pub struct Pen<'a> { /* private fields */ }
Expand description
Notice these docs are heavy WIP and not very relevent yet
A pen has a style(), width(), brush(), capStyle() and joinStyle().
The pen style defines the line type. The brush is used to fill strokes generated with the pen. Use the QBrush class to specify fill styles. The cap style determines the line end caps that can be drawn using QPainter, while the join style describes how joins between two lines are drawn. The pen width can be specified in both integer (width()) and floating point (widthF()) precision. A line width of zero indicates a cosmetic pen. This means that the pen width is always drawn one pixel wide, independent of the transformation set on the painter.
The various settings can easily be modified using the corresponding setStyle(), setWidth(), setBrush(), setCapStyle() and setJoinStyle() functions (note that the painter’s pen must be reset when altering the pen’s properties).
For example:
which is equivalent to
The default pen is a solid black brush with 1 width, square cap style (Qt::SquareCap), and bevel join style (Qt::BevelJoin).
In addition QPen provides the color() and setColor() convenience functions to extract and set the color of the pen’s brush, respectively. Pens may also be compared and streamed.
For more information about painting in general, see the Paint System documentation.
Pen Style
Qt provides several built-in styles represented by the Qt::PenStyle enum:
-
Qt::SolidLine
-
Qt::DashLine
-
Qt::DotLine
-
Qt::DashDotLine
-
Qt::DashDotDotLine
-
Qt::CustomDashLine
Simply use the setStyle() function to convert the pen style to either of the built-in styles, except the Qt::CustomDashLine style which we will come back to shortly. Setting the style to Qt::NoPen tells the painter to not draw lines or outlines. The default pen style is Qt::SolidLine.
Since Qt 4.1 it is also possible to specify a custom dash pattern using the setDashPattern() function which implicitly converts the style of the pen to Qt::CustomDashLine. The pattern argument, a QVector, must be specified as an even number of qreal entries where the entries 1, 3, 5… are the dashes and 2, 4, 6… are the spaces. For example, the custom pattern shown above is created using the following code:
Note that the dash pattern is specified in units of the pens width, e.g. a dash of length 5 in width 10 is 50 pixels long.
The currently set dash pattern can be retrieved using the dashPattern() function. Use the isSolid() function to determine whether the pen has a solid fill, or not.
Cap Style
The cap style defines how the end points of lines are drawn using QPainter. The cap style only apply to wide lines, i.e. when the width is 1 or greater. The Qt::PenCapStyle enum provides the following styles:
-
Qt::SquareCap
-
Qt::FlatCap
-
Qt::RoundCap
The Qt::SquareCap style is a square line end that covers the end point and extends beyond it by half the line width. The Qt::FlatCap style is a square line end that does not cover the end point of the line. And the Qt::RoundCap style is a rounded line end covering the end point.
The default is Qt::SquareCap.
Whether or not end points are drawn when the pen width is 0 or 1 depends on the cap style. Using Qt::SquareCap or Qt::RoundCap they are drawn, using Qt::FlatCap they are not drawn.
Join Style
The join style defines how joins between two connected lines can be drawn using QPainter. The join style only apply to wide lines, i.e. when the width is 1 or greater. The Qt::PenJoinStyle enum provides the following styles:
-
Qt::BevelJoin
-
Qt::MiterJoin
-
Qt::RoundJoin
The Qt::BevelJoin style fills the triangular notch between the two lines. The Qt::MiterJoin style extends the lines to meet at an angle. And the Qt::RoundJoin style fills a circular arc between the two lines.
The default is Qt::BevelJoin.
When the Qt::MiterJoin style is applied, it is possible to use the setMiterLimit() function to specify how far the miter join can extend from the join point. The miterLimit() is used to reduce artifacts between line joins where the lines are close to parallel.
The miterLimit() must be specified in units of the pens width, e.g. a miter limit of 5 in width 10 is 50 pixels long. The default miter limit is 2, i.e. twice the pen width in pixels.
