BufferedImageWorker

java.lang.Object

org.rrd4j.graph.ImageWorker

org.rrd4j.graph.BufferedImageWorker

class BufferedImageWorkerextends ImageWorker

Image worker implementation that creates buffered images for RRD graphs. Provides functionality to create, manipulate, and save graph images in various formats.

Nested Class Summary
Nested Classes
Modifier and Type
Class
Description
(package private) static class
BufferedImageWorker.Builder
Builder class for creating BufferedImageWorker instances with configurable parameters.
Field Summary
Fields
Modifier and Type
Field
Description
private BufferedImage
img
The image being written out.
private int
imgHeight
Height of the image.
private int
imgWidth
Width of the image.
private AffineTransform
initialAffineTransform
Initial affine transform
private final ImageWriteParam
iwp
Parameters given to the writer.
private final ImageWriter
writer
Writer that writes the image out.
Fields inherited from class ImageWorker
DEFAULT_TRANSITION_WIDTH
Modifier and Type
Field
Description
(package private) static final int
DEFAULT_TRANSITION_WIDTH
Default pixels of width given to a transition narrower than one pixel.
Constructor Summary
Constructors
Modifier
Constructor
Description
(package private)
BufferedImageWorker(int width, int height)
Not for use, only for tests
private
BufferedImageWorker(BufferedImageWorker.Builder builder)
Builds the worker from its builder.
Method Summary
Modifier and Type
Method
Description
static BufferedImageWorker.Builder
getBuilder()
Creates a new builder for BufferedImageWorker.
(package private) void
makeImage(OutputStream stream)
Creates and writes the image to the specified output stream.
protected void
reset(Graphics2D g2d)
Reset the allocator state
(package private) void
resize(int width, int height)
Resizes the worker to the specified dimensions.
Methods inherited from class ImageWorker
areaOutlineFlat, areaOutlineVariable, clip, dispose, drawLine, drawPolyline, drawPolylineSmooth, drawString, fillPolygon, fillPolygon, fillPolygonSmooth, fillRect, getFontAscent, getFontHeight, getImageBytes, getStringWidth, isSmoothing, loadImage, makeImage, reduceVertices, reset, resetState, runAnchorX, saveImage, setAntiAliasing, setG2d, setSmoothing, setTextAntiAliasing, setTransitionWidth, smoothedRun, transform
Modifier and Type
Method
Description
(package private) static int
areaOutlineFlat(double[] x, double[] yTop, int start, int end, double yBottom, int[] xDev, int[] yDev)
Builds the closed outline of an area whose lower boundary is the graph baseline.
(package private) static int
areaOutlineVariable(double[] x, double[] yBottom, double[] yTop, int start, int end, int[] xDev, int[] yDev)
Builds the closed outline of an area whose lower boundary is itself a plotted series, as used by stacked plots.
(package private) void
clip(int x, int y, int width, int height)
Set the clipping region for drawing operations.
(package private) void
dispose()
Dispose of the graphics context.
(package private) void
drawLine(int x1, int y1, int x2, int y2, Paint paint, Stroke stroke)
Draw a line with the given paint and stroke.
(package private) void
drawPolyline(double[] x, double[] y, Paint paint, Stroke stroke)
Draw a polyline with the given paint and stroke.
(package private) void
drawPolylineSmooth(double[] x, double[] y, Paint paint, Stroke stroke)
Draw a polyline as a smoothed curve.
(package private) void
drawString(String text, int x, int y, Font font, Paint paint)
Draw a string at the given position with the specified font and paint.
(package private) void
fillPolygon(double[] x, double[] yBottom, double[] yTop, Paint paint)
Fill a polygon with variable bottom points.
(package private) void
fillPolygon(double[] x, double yBottom, double[] yTop, Paint paint)
Fill a polygon with a flat bottom.
(package private) void
fillPolygonSmooth(double[] x, double yBottom, double[] yTop, Paint paint)
Fill an area with a flat lower boundary, drawn as a smoothed curve.
(package private) void
fillRect(int x, int y, int width, int height, Paint paint)
Fill a rectangle with the given paint.
(package private) double
getFontAscent(Font font)
Get the ascent of the given font.
(package private) double
getFontHeight(Font font)
