cz.vutbr.web.css

Class MediaSpec

java.lang.Object

cz.vutbr.web.css.MediaSpec

Direct Known Subclasses:

MediaSpecAll, MediaSpecNone, MediaSpecType

public class MediaSpec
extends Object

This class represents the features of the output media used for displaying the document. It specifies the name of the output media type (e.g. "screen", "print", etc.) and further features defined by the CSS3 specification. The default values of the features are the following (corresponding to a standard desktop station):

• width: 1100px
• height: 850px
• device-width: 1920px
• device-height: 1200px
• color: 8
• color-index: 0
• monochrome: 0
• resolution: 96dpi
• scan: progressive
• grid: 0

Author:

burgetr

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	MediaSpec.Feature Known media query features based on the specification

Field Summary

Fields

Modifier and Type	Field and Description
protected int	color Color depth (bits per color) or 0 for no colors
protected int	colorIndex Number of entries in the color lookup table or 0 when no indexed colors are used
protected float	deviceHeight Oputput device height in pixels
protected float	deviceWidth Output device width in pixels
static float	dpi CSS3 uses a fixed value of 96DPI for computing the lengths
static float	em the values of 'em' used for computing the pixel lengths
static float	ex the values of 'em' used for computing the pixel lengths
protected static Map<String,MediaSpec.Feature>	featureMap
protected int	grid 1 for a grid device, 0 for bitmap device
protected float	height Output area height in pixels
protected int	monochrome Bits per pixel of a monochrome frame buffer or 0 when the device is not monochrome
protected float	resolution Resolution in DPI
protected boolean	scanInterlace Indicates interlaced scanning for "tv" media types
protected String	type Media type name (e.g.
protected float	width Output area width in pixels

Constructor Summary

Constructors

Constructor and Description
MediaSpec(String type) Creates a new media specification with the given media type and default values of the features.

Method Summary

Modifier and Type	Method and Description
protected Float	dpiResolution(TermResolution spec) Converts a resolution from a CSS length to 'dpi'.
float	getAspectRatio() Obtains the aspect ratio of the display area defined as width / height.
int	getColor() Obtains the number of bits per color component of the output device.
int	getColorIndex() Obtains the number of entries in the color lookup table of the output device.
float	getDeviceAspectRation() Obtains the aspect ratio of the device defined as deviceWidth / deviceHeight.
float	getDeviceHeight() Obtains the height of the rendering surface of the output device.
float	getDeviceWidth() Obtains the width of the rendering surface of the output device.
protected String	getExpressionIdentifier(MediaExpression e) Obtains the identifier specified by the given media query expression.
protected Integer	getExpressionInteger(MediaExpression e) Obtains the integer specified by the given media query expression.
protected Float	getExpressionLengthPx(MediaExpression e) Obtains the length specified by the given media query expression.
protected Float	getExpressionRatio(MediaExpression e) Obtains the ratio specified by the given media query expression.
protected Float	getExpressionResolution(MediaExpression e) Obtains the resolution specified by the given media query expression.
protected MediaSpec.Feature	getFeatureByName(String name) Obtains the feature based on its name.
int	getGrid() Checks whether the output device is grid or bitmap.
float	getHeight() Obtains the height of the display area.
int	getMonochrome() Obtains the number of bits per pixel in a monochrome frame buffer.
float	getResolution() Sets the resolution of the output device, i.e. the density of the pixels.
String	getType() Obtains the media type of this specification.
float	getWidth() Obtains the width of the display area.
boolean	isPortrait() Checks whether the display area orientation is portrait or landscape.
boolean	isScanInterlace() Checks if the device is using the interlaced or progressive scanning (for "tv" media only).
protected void	loadDefaults() Loads some reasonable defaults that correspond to a normal desktop configuration.
boolean	matches(MediaExpression e) Checks if this media specification matches a given media query expression.
boolean	matches(MediaQuery q) Checks if this media specification matches a given media query.
boolean	matchesEmpty() Checks whether the media specification matches an empty or missing media query, i.e. whether the media or import rules with no media queries should be accepted with this media specification.
boolean	matchesOneOf(List<MediaQuery> queries) Checks whether this media specification matches to at least one of the given media queries.
protected Float	pxLength(TermLength spec) Converts a length from a CSS length to 'px'.
void	setColor(int color) Sets the number of bits per color component of the output device.
void	setColorIndex(int colorIndex) Sets the number of entries in the color lookup table of the output device.
void	setDeviceDimensions(float deviceWidth, float deviceHeight) Sets the width of the rendering surface of the output device.
void	setDeviceHeight(float deviceHeight) Sets the height of the rendering surface of the output device.
void	setDeviceWidth(float deviceWidth) Sets the width of the rendering surface of the output device.
void	setDimensions(float width, float height) Sets the width and height height of the display area.
void	setGrid(int grid) Sets whether the output device is grid or bitmap.
void	setHeight(float height) Sets the height of the display area.
void	setMonochrome(int monochrome) Sets the number of bits per pixel in a monochrome frame buffer.
void	setResolution(float resolution) Obtains the resolution of the output device, i.e. the density of the pixels.
void	setScanInterlace(boolean scanInterlace) Sets the device scanning process (for "tv" media only).
void	setWidth(float width) Sets the width of the display area.
String	toString()
protected boolean	valueMatches(Float required, float current, boolean min, boolean max) Checks whether a value coresponds to the given criteria.
protected boolean	valueMatches(Integer required, int current, boolean min, boolean max) Checks whether a value coresponds to the given criteria.

