Interface RenderingBackend
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- All Known Implementing Classes:
AwtRenderingBackend
,NoOpRenderingBackend
public interface RenderingBackend
Interface to the rendering context used byCanvasRenderingContext2D
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Nested Class Summary
Nested Classes Modifier and Type Interface Description static class
RenderingBackend.WindingRule
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Method Summary
All Methods Instance Methods Abstract Methods Modifier and Type Method Description void
arc(double x, double y, double radius, double startAngle, double endAngle, boolean anticlockwise)
Adds a circular arc to the current sub-path.void
beginPath()
Starts a new path by emptying the list of sub-paths.void
bezierCurveTo(double cp1x, double cp1y, double cp2x, double cp2y, double x, double y)
Adds a cubic Bézier curve to the current sub-path.void
clearRect(double x, double y, double w, double h)
Paints the specified rectangular area.void
clip(RenderingBackend.WindingRule windingRule, Path2D path)
Turns the current or given path into the current clipping region.void
closePath()
Attempts to add a straight line from the current point to the start of the current sub-path.void
drawImage(ImageData imageData, int sx, int sy, java.lang.Integer sWidth, java.lang.Integer sHeight, int dx, int dy, java.lang.Integer dWidth, java.lang.Integer dHeight)
Draws images onto the context.void
ellipse(double x, double y, double radiusX, double radiusY, double rotation, double startAngle, double endAngle, boolean anticlockwise)
Creates an elliptical arc centered at (x, y) with the radii radiusX and radiusY.java.lang.String
encodeToString(java.lang.String type)
Constructs a base64 encoded string out of the image data.void
fill()
Fills the current or given path with the current fillStyle.void
fillRect(int x, int y, int w, int h)
Paints the specified rectangular area.void
fillText(java.lang.String text, double x, double y)
Fills a given text at the given (x, y) position.byte[]
getBytes(int width, int height, int sx, int sy)
Creates a byte array containing the (4) color values of all pixels.double
getGlobalAlpha()
int
getLineWidth()
Returns thelineWidth
property.void
lineTo(double x, double y)
Adds a straight line to the current sub-path by connecting the sub-path's last point to the specified (x, y) coordinates.void
moveTo(double x, double y)
Begins a new sub-path at the point specified by the given (x, y) coordinates.void
putImageData(byte[] imageDataBytes, int imageDataHeight, int imageDataWidth, int dx, int dy, int dirtyX, int dirtyY, int dirtyWidth, int dirtyHeight)
Paints data from the given ImageData object onto the canvas.void
quadraticCurveTo(double cpx, double cpy, double x, double y)
Adds a quadratic Bézier curve to the current sub-path.void
rect(double x, double y, double w, double h)
Adds a rectangle to the current path.void
restore()
Restores the most recently saved canvas state by popping the top entry in the drawing state stack.void
rotate(double angle)
Adds a rotation to the transformation matrix.void
save()
Saves the entire state of the canvas by pushing the current state onto a stack.void
setFillStyle(java.lang.String fillStyle)
Sets thefillStyle
property.void
setGlobalAlpha(double globalAlpha)
Specifies the alpha (transparency) value that is applied to shapes and images before they are drawn onto the canvas.void
setLineWidth(int lineWidth)
Sets thelineWidth
property.void
setStrokeStyle(java.lang.String strokeStyle)
Sets thestrokeStyle
property.void
setTransform(double m11, double m12, double m21, double m22, double dx, double dy)
Resets (overrides) the current transformation to the identity matrix, and then invokes a transformation described by the arguments of this method.void
stroke()
Strokes (outlines) the current or given path with the current stroke style.void
strokeRect(int x, int y, int w, int h)
Paints the specified rectangular area.void
transform(double m11, double m12, double m21, double m22, double dx, double dy)
Multiplies the current transformation with the matrix described by the arguments of this method.void
translate(int x, int y)
Adds a translation transformation to the current matrix.
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Method Detail
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beginPath
void beginPath()
Starts a new path by emptying the list of sub-paths.
