gov.nasa.worldwind.render
Class MultiLineTextRenderer

java.lang.Object
  gov.nasa.worldwind.render.MultiLineTextRenderer

public class MultiLineTextRenderer
extends Object

Multi line, rectangle bound text renderer with (very) minimal html support.

The MultiLineTextRenderer (MLTR) handles wrapping, measuring and drawing of multiline text strings using Sun's JOGL TextRenderer.

A multiline text string is a character string containing new line characters in between lines.

MLTR can handle both regular text with new line separators and a very minimal implementation of HTML. Each type of text has its own methods though.

Usage:

Instantiation:

The MLTR needs a Font or a TextRenderer to be instantiated. This will be the font used for text drawing, wrapping and measuring. For HTML methods this font will be considered as the document default font.

 Font font = Font.decode("Arial-PLAIN-12");
 MultiLineTextRenderer mltr = new MultiLineTextRenderer(font);
 

or

 TextRenderer tr = new TextRenderer(Font.decode("Arial-PLAIN-10"));
 MultiLineTextRenderer mltr = new MultiLineTextRenderer(tr);
 

Drawing regular text:

 String text = "Line one.\nLine two.\nLine three...";
 int x = 10;             // Upper left corner of text rectangle.
 int y = 200;            // Origin at bottom left of screen.
 int lineHeight = 14;    // Line height in pixels.
 Color color = Color.RED;

 mltr.setTextColor(color);
 mltr.getTextRenderer().begin3DRendering();
 mltr.draw(text, x, y, lineHeight);
 mltr.getTextRenderer().end3DRendering();
 

Wrapping text to fit inside a width and optionally a height

The MLTR wrap method will insert new line characters inside the text so that it fits a given width in pixels.

If a height dimension above zero is specified too, the text will be truncated if needed, and a continuation string will be appended to the last line. The continuation string can be set with mltr.setContinuationString();

 // Fit inside 300 pixels, no height constraint
 String wrappedText = mltr.wrap(text, new Dimension(300, 0));

 // Fit inside 300x400 pixels, text may be truncated
 String wrappedText = mltr.wrap(text, new Dimension(300, 400));
 

Measuring text

 Rectangle2D textBounds = mltr.getBounds(text);
 

The textBounds rectangle returned contains the width and height of the text as it would be drawn with the current font.

Note that textBounds.minX is the number of lines found and textBounds.minY is the maximum line height for the font used. This value can be safely used as the lineHeight argument when drawing - or can even be ommited after a getBounds: draw(text, x, y); ...

HTML support

Supported tags are:

• <p></p>, <br> <br />
• <b></b>
• <i></i>
• <a href="..."></a>
• <font color="#ffffff"></font>

...

See AbstractAnnotation.drawAnnotation() for more usage details.

Nested Class Summary

static class

MultiLineTextRenderer.WordIteratorHTML Iterates through words from an HTML text line.

Constructor Summary

MultiLineTextRenderer(Font font)

MultiLineTextRenderer(TextRenderer textRenderer)

Method Summary

static boolean	containsHTML(String text) Return true if the text contains some sgml tags.
void	draw(String text, int x, int y) Draw a multi-line text string with bounding rectangle top starting at the y position.
void	draw(String text, int x, int y, int textLineHeight) Draw a multi-line text string with bounding rectangle top starting at the y position.
void	draw(String text, int x, int y, int textLineHeight, String effect) Draw a multi-line text string with bounding rectangle top starting at the y position.
void	draw(String text, int x, int y, String effect) Draw a multi-line text string with bounding rectangle top starting at the y position.
void	drawHTML(String text, double x, double y, TextRendererCache renderers) Draw a multi-line html text string with bounding rectangle top starting at the y position.
static String	getAttributeFromTagHTML(String text, String attributeName) Extract an attribute value from a HTML tag string.
Color	getBackColor() Get the background color used for EFFECT_SHADOW and EFFECT_OUTLINE.
Rectangle	getBounds(String text) Returns the bounding rectangle for a multi-line string.
Rectangle	getBoundsHTML(String text, TextRendererCache renderers) Returns the bounding rectangle for a multi-line html string.
int	getLineHeight() Get the current line height in pixels.
int	getLineSpacing() Get the current line spacing height in pixels.
Color	getLinkColor() Get the current link color.
double	getMaxLineHeight(TextRenderer tr) Get the maximum line height for the given text renderer.
String	getTextAlign() Get the current text alignment.
Color	getTextColor() Get the current text color.
TextRenderer	getTextRenderer() Get the current TextRenderer.
void	pick(String text, int x, int y, int textLineHeight, DrawContext dc, PickSupport pickSupport, Object refObject, Position refPosition) Draw text with unique colors word bounding rectangles and add each as a pickable object to the provided PickSupport instance.
void	pickHTML(String text, int x, int y, TextRendererCache renderers, DrawContext dc, PickSupport pickSupport, Object refObject, Position refPosition) Draw text with unique colors word bounding rectangles and add each as a pickable object to the provided PickSupport instance.
static String	processLineBreaksHTML(String text) Remove new line characters then replace BR and P tags with appropriate new lines.
static String	removeTagsHTML(String text) Remove all HTML tags from a text string.
void	setBackColor(Color color) Set the background color used for EFFECT_SHADOW and EFFECT_OUTLINE.
void	setContinuationString(String s) Set the character string appended at the end of text truncated during a wrap operation when exceeding the given height limit.
void	setLineHeight(int height) Set the current line height in pixels.
void	setLineSpacing(int height) Set the current line spacing height in pixels.
void	setLinkColor(Color color) Set the link color.
void	setTextAlign(String align) Set the current text alignment.
void	setTextColor(Color color) Set the text renderer color.
String	wrap(String text, int width, int height) Add 'new line' characters inside a string so that it's bounding rectangle tries not to exceed the given dimension width.
String	wrapHTML(String text, double width, double height, TextRendererCache renderers) Add 'new line' characters inside an html text string so that it's bounding rectangle tries not to exceed the given dimension width.