Methods inherited from class java.lang.Object

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

Field Detail

em

public static final float em

the values of 'em' used for computing the pixel lengths

See Also:

Constant Field Values

ex

public static final float ex

the values of 'em' used for computing the pixel lengths

See Also:

Constant Field Values

dpi

public static final float dpi

CSS3 uses a fixed value of 96DPI for computing the lengths

See Also:

Constant Field Values

featureMap

protected static Map<String,MediaSpec.Feature> featureMap

type

protected String type

Media type name (e.g. "screen")

width

protected float width

Output area width in pixels

height

protected float height

Output area height in pixels

deviceWidth

protected float deviceWidth

Output device width in pixels

deviceHeight

protected float deviceHeight

Oputput device height in pixels

color

protected int color

Color depth (bits per color) or 0 for no colors

colorIndex

protected int colorIndex

Number of entries in the color lookup table or 0 when no indexed colors are used

monochrome

protected int monochrome

Bits per pixel of a monochrome frame buffer or 0 when the device is not monochrome

resolution

protected float resolution

Resolution in DPI

scanInterlace

protected boolean scanInterlace

Indicates interlaced scanning for "tv" media types

grid

protected int grid

1 for a grid device, 0 for bitmap device

Constructor Detail

MediaSpec

public MediaSpec(String type)

Creates a new media specification with the given media type and default values of the features.

Parameters:

type - The media type (e.g. "screen")

Method Detail

getType

public String getType()

Obtains the media type of this specification.

Returns:

The media type name (e.g. "screen")

getWidth

public float getWidth()

Obtains the width of the display area.

Returns:

the width in pixels.

setWidth

public void setWidth(float width)

Sets the width of the display area.

Parameters:

width - The width in pixels.

getHeight

public float getHeight()

Obtains the height of the display area.

Returns:

the height in pixels.

setHeight

public void setHeight(float height)

Sets the height of the display area.

Parameters:

height - The height in pixels.

setDimensions

public void setDimensions(float width,
                          float height)

Sets the width and height height of the display area.

Parameters:

width - The width in pixels.

height - The height in pixels.

getDeviceWidth

public float getDeviceWidth()

Obtains the width of the rendering surface of the output device.

Returns:

the width in pixels.

setDeviceWidth

public void setDeviceWidth(float deviceWidth)

Sets the width of the rendering surface of the output device.

Parameters:

deviceWidth - the width in pixels.

getDeviceHeight

public float getDeviceHeight()

Obtains the height of the rendering surface of the output device.

Returns:

the height in pixels.

setDeviceHeight

public void setDeviceHeight(float deviceHeight)

Sets the height of the rendering surface of the output device.

Parameters:

deviceHeight - the height in pixels.

setDeviceDimensions

public void setDeviceDimensions(float deviceWidth,
                                float deviceHeight)

Sets the width of the rendering surface of the output device.

Parameters:

deviceWidth - the width in pixels.

deviceHeight - the height in pixels.

getColor

public int getColor()

Obtains the number of bits per color component of the output device.

Returns:

The number of bits or 0 if the device is not a color device.

setColor

public void setColor(int color)

Sets the number of bits per color component of the output device.

Parameters:

color - The number of bits or 0 if the device is not a color device.

getColorIndex

public int getColorIndex()

Obtains the number of entries in the color lookup table of the output device.

Returns:

The number of lookup table entries or 0 if the device does not use a color lookup table.

setColorIndex

public void setColorIndex(int colorIndex)

Sets the number of entries in the color lookup table of the output device.

Parameters:

colorIndex - The number of lookup table entries or 0 if the device does not use a color lookup table.

getMonochrome

public int getMonochrome()

Obtains the number of bits per pixel in a monochrome frame buffer.

Returns:

The number of bits per pixel or 0 if the device is not a monochrome device.

setMonochrome

public void setMonochrome(int monochrome)

Sets the number of bits per pixel in a monochrome frame buffer.

Parameters:

monochrome - The number of bits per pixel or 0 if the device is not a monochrome device.

getResolution

public float getResolution()

Sets the resolution of the output device, i.e. the density of the pixels.

Returns:

The resolution in DPI.

setResolution

public void setResolution(float resolution)

Obtains the resolution of the output device, i.e. the density of the pixels.

Parameters:

resolution - The resolution in DPI.

isScanInterlace

public boolean isScanInterlace()

Checks if the device is using the interlaced or progressive scanning (for "tv" media only).

