Canvas
using a buffer.
Each call pushes the necessary parameters onto the buffer
where they will be later rendered onto the image of the Canvas
node
by the rendering thread at the end of a pulse.
A Canvas
only contains one GraphicsContext
, and only one buffer.
If it is not attached to any scene, then it can be modified by any thread,
as long as it is only used from one thread at a time. Once a Canvas
node is attached to a scene, it must be modified on the JavaFX Application
Thread.
Calling any method on the GraphicsContext
is considered modifying
its corresponding Canvas
and is subject to the same threading
rules.
A GraphicsContext
also manages a stack of state objects that can
be saved or restored at anytime.
The GraphicsContext
maintains the following rendering attributes
which affect various subsets of the rendering methods:
Attribute | Save/Restore? | Default value | Description |
---|---|---|---|
Common Rendering Attributes | |||
Clip |
Yes | No clipping | An anti-aliased intersection of various clip paths to which rendering is restricted. |
Global Alpha |
Yes | 1.0 |
An opacity value that controls the visibility or fading of each rendering operation. |
Global Blend Mode |
Yes | SRC_OVER |
A BlendMode enum value that controls how pixels from each rendering
operation are composited into the existing image.
|
Transform |
Yes | Identity |
A 3x2 2D affine transformation matrix that controls how coordinates are mapped onto the logical pixels of the canvas image. |
Effect |
Yes | null |
An Effect applied individually to each rendering operation.
|
Fill Attributes | |||
Fill Paint |
Yes | BLACK |
The Paint to be applied to the interior of shapes in a
fill operation.
|
Stroke Attributes | |||
Stroke Paint |
Yes | BLACK |
The Paint to be applied to the boundary of shapes in a
stroke operation.
|
Line Width |
Yes | 1.0 |
The width of the stroke applied to the boundary of shapes in a stroke operation. |
Line Cap |
Yes | SQUARE |
The style of the end caps applied to the beginnings and ends of each dash and/or subpath in a stroke operation. |
Line Join |
Yes | MITER |
The style of the joins applied between individual segments in the boundary paths of shapes in a stroke operation. |
Miter Limit |
Yes | 10.0 |
The ratio limit of how far a MITER line join
may extend in the direction of a sharp corner between segments in the
boundary path of a shape, relative to the line width, before it is truncated
to a BEVEL join in a stroke operation.
|
Dashes |
Yes | null |
The array of dash lengths to be applied to the segments in the boundary of shapes in a stroke operation. |
Dash Offset |
Yes | 0.0 |
The distance offset into the array of dash lengths at which to start the dashing of the segments in the boundary of shapes in a stroke operation. |
Text Attributes | |||
Font |
Yes | Default Font |
The font used for all fill and stroke text operations. |
Text Align |
Yes | LEFT |
The horizontal alignment of text with respect to the X coordinate
specified in the text operation.
|
Text Baseline |
Yes | BASELINE |
The vertical position of the text relative to the Y coordinate
specified in the text operation.
|
Font Smoothing |
Yes | GRAY |
The type of smoothing (antialiasing) applied to the glyphs in the font for all fill text operations. |
Path Attributes | |||
Current Path |
No | Empty path | The path constructed using various path construction methods to be used in various path filling, stroking, or clipping operations. |
Fill Rule |
Yes | NON_ZERO |
The method used to determine the interior of paths for a path fill or clip operation. |
Image Attributes | |||
Image Smoothing |
Yes | true |
A boolean state which enables or disables image smoothing for
drawImage(all forms) .
|
The various rendering methods on the GraphicsContext
use the
following sets of rendering attributes:
Method | Common Rendering Attributes | Fill Attributes | Stroke Attributes | Text Attributes | Path Attributes | Image Attributes |
---|---|---|---|---|---|---|
Basic Shape Rendering | ||||||
fillRect() ,
fillRoundRect() ,
fillOval() ,
fillArc()
|
Yes | Yes | No | No | No | No |
strokeLine() ,
strokeRect() ,
strokeRoundRect() ,
strokeOval() ,
strokeArc()
|
Yes | No | Yes | No | No | No |
clearRect()
|
Yes [1] | No | No | No | No | No |
fillPolygon()
|
Yes | Yes | No | No | Yes [2] | No |
strokePolygon() ,
strokePolyline()
|
Yes | No | Yes | No | No | No |
[1] Only the Transform, Clip, and Effect apply to clearRect() [2] Only the Fill Rule applies to fillPolygon(), the current path is left unchanged | ||||||
Text Rendering | ||||||
fillText() ,
fillText(with maxWidth)
|
Yes | Yes | No | Yes [3] | No | No |
strokeText() ,
strokeText(with maxWidth)
|
Yes | No | Yes | Yes [3] | No | No |
[3] The Font Smoothing attribute only applies to filled text | ||||||
Path Rendering | ||||||
beginPath() ,
moveTo() ,
lineTo() ,
quadraticCurveTo() ,
bezierCurveTo() ,
arc() ,
arcTo() ,
appendSVGPath() ,
closePath() ,
rect()
|
Yes [4] | No | No | No | No | No |
fill()
|
Yes [4] | Yes | No | No | Yes | No |
stroke()
|
Yes [4] | No | Yes | No | Yes [5] | No |
clip()
|
No | No | No | No | Yes | No |
[4] Transform applied only during path construction [5] Fill Rule only used for fill() and clip() | ||||||
Image Rendering | ||||||
drawImage(all forms)
|
Yes | No | No | No | No | Yes |
Miscellaneous | ||||||
applyEffect() ,
PixelWriter methods
|
No | No | No | No | No | No |
Example:
import javafx.scene.*; import javafx.scene.paint.*; import javafx.scene.canvas.*; Group root = new Group(); Scene s = new Scene(root, 300, 300, Color.BLACK); final Canvas canvas = new Canvas(250,250); GraphicsContext gc = canvas.getGraphicsContext2D(); gc.setFill(Color.BLUE); gc.fillRect(75,75,100,100); root.getChildren().add(canvas);
- Since:
- JavaFX 2.2
- See Also:
-
Method Summary
Modifier and TypeMethodDescriptionvoid
appendSVGPath
(String svgpath) Appends an SVG Path string to the current path.void
Applies the given effect to the entire bounds of the canvas and stores the result back into the same canvas.void
arc
(double centerX, double centerY, double radiusX, double radiusY, double startAngle, double length) Adds path elements to the current path to make an arc that uses Euclidean degrees.void
arcTo
(double x1, double y1, double x2, double y2, double radius) Adds segments to the current path to make an arc.void
Resets the current path to empty.void
bezierCurveTo
(double xc1, double yc1, double xc2, double yc2, double x1, double y1) Adds segments to the current path to make a cubic Bezier curve.void