Methods inherited from class java.lang.Object

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

Constructor Detail

MultiLineTextRenderer

public MultiLineTextRenderer(Font font)

MultiLineTextRenderer

public MultiLineTextRenderer(TextRenderer textRenderer)

Method Detail

containsHTML

public static boolean containsHTML(String text)

Return true if the text contains some sgml tags.

Parameters:

text - The text string to evaluate.

Returns:

true if the string contains sgml or html tags

draw

public void draw(String text,
                 int x,
                 int y)

Draw a multi-line text string with bounding rectangle top starting at the y position. Depending on the current textAlign, the x position is either the rectangle left side, middle or right side.

Uses the current line height.

Parameters:

text - the multi-line text to draw.

x - the x position for top left corner of text rectangle.

y - the y position for top left corner of the text rectangle.

draw

public void draw(String text,
                 int x,
                 int y,
                 int textLineHeight)

Draw a multi-line text string with bounding rectangle top starting at the y position. Depending on the current textAlign, the x position is either the rectangle left side, middle or right side.

Uses the given line height.

Parameters:

text - the multi-line text to draw.

x - the x position for top left corner of text rectangle.

y - the y position for top left corner of the text rectangle.

textLineHeight - the line height in pixels.

draw

public void draw(String text,
                 int x,
                 int y,
                 int textLineHeight,
                 String effect)

Draw a multi-line text string with bounding rectangle top starting at the y position. Depending on the current textAlign, the x position is either the rectangle left side, middle or right side.

Uses the given line height and effect.

Parameters:

text - the multi-line text to draw.

x - the x position for top left corner of text rectangle.

y - the y position for top left corner of the text rectangle.

textLineHeight - the line height in pixels.

effect - the effect to use for the text rendering. Can be one of EFFECT_NONE, EFFECT_SHADOW or EFFECT_OUTLINE.

draw

public void draw(String text,
                 int x,
                 int y,
                 String effect)

Draw a multi-line text string with bounding rectangle top starting at the y position. Depending on the current textAlign, the x position is either the rectangle left side, middle or right side.

Uses the current line height and the given effect.

Parameters:

text - the multi-line text to draw.

x - the x position for top left corner of text rectangle.

y - the y position for top left corner of the text rectangle.

effect - the effect to use for the text rendering. Can be one of EFFECT_NONE, EFFECT_SHADOW or EFFECT_OUTLINE.

drawHTML

public void drawHTML(String text,
                     double x,
                     double y,
                     TextRendererCache renderers)

Draw a multi-line html text string with bounding rectangle top starting at the y position. The x position is eiher the rectangle left side, middle or right side depending on the current text alignement.

Parameters:

text - the multi-line text to draw

x - the x position for top left corner of text rectangle

y - the y position for top left corner of the text rectangle

renderers - a TextRendererCache instance.

getAttributeFromTagHTML

public static String getAttributeFromTagHTML(String text,
                                             String attributeName)

Extract an attribute value from a HTML tag string. The attribute is expected to be formed on the pattern: name="...". Other variants will likely fail.

Parameters:

text - the HTML tage string.

attributeName - the attribute name.

Returns:

the attribute value found. Null if empty or not found.

getBackColor

public Color getBackColor()

Get the background color used for EFFECT_SHADOW and EFFECT_OUTLINE.

Returns:

the current background color used when drawing shadow or outline..

getBounds

public Rectangle getBounds(String text)

Returns the bounding rectangle for a multi-line string.

Note that the X component of the rectangle is the number of lines found in the text and the Y component of the rectangle is the max line height encountered.

Note too that this method will automatically set the current line height to the max height found.

Parameters:

text - the multi-line text to evaluate.

Returns:

the bounding rectangle for the string.

getBoundsHTML

public Rectangle getBoundsHTML(String text,
                               TextRendererCache renderers)

Returns the bounding rectangle for a multi-line html string.

Parameters:

text - the multi-line html text to evaluate.

renderers - a TextRendererCache instance.

