ach
Class ImgCanvas

java.lang.Object
  |
  +--java.awt.Component
        |
        +--java.awt.Canvas
              |
              +--ach.ImgCanvas

All Implemented Interfaces:

javax.accessibility.Accessible, java.awt.image.ImageObserver, ImgComponentIntf, java.awt.MenuContainer, java.io.Serializable

public class ImgCanvas

extends java.awt.Canvas

implements ImgComponentIntf

ImgCanvas.java
Copyright (c) 1999-2002 Helge Hackbarth, All Rights Reserved.
Extends Canvas with comfortable image display functions and automatic drawing of background patterns. This component is heavyweight. In order to use the same functionality but as lightweight component e.g. for a JInternalFrame please use class ImgComponent.

THE AUTHOR MAKES NO REPRESENTATIONS OR WARRANTIES ABOUT THE SUITABILITY OF THE SOFTWARE, EITHER EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE IMPLIED WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, OR NON-INFRINGEMENT. THE AUTHOR SHALL NOT BE LIABLE FOR ANY DAMAGES SUFFERED BY LICENSEE AS A RESULT OF USING, MODIFYING OR DISTRIBUTING THIS SOFTWARE OR ITS DERIVATIVES.

See Also:

Serialized Form

Inner classes inherited from class java.awt.Canvas

java.awt.Canvas.AccessibleAWTCanvas

Inner classes inherited from class java.awt.Component

java.awt.Component.AccessibleAWTComponent

Field Summary

boolean	clearBackground Flag if background is simply cleared or drawn with a black-and-white pattern
boolean	clearBeforePaint Flag if canvas needs to be cleared before paint.
boolean	needsFocus Flag if canvas needs to request focus (e.g. in order to receive events in JDK 1.0).

Fields inherited from class java.awt.Component

BOTTOM_ALIGNMENT, CENTER_ALIGNMENT, LEFT_ALIGNMENT, RIGHT_ALIGNMENT, TOP_ALIGNMENT

Fields inherited from interface java.awt.image.ImageObserver

ABORT, ALLBITS, ERROR, FRAMEBITS, HEIGHT, PROPERTIES, SOMEBITS, WIDTH

Constructor Summary

ImgCanvas(java.awt.Container parent)
constructor for ImgCanvas

ImgCanvas(java.awt.Container parent, java.awt.image.ImageObserver observer)
constructor for ImgCanvas chaining to additional image observer

Method Summary

void	checkFocus() request focus if boolean var needsFocus is set true
void	drawError(java.lang.String errorMsg) schedule a repaint that will draw an error messages (may contain \r\n)
void	drawImage(java.awt.Image img, int x, int y) schedule a repaint with drawing the given image (not scaled)
void	drawImage(java.awt.Image img, int x, int y, int width, int height, int hints) schedule a repaint with drawing the given image (scaled)
void	drawShapes(ShapeList sl) draw vector graphics objects
void	fitInImage(java.awt.Image img, java.awt.Dimension imgDim, int hints) schedule a repaint with an image proportionally scaled to fit in canvas
boolean	getDoubleBuffering() Retrieve current setting of double buffering mode
java.awt.Image	getOffscreen() Get offscreen image
boolean	imageUpdate(java.awt.Image img, int flags, int x, int y, int w, int h) Image canvas is a modified ImageObserver to retry after ABORT and to be able to chain in another ImageObserver
void	paint(java.awt.Graphics g) the paint method of the image canvas
void	requestFocus()
void	resize(java.awt.Dimension d)
void	resize(int width, int height)
void	setBackground(java.awt.Color c)
void	setBackgroundExclusion(int x, int y, int width, int height) Specify the area that has to be excluded from drawing the background
void	setDoubleBuffering(boolean dblBufMode) Enable or disable double buffering when component is painted
void	setSize(java.awt.Dimension d)
void	setSize(int width, int height)
void	update(java.awt.Graphics g) the update method of the image canvas (calling paint()); drawing of the background is controlled by clearBeforePaint-flag