clearRect
(double x, double y, double w, double h) Clears a portion of the canvas with a transparent color value.void
clip()
Intersects the current clip with the current path and applies it to subsequent rendering operation as an anti-aliased mask.void
Closes the path.void
Draws an image at the given x, y position using the width and height of the given image.void
Draws an image into the given destination rectangle of the canvas.void
drawImage
(Image img, double sx, double sy, double sw, double sh, double dx, double dy, double dw, double dh) Draws the specified source rectangle of the given image to the given destination rectangle of the Canvas.void
fill()
Fills the path with the current fill paint.void
fillArc
(double x, double y, double w, double h, double startAngle, double arcExtent, ArcType closure) Fills an arc using the current fill paint.void
fillOval
(double x, double y, double w, double h) Fills an oval using the current fill paint.void
fillPolygon
(double[] xPoints, double[] yPoints, int nPoints) Fills a polygon with the given points using the currently set fill paint.void
fillRect
(double x, double y, double w, double h) Fills a rectangle using the current fill paint.void
fillRoundRect
(double x, double y, double w, double h, double arcWidth, double arcHeight) Fills a rounded rectangle using the current fill paint.void
Fills the given string of text at position x, y with the current fill paint attribute.void
Fills text and includes a maximum width of the string.Gets theCanvas
that theGraphicsContext
is issuing draw commands to.Gets a copy of the effect to be applied after the next draw call.getFill()
Gets the current fill paint attribute.Get the filling rule attribute for determining the interior of paths in fill and clip operations.getFont()
Gets the current Font.Gets the current Font Smoothing Type.double
Gets the current global alpha.Gets the global blend mode.Gets the current stroke line cap.double[]
Gets a copy of the current line dash array.double
Gets the current line dash offset.Gets the current stroke line join.double
Gets the current line width.double
Gets the current miter limit.Returns aPixelWriter
object that can be used to modify the pixels of theCanvas
associated with thisGraphicsContext
.Gets the current stroke.Gets the currentTextAlignment
.Gets the current Text Baseline.Returns a copy of the current transform.getTransform
(Affine xform) Copies the current transform into the supplied object, creating a newAffine
object if it is null, and returns the object containing the copy.boolean
Gets the current image smoothing state.boolean
isPointInPath
(double x, double y) Returns true if the the given x,y point is inside the path.void
lineTo
(double x1, double y1) Adds segments to the current path to make a line to the given x,y coordinate.void
moveTo
(double x0, double y0) Issues a move command for the current path to the given x,y coordinate.void
quadraticCurveTo
(double xc, double yc, double x1, double y1) Adds segments to the current path to make a quadratic Bezier curve.void
rect
(double x, double y, double w, double h) Adds path elements to the current path to make a rectangle.void
restore()
Pops the state off of the stack, setting the following attributes to their value at the time when that state was pushed onto the stack.void
rotate
(double degrees) Rotates the current transform in degrees.void
save()
Saves the following attributes onto a stack.void
scale
(double x, double y) Scales the current transform by x, y.void
Sets the effect to be applied after the next draw call, or null to disable effects.void
Sets the current fill paint attribute.void
setFillRule
(FillRule fillRule) Set the filling rule attribute for determining the interior of paths in fill or clip operations.void
Sets the current Font.void
setFontSmoothingType
(FontSmoothingType fontsmoothing) Sets the current Font Smoothing Type.void
setGlobalAlpha
(double alpha) Sets the global alpha of the current state.void
Sets the global blend mode.void
setImageSmoothing
(boolean imageSmoothing) Sets the image smoothing state.void
setLineCap
(StrokeLineCap cap) Sets the current stroke line cap.void
setLineDashes
(double... dashes) Sets the current stroke line dash pattern to a normalized copy of the argument.void
setLineDashOffset
(double dashOffset) Sets the line dash offset.void
setLineJoin
(StrokeLineJoin join) Sets the current stroke line join.void
setLineWidth
(double lw) Sets the current line width.void
setMiterLimit
(double ml) Sets the current miter limit.void
Sets the current stroke paint attribute.void
setTextAlign
(TextAlignment align) Defines horizontal text alignment, relative to the textx
origin.void
setTextBaseline
(VPos baseline) Sets the current Text Baseline.void
setTransform
(double mxx, double myx, double mxy, double myy, double mxt, double myt) Sets the current transform.void
setTransform
(Affine xform) Sets the current transform.void
stroke()
Strokes the path with the current stroke paint.void
strokeArc
(double x, double y, double w, double h, double startAngle, double arcExtent, ArcType closure) Strokes an Arc using the current stroke paint.void
strokeLine
(double x1, double y1, double x2, double y2) Strokes a line using the current stroke paint.void
strokeOval
(double x, double y, double w, double h) Strokes an oval using the current stroke paint.void
strokePolygon
(double[] xPoints, double[] yPoints, int nPoints) Strokes a polygon with the given points using the currently set stroke paint.void
strokePolyline
(double[] xPoints, double[] yPoints, int nPoints) Strokes a polyline with the given points using the currently set stroke paint attribute.void
strokeRect
(double x, double y, double w, double h) Strokes a rectangle using the current stroke paint.void
strokeRoundRect
(double x, double y, double w, double h, double arcWidth, double arcHeight) Strokes a rounded rectangle using the current stroke paint.void
strokeText
(String text, double x, double y) Draws the given string of text at position x, y with the current stroke paint attribute.void
strokeText
(String text, double x, double y, double maxWidth) Draws text with stroke paint and includes a maximum width of the string.void
transform
(double mxx, double myx, double mxy, double myy, double mxt, double myt) Concatenates the input with the current transform.void
Concatenates the input with the current transform.void
translate
(double x, double y) Translates the current transform by x, y.