Returns:

the bounding rectangle for the rendered text.

getLineHeight

public int getLineHeight()

Get the current line height in pixels.

Returns:

the current line height in pixels.

getLineSpacing

public int getLineSpacing()

Get the current line spacing height in pixels.

Returns:

the current line spacing height in pixels.

getLinkColor

public Color getLinkColor()

Get the current link color.

Returns:

the current link color.

getMaxLineHeight

public double getMaxLineHeight(TextRenderer tr)

Get the maximum line height for the given text renderer.

Parameters:

tr - the TextRenderer.

Returns:

the maximum line height.

getTextAlign

public String getTextAlign()

Get the current text alignment. Can be one of AVKey.LEFT the default, AVKey.CENTER or AVKey.RIGHT.

Returns:

the current text alignment.

getTextColor

public Color getTextColor()

Get the current text color.

Returns:

the current text color.

getTextRenderer

public TextRenderer getTextRenderer()

Get the current TextRenderer.

Returns:

the current TextRenderer.

pick

public void pick(String text,
                 int x,
                 int y,
                 int textLineHeight,
                 DrawContext dc,
                 PickSupport pickSupport,
                 Object refObject,
                 Position refPosition)

Draw text with unique colors word bounding rectangles and add each as a pickable object to the provided PickSupport instance.

Parameters:

text - the multi-line text to draw.

x - the x position for top left corner of text rectangle.

y - the y position for top left corner of the text rectangle.

textLineHeight - the line height in pixels.

dc - the current DrawContext.

pickSupport - the PickSupport instance to be used.

refObject - the user reference object associated with every picked word.

refPosition - the user reference Position associated with every picked word.

pickHTML

public void pickHTML(String text,
                     int x,
                     int y,
                     TextRendererCache renderers,
                     DrawContext dc,
                     PickSupport pickSupport,
                     Object refObject,
                     Position refPosition)

Draw text with unique colors word bounding rectangles and add each as a pickable object to the provided PickSupport instance.

Parameters:

text - the multi-line text to draw.

x - the x position for top left corner of text rectangle.

y - the y position for top left corner of the text rectangle.

renderers - a TextRendererCache instance.

dc - the current DrawContext.

pickSupport - the PickSupport instance to be used.

refObject - the user reference object associated with every picked word.

refPosition - the user reference Position associated with every picked word.

processLineBreaksHTML

public static String processLineBreaksHTML(String text)

Remove new line characters then replace BR and P tags with appropriate new lines.

Parameters:

text - The html text string to process.

Returns:

The processed text string.

removeTagsHTML

public static String removeTagsHTML(String text)

Remove all HTML tags from a text string.

Parameters:

text - the string to filter.

Returns:

the filtered string.

setBackColor

public void setBackColor(Color color)

Set the background color used for EFFECT_SHADOW and EFFECT_OUTLINE.

Parameters:

color - the color to use when drawing shadow or outline.

setContinuationString

public void setContinuationString(String s)

Set the character string appended at the end of text truncated during a wrap operation when exceeding the given height limit.

Parameters:

s - the continuation character string.

setLineHeight

public void setLineHeight(int height)

Set the current line height in pixels.

Parameters:

height - the current line height in pixels.

setLineSpacing

public void setLineSpacing(int height)

Set the current line spacing height in pixels.

Parameters:

height - the line spacing height in pixels.

setLinkColor

public void setLinkColor(Color color)

Set the link color.

Parameters:

color - the color to use when drawing hyperlinks.

setTextAlign

public void setTextAlign(String align)

Set the current text alignment. Can be one of AVKey.LEFT the default, AVKey.CENTER or AVKey.RIGHT.

Parameters:

align - the current text alignment.

setTextColor

public void setTextColor(Color color)

Set the text renderer color.

Parameters:

color - the color to use when drawing text.

wrap

public String wrap(String text,
                   int width,
                   int height)

Add 'new line' characters inside a string so that it's bounding rectangle tries not to exceed the given dimension width.

If the dimension height is more than zero, the text will be truncated accordingly and the continuation string will be appended to the last line.

Note that words will not be split and at least one word will be used per line so the longest word defines the final width of the bounding rectangle. Each line is trimmed of leading and trailing spaces.

Parameters:

text - the text string to wrap

width - the maximum width in pixels the text can occupy.

height - if not zero, the maximum height in pixels the text can occupy.

Returns:

the wrapped string.

wrapHTML

public String wrapHTML(String text,
                       double width,
                       double height,
                       TextRendererCache renderers)

Add 'new line' characters inside an html text string so that it's bounding rectangle tries not to exceed the given dimension width.

If the dimension height is more than zero, the text will be truncated accordingly and the continuation string will be appended to the last line.

Note that words will not be split and at least one word will be used per line so the longest word defines the final width of the bounding rectangle. Each line is trimmed of leading and trailing spaces.

Parameters:

text - the html text string to wrap

width - the maximum width in pixels one text line can occupy.

height - if not zero, the maximum height the text can occupy.

renderers - a TextRendererCache instance.

Returns:

the wrapped html string