On this page:
get-color
get-stipple
get-gradient
get-style
get-transformation
set-color
set-stipple
set-style

brush% : class?

  superclass: object%

A brush is a drawing tool with a color and a style that is used for filling in areas, such as the interior of a rectangle or ellipse. In a monochrome destination, all non-white brushes are drawn as black.

In addition to its color and style, a brush can have a brush stipple bitmap. Painting with a stipple brush is similar to calling draw-bitmap with the stipple bitmap in the filled region.

As an alternative to a color, style, and stipple, a brush can have a gradient that is a linear-gradient% or radial-gradient%. When a brush has a gradient and the target for drawing is not monochrome, then other brush settings are ignored. With a gradient, for each point in a drawing destination, the gradient associates a color to the point based on starting and ending colors and starting and ending lines (for a linear gradient) or circles (for a radial gradient); a gradient-assigned color is applied for each point that is touched when drawing with the brush. By default, coordinates in the gradient are transformed by the drawing context’s transformation when the brush is used, but a brush can have its own gradient transformation that is used, instead. A gradient transformation has the same representation and meaning as for get-transformation in dc<%>.

A brush style is one of the following (but is ignored if the brush has a gradient and the target is not monochrome):

To draw outline shapes (such as unfilled boxes and ellipses), use the 'transparent brush style.

To avoid creating multiple brushes with the same characteristics, use the global brush-list% object the-brush-list, or provide a color and style to set-brush in dc<%>.

(new brush% [[color color] 
  [style style] 
  [stipple stipple] 
  [gradient gradient]] 
  [transformation transformation]) 
  (is-a?/c brush%)
  color : (or/c string? (is-a?/c color%)) = "black"
  style : 
(one-of/c 'transparent 'solid 'opaque
          'xor 'hilite 'panel
          'bdiagonal-hatch 'crossdiag-hatch
          'fdiagonal-hatch 'cross-hatch
          'horizontal-hatch 'vertical-hatch)
 = 'solid
  stipple : (or/c #f (is-a?/c bitmap%)) = #f
  gradient : 
(or/c #f
      (is-a?/c linear-gradient%)
      (is-a?/c radial-gradient%))
 = #f
  transformation : 
(or/c #f (vector/c (vector/c real? real? real?
                             real? real? real?)
                    real? real? real? real? real?))
Creates a brush with the given color, brush style, brush stipple, gradient, and gradient transformation. For the case that the color is specified using a name, see color-database<%> for information about color names; if the name is not known, the brush’s color is black.

(send a-brush get-color)  (is-a?/c color%)
Returns the brush’s color.

(send a-brush get-stipple)  (or/c (is-a?/c bitmap%) #f)
Gets the brush stipple bitmap, or #f if the brush has no stipple.

(send a-brush get-gradient)  
(or/c (is-a?/c linear-gradient%)
      (is-a?/c radial-gradient%)
      #f)
Gets the gradient, or #f if the brush has no gradient.

(send a-brush get-style)
  
(one-of/c 'transparent 'solid 'opaque
          'xor 'hilite 'panel
          'bdiagonal-hatch 'crossdiag-hatch
          'fdiagonal-hatch 'cross-hatch
          'horizontal-hatch 'vertical-hatch)
Returns the brush style. See brush% for information about brush styles.

(send a-brush get-transformation)
  
(or/c #f (vector/c (vector/c real? real? real? real? real? real?)
                   real? real? real? real? real?))
Returns the brush’s gradient transformation, if any.

If a brush with a gradient also has a transformation, then the transformation applies to the gradient’s coordinates instead of the target drawing context’s transformation; otherwise, the target drawing context’s transformation applies to gradient coordinates.

(send a-brush set-color color)  void?
  color : (is-a?/c color%)
(send a-brush set-color color-name)  void?
  color-name : string?
(send a-brush set-color red green blue)  void?
  red : (integer-in 0 255)
  green : (integer-in 0 255)
  blue : (integer-in 0 255)
Sets the brush’s color. A brush cannot be modified if it was obtained from a brush-list% or while it is selected into a drawing context.

For the case that the color is specified using a string, see color-database<%> for information about color names.

(send a-brush set-stipple bitmap)  void?
  bitmap : (or/c (is-a?/c bitmap%) #f)
Sets or removes the brush stipple bitmap, where #f removes the stipple. See brush% for information about drawing with stipples.

If bitmap is modified while is associated with a brush, the effect on the brush is unspecified. A brush cannot be modified if it was obtained from a brush-list% or while it is selected into a drawing context.

(send a-brush set-style style)  void?
  style : 
(one-of/c 'transparent 'solid 'opaque
          'xor 'hilite 'panel
          'bdiagonal-hatch 'crossdiag-hatch
          'fdiagonal-hatch 'cross-hatch
          'horizontal-hatch 'vertical-hatch)
Sets the brush style. See brush% for information about the possible styles.

A brush cannot be modified if it was obtained from a brush-list% or while it is selected into a drawing context.