-
Method Details
-
getCanvas
Gets theCanvas
that theGraphicsContext
is issuing draw commands to. There is only ever oneCanvas
for aGraphicsContext
.- Returns:
- Canvas the canvas that this
GraphicsContext
is issuing draw commands to.
-
save
public void save()Saves the following attributes onto a stack.- Global Alpha
- Global Blend Operation
- Transform
- Fill Paint
- Stroke Paint
- Line Width
- Line Cap
- Line Join
- Miter Limit
- Clip
- Font
- Text Align
- Text Baseline
- Effect
- Fill Rule
-
restore
public void restore()Pops the state off of the stack, setting the following attributes to their value at the time when that state was pushed onto the stack. If the stack is empty then nothing is changed.- Global Alpha
- Global Blend Operation
- Transform
- Fill Paint
- Stroke Paint
- Line Width
- Line Cap
- Line Join
- Miter Limit
- Clip
- Font
- Text Align
- Text Baseline
- Effect
- Fill Rule
-
translate
public void translate(double x, double y) Translates the current transform by x, y.- Parameters:
x
- value to translate along the x axis.y
- value to translate along the y axis.
-
scale
public void scale(double x, double y) Scales the current transform by x, y.- Parameters:
x
- value to scale in the x axis.y
- value to scale in the y axis.
-
rotate
public void rotate(double degrees) Rotates the current transform in degrees.- Parameters:
degrees
- value in degrees to rotate the current transform.
-
transform
public void transform(double mxx, double myx, double mxy, double myy, double mxt, double myt) Concatenates the input with the current transform.- Parameters:
mxx
- - the X coordinate scaling element of the 3x4 matrixmyx
- - the Y coordinate shearing element of the 3x4 matrixmxy
- - the X coordinate shearing element of the 3x4 matrixmyy
- - the Y coordinate scaling element of the 3x4 matrixmxt
- - the X coordinate translation element of the 3x4 matrixmyt
- - the Y coordinate translation element of the 3x4 matrix
-
transform
Concatenates the input with the current transform. Only 2D transforms are supported. The only values used are the X and Y scaling, translation, and shearing components of a transform. Anull
value is treated as identity.- Parameters:
xform
- The affine to be concatenated with the current transform or null.
-
setTransform
public void setTransform(double mxx, double myx, double mxy, double myy, double mxt, double myt) Sets the current transform.- Parameters:
mxx
- - the X coordinate scaling element of the 3x4 matrixmyx
- - the Y coordinate shearing element of the 3x4 matrixmxy
- - the X coordinate shearing element of the 3x4 matrixmyy
- - the Y coordinate scaling element of the 3x4 matrixmxt
- - the X coordinate translation element of the 3x4 matrixmyt
- - the Y coordinate translation element of the 3x4 matrix
-
setTransform
Sets the current transform. Only 2D transforms are supported. The only values used are the X and Y scaling, translation, and shearing components of a transform.- Parameters:
xform
- The affine to be copied and used as the current transform.
-
getTransform
Copies the current transform into the supplied object, creating a newAffine
object if it is null, and returns the object containing the copy.- Parameters:
xform
- A transform object that will be used to hold the result. If xform is non null, then this method will copy the current transform into that object. If xform is null a new transform object will be constructed. In either case, the return value is a copy of the current transform.- Returns:
- A copy of the current transform.
-
getTransform
Returns a copy of the current transform.- Returns:
- a copy of the transform of the current state.
-
setGlobalAlpha
public void setGlobalAlpha(double alpha) Sets the global alpha of the current state. The default value is1.0
. Any valid double can be set, but only values in the range[0.0, 1.0]
are valid and the nearest value in that range will be used for rendering. The global alpha is a common attribute used for nearly all rendering methods as specified in the Rendering Attributes Table.- Parameters:
alpha
- the new alpha value, clamped to[0.0, 1.0]
during actual use.
-
getGlobalAlpha
public double getGlobalAlpha()Gets the current global alpha. The default value is1.0
. The global alpha is a common attribute used for nearly all rendering methods as specified in the Rendering Attributes Table.- Returns:
- the current global alpha.
-
setGlobalBlendMode
Sets the global blend mode. The default value isSRC_OVER
. Anull
value will be ignored and the current value will remain unchanged. The blend mode is a common attribute used for nearly all rendering methods as specified in the Rendering Attributes Table.- Parameters:
op
- theBlendMode
that will be set or null.
