org.havi.ui

Class HGraphicsDevice

java.lang.Object

org.havi.ui.HScreenDevice

org.havi.ui.HGraphicsDevice

All Implemented Interfaces:

ResourceProxy, ResourceServer

Direct Known Subclasses:

HEmulatedGraphicsDevice

public class HGraphicsDevice
extends HScreenDevice

The HGraphicsDevice class describes the raster graphics devices that are available for a particular HScreen. Each HGraphicsDevice has one or more HGraphicsConfiguration objects associated with it. These objects specify the different configurations (settings) in which the HGraphicsDevice can be used. The parameters to the constructors are as follows, in cases where parameters are not used, then the constructor should use the default values.

Default parameter values exposed in the constructors

Parameter	Description	Default value	Set method	Get method
None.

Default parameter values not exposed in the constructors

Description	Default value	Set method	Get method
None.

See Also:

HGraphicsConfiguration, HScreenDevice, HScreen

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	HGraphicsDevice() An interoperable application shall not subclass the HGraphicsDevice class.

Method Summary

Methods

Modifier and Type	Method and Description
HGraphicsConfiguration	getBestConfiguration(HGraphicsConfigTemplate hgct) The getBestConfiguration method attempts to return an HGraphicsConfiguration that matches the specified HGraphicsConfigTemplate.
HGraphicsConfiguration	getBestConfiguration(HGraphicsConfigTemplate[] hgcta) The getBestConfiguration method attempts to return an HGraphicsConfiguration that matches the specified HGraphicsConfigTemplate objects within the specified array.
HGraphicsConfiguration[]	getConfigurations() Returns all of the HGraphicsConfiguration objects associated with this HGraphicsDevice.
HGraphicsConfiguration	getCurrentConfiguration() Returns the current HGraphicsConfiguration for this HGraphicsDevice.
HGraphicsConfiguration	getDefaultConfiguration() Returns the default HGraphicsConfiguration associated with this HGraphicsDevice.
boolean	setGraphicsConfiguration(HGraphicsConfiguration hgc) Set the graphics configuration for the device.

Methods inherited from class org.havi.ui.HScreenDevice

addResourceStatusEventListener, addScreenConfigurationListener, addScreenConfigurationListener, getClient, getIDstring, getScreenAspectRatio, releaseDevice, removeResourceStatusEventListener, removeScreenConfigurationListener, reserveDevice

Methods inherited from class java.lang.Object

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

Constructor Detail

HGraphicsDevice

protected HGraphicsDevice()

An interoperable application shall not subclass the HGraphicsDevice class.

Creates an HGraphicsDevice object. See the class description for details of constructor parameters and default values.

Method Detail

getConfigurations

public HGraphicsConfiguration[] getConfigurations()

Returns all of the HGraphicsConfiguration objects associated with this HGraphicsDevice. The set of configurations returned may include ones which are only valid for the device at particular times or when the device is in a particular mode.

Returns:

an array of HGraphicsConfiguration objects that are associated with this HGraphicsDevice. The class of the objects returned can also be a class inheriting from HGraphicsConfiguration (e.g. HEmulatedGraphicsConfiguration).

See Also:

HGraphicsConfiguration

getDefaultConfiguration

public HGraphicsConfiguration getDefaultConfiguration()

Returns the default HGraphicsConfiguration associated with this HGraphicsDevice. This (single) default configuration should correspond to some well-behaved settings for the device, such as, a minimal configuration, or factory preset settings.

Returns:

the default HGraphicsConfiguration of this HGraphicsDevice. The class of the object returned can also be a class inheriting from HGraphicsConfiguration (e.g. HEmulatedGraphicsConfiguration).

getBestConfiguration

public HGraphicsConfiguration getBestConfiguration(HGraphicsConfigTemplate hgct)

The getBestConfiguration method attempts to return an HGraphicsConfiguration that matches the specified HGraphicsConfigTemplate. If this is not possible it will attempt to construct an HEmulatedGraphicsConfiguration where the emulated configuration best matches this HGraphicsConfigTemplate. If this is not possible, null is returned. Note that the algorithm used for this behavior, and the extent and behavior of HEmulatedGraphicsConfiguration are platform specific.

Equally best in this sense means that the configurations satisfy an equal number of preferences with priorities PREFERRED and PREFERRED_NOT and all preferences with priorities REQUIRED and REQUIRED_NOT. If there are such equally best configurations, the one which is returned by this method is an implementation dependent selection from among those which are equally best.

Configurations are chosen according to the following algorithm, based on the priority as supplied to setPreference. Configurations must:

1. satisfy ALL the preferences whose priority was REQUIRED
2. satisfy NONE of the preferences whose priority was REQUIRED_NOT
3. satisfy as many as possible of the preferences whose priority was PREFERRED.
4. satisfy as few as possible of the preferences whose priority was PREFERRED_NOT.

Preferences whose priority was DONT_CARE are ignored.

This method returns null if no configuration exists that satisfies all REQUIRED and REQUIRED_NOT priorities.

Parameters:

hgct - an HGraphicsConfigTemplate object used to obtain a valid HGraphicsConfiguration. If this parameter is null the default configuration for the platform shall be returned.

