org.htmlunit.platform.canvas.rendering

Interface RenderingBackend

All Known Implementing Classes:

AwtRenderingBackend, NoOpRenderingBackend

public interface RenderingBackend

Interface to the rendering context used by CanvasRenderingContext2D.

Author:

Ronald Brill

Nested Class Summary

Nested Classes

Modifier and Type	Interface and Description
static class	RenderingBackend.WindingRule WindingRule to be used while rendering.

Method Summary

Modifier and Type	Method and 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, Integer sWidth, Integer sHeight, int dx, int dy, Integer dWidth, 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.
String	encodeToString(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(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 the lineWidth 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(String fillStyle) Sets the fillStyle 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 the lineWidth property.
void	setStrokeStyle(String strokeStyle) Sets the strokeStyle 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.

Method Detail

beginPath

void beginPath()

Starts a new path by emptying the list of sub-paths.

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 cp1x

cp1y - the cp1y

cp2x - the cp2x

cp2y - the cp2y

x - the x

y - the y

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 x

y - the y

radius - the radius

startAngle - the start angle

endAngle - the end angle

anticlockwise - is anti-clockwise

clearRect

void clearRect(double x,
               double y,
               double w,
               double h)

Paints the specified rectangular area.

Parameters:

x - the x

y - the y

w - the width

h - the height

drawImage

void drawImage(ImageData imageData,
               int sx,
               int sy,
               Integer sWidth,
               Integer sHeight,
               int dx,
               int dy,
               Integer dWidth,
               Integer dHeight)
        throws 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 context

sy - the Y coordinate of the top left corner of the sub-rectangle of the source image to draw into the destination context

sWidth - the width of the sub-rectangle of the source image to draw into the destination context

sHeight - the height of the sub-rectangle of the source image to draw into the destination context

dx - the X coordinate in the destination canvas at which to place the top-left corner of the source image

dy - the Y coordinate in the destination canvas at which to place the top-left corner of the source image

dWidth - the width to draw the image in the destination canvas. This allows scaling of the drawn image

dHeight - the height to draw the image in the destination canvas. This allows scaling of the drawn image

Throws:

IOException - in case o problems

encodeToString

String encodeToString(String type)
               throws 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:

IOException - in case o problems

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 x

y - the y

radiusX - the radiusX

radiusY - the radiusY

rotation - the rotation

startAngle - the start angle

endAngle - the end angle

anticlockwise - is anti-clockwise

fill

void fill()

Fills the current or given path with the current fillStyle.

fillRect

void fillRect(int x,
              int y,
              int w,
              int h)

Paints the specified rectangular area.

Parameters:

x - the x

y - the y

w - the width

h - the height

fillText

void fillText(String text,
              double x,
              double y)

Fills a given text at the given (x, y) position.

Parameters:

text - the text

x - the x

y - the y

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 width

height - the height

sx - start point x

sy - start point y

Returns:

the bytes

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 x

y - the y

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 x

y - the y

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 values

imageDataHeight - the height of the imageData

imageDataWidth - the width of the imageData

dx - horizontal position (x coordinate) at which to place the image data in the destination canvas

dy - vertical position (y coordinate) at which to place the image data in the destination canvas

dirtyX - 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.

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 cpx

cpy - the cpy

x - the x

y - the y

rect

void rect(double x,
          double y,
          double w,
          double h)

Adds a rectangle to the current path.

Parameters:

x - the x

y - the y

w - the width

h - the height

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.

rotate

void rotate(double angle)

Adds a rotation to the transformation matrix.

Parameters:

angle - the angle

save

void save()

Saves the entire state of the canvas by pushing the current state onto a stack.

setFillStyle

void setFillStyle(String fillStyle)

Sets the fillStyle property.

Parameters:

fillStyle - the fillStyle property

setStrokeStyle

void setStrokeStyle(String strokeStyle)

Sets the strokeStyle property.

Parameters:

strokeStyle - the strokeStyle property

getLineWidth

int getLineWidth()

Returns the lineWidth property.

Returns:

the lineWidth property

setLineWidth

void setLineWidth(int lineWidth)

Sets the lineWidth property.

Parameters:

lineWidth - the lineWidth property

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 scaling

m12 - Vertical skewing

m21 - Horizontal skewing

m22 - Vertical scaling. A value of 1 results in no scaling

dx - Horizontal translation (moving)

dy - Vertical translation (moving).

stroke

void stroke()

Strokes (outlines) the current or given path with the current stroke style.

strokeRect

void strokeRect(int x,
                int y,
                int w,
                int h)

Paints the specified rectangular area.

Parameters:

x - the x

y - the y

w - the width

h - the height

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 scaling

m12 - Vertical skewing

m21 - Horizontal skewing

m22 - Vertical scaling. A value of 1 results in no scaling

dx - Horizontal translation (moving)

dy - Vertical translation (moving).

translate

void translate(int x,
               int y)

Adds a translation transformation to the current matrix.

Parameters:

x - the x

y - the y

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.WindingRule RenderingBackend.WindingRule to be used

path - the path or null if the current path should be used

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.

getGlobalAlpha

double getGlobalAlpha()

Returns:

the alpha (transparency) value that is applied to shapes and images before they are drawn onto the canvas.

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