-
getGlobalBlendMode
Gets the global blend mode. The default value isSRC_OVER
. The blend mode is a common attribute used for nearly all rendering methods as specified in the Rendering Attributes Table.- Returns:
- the global
BlendMode
of the current state.
-
setFill
Sets the current fill paint attribute. The default value isBLACK
. The fill paint is a fill attribute used for any of the fill methods as specified in the Rendering Attributes Table. Anull
value will be ignored and the current value will remain unchanged.- Parameters:
p
- ThePaint
to be used as the fillPaint
or null.
-
getFill
Gets the current fill paint attribute. The default value isBLACK
. The fill paint is a fill attribute used for any of the fill methods as specified in the Rendering Attributes Table.- Returns:
- p The
Paint
to be used as the fillPaint
.
-
setStroke
Sets the current stroke paint attribute. The default value isBLACK
. The stroke paint is a stroke attribute used for any of the stroke methods as specified in the Rendering Attributes Table. Anull
value will be ignored and the current value will remain unchanged.- Parameters:
p
- The Paint to be used as the stroke Paint or null.
-
getStroke
Gets the current stroke. The default value isBLACK
. The stroke paint is a stroke attribute used for any of the stroke methods as specified in the Rendering Attributes Table.- Returns:
- the
Paint
to be used as the strokePaint
.
-
setLineWidth
public void setLineWidth(double lw) Sets the current line width. The default value is1.0
. The line width is a stroke attribute used for any of the stroke methods as specified in the Rendering Attributes Table. An infinite or non-positive value outside of the range(0, +inf)
will be ignored and the current value will remain unchanged.- Parameters:
lw
- value in the range {0-positive infinity}, with any other value being ignored and leaving the value unchanged.
-
getLineWidth
public double getLineWidth()Gets the current line width. The default value is1.0
. The line width is a stroke attribute used for any of the stroke methods as specified in the Rendering Attributes Table.- Returns:
- value between 0 and infinity.
-
setLineCap
Sets the current stroke line cap. The default value isSQUARE
. The line cap is a stroke attribute used for any of the stroke methods as specified in the Rendering Attributes Table. Anull
value will be ignored and the current value will remain unchanged.- Parameters:
cap
-StrokeLineCap
with a value of Butt, Round, or Square or null.
-
getLineCap
Gets the current stroke line cap. The default value isSQUARE
. The line cap is a stroke attribute used for any of the stroke methods as specified in the Rendering Attributes Table.- Returns:
StrokeLineCap
with a value of Butt, Round, or Square.
-
setLineJoin
Sets the current stroke line join. The default value isStrokeLineJoin.MITER
. The line join is a stroke attribute used for any of the stroke methods as specified in the Rendering Attributes Table. Anull
value will be ignored and the current value will remain unchanged.- Parameters:
join
-StrokeLineJoin
with a value of Miter, Bevel, or Round or null.
-
getLineJoin
Gets the current stroke line join. The default value isStrokeLineJoin.MITER
. The line join is a stroke attribute used for any of the stroke methods as specified in the Rendering Attributes Table.- Returns:
StrokeLineJoin
with a value of Miter, Bevel, or Round.
-
setMiterLimit
public void setMiterLimit(double ml) Sets the current miter limit. The default value is10.0
. The miter limit is a stroke attribute used for any of the stroke methods as specified in the Rendering Attributes Table. An infinite or non-positive value outside of the range(0, +inf)
will be ignored and the current value will remain unchanged.- Parameters:
ml
- miter limit value between 0 and positive infinity with any other value being ignored and leaving the value unchanged.
-
getMiterLimit
public double getMiterLimit()Gets the current miter limit. The default value is10.0
. The miter limit is a stroke attribute used for any of the stroke methods as specified in the Rendering Attributes Table.- Returns:
- the miter limit value in the range
0.0-positive infinity
-
setLineDashes
public void setLineDashes(double... dashes) Sets the current stroke line dash pattern to a normalized copy of the argument. The default value isnull
. The line dash array is a stroke attribute used for any of the stroke methods as specified in the Rendering Attributes Table. If the array isnull
or empty or contains all0
elements then dashing will be disabled and the current dash array will be set tonull
. If any of the elements of the array are a negative, infinite, or NaN value outside the range[0, +inf)
then the entire array will be ignored and the current dash array will remain unchanged. If the array is an odd length then it will be treated as if it were two copies of the array appended to each other.- Parameters:
dashes
- the array of finite non-negative dash lengths- Since:
- JavaFX 8u40
-
getLineDashes
public double[] getLineDashes()Gets a copy of the current line dash array. The default value isnull
. The array may be normalized by the validation tests in thesetLineDashes(double...)
method. The line dash array is a stroke attribute used for any of the stroke methods as specified in the Rendering Attributes Table.- Returns:
- a copy of the current line dash array.
- Since:
- JavaFX 8u40
-
setLineDashOffset
public void setLineDashOffset(double dashOffset) Sets the line dash offset. The default value is0.0
. The line dash offset is a stroke attribute used for any of the stroke methods as specified in the Rendering Attributes Table. An infinite or NaN value outside of the range(-inf, +inf)
will be ignored and the current value will remain unchanged.- Parameters:
dashOffset
- the line dash offset in the range(-inf, +inf)
- Since:
- JavaFX 8u40
-
getLineDashOffset
public double getLineDashOffset()Gets the current line dash offset. The default value is0.0
. The line dash offset is a stroke attribute used for any of the stroke methods as specified in the Rendering Attributes Table.- Returns:
- the line dash offset in the range
(-inf, +inf)
- Since:
- JavaFX 8u40
-
setFont
Sets the current Font. The default value is specified byFont.getDefault()
. The font is a text attribute used for any of the text methods as specified in the Rendering Attributes Table. Anull
value will be ignored and the current value will remain unchanged.- Parameters:
f
- the Font or null.
