240 lines
8.7 KiB
Python
240 lines
8.7 KiB
Python
"""Reusable full-image preview dialog for desktop image workflows."""
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from __future__ import annotations
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import math
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import os
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from PySide6.QtCore import QSize, Qt, QTimer
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from PySide6.QtGui import QImageReader, QPixmap
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from PySide6.QtWidgets import (
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QApplication,
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QDialog,
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QHBoxLayout,
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QLabel,
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QPushButton,
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QScrollArea,
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QToolButton,
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QVBoxLayout,
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)
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class ImagePreviewDialog(QDialog):
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"""Preview a local image with bounded zoom and fit-to-window behavior."""
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MIN_ZOOM = 0.25
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MAX_ZOOM = 4.0
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ZOOM_STEP = 0.25
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def __init__(self, path, title="图片预览", parent=None):
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super().__init__(parent)
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self._base_title = str(title or "图片预览")
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self._source = self._load_source(path)
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self.fit_to_window = True
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self.zoom_factor = 1.0
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self._effective_zoom = 1.0
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self._display_size = QSize()
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self._resize_timer = QTimer(self)
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self._resize_timer.setSingleShot(True)
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self._resize_timer.setInterval(50)
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self._resize_timer.timeout.connect(self._render)
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self.setWindowTitle(self._window_title())
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layout = QVBoxLayout(self)
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self.scroll = QScrollArea()
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self.scroll.setObjectName("imagePreviewScrollArea")
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self.scroll.setWidgetResizable(False)
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self.scroll.setAlignment(Qt.AlignCenter)
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self.image_label = QLabel()
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self.image_label.setObjectName("imagePreviewLabel")
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self.image_label.setAlignment(Qt.AlignCenter)
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self.scroll.setWidget(self.image_label)
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layout.addWidget(self.scroll, 1)
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controls = QHBoxLayout()
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self.zoom_out_button = QToolButton()
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self.zoom_out_button.setObjectName("imagePreviewZoomOutButton")
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self.zoom_out_button.setText("-")
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self.zoom_out_button.setToolTip("缩小图片")
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self.zoom_out_button.setAccessibleName("缩小图片")
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self.zoom_out_button.setMinimumSize(32, 32)
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self.zoom_out_button.clicked.connect(self.zoom_out)
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controls.addWidget(self.zoom_out_button)
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self.zoom_label = QLabel("适应窗口")
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self.zoom_label.setObjectName("imagePreviewZoomLabel")
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self.zoom_label.setAlignment(Qt.AlignCenter)
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self.zoom_label.setMinimumWidth(72)
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controls.addWidget(self.zoom_label)
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self.zoom_in_button = QToolButton()
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self.zoom_in_button.setObjectName("imagePreviewZoomInButton")
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self.zoom_in_button.setText("+")
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self.zoom_in_button.setToolTip("放大图片")
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self.zoom_in_button.setAccessibleName("放大图片")
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self.zoom_in_button.setMinimumSize(32, 32)
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self.zoom_in_button.clicked.connect(self.zoom_in)
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controls.addWidget(self.zoom_in_button)
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self.fit_button = QPushButton("适应窗口")
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self.fit_button.setObjectName("imagePreviewFitButton")
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self.fit_button.setCheckable(True)
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self.fit_button.setChecked(True)
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self.fit_button.setToolTip("完整显示图片且不放大超过原始尺寸")
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self.fit_button.clicked.connect(self.show_fit)
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controls.addWidget(self.fit_button)
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self.actual_size_button = QPushButton("100%")
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self.actual_size_button.setObjectName("imagePreviewActualSizeButton")
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self.actual_size_button.setToolTip("按图片原始像素查看")
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self.actual_size_button.clicked.connect(self.show_actual_size)
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controls.addWidget(self.actual_size_button)
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controls.addStretch(1)
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close_button = QPushButton("关闭")
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close_button.clicked.connect(self.reject)
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controls.addWidget(close_button)
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layout.addLayout(controls)
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self._fit_to_screen()
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self._render()
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QTimer.singleShot(0, self._render)
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@staticmethod
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def _load_source(path):
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normalized = str(path or "")
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if not normalized or not os.path.isfile(normalized):
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return QPixmap()
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reader = QImageReader(normalized)
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reader.setAutoTransform(True)
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image = reader.read()
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return QPixmap.fromImage(image) if not image.isNull() else QPixmap()
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def _window_title(self):
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if self._source.isNull():
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return self._base_title
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return "%s · %dx%d" % (
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self._base_title,
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self._source.width(),
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self._source.height(),
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)
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def resizeEvent(self, event):
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super().resizeEvent(event)
