ImageView (Java 2 Platform SE 5.0) - JDK 5 Documentation v1.5.0, Java 2 SDK 英文文档

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Java^TM 2 Platform
Standard Ed. 5.0

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javax.swing.text.html
Class ImageView

java.lang.Object
  javax.swing.text.View
      javax.swing.text.html.ImageView

All Implemented Interfaces:: SwingConstants

public class ImageView
extends View
extends View

View of an Image, intended to support the HTML <IMG> tag. Supports scaling via the HEIGHT and WIDTH attributes of the tag. If the image is unable to be loaded any text specified via the ALT attribute will be rendered.

While this class has been part of swing for a while now, it is public as of 1.4.

Since:: 1.4
See Also:: IconView

Field Summary

Fields inherited from class javax.swing.text.View

BadBreakWeight, ExcellentBreakWeight, ForcedBreakWeight, GoodBreakWeight, X_AXIS, Y_AXIS

Fields inherited from interface javax.swing.SwingConstants

BOTTOM, CENTER, EAST, HORIZONTAL, LEADING, LEFT, NEXT, NORTH, NORTH_EAST, NORTH_WEST, PREVIOUS, RIGHT, SOUTH, SOUTH_EAST, SOUTH_WEST, TOP, TRAILING, VERTICAL, WEST

Constructor Summary

ImageView(Element elem)
          Creates a new view that represents an IMG element.

Method Summary

void changedUpdate(DocumentEvent e, Shape a, ViewFactory f)
          Invoked when the Elements attributes have changed.

float getAlignment(int axis)
          Determines the desired alignment for this view along an axis.

String getAltText()
          Returns the text to display if the image can't be loaded.

AttributeSet getAttributes()
          Fetches the attributes to use when rendering.

Image getImage()
          Returns the image to render.

URL getImageURL()
          Return a URL for the image source, or null if it could not be determined.

Icon getLoadingImageIcon()
          Returns the icon to use while in the process of loading the image.

boolean getLoadsSynchronously()
          Returns true if the image should be loaded when first asked for.

Icon getNoImageIcon()
          Returns the icon to use if the image couldn't be found.

float getPreferredSpan(int axis)
          Determines the preferred span for this view along an axis.

protected StyleSheet getStyleSheet()
          Convenience method to get the StyleSheet.

String getToolTipText(float x, float y, Shape allocation)
          For images the tooltip text comes from text specified with the ALT attribute.

Shape modelToView(int pos, Shape a, Position.Bias b)
          Provides a mapping from the document model coordinate space to the coordinate space of the view mapped to it.

void paint(Graphics g, Shape a)
          Paints the View.

void setLoadsSynchronously(boolean newValue)
          Sets how the image is loaded.

void setParent(View parent)
          Establishes the parent view for this view.

protected void setPropertiesFromAttributes()
          Update any cached values that come from attributes.

void setSize(float width, float height)
          Sets the size of the view.

int viewToModel(float x, float y, Shape a, Position.Bias[] bias)
          Provides a mapping from the view coordinate space to the logical coordinate space of the model.

Methods inherited from class javax.swing.text.View

append, breakView, createFragment, forwardUpdate, forwardUpdateToView, getBreakWeight, getChildAllocation, getContainer, getDocument, getElement, getEndOffset, getGraphics, getMaximumSpan, getMinimumSpan, getNextVisualPositionFrom, getParent, getResizeWeight, getStartOffset, getView, getViewCount, getViewFactory, getViewIndex, getViewIndex, insert, insertUpdate, isVisible, modelToView, modelToView, preferenceChanged, remove, removeAll, removeUpdate, replace, updateChildren, updateLayout, viewToModel

Methods inherited from class java.lang.Object

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

Fields inherited from class javax.swing.text.View
`BadBreakWeight, ExcellentBreakWeight, ForcedBreakWeight, GoodBreakWeight, X_AXIS, Y_AXIS`

Fields inherited from interface javax.swing.SwingConstants
`BOTTOM, CENTER, EAST, HORIZONTAL, LEADING, LEFT, NEXT, NORTH, NORTH_EAST, NORTH_WEST, PREVIOUS, RIGHT, SOUTH, SOUTH_EAST, SOUTH_WEST, TOP, TRAILING, VERTICAL, WEST`

Constructor Summary
`ImageView(Element elem)` Creates a new view that represents an IMG element.