-
getFont
Gets the current Font. The default value is specified byFont.getDefault()
. The font is a text attribute used for any of the text methods as specified in the Rendering Attributes Table.- Returns:
- the Font
-
setFontSmoothingType
Sets the current Font Smoothing Type. The default value isGRAY
. The font smoothing type is a text attribute used for any of the text methods as specified in the Rendering Attributes Table. Anull
value will be ignored and the current value will remain unchanged.Note that the
FontSmoothingType
value ofLCD
is only supported over an opaque background.LCD
text will generally appear asGRAY
text over transparent or partially transparent pixels, and in some implementations it may not be supported at all on aCanvas
because the required support does not exist for surfaces which contain an alpha channel as allCanvas
objects do.- Parameters:
fontsmoothing
- theFontSmoothingType
or null- Since:
- JavaFX 8u40
-
getFontSmoothingType
Gets the current Font Smoothing Type. The default value isGRAY
. The font smoothing type is a text attribute used for any of the text methods as specified in the Rendering Attributes Table.- Returns:
- the
FontSmoothingType
- Since:
- JavaFX 8u40
-
setTextAlign
Defines horizontal text alignment, relative to the textx
origin. The default value isLEFT
. The text alignment is a text attribute used for any of the text methods as specified in the Rendering Attributes Table.Let horizontal bounds represent the logical width of a single line of text. Where each line of text has a separate horizontal bounds.
Then TextAlignment is specified as:
- Left: the left edge of the horizontal bounds will be at
x
. - Center: the center, halfway between left and right edge, of the
horizontal bounds will be at
x
. - Right: the right edge of the horizontal bounds will be at
x
.
Note: Canvas does not support line wrapping, therefore the text alignment Justify is identical to left aligned text.
A
null
value will be ignored and the current value will remain unchanged.- Parameters:
align
-TextAlignment
with values of Left, Center, Right or null.
- Left: the left edge of the horizontal bounds will be at
-
getTextAlign
Gets the currentTextAlignment
. The default value isLEFT
. The text alignment is a text attribute used for any of the text methods as specified in the Rendering Attributes Table.- Returns:
TextAlignment
with values of Left, Center, Right, or Justify.
-
setTextBaseline
Sets the current Text Baseline. The default value isBASELINE
. The text baseline is a text attribute used for any of the text methods as specified in the Rendering Attributes Table. Anull
value will be ignored and the current value will remain unchanged.- Parameters:
baseline
-VPos
with values of Top, Center, Baseline, or Bottom or null.
-
getTextBaseline
Gets the current Text Baseline. The default value isBASELINE
. The text baseline is a text attribute used for any of the text methods as specified in the Rendering Attributes Table.- Returns:
VPos
with values of Top, Center, Baseline, or Bottom
-
fillText
Fills the given string of text at position x, y with the current fill paint attribute. Anull
text value will be ignored.This method will be affected by any of the global common, fill, or text attributes as specified in the Rendering Attributes Table.
- Parameters:
text
- the string of text or null.x
- position on the x axis.y
- position on the y axis.
-
strokeText
Draws the given string of text at position x, y with the current stroke paint attribute. Anull
text value will be ignored.This method will be affected by any of the global common, stroke, or text attributes as specified in the Rendering Attributes Table.
- Parameters:
text
- the string of text or null.x
- position on the x axis.y
- position on the y axis.
-
fillText
Fills text and includes a maximum width of the string. If the width of the text extends past max width, then it will be sized to fit. Anull
text value will be ignored.This method will be affected by any of the global common, fill, or text attributes as specified in the Rendering Attributes Table.
- Parameters:
text
- the string of text or null.x
- position on the x axis.y
- position on the y axis.maxWidth
- maximum width the text string can have.
-
strokeText
Draws text with stroke paint and includes a maximum width of the string. If the width of the text extends past max width, then it will be sized to fit. Anull
text value will be ignored.This method will be affected by any of the global common, stroke, or text attributes as specified in the Rendering Attributes Table.
- Parameters:
text
- the string of text or null.x
- position on the x axis.y
- position on the y axis.maxWidth
- maximum width the text string can have.
-
setFillRule
Set the filling rule attribute for determining the interior of paths in fill or clip operations. The default value isFillRule.NON_ZERO
. Anull
value will be ignored and the current value will remain unchanged. The fill rule is a path attribute used for any of the fill or clip path methods as specified in the Rendering Attributes Table.- Parameters:
fillRule
-FillRule
with a value of Even_odd or Non_zero or null.
-
getFillRule
Get the filling rule attribute for determining the interior of paths in fill and clip operations. The default value isFillRule.NON_ZERO
. The fill rule is a path attribute used for any of the fill or clip path methods as specified in the Rendering Attributes Table.- Returns:
- current fill rule.
-
setImageSmoothing
public void setImageSmoothing(boolean imageSmoothing) Sets the image smoothing state. Image smoothing is an Image attribute used to enable or disable image smoothing fordrawImage(all forms)
as specified in the Rendering Attributes Table.
If image smoothing istrue
, images will be scaled using a higher quality filtering when transforming or scaling the source image to fit in the destination rectangle.