Methods inherited from class java.awt.Canvas

addNotify, getAccessibleContext

Methods inherited from class java.awt.Component

action, add, addComponentListener, addFocusListener, addHierarchyBoundsListener, addHierarchyListener, addInputMethodListener, addKeyListener, addMouseListener, addMouseMotionListener, addPropertyChangeListener, addPropertyChangeListener, bounds, checkImage, checkImage, coalesceEvents, contains, contains, createImage, createImage, deliverEvent, disable, disableEvents, dispatchEvent, doLayout, enable, enable, enableEvents, enableInputMethods, firePropertyChange, getAlignmentX, getAlignmentY, getBackground, getBounds, getBounds, getColorModel, getComponentAt, getComponentAt, getComponentOrientation, getCursor, getDropTarget, getFont, getFontMetrics, getForeground, getGraphics, getGraphicsConfiguration, getHeight, getInputContext, getInputMethodRequests, getListeners, getLocale, getLocation, getLocation, getLocationOnScreen, getMaximumSize, getMinimumSize, getName, getParent, getPeer, getPreferredSize, getSize, getSize, getToolkit, getTreeLock, getWidth, getX, getY, gotFocus, handleEvent, hasFocus, hide, inside, invalidate, isDisplayable, isDoubleBuffered, isEnabled, isFocusTraversable, isLightweight, isOpaque, isShowing, isValid, isVisible, keyDown, keyUp, layout, list, list, list, list, list, locate, location, lostFocus, minimumSize, mouseDown, mouseDrag, mouseEnter, mouseExit, mouseMove, mouseUp, move, nextFocus, paintAll, paramString, postEvent, preferredSize, prepareImage, prepareImage, print, printAll, processComponentEvent, processEvent, processFocusEvent, processHierarchyBoundsEvent, processHierarchyEvent, processInputMethodEvent, processKeyEvent, processMouseEvent, processMouseMotionEvent, remove, removeComponentListener, removeFocusListener, removeHierarchyBoundsListener, removeHierarchyListener, removeInputMethodListener, removeKeyListener, removeMouseListener, removeMouseMotionListener, removeNotify, removePropertyChangeListener, removePropertyChangeListener, repaint, repaint, repaint, repaint, reshape, setBounds, setBounds, setComponentOrientation, setCursor, setDropTarget, setEnabled, setFont, setForeground, setLocale, setLocation, setLocation, setName, setVisible, show, show, size, toString, transferFocus, validate

Methods inherited from class java.lang.Object

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

Field Detail

needsFocus

public boolean needsFocus

Flag if canvas needs to request focus (e.g. in order to receive events in JDK 1.0).

clearBeforePaint

public boolean clearBeforePaint

Flag if canvas needs to be cleared before paint. This class automatically draws a background pattern around the image, so usually clearing the background before painting is not necessary

clearBackground

public boolean clearBackground

Flag if background is simply cleared or drawn with a black-and-white pattern

Constructor Detail

ImgCanvas

public ImgCanvas(java.awt.Container parent)

constructor for ImgCanvas

Parameters:

parent - is the container where this canvas is to be embedded

ImgCanvas

public ImgCanvas(java.awt.Container parent,
                 java.awt.image.ImageObserver observer)

constructor for ImgCanvas chaining to additional image observer

Parameters:

parent - is the container where this canvas is to be embedded

observer - additional image observer to be chained in at drawImage

Method Detail

setDoubleBuffering

public void setDoubleBuffering(boolean dblBufMode)

Enable or disable double buffering when component is painted

Specified by:

setDoubleBuffering in interface ImgComponentIntf

Parameters:

dblBufMode - true to enable double buffering, false otherwise

getDoubleBuffering

public boolean getDoubleBuffering()

Retrieve current setting of double buffering mode

Specified by:

getDoubleBuffering in interface ImgComponentIntf

Returns:

true if double buffering is enabled, false otherwise

getOffscreen

public java.awt.Image getOffscreen()

Get offscreen image

Specified by:

getOffscreen in interface ImgComponentIntf

Returns:

image representing the current double buffer screen or null

resize

public void resize(java.awt.Dimension d)

