Qt-加载错误扩展名的图像 [英] Qt - Loading image with wrong extension

问题描述

我目前正在开发一个Qt程序，该程序可以处理用户提供的图像.我遇到的一个问题是，许多图像使用错误的扩展名保存-例如图像以JPG格式保存，但扩展名为PNG.

I'm currently working on a Qt program that works with images that are supplied by the users. One problem I've run into is that a lot of images are saved with the wrong extension - e.g. an image is saved in JPG format but has a PNG extension.

Qt似乎不能很好地解决这一问题.当我将这样的图像加载到QImage中时，QImage无法加载.我一直在浏览文档，但没有遇到任何与此相关的信息.

Qt doesn't seem to deal well with this. When I load an image like this into a QImage, the QImage fails to load. I've been looking through the docs, but I haven't come across anything relating to this.

尽管使用了PNG扩展名，但我使用的其他程序仍能够正确地将图像识别为JPG，因此Qt应该没有理由无法做到这一点，但是我没有任何运气.

Other programs I've used are able to correctly identify the image as a JPG despite the PNG extension, so there should be no reason for Qt to be unable to do this, but I'm not having any luck.

有什么建议吗?

推荐答案

我通过使用QImageReader解决了这个问题.下面显示了使用PySide的示例.首先，我创建了一个QImageReader实例，并将其设置为从内容中读取格式.

I solved this by using a QImageReader. An example is shown below using PySide. First I created an instance of QImageReader and set it to read the format from the content.

image_reader = QtGui.QImageReader()
image_reader.setDecideFromContent(True)

此设置告诉读者仅查看图像数据来确定其格式，而不是扩展名.

This setting tells the reader to only look at the image's data to determine its format and not the extension.

然后，我将文件名设置为要加载的图像的文件名，并命名为read().

Then I set the filename to the filename of the image I wanted to load and called read().

image_reader.setFileName(file_path_here)
image = image_reader.read()

Read返回一个QImage对象，所以我从那里继续其余的代码.

Read returns a QImage object, so I proceeded with the rest of my code from there.

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