If image smoothing isfalse
, images will be scaled without filtering (or by using a lower quality filtering) when transforming or scaling the source image to fit in the destination rectangle.- Default value:
true
- Parameters:
imageSmoothing
-true
to enable orfalse
to disable smoothing- Since:
- 12
-
isImageSmoothing
public boolean isImageSmoothing()Gets the current image smoothing state.- Default value:
true
- Returns:
- image smoothing state
- Since:
- 12
-
beginPath
public void beginPath()Resets the current path to empty. The default path is empty. The current path is a path attribute used for any of the path methods as specified in the Rendering Attributes Table and is not affected by thesave()
andrestore()
operations. -
moveTo
public void moveTo(double x0, double y0) Issues a move command for the current path to the given x,y coordinate. The coordinates are transformed by the current transform as they are added to the path and unaffected by subsequent changes to the transform. The current path is a path attribute used for any of the path methods as specified in the Rendering Attributes Table and is not affected by thesave()
andrestore()
operations.- Parameters:
x0
- the X position for the move to command.y0
- the Y position for the move to command.
-
lineTo
public void lineTo(double x1, double y1) Adds segments to the current path to make a line to the given x,y coordinate. The coordinates are transformed by the current transform as they are added to the path and unaffected by subsequent changes to the transform. The current path is a path attribute used for any of the path methods as specified in the Rendering Attributes Table and is not affected by thesave()
andrestore()
operations.- Parameters:
x1
- the X coordinate of the ending point of the line.y1
- the Y coordinate of the ending point of the line.
-
quadraticCurveTo
public void quadraticCurveTo(double xc, double yc, double x1, double y1) Adds segments to the current path to make a quadratic Bezier curve. The coordinates are transformed by the current transform as they are added to the path and unaffected by subsequent changes to the transform. The current path is a path attribute used for any of the path methods as specified in the Rendering Attributes Table and is not affected by thesave()
andrestore()
operations.- Parameters:
xc
- the X coordinate of the control pointyc
- the Y coordinate of the control pointx1
- the X coordinate of the end pointy1
- the Y coordinate of the end point
-
bezierCurveTo
public void bezierCurveTo(double xc1, double yc1, double xc2, double yc2, double x1, double y1) Adds segments to the current path to make a cubic Bezier curve. The coordinates are transformed by the current transform as they are added to the path and unaffected by subsequent changes to the transform. The current path is a path attribute used for any of the path methods as specified in the Rendering Attributes Table and is not affected by thesave()
andrestore()
operations.- Parameters:
xc1
- the X coordinate of first Bezier control point.yc1
- the Y coordinate of the first Bezier control point.xc2
- the X coordinate of the second Bezier control point.yc2
- the Y coordinate of the second Bezier control point.x1
- the X coordinate of the end point.y1
- the Y coordinate of the end point.
-
arcTo
public void arcTo(double x1, double y1, double x2, double y2, double radius) Adds segments to the current path to make an arc. The coordinates are transformed by the current transform as they are added to the path and unaffected by subsequent changes to the transform. The current path is a path attribute used for any of the path methods as specified in the Rendering Attributes Table and is not affected by thesave()
andrestore()
operations.If
p0
is the current point in the path andp1
is the point specified by(x1, y1)
andp2
is the point specified by(x2, y2)
, then the arc segments appended will be segments along the circumference of a circle of the specified radius touching and inscribed into the convex (interior) side ofp0->p1->p2
. The path will contain a line segment (if needed) to the tangent point between that circle andp0->p1
followed by circular arc segments to reach the tangent point between the circle andp1->p2
and will end with the current point at that tangent point (not atp2
). Note that the radius and circularity of the arc segments will be measured or considered relative to the current transform, but the resulting segments that are computed from those untransformed points will then be transformed when they are added to the path. Since all computation is done in untransformed space, but the pre-existing path segments are all transformed, the ability to correctly perform the computation may implicitly depend on being able to inverse transform the current end of the current path back into untransformed coordinates.If there is no way to compute and inscribe the indicated circle for any reason then the entire operation will simply append segments to force a line to point
p1
. Possible reasons that the computation may fail include:- The current path is empty.
- The segments
p0->p1->p2
are colinear. - the current transform is non-invertible so that the current end point of the current path cannot be untransformed for computation.
- Parameters:
x1
- the X coordinate of the first point of the arc.y1
- the Y coordinate of the first point of the arc.x2
- the X coordinate of the second point of the arc.y2
- the Y coordinate of the second point of the arc.radius
- the radius of the arc in the range {0.0-positive infinity}.
-
arc
public void arc(double centerX, double centerY, double radiusX, double radiusY, double startAngle, double length) Adds path elements to the current path to make an arc that uses Euclidean degrees. This Euclidean orientation sweeps from East to North, then West, then South, then back to East. The coordinates are transformed by the current transform as they are added to the path and unaffected by subsequent changes to the transform. The current path is a path attribute used for any of the path methods as specified in the Rendering Attributes Table and is not affected by thesave()
andrestore()
operations.- Parameters:
centerX
- the center x position of the arc.centerY
- the center y position of the arc.radiusX
- the x radius of the arc.radiusY
- the y radius of the arc.startAngle
- the starting angle of the arc in the range0-360.0
length
- the length of the baseline of the arc.
-
rect
public void rect(double x, double y, double w, double h) Adds path elements to the current path to make a rectangle. The coordinates are transformed by the current transform as they are added to the path and unaffected by subsequent changes to the transform. The current path is a path attribute used for any of the path methods as specified in the Rendering Attributes Table and is not affected by thesave()
andrestore()
operations.- Parameters:
x
- x position of the upper left corner of the rectangle.y
- y position of the upper left corner of the rectangle.w
- width of the rectangle.h
- height of the rectangle.