Specified by:

resize in interface ImgComponentIntf

Overrides:

resize in class java.awt.Component

resize

public void resize(int width,
                   int height)

Specified by:

resize in interface ImgComponentIntf

Overrides:

resize in class java.awt.Component

setSize

public void setSize(java.awt.Dimension d)

Specified by:

setSize in interface ImgComponentIntf

Overrides:

setSize in class java.awt.Component

setSize

public void setSize(int width,
                    int height)

Specified by:

setSize in interface ImgComponentIntf

Overrides:

setSize in class java.awt.Component

setBackground

public void setBackground(java.awt.Color c)

Specified by:

setBackground in interface ImgComponentIntf

Overrides:

setBackground in class java.awt.Component

setBackgroundExclusion

public void setBackgroundExclusion(int x,
                                   int y,
                                   int width,
                                   int height)

Specify the area that has to be excluded from drawing the background

Specified by:

setBackgroundExclusion in interface ImgComponentIntf

Parameters:

x - the X-coordinate of the excluded area

y - the Y-coordinate of the excluded area

width - the width of the excluded area

height - the height of the excluded area

checkFocus

public void checkFocus()

Description copied from interface: ImgComponentIntf

request focus if boolean var needsFocus is set true

Specified by:

checkFocus in interface ImgComponentIntf

drawImage

public void drawImage(java.awt.Image img,
                      int x,
                      int y,
                      int width,
                      int height,
                      int hints)

schedule a repaint with drawing the given image (scaled)

Specified by:

drawImage in interface ImgComponentIntf

Parameters:

img - the image to be drawn

x - the X-coordinate of the image relative to canvas

y - the Y-coordinate of the image relative to canvas

width - the scaled width of the image

height - the scaled height of the image

hints - options for scaling method, see getScaledInstance (e.g. SCALE_SMOOTH)

See Also:

Image.getScaledInstance(int width, int height, int hints)

drawImage

public void drawImage(java.awt.Image img,
                      int x,
                      int y)

schedule a repaint with drawing the given image (not scaled)

Specified by:

drawImage in interface ImgComponentIntf

Parameters:

img - the image to be drawn

x - the X-coordinate of the image relative to canvas

y - the Y-coordinate of the image relative to canvas

fitInImage

public void fitInImage(java.awt.Image img,
                       java.awt.Dimension imgDim,
                       int hints)

schedule a repaint with an image proportionally scaled to fit in canvas

Specified by:

fitInImage in interface ImgComponentIntf

Parameters:

img - the image to be drawn

imgDim - the size of the image

hints - options for scaling method, see getScaledInstance (e.g. SCALE_SMOOTH)

See Also:

Image.getScaledInstance(int width, int height, int hints)

drawError

public void drawError(java.lang.String errorMsg)

schedule a repaint that will draw an error messages (may contain \r\n)

Specified by:

drawError in interface ImgComponentIntf

Parameters:

errorMsg - the error message

drawShapes

public void drawShapes(ShapeList sl)

draw vector graphics objects

Specified by:

drawShapes in interface ImgComponentIntf

Parameters:

ShapeList - containing vector graphics (e.g. annotations)

requestFocus

public void requestFocus()

Overrides:

requestFocus in class java.awt.Component

paint

public void paint(java.awt.Graphics g)

the paint method of the image canvas

Specified by:

paint in interface ImgComponentIntf

Overrides:

paint in class java.awt.Canvas

update

public void update(java.awt.Graphics g)

the update method of the image canvas (calling paint()); drawing of the background is controlled by clearBeforePaint-flag

Specified by:

update in interface ImgComponentIntf

Overrides:

update in class java.awt.Component

imageUpdate

public boolean imageUpdate(java.awt.Image img,
                           int flags,
                           int x,
                           int y,
                           int w,
                           int h)

Image canvas is a modified ImageObserver to retry after ABORT and to be able to chain in another ImageObserver

Specified by:

imageUpdate in interface ImgComponentIntf

Overrides:

imageUpdate in class java.awt.Component