Qt 5.13 | Qt Graphical Effects | QML Types | RadialGradient QML Type

Qt 5.13.2 Reference Documentation

# RadialGradient QML Type

Draws a radial gradient. More...

Import Statement: | import QtGraphicalEffects 1.13
Since: | QtGraphicalEffects 1.0

- List of all members, including inherited members

## Properties

- angle : real
- cached : bool
- gradient : Gradient
- horizontalOffset : real
- horizontalRadius : real
- source : variant
- verticalOffset : real
- verticalRadius : real

## Detailed Description

A gradient is defined by two or more colors, which are blended seamlessly. The colors start from the middle of the item and end at the borders.

Effect applied

Note: This effect is available when running with OpenGL.

## Example

The following example shows how to apply the effect.

      import QtQuick 2.12
      import QtGraphicalEffects 1.12

      Item {
          width: 300
          height: 300

          RadialGradient {
              anchors.fill: parent
              gradient: Gradient {
                  GradientStop { position: 0.0; color: "white" }
                  GradientStop { position: 0.5; color: "black" }
              }
          }
      }

## Property Documentation

angle : real

This property defines the rotation of the gradient around its center point. The rotation is only visible when the horizontalRadius and verticalRadius properties are not equal. The angle is given in degrees and the default value is `0`.

Output examples with different angle values |  |
--- | --- | ---
angle: 0 | angle: 45 | angle: 90
horizontalOffset: 0 | horizontalOffset: 0 | horizontalOffset: 0
verticalOffset: 0 | verticalOffset: 0 | verticalOffset: 0
horizontalRadius: 100 | horizontalRadius: 100 | horizontalRadius: 100
verticalRadius: 300 | verticalRadius: 300 | verticalRadius: 300

cached : bool

This property allows the effect output pixels to be cached in order to improve the rendering performance.

Every time the source or effect properties are changed, the pixels in the cache must be updated. Memory consumption is increased, because an extra buffer of memory is required for storing the effect output.

It is recommended to disable the cache when the source or the effect properties are animated.

By default, the property is set to `false`.

gradient : Gradient

A gradient is defined by two or more colors, which are blended seamlessly. The colors are specified as a set of GradientStop child items, each of which defines a position on the gradient from 0.0 to 1.0 and a color. The position of each GradientStop is defined by setting the position property. The color is defined by setting the color property.

Output examples with different gradient values |  |
--- | --- | ---

gradient:

      Gradient {
        GradientStop {
         position: 0.000
         color: Qt.rgba(1, 0, 0, 1)
        }
        GradientStop {
         position: 0.167
         color: Qt.rgba(1, 1, 0, 1)
        }
        GradientStop {
         position: 0.333
         color: Qt.rgba(0, 1, 0, 1)
        }
        GradientStop {
         position: 0.500
         color: Qt.rgba(0, 1, 1, 1)
         }
        GradientStop {
         position: 0.667
         color: Qt.rgba(0, 0, 1, 1)
        }
        GradientStop {
         position: 0.833
         color: Qt.rgba(1, 0, 1, 1)
        }
        GradientStop {
         position: 1.000
         color: Qt.rgba(1, 0, 0, 1)
        }
      }

gradient:

      Gradient {
        GradientStop {
          position: 0.0
          color: "#F0F0F0"
        }
        GradientStop {
          position: 0.5
          color: "#000000"
        }
        GradientStop {
          position: 1.0
          color: "#F0F0F0"
        }
      }

gradient:

      Gradient {
        GradientStop {
          position: 0.0
          color: "#00000000"
        }
        GradientStop {
          position: 1.0
          color: "#FF000000"
        }
      }

horizontalOffset: 0 | horizontalOffset: 0 | horizontalOffset: 0
verticalOffset: 0 | verticalOffset: 0 | verticalOffset: 0
horizontalRadius: 300 | horizontalRadius: 300 | horizontalRadius: 300
verticalRadius: 300 | verticalRadius: 300 | verticalRadius: 300
angle: 0 | angle: 0 | angle: 0

horizontalOffset : real

The horizontalOffset and verticalOffset properties define the offset in pixels for the center point of the gradient compared to the item center.

The values range from -inf to inf. By default, these properties are set to `0`.

Output examples with different horizontalOffset values |  |
--- | --- | ---
horizontalOffset: -150 | horizontalOffset: 0 | horizontalOffset: 150
verticalOffset: 0 | verticalOffset: 0 | verticalOffset: 0
horizontalRadius: 300 | horizontalRadius: 300 | horizontalRadius: 300
verticalRadius: 300 | verticalRadius: 300 | verticalRadius: 300
angle: 0 | angle: 0 | angle: 0

horizontalRadius : real

The horizontalRadius and verticalRadius properties define the shape and size of the radial gradient. If the radiuses are equal, the shape of the gradient is a circle. If the horizontal and vertical radiuses differ, the shape is elliptical. The radiuses are given in pixels.

The value ranges from -inf to inf. By default, horizontalRadius is bound to width and verticalRadius is bound to height.

Output examples with different horizontalRadius values |  |
--- | --- | ---
horizontalRadius: 300 | horizontalRadius: 100
horizontalOffset: 0 | horizontalOffset: 0
verticalOffset: 0 | verticalOffset: 0
verticalRadius: 300 | verticalRadius: 300
angle: 0 | angle: 0
gradient: QQuickGradient(0xa05fb10) | gradient: QQuickGradient(0xa05fb10)

source : variant

This property defines the item that is going to be filled with gradient. Source item gets rendered into an intermediate pixel buffer and the alpha values from the result are used to determine the gradient's pixels visibility in the display. The default value for source is undefined and in that case whole effect area is filled with gradient.

Output examples with different source values |  |
--- | --- | ---
source: undefined | source: Image { source: images/butterfly.png }
horizontalOffset: 0 | horizontalOffset: 0
verticalOffset: 0 | verticalOffset: 0
horizontalRadius: 300 | horizontalRadius: 300
verticalRadius: 300 | verticalRadius: 300
angle: 0 | angle: 0

Note: It is not supported to let the effect include itself, for instance by setting source to the effect's parent.

verticalOffset : real

The horizontalOffset and verticalOffset properties define the offset in pixels for the center point of the gradient compared to the item center.

The values range from -inf to inf. By default, these properties are set to `0`.

Output examples with different horizontalOffset values |  |
--- | --- | ---
horizontalOffset: -150 | horizontalOffset: 0 | horizontalOffset: 150
verticalOffset: 0 | verticalOffset: 0 | verticalOffset: 0
horizontalRadius: 300 | horizontalRadius: 300 | horizontalRadius: 300
verticalRadius: 300 | verticalRadius: 300 | verticalRadius: 300
angle: 0 | angle: 0 | angle: 0

verticalRadius : real

The horizontalRadius and verticalRadius properties define the shape and size of the radial gradient. If the radiuses are equal, the shape of the gradient is a circle. If the horizontal and vertical radiuses differ, the shape is elliptical. The radiuses are given in pixels.

The value ranges from -inf to inf. By default, horizontalRadius is bound to width and verticalRadius is bound to height.

Output examples with different horizontalRadius values |  |
--- | --- | ---
horizontalRadius: 300 | horizontalRadius: 100
horizontalOffset: 0 | horizontalOffset: 0
verticalOffset: 0 | verticalOffset: 0
verticalRadius: 300 | verticalRadius: 300
angle: 0 | angle: 0
gradient: QQuickGradient(0xa05fb10) | gradient: QQuickGradient(0xa05fb10)