-
appendSVGPath
Appends an SVG Path string to the current path. If there is no current path the string must then start with either type of move command. Anull
value or incorrect SVG path will be ignored. The coordinates are transformed by the current transform as they are added to the path and unaffected by subsequent changes to the transform. The current path is a path attribute used for any of the path methods as specified in the Rendering Attributes Table and is not affected by thesave()
andrestore()
operations.- Parameters:
svgpath
- the SVG Path string.
-
closePath
public void closePath()Closes the path. The current path is a path attribute used for any of the path methods as specified in the Rendering Attributes Table and is not affected by thesave()
andrestore()
operations. -
fill
public void fill()Fills the path with the current fill paint.This method will be affected by any of the global common, fill, or path attributes as specified in the Rendering Attributes Table. Note that the path segments were transformed as they were originally added to the current path so the current transform will not affect those path segments again, but it may affect other attributes in affect at the time of the
fill()
operation. -
stroke
public void stroke()Strokes the path with the current stroke paint.This method will be affected by any of the global common, stroke, or path attributes as specified in the Rendering Attributes Table. Note that the path segments were transformed as they were originally added to the current path so the current transform will not affect those path segments again, but it may affect other attributes in affect at the time of the
stroke()
operation. -
clip
public void clip()Intersects the current clip with the current path and applies it to subsequent rendering operation as an anti-aliased mask. The current clip is a common attribute used for nearly all rendering operations as specified in the Rendering Attributes Table.This method will itself be affected only by the path attributes as specified in the Rendering Attributes Table. Note that the path segments were transformed as they were originally added to the current path so the current transform will not affect those path segments again, but it may affect other attributes in affect at the time of the
stroke()
operation. -
isPointInPath
public boolean isPointInPath(double x, double y) Returns true if the the given x,y point is inside the path.- Parameters:
x
- the X coordinate to use for the check.y
- the Y coordinate to use for the check.- Returns:
- true if the point given is inside the path, false otherwise.
-
clearRect
public void clearRect(double x, double y, double w, double h) Clears a portion of the canvas with a transparent color value.This method will be affected only by the current transform, clip, and effect.
- Parameters:
x
- X position of the upper left corner of the rectangle.y
- Y position of the upper left corner of the rectangle.w
- width of the rectangle.h
- height of the rectangle.
-
fillRect
public void fillRect(double x, double y, double w, double h) Fills a rectangle using the current fill paint.This method will be affected by any of the global common or fill attributes as specified in the Rendering Attributes Table.
- Parameters:
x
- the X position of the upper left corner of the rectangle.y
- the Y position of the upper left corner of the rectangle.w
- the width of the rectangle.h
- the height of the rectangle.
-
strokeRect
public void strokeRect(double x, double y, double w, double h) Strokes a rectangle using the current stroke paint.This method will be affected by any of the global common or stroke attributes as specified in the Rendering Attributes Table.
- Parameters:
x
- the X position of the upper left corner of the rectangle.y
- the Y position of the upper left corner of the rectangle.w
- the width of the rectangle.h
- the height of the rectangle.
-
fillOval
public void fillOval(double x, double y, double w, double h) Fills an oval using the current fill paint.This method will be affected by any of the global common or fill attributes as specified in the Rendering Attributes Table.
- Parameters:
x
- the X coordinate of the upper left bound of the oval.y
- the Y coordinate of the upper left bound of the oval.w
- the width at the center of the oval.h
- the height at the center of the oval.
-
strokeOval
public void strokeOval(double x, double y, double w, double h) Strokes an oval using the current stroke paint.This method will be affected by any of the global common or stroke attributes as specified in the Rendering Attributes Table.
- Parameters:
x
- the X coordinate of the upper left bound of the oval.y
- the Y coordinate of the upper left bound of the oval.w
- the width at the center of the oval.h
- the height at the center of the oval.
-
fillArc
public void fillArc(double x, double y, double w, double h, double startAngle, double arcExtent, ArcType closure) Fills an arc using the current fill paint. Anull
ArcType or non positive width or height will cause the render command to be ignored.This method will be affected by any of the global common or fill attributes as specified in the Rendering Attributes Table.
- Parameters:
x
- the X coordinate of the arc.y
- the Y coordinate of the arc.w
- the width of the arc.h
- the height of the arc.startAngle
- the starting angle of the arc in degrees.arcExtent
- the angular extent of the arc in degrees.closure
- closure type (Round, Chord, Open) or null.
-
strokeArc
public void strokeArc(double x, double y, double w, double h, double startAngle, double arcExtent, ArcType closure) Strokes an Arc using the current stroke paint. Anull
ArcType or non positive width or height will cause the render command to be ignored.This method will be affected by any of the global common or stroke attributes as specified in the Rendering Attributes Table.
- Parameters:
x
- the X coordinate of the arc.y
- the Y coordinate of the arc.w
- the width of the arc.h
- the height of the arc.startAngle
- the starting angle of the arc in degrees.arcExtent
- arcExtent the angular extent of the arc in degrees.closure
- closure type (Round, Chord, Open) or null
-
fillRoundRect
public void fillRoundRect(double x, double y, double w, double h, double arcWidth, double arcHeight) Fills a rounded rectangle using the current fill paint.This method will be affected by any of the global common or fill attributes as specified in the Rendering Attributes Table.
- Parameters:
x
- the X coordinate of the upper left bound of the oval.y
- the Y coordinate of the upper left bound of the oval.w
- the width at the center of the oval.h
- the height at the center of the oval.arcWidth
- the arc width of the rectangle corners.arcHeight
- the arc height of the rectangle corners.
