I am doing a mobile application using symbian and Qt 4.7
I have a CFBSBitmap data when i save the CFBSBitmap data, the format is a .mbm file and I wish to convert it to be saved as jpg format.
Can anyone help me in this area as I am quite a newbie in Qt and Symbian
QImage provides a save function that takes a parameter format. Just specify the JPG format.
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I'm working with Visual Studio and OpenCV for image processing, but all my documents are PDF so I need to convert them to image format so I can compatibilize them with OpenCV
This is my code to open a image:
enter image description here
Is there any way to modify it to open and read PDF's as an image?
Many thanks!
You may want to take a look at ImageMagick. The CLI tool is able to convert PDF to images and I believe they provide C libraries too.
I am new to Qt. I want to know how to read or write the thumbnail embedded in JPEG image using QT classes.
I found that the “QMediaMetaData Namespace” contains the “ThumbnailImage” identifier containing the thumbnail data. But I didn’t get any examples related to that.
Please help me to find a solution.
I need to read/store binary data in the metadata of a PNG image. Specifically, it will be gzipped data which has been serialized by Google's protobuf library.
I'm using the QImage library of Qt5 to load and store the images, so it would be extremely convenient if I could find a way to use some Qt library to add this binary data to the QImage I'm already using.
I see that the QImage class has a setText method which appears to do exactly what I want, except for one caveat: It takes a QString as an argument and not a QByteArray, and the QString constructor mangles my binary data.
How can I force QString to preserve my binary data, both when storing and loading? If that's not possible, is there some other way in Qt5 to add metadata to a PNG image?
You could try to encode the data as Base64 before converting to QString, and then decode when reading back. I do understand that this significantly reduces the benefits of your gzip compression, but at least you could try to see if that helps.
I need to process multi-page PDFs that are scanned in to me using a program I wrote in C++ using OpenCV libraries. OpenCV does not read in PDFs, so I am currently using pdftk to break up the PDF, and convert -density 300 page##.pdf page##.png to convert the individual pages to PNGs before reading them in with my program.
The issue is convert takes about 30 seconds on my Raspberry Pi to do this conversion. Is there an easier way to convert multi-page PDFs in a way that can be read in my C++/OpenCV?
You can try converting PDF to PNG with
http://www.foolabs.com/xpdf/
https://github.com/coolwanglu/pdf2htmlEX (it convert PDF to html, but do generate png as images corresponding to each page, which can be used)
Is it possible to convert a PDF file to cv::Mat?
I know that PDF file is generally vector of objects, but given a required resolution. Is there any tool that can do such a conversion?
OpenCV doesn't support pdf format at all, so you should convert pdf page to image using another library. Read this discussion: Open source PDF library for C/C++ application?
Also this question is similar to yours: What C++ library can I use to convert a PDF to an image on windows?