wx:style-delta%

Superclass: wx:object%

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

• changing the font family
• changing the font face
• changing the font size to a new value
• enlarging the font by an additive amount
• enlarging the font by a multiplicative amount, etc.
• changing the font style (normal, italic, or slant)
• toggling the font style
• changing the font to italic if it is currently slant, etc.
• changing the font weight, etc.
• changing the underline, etc.
• changing the vertical alignment, etc.
• changing the foreground color
• dimming or brightening the foreground color, etc.
• changing the background color, etc.
• changing text backing transparency

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:

• If both weight-on and weight-off are set to wx:const-base, then the font weight is not changed.
• If weight-on is not wx:const-base, then the weight is set to weight-on.
• If weight-off is not wx:const-base, then the weight will be set back to wx:const-normal when the base style has the weight weight-off.
• If both weight-on and weight-off are set to the same value, then the weight is toggled with respect to that value: if the base style has the weight weight-on, then weight is changed to wx:const-normal; if the base style has a different weight, it is changed to weight-on.
• If both weight-on and weight-off are set, but to different values, then the weight is changed to weight-on only when the base style has the weight weight-off.

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

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

• wx:const-base
• wx:const-align-top
• wx:const-align-center
• wx:const-align-bottom

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

• wx:const-base
• wx:const-normal
• wx:const-italic
• wx:const-slant

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

• #f (acts like wx:const-base)
• #t

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

• #f (acts like wx:const-base)
• #t

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

• wx:const-base
• wx:const-normal
• wx:const-bold
• wx:const-light

The family and face settings in a style delta are not independent. If both are set within a style delta, the face setting overrides the family setting. However, if a style delta with a family setting and no face setting is applied to a style with a face setting, then the delta application overrides the face setting in the base style.

• (make-object wx:style-delta% change-command) -> wx:style-delta% object
      change-command = wx:const-change-nothing : small integer

  
  

• (make-object wx:style-delta% change-command v) -> wx:style-delta% object
      change-command : small integer
      v : small integer

  
  

• (make-object wx:style-delta% change-command v) -> wx:style-delta% object
      change-command : small integer
      v : boolean

  The initialization arguments are passed on to set-delta.

  
  

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-mult
• 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-mult
• 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