-
strokeRoundRect
public void strokeRoundRect(double x, double y, double w, double h, double arcWidth, double arcHeight) Strokes a rounded rectangle using the current stroke paint.This method will be affected by any of the global common or stroke attributes as specified in the Rendering Attributes Table.
- Parameters:
x
- the X coordinate of the upper left bound of the oval.y
- the Y coordinate of the upper left bound of the oval.w
- the width at the center of the oval.h
- the height at the center of the oval.arcWidth
- the arc width of the rectangle corners.arcHeight
- the arc height of the rectangle corners.
-
strokeLine
public void strokeLine(double x1, double y1, double x2, double y2) Strokes a line using the current stroke paint.This method will be affected by any of the global common or stroke attributes as specified in the Rendering Attributes Table.
- Parameters:
x1
- the X coordinate of the starting point of the line.y1
- the Y coordinate of the starting point of the line.x2
- the X coordinate of the ending point of the line.y2
- the Y coordinate of the ending point of the line.
-
fillPolygon
public void fillPolygon(double[] xPoints, double[] yPoints, int nPoints) Fills a polygon with the given points using the currently set fill paint. Anull
value for any of the arrays will be ignored and nothing will be drawn.This method will be affected by any of the global common, fill, or Fill Rule attributes as specified in the Rendering Attributes Table.
- Parameters:
xPoints
- array containing the x coordinates of the polygon's points or null.yPoints
- array containing the y coordinates of the polygon's points or null.nPoints
- the number of points that make the polygon.
-
strokePolygon
public void strokePolygon(double[] xPoints, double[] yPoints, int nPoints) Strokes a polygon with the given points using the currently set stroke paint. Anull
value for any of the arrays will be ignored and nothing will be drawn.This method will be affected by any of the global common or stroke attributes as specified in the Rendering Attributes Table.
- Parameters:
xPoints
- array containing the x coordinates of the polygon's points or null.yPoints
- array containing the y coordinates of the polygon's points or null.nPoints
- the number of points that make the polygon.
-
strokePolyline
public void strokePolyline(double[] xPoints, double[] yPoints, int nPoints) Strokes a polyline with the given points using the currently set stroke paint attribute. Anull
value for any of the arrays will be ignored and nothing will be drawn.This method will be affected by any of the global common or stroke attributes as specified in the Rendering Attributes Table.
- Parameters:
xPoints
- array containing the x coordinates of the polyline's points or null.yPoints
- array containing the y coordinates of the polyline's points or null.nPoints
- the number of points that make the polyline.
-
drawImage
Draws an image at the given x, y position using the width and height of the given image. Anull
image value or an image still in progress will be ignored.This method will be affected by any of the global common or image attributes as specified in the Rendering Attributes Table.
- Parameters:
img
- the image to be drawn or null.x
- the X coordinate on the destination for the upper left of the image.y
- the Y coordinate on the destination for the upper left of the image.
-
drawImage
Draws an image into the given destination rectangle of the canvas. The Image is scaled to fit into the destination rectangle. Anull
image value or an image still in progress will be ignored.This method will be affected by any of the global common or image attributes as specified in the Rendering Attributes Table.
- Parameters:
img
- the image to be drawn or null.x
- the X coordinate on the destination for the upper left of the image.y
- the Y coordinate on the destination for the upper left of the image.w
- the width of the destination rectangle.h
- the height of the destination rectangle.
-
drawImage
public void drawImage(Image img, double sx, double sy, double sw, double sh, double dx, double dy, double dw, double dh) Draws the specified source rectangle of the given image to the given destination rectangle of the Canvas. Anull
image value or an image still in progress will be ignored.This method will be affected by any of the global common or image attributes as specified in the Rendering Attributes Table.
- Parameters:
img
- the image to be drawn or null.sx
- the source rectangle's X coordinate position.sy
- the source rectangle's Y coordinate position.sw
- the source rectangle's width.sh
- the source rectangle's height.dx
- the destination rectangle's X coordinate position.dy
- the destination rectangle's Y coordinate position.dw
- the destination rectangle's width.dh
- the destination rectangle's height.
-
getPixelWriter
Returns aPixelWriter
object that can be used to modify the pixels of theCanvas
associated with thisGraphicsContext
. All coordinates in thePixelWriter
methods on the returned object will be in device space since they refer directly to pixels and no other rendering attributes will be applied when modifying pixels using this object.- Returns:
- the
PixelWriter
for modifying the pixels of thisCanvas
-
setEffect
Sets the effect to be applied after the next draw call, or null to disable effects. The current effect is a common attribute used for nearly all rendering operations as specified in the Rendering Attributes Table.- Parameters:
e
- the effect to use, or null to disable effects
-
getEffect
Gets a copy of the effect to be applied after the next draw call. A null return value means that no effect will be applied after subsequent rendering calls. The current effect is a common attribute used for nearly all rendering operations as specified in the Rendering Attributes Table.- Parameters:
e
- anEffect
object that may be used to store the copy of the current effect, if it is of a compatible type- Returns:
- the current effect used for all rendering calls, or null if there is no current effect
-
applyEffect
Applies the given effect to the entire bounds of the canvas and stores the result back into the same canvas. Anull
value will be ignored. The effect will be applied without any other rendering attributes and under an Identity coordinate transform. Since the effect is applied to the entire bounds of the canvas, some effects may have a confusing result, such as a Reflection effect that will apply its reflection off of the bottom of the canvas even if only a portion of the canvas has been rendered to and will not be visible unless a negative offset is used to bring the reflection back into view.- Parameters:
e
- the effect to apply onto the entire destination or null.
-