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com.cosylab.gui.components.gauger
Class ScaleTransform

java.lang.Object
  com.cosylab.gui.components.gauger.ScaleTransform

Direct Known Subclasses:

LinearHorizontalTransform, LinearVerticalTransform, PolarTransform

public abstract class ScaleTransform
extends java.lang.Object

Abstract utility class that provides the mathematic foundation for drawing the Gauger scales. Scale is defined in its own coordinate system with the axis (u, v). In this system the extents of the scale are defined to be (0, 0) and (1, 1), meaning that any point on this scale can be specified with the (u, v) parameter value between 0 and 1. This class is the implementation of this transformation and the component cartesian coordinate system.

Version:

$id$

Author:

Ales Pucelj

Nested Class Summary

class	ScaleTransform.ArcSegment Definition of arc scale segment.
class	ScaleTransform.LineSegment Class defining linear scale segment.
class	ScaleTransform.RectangleSegment Defines rectangular scale segment.
class	ScaleTransform.ScaleSegment Abstract base class for scale segments.

Constructor Summary

ScaleTransform()
Creates a new ScaleTransform object.

Method Summary

protected void	addSegment(ScaleTransform.ScaleSegment segment) Adds segment to this transform.
double	getAngle(double x) Returns angle between horizontal and specified relative position in scale space.
java.awt.Point	getLabelPosition() Returns the point where the label should be positioned.
ScaleTransform.ScaleSegment	getSegment(int i) Returns scale segment at specified index.
int	getSegmentCount() Returns the number of segments describing this scale.
boolean	isPolar() Returns whether this scale is polar.
java.awt.geom.Point2D	mapUVtoXY(double u, double v) Maps point specified with (u, v) coordinates in scale space to cartesian space with coordinates (x, y)
void	mapUVtoXY(double u, double v, java.awt.geom.Point2D cartesianSpace) Maps the point specified with (u, v) coordinates in the scale space to cartesian space with coordinates (x, y).
abstract void	mapUVtoXY(java.awt.geom.Point2D scaleSpace, java.awt.geom.Point2D cartesianSpace) Maps the point specified with (u, v) coordinates in the scale space to cartesian space with coordinates (x, y).
abstract int	measureTick(java.awt.Graphics g, double x, java.lang.String text) Measues the width of tick label.
abstract double	scaleHeight(double u) Returns the height of scale in pixels at the specified location u in the scale space.
abstract double	scaleWidth(double v) Returns the width of scale in pixels at the specified location v in the scale space.
protected void	setLabelPosition(int x, int y) Sets position of value label.
abstract void	setParameters(int w, int h, int marginX, int marginY, int tickOffset) Sets the component parameters for this transformation.
void	setPolar(boolean value) Sets whether this transform is polar.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

ScaleTransform

public ScaleTransform()

Creates a new ScaleTransform object.

Method Detail

setPolar

public void setPolar(boolean value)

Sets whether this transform is polar. A polar scale will be rendered in polar coordinates rather then cartesian. Lines will be rendered as arcs and text will be rotated.

Parameters:

value - True if polar.

isPolar

public boolean isPolar()

Returns whether this scale is polar.

Returns:

True if polar.

See Also:

setPolar(boolean)

setParameters

public abstract void setParameters(int w,
                                   int h,
                                   int marginX,
                                   int marginY,
                                   int tickOffset)

Sets the component parameters for this transformation.

Parameters:

w - width of the component that will display this transformation

h - height of the component that will display this transformation

marginX - not used

marginY - not used

tickOffset - space between the edge of the scale and the first tick

mapUVtoXY

public abstract void mapUVtoXY(java.awt.geom.Point2D scaleSpace,
                               java.awt.geom.Point2D cartesianSpace)

Maps the point specified with (u, v) coordinates in the scale space to cartesian space with coordinates (x, y). (u, v) values must be in [0..1] range, the (x, y) points will be in (0..w-1, 0..h-1) range.

Parameters:

scaleSpace - point in scale space

cartesianSpace - point in cartesian space

mapUVtoXY

public void mapUVtoXY(double u,
                      double v,
                      java.awt.geom.Point2D cartesianSpace)

Maps the point specified with (u, v) coordinates in the scale space to cartesian space with coordinates (x, y). (u, v) values must be in [0..1] range, the (x, y) points will be in (0..w-1, 0..h-1) range.

Parameters:

u - coordinate in scale space

v - coordinate in scale space

cartesianSpace - point in cartesian space

mapUVtoXY

public java.awt.geom.Point2D mapUVtoXY(double u,
                                       double v)

Maps point specified with (u, v) coordinates in scale space to cartesian space with coordinates (x, y)

Parameters:

u - coordinate in scale space.

v - coordinate in scale space.

Returns:

Point2D cartesianSpace point.

See Also:

mapUVtoXY(u, v, Point2D)

getAngle

public final double getAngle(double x)

Returns angle between horizontal and specified relative position in scale space. This angle is defined as angle between X axis and line from point (x, 0.0) to point (x, 100.0). This is the angle at which vertical straight line in polar mode is rotated in cartesian space.

Parameters:

x - Relative point in scale space in range 0.0 to 1.0.

Returns:

double angle in radians

scaleWidth

public abstract double scaleWidth(double v)

Returns the width of scale in pixels at the specified location v in the scale space. Although the scale for v is only defined in the range [0..1], this value can generaly return even values outside this range, although this is not guaranteed.

Returns:

Width of scale in pixels.

scaleHeight

public abstract double scaleHeight(double u)

Returns the height of scale in pixels at the specified location u in the scale space. Although the scale for u is only defined in the range [0..1], this value can generaly return even values outside this range, although this is not guaranteed.

Returns:

Height of scale in pixels.

getLabelPosition

public java.awt.Point getLabelPosition()

Returns the point where the label should be positioned. This point represents geometric center of the text. There are no limits to the size of the text written around this position.

Returns:

Center point for label.

getSegmentCount

public int getSegmentCount()

Returns the number of segments describing this scale. Even if the value is zero, this transform may still provide space transformation functionality.

Returns:

Number of segments.

addSegment

protected void addSegment(ScaleTransform.ScaleSegment segment)

Adds segment to this transform.

Parameters:

segment - to add.

getSegment

public ScaleTransform.ScaleSegment getSegment(int i)

Returns scale segment at specified index.

Parameters:

i - Index of segment.

Returns:

Scale segment.

setLabelPosition

protected void setLabelPosition(int x,
                                int y)

Sets position of value label. The position is center point of label.

Parameters:

x - coordinate of label center.

y - coordinate of label center.

measureTick

public abstract int measureTick(java.awt.Graphics g,
                                double x,
                                java.lang.String text)

Measues the width of tick label.

Parameters:

g - Graphic context.

x - Relative position of tick.

text - Tick label.

Returns:

Width of label in pixels.