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bezierCurveTo
void bezierCurveTo(double cp1x, double cp1y, double cp2x, double cp2y, double x, double y)
Adds a cubic Bézier curve to the current sub-path. It requires three points: the first two are control points and the third one is the end point. The starting point is the latest point in the current path, which can be changed using moveTo() before creating the Bézier curve.- Parameters:
cp1x
- the cp1xcp1y
- the cp1ycp2x
- the cp2xcp2y
- the cp2yx
- the xy
- the y
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arc
void arc(double x, double y, double radius, double startAngle, double endAngle, boolean anticlockwise)
Adds a circular arc to the current sub-path.- Parameters:
x
- the xy
- the yradius
- the radiusstartAngle
- the start angleendAngle
- the end angleanticlockwise
- is anti-clockwise
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clearRect
void clearRect(double x, double y, double w, double h)
Paints the specified rectangular area.- Parameters:
x
- the xy
- the yw
- the widthh
- the height
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drawImage
void drawImage(ImageData imageData, int sx, int sy, java.lang.Integer sWidth, java.lang.Integer sHeight, int dx, int dy, java.lang.Integer dWidth, java.lang.Integer dHeight) throws java.io.IOException
Draws images onto the context.- Parameters:
imageData
- the reader to read the image from 8the first one)sx
- the X coordinate of the top left corner of the sub-rectangle of the source image to draw into the destination contextsy
- the Y coordinate of the top left corner of the sub-rectangle of the source image to draw into the destination contextsWidth
- the width of the sub-rectangle of the source image to draw into the destination contextsHeight
- the height of the sub-rectangle of the source image to draw into the destination contextdx
- the X coordinate in the destination canvas at which to place the top-left corner of the source imagedy
- the Y coordinate in the destination canvas at which to place the top-left corner of the source imagedWidth
- the width to draw the image in the destination canvas. This allows scaling of the drawn imagedHeight
- the height to draw the image in the destination canvas. This allows scaling of the drawn image- Throws:
java.io.IOException
- in case o problems
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encodeToString
java.lang.String encodeToString(java.lang.String type) throws java.io.IOException
Constructs a base64 encoded string out of the image data.- Parameters:
type
- the name of the image format- Returns:
- the base64 encoded string
- Throws:
java.io.IOException
- in case o problems
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ellipse
void ellipse(double x, double y, double radiusX, double radiusY, double rotation, double startAngle, double endAngle, boolean anticlockwise)
Creates an elliptical arc centered at (x, y) with the radii radiusX and radiusY. The path starts at startAngle and ends at endAngle, and travels in the direction given by anticlockwise (defaulting to clockwise).- Parameters:
x
- the xy
- the yradiusX
- the radiusXradiusY
- the radiusYrotation
- the rotationstartAngle
- the start angleendAngle
- the end angleanticlockwise
- is anti-clockwise
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fill
void fill()
Fills the current or given path with the current fillStyle.
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fillRect
void fillRect(int x, int y, int w, int h)
Paints the specified rectangular area.- Parameters:
x
- the xy
- the yw
- the widthh
- the height
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fillText
void fillText(java.lang.String text, double x, double y)
Fills a given text at the given (x, y) position.- Parameters:
text
- the textx
- the xy
- the y
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getBytes
byte[] getBytes(int width, int height, int sx, int sy)
Creates a byte array containing the (4) color values of all pixels.- Parameters:
width
- the widthheight
- the heightsx
- start point xsy
- start point y- Returns:
- the bytes
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lineTo
void lineTo(double x, double y)
Adds a straight line to the current sub-path by connecting the sub-path's last point to the specified (x, y) coordinates.- Parameters:
x
- the xy
- the y
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moveTo
void moveTo(double x, double y)
Begins a new sub-path at the point specified by the given (x, y) coordinates.- Parameters:
x
- the xy
- the y
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putImageData
void putImageData(byte[] imageDataBytes, int imageDataHeight, int imageDataWidth, int dx, int dy, int dirtyX, int dirtyY, int dirtyWidth, int dirtyHeight)
Paints data from the given ImageData object onto the canvas.- Parameters:
imageDataBytes
- an array of pixel valuesimageDataHeight
- the height of the imageDataimageDataWidth
- the width of the imageDatadx
- horizontal position (x coordinate) at which to place the image data in the destination canvasdy
- vertical position (y coordinate) at which to place the image data in the destination canvasdirtyX
- horizontal position (x coordinate) of the top-left corner from which the image data will be extracted. Defaults to 0.dirtyY
- vertical position (y coordinate) of the top-left corner from which the image data will be extracted. Defaults to 0.dirtyWidth
- width of the rectangle to be painted. Defaults to the width of the image data.dirtyHeight
- height of the rectangle to be painted. Defaults to the height of the image data.