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if self.fit_to_window:
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self._resize_timer.start()
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def showEvent(self, event):
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super().showEvent(event)
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QTimer.singleShot(0, self._render)
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def show_fit(self, checked=False):
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self.fit_to_window = True
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self._display_size = QSize()
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self._render()
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def show_actual_size(self, checked=False):
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self.fit_to_window = False
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self.zoom_factor = 1.0
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self._display_size = QSize()
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self._render()
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def zoom_in(self, checked=False):
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self._step_zoom(1)
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def zoom_out(self, checked=False):
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self._step_zoom(-1)
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def _step_zoom(self, direction):
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if self._source.isNull():
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return
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current = self._effective_zoom if self.fit_to_window else self.zoom_factor
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if direction > 0:
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stepped = (math.floor(current / self.ZOOM_STEP + 1e-9) + 1) * self.ZOOM_STEP
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else:
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stepped = (math.ceil(current / self.ZOOM_STEP - 1e-9) - 1) * self.ZOOM_STEP
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self.fit_to_window = False
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self.zoom_factor = max(self.MIN_ZOOM, min(self.MAX_ZOOM, stepped))
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self._display_size = QSize()
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self._render()
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def _fit_scale(self):
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viewport = self.scroll.viewport().size()
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if self._source.isNull() or viewport.width() <= 0 or viewport.height() <= 0:
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return 1.0
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return min(
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1.0,
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viewport.width() / self._source.width(),
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viewport.height() / self._source.height(),
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)
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def _render(self):
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viewport = self.scroll.viewport().size()
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viewport_width = max(1, viewport.width())
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viewport_height = max(1, viewport.height())
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if self._source.isNull():
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self.image_label.clear()
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self.image_label.setText("图片文件不存在或无法读取")
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self.image_label.resize(max(320, viewport_width), max(240, viewport_height))
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self.zoom_label.setText("无法预览")
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self._set_controls_enabled(False)
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return
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if self.fit_to_window:
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scale = max(1e-6, min(1.0, self._fit_scale()))
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else:
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scale = max(self.MIN_ZOOM, min(self.MAX_ZOOM, self.zoom_factor))
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self._effective_zoom = scale
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display_size = QSize(
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max(1, int(round(self._source.width() * scale))),
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max(1, int(round(self._source.height() * scale))),
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)
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if display_size == self._source.size():
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pixmap = self._source
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else:
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pixmap = self._source.scaled(
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display_size,
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Qt.KeepAspectRatio,
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Qt.SmoothTransformation,
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)
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if display_size != self._display_size or self.image_label.pixmap() is None:
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self.image_label.setPixmap(pixmap)
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self.image_label.resize(pixmap.size())
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self._display_size = QSize(pixmap.size())
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self.zoom_label.setText(
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"适应窗口" if self.fit_to_window else "%d%%" % int(round(scale * 100))
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)
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self.fit_button.setChecked(self.fit_to_window)
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self._set_controls_enabled(True)
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def _set_controls_enabled(self, available):
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self.fit_button.setEnabled(available)
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self.actual_size_button.setEnabled(available)
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self.zoom_out_button.setEnabled(
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available and self._effective_zoom > self.MIN_ZOOM + 1e-9
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)
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self.zoom_in_button.setEnabled(
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available and self._effective_zoom < self.MAX_ZOOM - 1e-9
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)
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def _fit_to_screen(self):
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screen = self.parentWidget().screen() if self.parentWidget() is not None else None
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screen = screen or QApplication.primaryScreen()
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if screen is None:
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self.resize(720, 520)
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return
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available = screen.availableGeometry()
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max_width = max(1, int(available.width() * 0.9))
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max_height = max(1, int(available.height() * 0.9))
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min_width = min(560, max_width)
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min_height = min(420, max_height)
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source_width = self._source.width() if not self._source.isNull() else 640
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source_height = self._source.height() if not self._source.isNull() else 480
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self.resize(
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min(max_width, max(min_width, source_width + 48)),
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min(max_height, max(min_height, source_height + 104)),
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)
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frame = self.frameGeometry()
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frame.moveCenter(available.center())
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self.move(frame.topLeft())
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