multiArrayLayout QML Value Type

This was originally provided as an example message. More...

This type is deprecated since QtRos2.StdMsgs Foxy. We strongly advise against using it in new code.

Properties

• dataOffset : uint32_t
• dim : list<multiArrayDimension>

Detailed Description

It is recommended to create your own semantically meaningful message. However if you would like to continue using this please use the equivalent in example_msgs.

The multiarray declares a generic multi-dimensional array of a particular data type. Dimensions are ordered from outer most to inner most.

Accessors should ALWAYS be written in terms of dimension stride and specified outer-most dimension first.

multiarray(i,j,k) = data[data_offset + dim_stride[1]*i + dim_stride[2]*j + k]

A standard, 3-channel 640x480 image with interleaved color channels would be specified as:

dim[0].label = "height" dim[0].size = 480 dim[0].stride = 3*640*480 = 921600 (note dim[0] stride is just size of image) dim[1].label = "width" dim[1].size = 640 dim[1].stride = 3*640 = 1920 dim[2].label = "channel" dim[2].size = 3 dim[2].stride = 3

multiarray(i,j,k) refers to the ith row, jth column, and kth channel.

multiArrayLayout is a structured value type usable in QML. It maps directly to the std_msgs::msg::MultiArrayLayout ROS 2 message type.

Construct a multiArrayLayout in QML by assigning a JavaScript object whose keys are its component properties, or by setting those properties individually.

See also MultiArrayLayoutPublisher and MultiArrayLayoutSubscriber.

Property Documentation

dataOffset : uint32_t

dim : list<multiArrayDimension>