显示图片及缩放

.settings/org.eclipse.core.resources.prefs

@@ -8,6 +8,7 @@ encoding//PyQtChart\u7EC3\u4E60/test/LineChart.py=utf-8
 encoding//PyQtChart\u7EC3\u4E60/test/LineChart\u81EA\u5B9A\u4E49xy\u8F74.py=utf-8
 encoding//PyQtChart\u7EC3\u4E60/test/ToolTip.py=utf-8
 encoding//PyQtChart\u7EC3\u4E60/test/ToolTip2.py=utf-8
+encoding//QGraphicsView\u7EC3\u4E60/ImageView.py=utf-8
 encoding//QGraphicsView\u7EC3\u4E60/\u4E16\u754C\u5730\u56FE/WorldMap.py=utf-8
 encoding//QGraphicsView\u7EC3\u4E60/\u6DFB\u52A0QWidget.py=utf-8
 encoding//tmp/Material/Effect/LineEffect.py=utf-8

.settings/org.eclipse.ltk.core.refactoring.prefs

@@ -0,0 +1,2 @@
+eclipse.preferences.version=1
+org.eclipse.ltk.core.refactoring.enable.project.refactoring.history=false

QGraphicsView练习/ImageView.py

@@ -0,0 +1,108 @@
+#!/usr/bin/env python
+# -*- coding: utf-8 -*-
+
+"""
+Created on 2018年3月23日
+@author: Irony
+@site: https://github.com/892768447
+@email: 892768447@qq.com
+@file: ImageView
+@description: 图片查看
+"""
+from PyQt5.QtCore import QStandardPaths, Qt
+from PyQt5.QtGui import QColor, QPainter, QPixmap
+from PyQt5.QtOpenGL import QGLFormat
+from PyQt5.QtWidgets import QGraphicsView, QGraphicsScene, QFileDialog, \
+    QGraphicsItem
+
+
+__Author__ = 'By: Irony\nQQ: 892768447\nEmail: 892768447@qq.com'
+__Copyright__ = 'Copyright (c) 2018 Irony'
+__Version__ = 1.0
+
+
+class GraphicsView(QGraphicsView):
+
+    # 背景区域颜色
+    backgroundColor = QColor(28, 31, 34)
+
+    def __init__(self, *args, **kwargs):
+        super(GraphicsView, self).__init__(*args, **kwargs)
+        self.resize(800, 600)
+        # 设置背景颜色
+        self.setBackgroundBrush(self.backgroundColor)
+        # 缓存背景
+        self.setCacheMode(self.CacheBackground)
+        # 设置拖拽样式
+        # self.setDragMode(self.ScrollHandDrag)
+        self.setRenderHints(
+            QPainter.Antialiasing | QPainter.TextAntialiasing | QPainter.SmoothPixmapTransform)
+        # opengl
+        if QGLFormat.hasOpenGL():
+            self.setRenderHint(QPainter.HighQualityAntialiasing)
+        # 尝试通过分析需要重绘的区域来找到最佳的更新模式
+        self.setViewportUpdateMode(self.SmartViewportUpdate)
+        self._scene = QGraphicsScene(-400, -300, 800, 600, self)
+        self.setScene(self._scene)
+
+        # 图片item
+        self._itemImage = None
+
+    def keyReleaseEvent(self, event):
+        """按键处理事件"""
+        self._scaleImage(event)
+        super(GraphicsView, self).keyReleaseEvent(event)
+
+    def closeEvent(self, event):
+        """窗口关闭时清空场景中的所有item"""
+        self._scene.clear()
+        self._itemImage = None
+        super(GraphicsView, self).closeEvent(event)
+
+    def _scaleImage(self, event):
+        """缩放图片操作"""
+        if not self._itemImage:
+            return
+        scale = self._itemImage.scale()
+        if event.key() == Qt.Key_Plus:
+            # 放大
+            if scale >= 0.91:
+                return
+            self._itemImage.setScale(scale + 0.1)
+        elif event.key() == Qt.Key_Minus:
+            # 缩小
+            if scale <= 0.11:
+                return
+            self._itemImage.setScale(scale - 0.1)
+
+    def loadImage(self):
+        path, _ = QFileDialog.getOpenFileName(
+            self, '请选择图片', QStandardPaths.writableLocation(QStandardPaths.DesktopLocation), '图片文件(*.jpg *.png)')
+        if not path:
+            return
+        if self._itemImage:
+            # 删除以前的item
+            self._scene.removeItem(self._itemImage)
+            del self._itemImage
+        self._itemImage = self._scene.addPixmap(QPixmap(path))
+        self._itemImage.setFlag(QGraphicsItem.ItemIsMovable)
+        self._itemImage.setScale(0.1)  # 默认加载比例
+
+        size = self._itemImage.pixmap().size()
+        # 调整图片在中间
+        self._itemImage.setPos(
+            -size.width() * self._itemImage.scale() / 2,
+            -size.height() * self._itemImage.scale() / 2
+        )
+
+if __name__ == '__main__':
+    import sys
+    import os
+    print(os.getpid())
+    from PyQt5.QtWidgets import QApplication, QPushButton
+    app = QApplication(sys.argv)
+    w = GraphicsView()
+    w.show()
+    ww = QPushButton('选择文件', clicked=w.loadImage)
+    ww.show()
+    sys.exit(app.exec_())

QGraphicsView练习/README.md

@@ -6,3 +6,6 @@
 
 ### [2.添加QWidget](添加QWidget.py)
 ![添加QWidget](ScreenShot/1.png)
+
+### [3.显示图片及缩放](ImageView.py) - 按下小键盘-为缩小, +为放大
+![显示图片及缩放](ScreenShot/ImageView.gif)