pango:context-matrix (context)

context -- a pango:context object
matrix -- a pango:matrix instance, or nil to unset any existing matrix, no matrix set is the same as setting the identity matrix

Gets or sets the transformation matrix that will be applied when rendering with this Pango context. Note that reported metrics are in the user space coordinates before the application of the matrix, not device-space coordinates after the application of the matrix. So, they do not scale with the matrix, though they may change slightly for different matrices, depending on how the text is fit to the pixel grid.