KSvg

A library for rendering SVG-based themes with stylesheet re-coloring and on-disk caching.

Introduction

KSvg provides both C++ classes and QtQuick components to render svgs based on image packs. Compared to plain QSvg, it caches the rendered images on disk with KImageCache, and can re-color properly crafted svg shapes that include internal stylesheets.

The default behavior is to re-color with the application palette, making it possible to create UI elements in SVG.

C++

In C++ there are 3 main classes, usable also in QWidget applications with a QPainter-compatible API:

• ImageSet: Used to tell the other classes where to find the SVG files: by default, SVG "themes" will be searched in the application data dir (share/application_name/theme_name)
• Svg: Class to used to render Svg files: it loads a file with setImagePath using relative paths to the theme specified in ImageSet
• FrameSvg: A subclass of Svg used to render 9-patch images, such as Buttons, where you want to stretch only the central area but not the edges

QML

Import QML bindings with import org.kde.ksvg 1.0 as KSvg.

ImageSet is exported directly to QML which makes it possible to set the theme from QML.

Svg and FrameSvg have corresponding items, SvgItem and FrameSvgItem, which inherit from QQuickItem and will paint their associated Svg or FrameSvg stretched to their full geometry.

QML code example:

FrameSvgItem {
    // This resolves to a file like /usr/share/myapp/mytheme/widgets/button.svgz
    imagePath: "widgets/button"
    prefix: "pressed"
}

More documentation

Assume the theme filesystem hierarchy used by the Plasma shell, but the general concepts apply everywhere:

• https://develop.kde.org/docs/plasma/theme/theme-elements/
• https://develop.kde.org/docs/plasma/theme/quickstart/