com.nokia.mid.ui
Class CanvasGraphicsItem

java.lang.Object
  com.nokia.mid.ui.CanvasItem
      com.nokia.mid.ui.CanvasGraphicsItem

public abstract class CanvasGraphicsItem
extends CanvasItem

A paintable item that can be used on top of Canvas or CustomItem

Field Summary

Fields inherited from class com.nokia.mid.ui.CanvasItem

SCALE_AVERAGE, SCALE_NEAREST, SCALE_NOT_ALLOWED

Constructor Summary

CanvasGraphicsItem(int width, int height)

Method Summary

int	getContentHeight() Gets the content's height in pixels.
int	getContentWidth() Gets the content's width in pixels.
protected abstract void	paint(javax.microedition.lcdui.Graphics g) Renders the CanvasGraphicsItem.
void	repaint() Requests a repaint for the entire CanvasGraphicsItem.
void	repaint(int x, int y, int width, int height) Requests a repaint for the specified region of the CanvasGraphicsItem.
void	setParent(java.lang.Object theParent) Set the parent object of this CanvasItem.

Methods inherited from class com.nokia.mid.ui.CanvasItem

getHeight, getParent, getPositionX, getPositionY, getWidth, getZPosition, isValidImageAnchor, isVisible, scale, scale, setPosition, setScalingMode, setSize, setSize, setVisible, setZPosition

Methods inherited from class java.lang.Object

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

Constructor Detail

CanvasGraphicsItem

public CanvasGraphicsItem(int width,
                          int height)
                   throws java.lang.IllegalArgumentException

Throws:

java.lang.IllegalArgumentException

Method Detail

setParent

public void setParent(java.lang.Object theParent)

Set the parent object of this CanvasItem. Typically in the parent object would be Canvas or CustomItem. Setting the parameter to null removes the association to the parent. If setParent(null) is called for a CanvasItem yet not having any parent the call is silently ignored.

Overrides:

setParent in class CanvasItem

Parameters:

theParent - the parent object

Throws:

java.lang.IllegalArgumentException - if parent is not a valid object with which a TextEditor can be associated, or if CanvasItem is already set to another another parent

paint

protected abstract void paint(javax.microedition.lcdui.Graphics g)

Renders the CanvasGraphicsItem. The application implements this method to paint graphics on CanvasGraphicsItem. CanvasGraphicsItem paint works in the same way as Canvas paint method. The only difference to Canvas paint method is that application does not need to paint all the pixels of the clip region as platform ensures that the clip region needing updating is cleared and fully transparent before paint is called. Content rendered by application in previous paint method calls is not available in the clip region. Coordinates used in Graphics methods are relative to CanvasGraphicsItem itself. This means (0,0) coordinate is top left pixel of CanvasGraphicsItem as positioned in the containing parent (e.g. Canvas).

Parameters:

g - the Graphics object to be used for rendering the Canvas

repaint

public void repaint()

Requests a repaint for the entire CanvasGraphicsItem. The effect is identical to repaint(0, 0, getWidth(), getHeight());

repaint

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

Requests a repaint for the specified region of the CanvasGraphicsItem. Coordinates are relative to the CanvasGraphicsItem coordinates. The method works in similar manner as Canvas repaint method.

Parameters:

x - the x coordinate of the rectangle to be repainted

y - the y coordinate of the rectangle to be repainted

width - the width of the rectangle to be repainted

height - the height of the rectangle to be repainted

getContentWidth

public int getContentWidth()

Gets the content's width in pixels. When widget is not scaled this is same as calling CanvasItem.getWidth().

Returns:

width in pixels.

getContentHeight

public int getContentHeight()

Gets the content's height in pixels. When widget is not scaled this is same as calling CanvasItem.getHeight().

Returns:

width in pixels.