Method Summary
`void`	`changedUpdate(DocumentEvent e, Shape a, ViewFactory f)` Invoked when the Elements attributes have changed.
`float`	`getAlignment(int axis)` Determines the desired alignment for this view along an axis.
`String`	`getAltText()` Returns the text to display if the image can't be loaded.
`AttributeSet`	`getAttributes()` Fetches the attributes to use when rendering.
`Image`	`getImage()` Returns the image to render.
`URL`	`getImageURL()` Return a URL for the image source, or null if it could not be determined.
`Icon`	`getLoadingImageIcon()` Returns the icon to use while in the process of loading the image.
`boolean`	`getLoadsSynchronously()` Returns true if the image should be loaded when first asked for.
`Icon`	`getNoImageIcon()` Returns the icon to use if the image couldn't be found.
`float`	`getPreferredSpan(int axis)` Determines the preferred span for this view along an axis.
`protected StyleSheet`	`getStyleSheet()` Convenience method to get the StyleSheet.
`String`	`getToolTipText(float x, float y, Shape allocation)` For images the tooltip text comes from text specified with the `ALT` attribute.
`Shape`	`modelToView(int pos, Shape a, Position.Bias b)` Provides a mapping from the document model coordinate space to the coordinate space of the view mapped to it.
`void`	`paint(Graphics g, Shape a)` Paints the View.
`void`	`setLoadsSynchronously(boolean newValue)` Sets how the image is loaded.
`void`	`setParent(View parent)` Establishes the parent view for this view.
`protected void`	`setPropertiesFromAttributes()` Update any cached values that come from attributes.
`void`	`setSize(float width, float height)` Sets the size of the view.
`int`	`viewToModel(float x, float y, Shape a, Position.Bias[] bias)` Provides a mapping from the view coordinate space to the logical coordinate space of the model.

Methods inherited from class javax.swing.text.View
append, breakView, createFragment, forwardUpdate, forwardUpdateToView, getBreakWeight, getChildAllocation, getContainer, getDocument, getElement, getEndOffset, getGraphics, getMaximumSpan, getMinimumSpan, getNextVisualPositionFrom, getParent, getResizeWeight, getStartOffset, getView, getViewCount, getViewFactory, getViewIndex, getViewIndex, insert, insertUpdate, isVisible, modelToView, modelToView, preferenceChanged, remove, removeAll, removeUpdate, replace, updateChildren, updateLayout, viewToModel

Methods inherited from class java.lang.Object
`clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait`

Constructor Detail

ImageView

public ImageView(Element elem)

Creates a new view that represents an IMG element.

Parameters:: elem - the element to create a view for

Method Detail

getAltText

public String getAltText()

Returns the text to display if the image can't be loaded. This is obtained from the Elements attribute set with the attribute name HTML.Attribute.ALT.

getImageURL

public URL getImageURL()

Return a URL for the image source, or null if it could not be determined.

getNoImageIcon

public Icon getNoImageIcon()

Returns the icon to use if the image couldn't be found.

getLoadingImageIcon

public Icon getLoadingImageIcon()

Returns the icon to use while in the process of loading the image.

getImage

public Image getImage()

Returns the image to render.

setLoadsSynchronously

public void setLoadsSynchronously(boolean newValue)

Sets how the image is loaded. If newValue is true, the image we be loaded when first asked for, otherwise it will be loaded asynchronously. The default is to not load synchronously, that is to load the image asynchronously.

getLoadsSynchronously

public boolean getLoadsSynchronously()

Returns true if the image should be loaded when first asked for.

getStyleSheet

protected StyleSheet getStyleSheet()

Convenience method to get the StyleSheet.

getAttributes

public AttributeSet getAttributes()

Fetches the attributes to use when rendering. This is implemented to multiplex the attributes specified in the model with a StyleSheet.