-
\l {painting/pathstroke {The Path Stroking Example}} The Path Stroking example shows Qt’s built-in dash patterns and shows how custom patterns can be used to extend the range of available patterns.
See also: Painter
Brush
{painting/pathstroke}{Path Stroking Example}
{Scribble Example}
Licence
The documentation is an adoption of the original Qt Documentation and provided herein is licensed under the terms of the GNU Free Documentation License version 1.3 as published by the Free Software Foundation.
Implementations
sourceimpl<'a> Pen<'a>
impl<'a> Pen<'a>
pub fn new() -> Pen<'a>
sourcepub fn swap<P: PenTrait<'a>>(&self, other: &P) -> &Self
pub fn swap<P: PenTrait<'a>>(&self, other: &P) -> &Self
Swaps pen other with this pen. This operation is very fast and never fails.
sourcepub fn style(&self) -> PenStyle
pub fn style(&self) -> PenStyle
Returns the pen style.
See also: [set_style()
]
{QPen#Pen Style}{Pen Style}
sourcepub fn set_style(&self, arg0: PenStyle) -> &Self
pub fn set_style(&self, arg0: PenStyle) -> &Self
Sets the pen style to the given style.
See the Qt::PenStyle documentation for a list of the available styles. Since Qt 4.1 it is also possible to specify a custom dash pattern using the setDashPattern() function which implicitly converts the style of the pen to Qt::CustomDashLine.
Note: This function resets the dash offset to zero.
See also: [style()
]
{QPen#Pen Style}{Pen Style}
pub fn dash_pattern(&self) -> PrimitiveArray<f32> ⓘ
sourcepub fn dash_offset(&self) -> f32
pub fn dash_offset(&self) -> f32
Returns the dash offset for the pen.
See also: [set_dash_offset()
]
sourcepub fn set_dash_offset(&self, doffset: f32) -> &Self
pub fn set_dash_offset(&self, doffset: f32) -> &Self
Sets the dash offset (the starting point on the dash pattern) for this pen to the offset specified. The offset is measured in terms of the units used to specify the dash pattern.
-
For example, a pattern where each stroke is four units long, followed by a gap of two units, will begin with the stroke when drawn as a line. However, if the dash offset is set to 4.0, any line drawn will begin with the gap. Values of the offset up to 4.0 will cause part of the stroke to be drawn first, and values of the offset between 4.0 and 6.0 will cause the line to begin with part of the gap.
Note: This implicitly converts the style of the pen to Qt::CustomDashLine.
sourcepub fn miter_limit(&self) -> f32
pub fn miter_limit(&self) -> f32
Returns the miter limit of the pen. The miter limit is only relevant when the join style is set to Qt::MiterJoin.
See also: [set_miter_limit()
]
{QPen#Join Style}{Join Style}
sourcepub fn set_miter_limit(&self, limit: f32) -> &Self
pub fn set_miter_limit(&self, limit: f32) -> &Self
Sets the miter limit of this pen to the given limit.
The miter limit describes how far a miter join can extend from the join point. This is used to reduce artifacts between line joins where the lines are close to parallel.
This value does only have effect when the pen style is set to Qt::MiterJoin. The value is specified in units of the pen’s width, e.g. a miter limit of 5 in width 10 is 50 pixels long. The default miter limit is 2, i.e. twice the pen width in pixels.
See also: [miter_limit()
]
[set_join_style()
]
{QPen#Join Style}{Join Style}
sourcepub fn width_f(&self) -> f32
pub fn width_f(&self) -> f32
Returns the pen width with floating point precision.
See also: [set_width_f()
]
[width()
]
sourcepub fn set_width_f(&self, width: f32) -> &Self
pub fn set_width_f(&self, width: f32) -> &Self
Sets the pen width to the given width in pixels with floating point precision.
A line width of zero indicates a cosmetic pen. This means that the pen width is always drawn one pixel wide, independent of the transformation on the painter.
Setting a pen width with a negative value is not supported.