Returns:

an HGraphicsConfiguration that passes the criteria defined in the specified HGraphicsConfigTemplate or null if no HGraphicsConfiguration or HEmulatedGraphicsConfiguration passes the criteria.

getBestConfiguration

public HGraphicsConfiguration getBestConfiguration(HGraphicsConfigTemplate[] hgcta)

The getBestConfiguration method attempts to return an HGraphicsConfiguration that matches the specified HGraphicsConfigTemplate objects within the specified array. The HGraphicsTemplate objects should be considered for matching in priority order from 0 to (hgcta.length - 1). If this is not possible, it will attempt to construct an HEmulatedGraphicsConfiguration where the emulated configuration best matches the specified HGraphicsConfigTemplate objects. If this is not possible, null is returned.

Equally best in this sense means that the configurations satisfy an equal number of preferences with priorities PREFERRED and PREFERRED_NOT and all preferences with priorities REQUIRED and REQUIRED_NOT. If there are such equally best configurations, the one which is returned by this method is an implementation dependent selection from among those which are equally best.

Configurations are chosen according to the following algorithm, based on the priority as supplied to setPreference. Configurations must:

1. satisfy ALL the preferences whose priority was REQUIRED
2. satisfy NONE of the preferences whose priority was REQUIRED_NOT
3. satisfy as many as possible of the preferences whose priority was PREFERRED.
4. satisfy as few as possible of the preferences whose priority was PREFERRED_NOT.

Preferences whose priority was DONT_CARE are ignored.

This method returns null if no configuration exists that satisfies all REQUIRED and REQUIRED_NOT priorities.

Parameters:

hgcta - the HGraphicsConfigTemplate array used to obtain a valid HGraphicsConfiguration.

Returns:

an HGraphicsConfiguration that passes the criteria defined in one of the HGraphicsConfigTemplate objects within the specified array. The class of the object returned can also be a class inheriting from HGraphicsConfiguration (e.g. HEmulatedGraphicsConfiguration).

getCurrentConfiguration

public HGraphicsConfiguration getCurrentConfiguration()

Returns the current HGraphicsConfiguration for this HGraphicsDevice.

Returns:

the current HGraphicsConfiguration for this HGraphicsDevice. The class of the object returned can also be a class inheriting from HGraphicsConfiguration (e.g. HEmulatedGraphicsConfiguration).

See Also:

HGraphicsConfiguration

setGraphicsConfiguration

public boolean setGraphicsConfiguration(HGraphicsConfiguration hgc)
                                 throws SecurityException,
                                        HPermissionDeniedException,
                                        HConfigurationException

Set the graphics configuration for the device.

An application is only allowed to call this method after it reserved the device explicitly and subject to the security policy of the platform. Subject to this, the following rules determine whether this method can succeed.

• If an application tries to select a configuration which is not valid for that device at that time or when the device is in a particular mode then an HConfigurationException shall be thrown.
• If the application selects a configuration that is not conflicting with the configurations of all the other devices on the same HScreen then that configuration is selected.
• If an application tries to select a configuration that conflicts with a configuration of another device on this HScreen which this application cannot control due to platform security policy then this method shall fail with a SecurityException.
• If an application tries to select a configuration that conflicts with a configuration of another device on this HScreen which this application cannot control due to another application owning the right to control that device and the platform not giving that right to this application then this method shall fail with an HPermissionDeniedException.
• If an application tries to select a configuration that conflicts with a configuration of another device which this application can control due to either this or no application having reserved the device, then the configuration of the other device is automatically changed. There is no change in the resource ownership of the other device.

Applications can prevent or limit changes to configurations of other, not intended, devices by using constants HScreenConfigTemplate.ZERO_GRAPHICS_IMPACT, HScreenConfigTemplate.ZERO_VIDEO_IMPACT and HScreenConfigTemplate.ZERO_BACKGROUND_IMPACT in their configuration templates. The first one will cause no changes to already running graphical applications. This means that no changes may be applied to the graphics device. Similarly the second constant will result in no changes to the video device.

Any modifications made to the configurations of other devices shall be reflected by the API for the devices concerned. The getCurrentConfiguration() method for those devices shall return the new configuration.

On successful change to the specified configuration, the device shall fire one or more HScreenConfigurationEvent for all listeners that are currently registered (if the criteria for receiving such an event has been satisfied). If the new configuration differs by more than one characteristic from the previous configuration then the device may fire one or more HScreenConfigurationEvent. This behavior is implementation specific.

If an attempt is made to set the identical configuration to that which is current, then no such event(s) shall be fired.

Parameters:

hgc - the HGraphicsConfiguration to which this device should be set.

Returns:

A boolean indicating whether the configuration could be applied successfully. If the configuration could not be applied successfully, the configuration after this method may not match the configuration of the device prior to this method being called --- applications should take steps to determine whether a partial change of settings has been made.

Throws:

SecurityException - if the application does not have sufficient rights to set the configuration for this device.

HPermissionDeniedException - if the application does not currently have the right to set the configuration for this device.

HConfigurationException - if the specified configuration is not valid for this device, or if it conflicts with other devices whose configuration(s) cannot be changed by this application.