Qt Quick 2D Renderer: Under LGPLv3 since Qt 5.8

I know that this is pretty old news. Unfortunately, it is not very well known. I have been asked half a dozen times over the last two months, whether the QML software renderer – officially known as the Qt Quick 2D renderer – is available under LGPLv3. Nobody belives me, when I answer with a firm “Yes!”.

Here is the official statement from the Qt blog.

With Qt 5.8 the Qt Quick 2D renderer is merged into qtdeclarative as the built-in software rendering backend for the Qt Quick SceneGraph. The code has also been relicensed to have the same licenses as QtDeclarative.

QtDeclarative comes under commercial license, GPLv3 and LGPLv3. So, the QML software renderer also comes under LGPLv3.

The Qt developers gave the software renderer a big performace boost with partial updates. From the same blog post:

Now with 5.8 the software backend is capable of only rendering what has changed between two frames, so for example if you have a blinking cursor in a text box, only the cursor and area under the cursor will be rendered and copied to the window surface […]

This performance boost is great news, if we want to run QML applications on SoCs without OpenGL acceleration like NXP’s i.MX7 and VF6xx. We should see quite a good graphics performance for QML applications.

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