November 2014
Beginner to intermediate
264 pages
5h 32m
English
Content preview from Application Development with Qt Creator - Second EditionBecome an O’Reilly member and get unlimited access to this title plus top books and audiobooks from O’Reilly and nearly 200 top publishers, thousands of courses curated by job role, 150+ live events each month,
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Drawing off screen
There are a number of reasons why you might like to draw offscreen: you might want to compose a collection of images and show them one after another (this is called double-buffering, which you can do to avoid screen painting flicker when you draw onscreen), or write a program that generates image files directly.
As I mentioned in the previous section, Qt provides several classes for offscreen drawing, each with different advantages and disadvantages. These classes are QImage, QPixmap, QBitmap, and QPicture. Under normal circumstances, you need to choose between QImage and QPixmap.
Tip
QImage is the class best-suited for general-purpose drawing where you're interested in loading the image from or saving the image to a file. If ...
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O’Reilly covers everything we've got, with content to help us build a world-class technology community, upgrade the capabilities and competencies of our teams, and improve overall team performance as well as their engagement.Julian F.
I wanted to learn C and C++, but it didn't click for me until I picked up an O'Reilly book. When I went on the O’Reilly platform, I was astonished to find all the books there, plus live events and sandboxes so you could play around with the technology.Addison B.
I’ve been on the O’Reilly platform for more than eight years. I use a couple of learning platforms, but I'm on O'Reilly more than anybody else. When you're there, you start learning. I'm never disappointed.Amir M.
I'm always learning. So when I got on to O'Reilly, I was like a kid in a candy store. There are playlists. There are answers. There's on-demand training. It's worth its weight in gold, in terms of what it allows me to do.