See also: [set_width()
]
[width_f()
]
sourcepub fn width(&self) -> i32
pub fn width(&self) -> i32
Returns the pen width with integer precision.
See also: [set_width()
]
[width_f()
]
Returns the pen width with floating point precision.
See also: [set_width_f()
]
[width()
]
sourcepub fn set_width(&self, width: i32) -> &Self
pub fn set_width(&self, width: i32) -> &Self
Sets the pen width to the given width in pixels with integer precision.
A line width of zero indicates a cosmetic pen. This means that the pen width is always drawn one pixel wide, independent of the transformation set on the painter.
Setting a pen width with a negative value is not supported.
See also: [set_width_f()
]
[width()
]
Sets the pen width to the given width in pixels with floating point precision.
A line width of zero indicates a cosmetic pen. This means that the pen width is always drawn one pixel wide, independent of the transformation on the painter.
Setting a pen width with a negative value is not supported.
See also: [set_width()
]
[width_f()
]
sourcepub fn color(&self) -> Color<'_>
pub fn color(&self) -> Color<'_>
Returns the color of this pen’s brush.
See also: [brush()
]
[set_color()
]
sourcepub fn set_color<C: ColorTrait<'a>>(&self, color: &C) -> &Self
pub fn set_color<C: ColorTrait<'a>>(&self, color: &C) -> &Self
Sets the color of this pen’s brush to the given color.
See also: [set_brush()
]
[color()
]
sourcepub fn brush(&self) -> Brush<'_>
pub fn brush(&self) -> Brush<'_>
Returns the brush used to fill strokes generated with this pen.
sourcepub fn set_brush<B: BrushTrait<'a>>(&self, brush: &B) -> &Self
pub fn set_brush<B: BrushTrait<'a>>(&self, brush: &B) -> &Self
Sets the brush used to fill strokes generated with this pen to the given brush.
See also: [brush()
]
[set_color()
]
sourcepub fn is_solid(&self) -> bool
pub fn is_solid(&self) -> bool
Returns true
if the pen has a solid fill, otherwise false.
See also: [style()
]
[dash_pattern()
]
sourcepub fn cap_style(&self) -> PenCapStyle
pub fn cap_style(&self) -> PenCapStyle
Returns the pen’s cap style.
See also: [set_cap_style()
]
{QPen#Cap Style}{Cap Style}
sourcepub fn set_cap_style(&self, pcs: PenCapStyle) -> &Self
pub fn set_cap_style(&self, pcs: PenCapStyle) -> &Self
Sets the pen’s cap style to the given style. The default value is Qt::SquareCap.
See also: [cap_style()
]
{QPen#Cap Style}{Cap Style}
sourcepub fn join_style(&self) -> PenJoinStyle
pub fn join_style(&self) -> PenJoinStyle
Returns the pen’s join style.
See also: [set_join_style()
]
{QPen#Join Style}{Join Style}
sourcepub fn set_join_style(&self, pcs: PenJoinStyle) -> &Self
pub fn set_join_style(&self, pcs: PenJoinStyle) -> &Self
Sets the pen’s join style to the given style. The default value is Qt::BevelJoin.
See also: [join_style()
]
{QPen#Join Style}{Join Style}
sourcepub fn is_cosmetic(&self) -> bool
pub fn is_cosmetic(&self) -> bool
Returns true
if the pen is cosmetic; otherwise returns false.
Cosmetic pens are used to draw strokes that have a constant width regardless of any transformations applied to the QPainter they are used with. Drawing a shape with a cosmetic pen ensures that its outline will have the same thickness at different scale factors.
A zero width pen is cosmetic by default.
See also: [set_cosmetic()
]
[width_f()
]
sourcepub fn set_cosmetic(&self, cosmetic: bool) -> &Self
pub fn set_cosmetic(&self, cosmetic: bool) -> &Self
Sets this pen to cosmetic or non-cosmetic, depending on the value of cosmetic.
See also: [is_cosmetic()
]