9.29  style-delta%

A style-delta% object encapsulates a style change. The changes expressible by a delta include:

The set-delta method is convenient for most style delta settings; it takes a high-level delta specification and sets the internal delta information.

To take full advantage of a style delta, it is necessary to understand the internal on/off settings that can be manipulated through methods such as set-weight-on. For example, the font weight change is specified through the weight-on and weight-off internal settings. Roughly, weight-on turns on a weight setting when it is not present and weight-off turns off a weight setting when it is present. These two interact precisely in the following way:

Font styles, smoothing, underlining, and alignment work in an analogous manner.

The possible values for alignment-on and alignment-off are:

The possible values for style-on and style-off are:

The possible values for smoothing-on and smoothing-off are:

The possible values for underlined-on and underlined-off are:

The possible values for size-in-pixels-on and size-in-pixels-off are:

The possible values for transparent-text-backing-on and transparent-text-backing-off are:

The possible values for weight-on and weight-off are:

The family and face settings in a style delta are interdependent:

Methods
    collapse
    copy
    equal?
    get-alignment-off
    get-alignment-on
    get-background-add
    get-background-mult
    get-face
    get-family
    get-foreground-add
    get-foreground-mult
    get-size-add
    get-size-in-pixels-off
    get-size-in-pixels-on
    get-size-mult
    get-smoothing-off
    get-smoothing-on
    get-style-off
    get-style-on
    get-transparent-text-backing-off
    get-transparent-text-backing-on
    get-underlined-off
    get-underlined-on
    get-weight-off
    get-weight-on
    set-alignment-off
    set-alignment-on
    set-delta
    set-delta-background
    set-delta-face
    set-delta-foreground
    set-face
    set-family
    set-size-add
    set-size-in-pixels-off
    set-size-in-pixels-on
    set-size-mult
    set-smoothing-off
    set-smoothing-on
    set-style-off
    set-style-on
    set-transparent-text-backing-off
    set-transparent-text-backing-on
    set-underlined-off
    set-underlined-on
    set-weight-off
    set-weight-on