Source code for qpageview.image

# -*- coding: utf-8 -*-
# This file is part of the qpageview package.
# Copyright (c) 2019 - 2019 by Wilbert Berendsen
# This program is free software; you can redistribute it and/or
# modify it under the terms of the GNU General Public License
# as published by the Free Software Foundation; either version 2
# of the License, or (at your option) any later version.
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# GNU General Public License for more details.
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
# See for more information.

A page that can display an image, loaded using QImage.

ImagePages are instantiated quite fast. The image is only really loaded on first


from PyQt5.QtCore import QPoint, QRect, QSize, Qt
from PyQt5.QtGui import QImage, QImageIOHandler, QImageReader, QPainter, QTransform

from . import document
from . import locking
from . import page
from . import render

[docs]class ImageContainer: """Represent an image, is shared among copies of the "same" Page.""" def __init__(self, image): """Init with a QImage.""" self._image = image
[docs] def size(self): return self._image.size()
[docs] def image(self, clip=None): if clip is None: return self._image return self._image.copy(clip)
[docs]class ImageLoader(ImageContainer): """Represent an image loaded from a file or IO device.""" def __init__(self, source, autoTransform=True): """Init with a filename or QIODevice. If autoTransform is True (the default), EXIF rotation is automatically applied when loading the image. """ self._size = None self.source = source self.autoTransform = autoTransform def _reader(self): """Return a QImageReader for the source.""" reader = QImageReader(self.source) reader.setAutoTransform(self.autoTransform) return reader
[docs] def size(self): """Return the size of the image. If the image can't be loaded, a null size is returned. The resulting value is cached. """ if self._size is None: self._size = QSize() reader = self._reader() if reader.canRead(): size = reader.size() if size: if self.autoTransform and reader.transformation() & 4: size.transpose() self._size = size return QSize(self._size)
[docs] def image(self, clip=None): """Load and return the image. If clip is given, it should be a QRect describing the area to load. """ with locking.lock(self): reader = self._reader() if clip: if self.autoTransform: size = reader.size() transf = reader.transformation() m = QTransform() m.translate(size.width() / 2, size.height() / 2) if transf & QImageIOHandler.TransformationMirror: # horizontal mirror m.scale(-1, 1) if transf & QImageIOHandler.TransformationFlip: # vertical mirror m.scale(1, -1) if transf & QImageIOHandler.TransformationRotate90: # rotate 90 m.rotate(-90) m.translate(size.height() / -2, size.width() / -2) else: m.translate(size.width() / -2, size.height() / -2) clip = m.mapRect(clip) reader.setClipRect(clip) return
[docs]class ImagePage(page.AbstractRenderedPage): """A Page that displays an image in any file format supported by Qt.""" autoTransform = True # whether to automatically apply exif transformations dpi = 96 # TODO: maybe this can be image dependent. def __init__(self, container, renderer=None): super().__init__(renderer) self.setPageSize(container.size()) self._ic = container
[docs] @classmethod def load(cls, filename, renderer=None): """Load the image and yield one ImagePage instance if loading was successful.""" loader = ImageLoader(filename, cls.autoTransform) if loader.size(): yield cls(loader, renderer)
[docs] @classmethod def fromImage(cls, image, renderer=None): """Instantiate one ImagePage from the supplied QImage. As the image is kept in memory, it is not advised to instantiate many Page instances this way. Use load() for images on the filesystem. The image must be valid, and have a size > 0. """ return cls(ImageContainer(image), renderer)
[docs] def print(self, painter, rect=None, paperColor=None): """Paint a page for printing.""" if rect is None: image = self._ic.image() else: rect = rect.normalized() & self.pageRect() # we copy the image, because QSvgGenerator otherwise includes the # full image in the resulting SVG file! image = self._ic.image(rect.toRect()) painter.drawImage(QPoint(0, 0), image)
[docs] def image(self, rect=None, dpiX=None, dpiY=None, paperColor=None): """Return a QImage of the specified rectangle.""" if rect is None: rect = self.rect() else: rect = rect & self.rect() if dpiX is None: dpiX = self.dpi if dpiY is None: dpiY = dpiX s = self.defaultSize() m = QTransform() m.scale(s.width() * dpiX / self.dpi, s.height() * dpiY / self.dpi) m.translate(.5, .5) m.rotate(self.computedRotation * 90) m.translate(-.5, -.5) m.scale(1 / self.pageWidth, 1 / self.pageHeight) source = self.transform().inverted()[0].mapRect(rect) return self._ic.image(source).transformed(m, Qt.SmoothTransformation)
[docs] def group(self): return self._ic
[docs] def mutex(self): return self._ic
[docs]class ImageDocument(document.MultiSourceDocument): """A Document representing a group of images. A source may be a filename, a QIODevice or a QImage. """ pageClass = ImagePage
[docs] def createPages(self): for s in self.sources(): if isinstance(s, QImage): if not s.isNull(): yield self.pageClass.fromImage(s, self.renderer) else: for p in self.pageClass.load(s, self.renderer): yield p
[docs]class ImageRenderer(render.AbstractRenderer):
[docs] def draw(self, page, painter, key, tile, paperColor=None): """Draw the specified tile of the page (coordinates in key) on painter.""" # determine the part to draw; convert tile to viewbox source =, page.pageRect()).mapRect(QRect(*tile)) target = QRect(0, 0, tile.w, tile.h) if key.rotation & 1: target.setSize(target.size().transposed()) image = page._ic.image(source).scaled( target.size(), Qt.KeepAspectRatio, Qt.SmoothTransformation) painter.drawImage(target, image)
# install a default renderer, so SvgPage can be used directly ImagePage.renderer = ImageRenderer()