Returns:

true if the device is using the interlaced scanning, false for progressive scanning.

setScanInterlace

public void setScanInterlace(boolean scanInterlace)

Sets the device scanning process (for "tv" media only).

Parameters:

scanInterlace - true if the device is using the interlaced scanning, false for progressive scanning.

getGrid

public int getGrid()

Checks whether the output device is grid or bitmap.

Returns:

If the output device is grid-based (e.g., a "tty" terminal, or a phone display with only one fixed font), the value will be 1. Otherwise, the value will be 0.

setGrid

public void setGrid(int grid)

Sets whether the output device is grid or bitmap.

Parameters:

grid - If the output device is grid-based (e.g., a "tty" terminal, or a phone display with only one fixed font), the value will be 1. Otherwise, the value will be 0.

getAspectRatio

public float getAspectRatio()

Obtains the aspect ratio of the display area defined as width / height.

Returns:

The aspect radio.

getDeviceAspectRation

public float getDeviceAspectRation()

Obtains the aspect ratio of the device defined as deviceWidth / deviceHeight.

Returns:

The aspect radio.

isPortrait

public boolean isPortrait()

Checks whether the display area orientation is portrait or landscape.

Returns:

true when the value of the height media feature is greater than or equal to the value of the width media feature.

matches

public boolean matches(MediaQuery q)

Checks if this media specification matches a given media query.

Parameters:

q - The media query

Returns:

true when this media specification matches the given media query.

matches

public boolean matches(MediaExpression e)

Checks if this media specification matches a given media query expression.

Parameters:

e - The media query expression

Returns:

true when this media specification matches the given expression.

matchesOneOf

public boolean matchesOneOf(List<MediaQuery> queries)

Checks whether this media specification matches to at least one of the given media queries.

Parameters:

queries - The list of media queries to be matched.

Returns:

true when at least one query matches, false when no query matches.

matchesEmpty

public boolean matchesEmpty()

Checks whether the media specification matches an empty or missing media query, i.e. whether the media or import rules with no media queries should be accepted with this media specification.

Returns:

true when this media specification matches an empty media query

getFeatureByName

protected MediaSpec.Feature getFeatureByName(String name)

Obtains the feature based on its name.

Parameters:

name - The name of the feature

Returns:

The feature corresponding to the name or null if the name is unknown

valueMatches

protected boolean valueMatches(Float required,
                               float current,
                               boolean min,
                               boolean max)

Checks whether a value coresponds to the given criteria.

Parameters:

current - the actual media value

required - the required value or null for invalid requirement

min - true when the required value is the minimal one

max - true when the required value is the maximal one

Returns:

true when the value matches the criteria.

valueMatches

protected boolean valueMatches(Integer required,
                               int current,
                               boolean min,
                               boolean max)

Checks whether a value coresponds to the given criteria.

Parameters:

required - the required value

current - the tested value or null for invalid value

min - true when the required value is the minimal one

max - true when the required value is the maximal one

Returns:

true when the value matches the criteria.

getExpressionLengthPx

protected Float getExpressionLengthPx(MediaExpression e)

Obtains the length specified by the given media query expression.

Parameters:

e - The media query expression specifying a length.

Returns:

The length converted to pixels or null when the value cannot be converted to length.

getExpressionResolution

protected Float getExpressionResolution(MediaExpression e)

Obtains the resolution specified by the given media query expression.

Parameters:

e - The media query expression specifying a resolution.

Returns:

The length converted to pixels or null when the value cannot be converted to resolution.

getExpressionRatio

protected Float getExpressionRatio(MediaExpression e)

Obtains the ratio specified by the given media query expression.

Parameters:

e - The media query expression specifying a ratio.

Returns:

The length converted to pixels or null when the value cannot be converted to ratio.

getExpressionInteger

protected Integer getExpressionInteger(MediaExpression e)

Obtains the integer specified by the given media query expression.

Parameters:

e - The media query expression specifying an integer.

Returns:

The length converted to pixels or null when the value cannot be converted to integer.

getExpressionIdentifier

protected String getExpressionIdentifier(MediaExpression e)

Obtains the identifier specified by the given media query expression.

Parameters:

e - The media query expression specifying an identifier.

Returns:

The identifier name or null when the value cannot be converted to an identifier.

pxLength

protected Float pxLength(TermLength spec)

Converts a length from a CSS length to 'px'.

Parameters:

spec - the CSS length specification

Returns:

the length in 'px' or null when the unit is invalid

dpiResolution

protected Float dpiResolution(TermResolution spec)

Converts a resolution from a CSS length to 'dpi'.

Parameters:

spec - the CSS resolution specification

Returns:

the resolution in 'dpi' or null when the unit is invalid

loadDefaults

protected void loadDefaults()

Loads some reasonable defaults that correspond to a normal desktop configuration.

toString

public String toString()

Overrides:

toString in class Object