Overrides:: getAttributes in class View

getToolTipText

public String getToolTipText(float x,
                             float y,
                             Shape allocation)

For images the tooltip text comes from text specified with the ALT attribute. This is overriden to return getAltText.

Overrides:: getToolTipText in class View

See Also:: JTextComponent.getToolTipText(java.awt.event.MouseEvent)

setPropertiesFromAttributes

protected void setPropertiesFromAttributes()

Update any cached values that come from attributes.

setParent

public void setParent(View parent)

Establishes the parent view for this view. Seize this moment to cache the AWT Container I'm in.

Overrides:: setParent in class View

Parameters:: parent - the new parent, or null if the view is being removed from a parent

changedUpdate

public void changedUpdate(DocumentEvent e,
                          Shape a,
                          ViewFactory f)

Invoked when the Elements attributes have changed. Recreates the image.

Overrides:: changedUpdate in class View

Parameters:: e - the change information from the associated document; a - the current allocation of the view; f - the factory to use to rebuild if the view has children
See Also:: View.changedUpdate(javax.swing.event.DocumentEvent, java.awt.Shape, javax.swing.text.ViewFactory)

paint

public void paint(Graphics g,
                  Shape a)

Paints the View.

Specified by:: paint in class View

Parameters:: g - the rendering surface to use; a - the allocated region to render into
See Also:: View.paint(java.awt.Graphics, java.awt.Shape)

getPreferredSpan

public float getPreferredSpan(int axis)

Determines the preferred span for this view along an axis.

Specified by:: getPreferredSpan in class View

Parameters:: axis - may be either X_AXIS or Y_AXIS
Returns:: the span the view would like to be rendered into; typically the view is told to render into the span that is returned, although there is no guarantee; the parent may choose to resize or break the view
See Also:: View.getPreferredSpan(int)

getAlignment

public float getAlignment(int axis)

Determines the desired alignment for this view along an axis. This is implemented to give the alignment to the bottom of the icon along the y axis, and the default along the x axis.

Overrides:: getAlignment in class View

Parameters:: axis - may be either X_AXIS or Y_AXIS
Returns:: the desired alignment; this should be a value between 0.0 and 1.0 where 0 indicates alignment at the origin and 1.0 indicates alignment to the full span away from the origin; an alignment of 0.5 would be the center of the view

modelToView

public Shape modelToView(int pos,
                         Shape a,
                         Position.Bias b)
                  throws BadLocationException

Provides a mapping from the document model coordinate space to the coordinate space of the view mapped to it.

Specified by:: modelToView in class View

Parameters:

pos - the position to convert

a - the allocated region to render into

b - the bias toward the previous character or the next character represented by the offset, in case the position is a boundary of two views; b will have one of these values:

Position.Bias.Forward
Position.Bias.Backward

Returns:

the bounding box of the given position

Throws:

BadLocationException - if the given position does not represent a valid location in the associated document

viewToModel

public int viewToModel(float x,
                       float y,
                       Shape a,
                       Position.Bias[] bias)

Provides a mapping from the view coordinate space to the logical coordinate space of the model.

Specified by:: viewToModel in class View

Parameters:: x - the X coordinate; y - the Y coordinate; a - the allocated region to render into
Returns:: the location within the model that best represents the given point of view
See Also:: View.viewToModel(float, float, java.awt.Shape, javax.swing.text.Position.Bias[])

setSize

public void setSize(float width,
                    float height)

Sets the size of the view. This should cause layout of the view if it has any layout duties.

Overrides:: setSize in class View

Parameters:: width - the width >= 0; height - the height >= 0