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quadraticCurveTo
void quadraticCurveTo(double cpx, double cpy, double x, double y)
Adds a quadratic Bézier curve to the current sub-path. It requires two points: the first one is a control point and the second one is the end point. The starting point is the latest point in the current path, which can be changed using moveTo() before creating the quadratic Bézier curve.- Parameters:
cpx
- the cpxcpy
- the cpyx
- the xy
- the y
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rect
void rect(double x, double y, double w, double h)
Adds a rectangle to the current path.- Parameters:
x
- the xy
- the yw
- the widthh
- the height
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restore
void restore()
Restores the most recently saved canvas state by popping the top entry in the drawing state stack. If there is no saved state, this method does nothing.
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rotate
void rotate(double angle)
Adds a rotation to the transformation matrix.- Parameters:
angle
- the angle
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save
void save()
Saves the entire state of the canvas by pushing the current state onto a stack.
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setFillStyle
void setFillStyle(java.lang.String fillStyle)
Sets thefillStyle
property.- Parameters:
fillStyle
- thefillStyle
property
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setStrokeStyle
void setStrokeStyle(java.lang.String strokeStyle)
Sets thestrokeStyle
property.- Parameters:
strokeStyle
- thestrokeStyle
property
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getLineWidth
int getLineWidth()
Returns thelineWidth
property.- Returns:
- the
lineWidth
property
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setLineWidth
void setLineWidth(int lineWidth)
Sets thelineWidth
property.- Parameters:
lineWidth
- thelineWidth
property
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setTransform
void setTransform(double m11, double m12, double m21, double m22, double dx, double dy)
Resets (overrides) the current transformation to the identity matrix, and then invokes a transformation described by the arguments of this method. This lets you scale, rotate, translate (move), and skew the context.- Parameters:
m11
- Horizontal scaling. A value of 1 results in no scalingm12
- Vertical skewingm21
- Horizontal skewingm22
- Vertical scaling. A value of 1 results in no scalingdx
- Horizontal translation (moving)dy
- Vertical translation (moving).
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stroke
void stroke()
Strokes (outlines) the current or given path with the current stroke style.
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strokeRect
void strokeRect(int x, int y, int w, int h)
Paints the specified rectangular area.- Parameters:
x
- the xy
- the yw
- the widthh
- the height
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transform
void transform(double m11, double m12, double m21, double m22, double dx, double dy)
Multiplies the current transformation with the matrix described by the arguments of this method. This lets you scale, rotate, translate (move), and skew the context.- Parameters:
m11
- Horizontal scaling. A value of 1 results in no scalingm12
- Vertical skewingm21
- Horizontal skewingm22
- Vertical scaling. A value of 1 results in no scalingdx
- Horizontal translation (moving)dy
- Vertical translation (moving).
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translate
void translate(int x, int y)
Adds a translation transformation to the current matrix.- Parameters:
x
- the xy
- the y
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clip
void clip(RenderingBackend.WindingRule windingRule, Path2D path)
Turns the current or given path into the current clipping region. It replaces any previous clipping region.- Parameters:
windingRule
- the RenderingBackend.WindingRuleRenderingBackend.WindingRule
to be usedpath
- the path or null if the current path should be used
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closePath
void closePath()
Attempts to add a straight line from the current point to the start of the current sub-path. If the shape has already been closed or has only one point, this function does nothing.
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getGlobalAlpha
double getGlobalAlpha()
- Returns:
- the alpha (transparency) value that is applied to shapes and images before they are drawn onto the canvas.
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setGlobalAlpha
void setGlobalAlpha(double globalAlpha)
Specifies the alpha (transparency) value that is applied to shapes and images before they are drawn onto the canvas.- Parameters:
globalAlpha
- the new alpha
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