev_action = QAction("上一页", self)
        prev_action.triggered.connect(self.prev_page)
        toolbar.addAction(prev_action)
        
        next_action = QAction("下一页", self)
        next_action.triggered.connect(self.next_page)
        toolbar.addAction(next_action)
        
        # 页面跳转
        toolbar.addSeparator()
        self.page_spin = QSpinBox()
        self.page_spin.setMinimum(1)
        self.page_spin.valueChanged.connect(self.go_to_page)
        toolbar.addWidget(self.page_spin)
        
        # 缩放控制
        toolbar.addSeparator()
        self.zoom_***bo = Q***boBox()
        self.zoom_***bo.addItems(["50%", "75%", "100%", "150%", "200%", "300%"])
        self.zoom_***bo.setCurrentText("100%")
        self.zoom_***bo.currentTextChanged.connect(self.apply_zoom)
        toolbar.addWidget(self.zoom_***bo)
        
        # 旋转按钮
        toolbar.addSeparator()
        rotate_left = QAction("左转90°", self)
        rotate_left.triggered.connect(lambda: self.rotate_page(-90))
        toolbar.addAction(rotate_left)
        
        rotate_right = QAction("右转90°", self)
        rotate_right.triggered.connect(lambda: self.rotate_page(90))
        toolbar.addAction(rotate_right)
    
    def load_pdf(self, file_path):
        self.doc = fitz.open(file_path)
        self.current_page = 0
        self.zoom_factor = 1.0
        self.rotation = 0
        
        # 初始化页面选择器
        self.page_spin.setMaximum(self.doc.page_count)
        self.page_spin.setValue(1)
        
        self.show_page(self.current_page)
    
    def show_page(self, page_num):
        if not 0 <= page_num < self.doc.page_count:
            return
            
        self.current_page = page_num
        page = self.doc.load_page(page_num)
        
        # 应用缩放和旋转
        mat = fitz.Matrix(self.zoom_factor, self.zoom_factor)
        mat.prerotate(self.rotation)
        
        pix = page.get_pixmap(matrix=mat, alpha=False)
        
        # 转换为Qt图像
        img = QImage(
            pix.samples, 
            pix.width, 
            pix.height, 
            pix.stride, 
            QImage.Format_RGB888
        )
        
        self.pdf_label.setPixmap(QPixmap.fromImage(img))
        self.page_spin.setValue(page_num + 1)
        self.setWindowTitle(f"PDF 查看器 - 第 {page_num+1}/{self.doc.page_count} 页")
    
    def prev_page(self):
        if self.current_page > 0:
            self.show_page(self.current_page - 1)
    
    def next_page(self):
        if self.current_page < self.doc.page_count - 1:
            self.show_page(self.current_page + 1)
    
    def go_to_page(self, page_num):
        self.show_page(page_num - 1)
    
    def apply_zoom(self, zoom_text):
        zoom_factor = float(zoom_text.strip("%")) / 100.0
        self.zoom_factor = zoom_factor
        self.show_page(self.current_page)
    
    def rotate_page(self, angle):
        self.rotation = (self.rotation + angle) % 360
        self.show_page(self.current_page)

if __name__ == "__main__":
    app = QApplication([])
    viewer = EnhancedPdfViewer()
    viewer.show()
    app.exec_()

3. 高级功能扩展

添加文本搜索功能

# 在EnhancedPdfViewer类中添加
def setup_toolbar(self):
    # ... 其他工具栏代码 ...
    
    # 添加搜索功能
    toolbar.addSeparator()
    self.search_input = QLineEdit()
    self.search_input.setPlaceholderText("搜索文本...")
    self.search_input.returnPressed.connect(self.search_text)
    toolbar.addWidget(self.search_input)
    
    search_action = QAction("搜索", self)
    search_action.triggered.connect(self.search_text)
    toolbar.addAction(search_action)

def search_text(self):
    search_term = self.search_input.text()
    if not search_term:
        return
    
    # 从当前页开始搜索
    for page_num in range(self.current_page, self.doc.page_count):
        page = self.doc.load_page(page_num)
        text_instances = page.search_for(search_term)
        
        if text_instances:
            self.show_page(page_num)
            # 高亮显示搜索结果（需要实现高亮逻辑）
            self.highlight_search_results(text_instances)
            break

def highlight_search_results(self, rect_list):
    # 创建透明的高亮层
    pixmap = self.pdf_label.pixmap().copy()
    painter = QPainter(pixmap)
    painter.setPen(QPen(Qt.red, 2))
    
    for rect in rect_list:
        # 将PDF坐标转换为屏幕坐标
        x, y = rect.x0 * self.zoom_factor, rect.y0 * self.zoom_factor
        width = (rect.x1 - rect.x0) * self.zoom_factor
        height = (rect.y1 - rect.y0) * self.zoom_factor
        
        # 绘制高亮矩形
        painter.drawRect(int(x), int(y), int(width), int(height))
    
    painter.end()
    self.pdf_label.setPixmap(pixmap)

4. 性能优化建议

1. 页面缓存：

from functools import lru_cache

class PdfViewer:
    def __init__(self):
        self.page_cache = {}
    
    @lru_cache(maxsize=10)
    def get_page_image(self, page_num, zoom_factor, rotation):
        # 实现带缓存的页面渲染
        pass

2. 后台渲染：

from PyQt5.QtCore import QThread, pyqtSignal

class RenderThread(QThread):
    finished = pyqtSignal(QImage)
    
    def __init__(self, doc, page_num, zoom, rotation):
        super().__init__()
        self.doc = doc
        self.page_num = page_num
        self.zoom = zoom
        self.rotation = rotation
    
    def run(self):
        page = self.doc.load_page(self.page_num)
        mat = fitz.Matrix(self.zoom, self.zoom)
        mat.prerotate(self.rotation)
        pix = page.get_pixmap(matrix=mat, alpha=False)
        
        img = QImage(
            pix.samples, 
            pix.width, 
            pix.height, 
            pix.stride, 
            QImage.Format_RGB888
        )
        self.finished.emit(img)

5. 替代方案比较

对于大多数应用，PyMuPDF方案是最佳选择，它提供了最佳的性能和灵活性平衡。