Get the total height of the given font.
(package private) byte[]
getImageBytes()
Get the image as a byte array.
(package private) double
getStringWidth(String text, Font font)
Get the width of the given text in the specified font.
(package private) boolean
isSmoothing()
Reports whether plots are drawn as bezier curves rather than as steps.
(package private) void
loadImage(RrdGraphDef.ImageSource imageSource, int x, int y, int w, int h)
Load and draw an image from the given source.
(package private) void
makeImage(Path path)
Write the image to the given path.
(package private) static int
reduceVertices(double[] x, double[] y, int from, int to, boolean reverse, int[] xDev, int[] yDev, int c)
Append the step-collapsed vertices of y over [start, end) into xDev/yDev, continuing from index c.
(package private) void
reset()
Reset the graphics state.
protected void
resetState()
Resets cached state tracking.
(package private) static int
runAnchorX(double[] x, int start)
Leftmost column a run of samples may be drawn at, matching where the step renderer anchors the same run.
(package private) void
saveImage(String path)
Save the image to the given file path.
(package private) void
setAntiAliasing(boolean enable)
Enable or disable anti-aliasing.
protected void
setG2d(Graphics2D g2d)
Sets the graphics context for drawing operations.
(package private) void
setSmoothing(boolean smoothing)
Selects whether plots are drawn as bezier curves or as steps.
(package private) void
setTextAntiAliasing(boolean enable)
Enable or disable text anti-aliasing.
(package private) void
setTransitionWidth(int pixels)
Sets how much width a sub-pixel transition may borrow from the flat runs beside it.
(package private) static GeneralPath
smoothedRun(double[] x, double[] y, int start, int end, int[] xDev, int[] yDev, int transitionWidth)
Builds the smoothed curve through one gap-free run of samples: the run is reduced to step-collapsed vertices, anchored and widened, and then interpolated.
(package private) void
transform(int x, int y, double angle)
Apply a translation and rotation transform.
Methods inherited from class Object
clone, equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Details
- img
  private BufferedImage img
  The image being written out.
- imgWidth
  private int imgWidth
  Width of the image.
- imgHeight
  private int imgHeight
  Height of the image.
- initialAffineTransform
  private AffineTransform initialAffineTransform
  Initial affine transform
- writer
  private final ImageWriter writer
  Writer that writes the image out.
- iwp
  private final ImageWriteParam iwp
  Parameters given to the writer.
Constructor Details
- BufferedImageWorker
  private BufferedImageWorker(BufferedImageWorker.Builder builder)
  Builds the worker from its builder.
  Parameters:
  builder - the builder holding the image and parameters
- BufferedImageWorker
  BufferedImageWorker(int width, int height)
  Not for use, only for tests
  Parameters:
  width - the width in pixels
  height - the height in pixels
Method Details
- getBuilder
  public static BufferedImageWorker.Builder getBuilder()
  Creates a new builder for BufferedImageWorker.
  Returns:
  A new builder instance.
- resize
  void resize(int width, int height)
  Resizes the worker to the specified dimensions.
  Specified by:
  resize in class ImageWorker
  Parameters:
  width - The new width in pixels.
  height - The new height in pixels.
- reset
  protected void reset(Graphics2D g2d)
  Reset the allocator state
  Specified by:
  reset in class ImageWorker
  Parameters:
  g2d - the graphics context
- makeImage
  void makeImage(OutputStream stream) throws IOException
  Creates and writes the image to the specified output stream.
  Specified by:
  makeImage in class ImageWorker
  Parameters:
  stream - The output stream to write the image to.
  Throws:
  IOException - If an I/O error occurs during writing.

Nested Class Summary

Field Summary

Fields inherited from class ImageWorker

Constructor Summary

Method Summary

Methods inherited from class ImageWorker

Methods inherited from class Object

Field Details

img

imgWidth

imgHeight

initialAffineTransform

writer

iwp

Constructor Details

BufferedImageWorker

Method Details

getBuilder

resize

reset

makeImage