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CSSBox is an (X)HTML/CSS rendering engine written in pure Java. Its primary purpose is to provide a
complete information about the rendered page suitable for further processing. However, it also allows
displaying the rendered document.
/*
* VisualContext.java
* Copyright (c) 2005-2014 Radek Burget
*
* CSSBox is free software: you can redistribute it and/or modify
* it under the terms of the GNU Lesser General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* CSSBox is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with CSSBox. If not, see textDecoration;
private double em; //number of pixels in 1em
private double rem; //number of pixels in 1rem
private double ex; //number of pixels in 1ex
private double ch; //number of pixels in 1ch
private double dpi; //number of pixels in 1 inch
public Color color; //current text color
public VisualContext(VisualContext parent, BoxFactory factory)
{
this.parent = parent;
this.factory = factory;
rootContext = (parent == null) ? this : parent.rootContext;
em = CSSUnits.medium_font;
rem = em;
ex = 0.6 * em;
ch = 0.8 * ch; //just an initial guess, updated in updateForGraphics()
dpi = org.fit.cssbox.css.CSSUnits.dpi;
font = new Font(Font.SERIF, Font.PLAIN, (int) CSSUnits.medium_font);
fontSize = CSSUnits.points(CSSUnits.medium_font);
fontWeight = CSSProperty.FontWeight.NORMAL;
fontStyle = CSSProperty.FontStyle.NORMAL;
fontVariant = CSSProperty.FontVariant.NORMAL;
textDecoration = new ArrayList(2); //it is not very probable to have more than two decorations
color = Color.BLACK;
}
public VisualContext create()
{
VisualContext ret = new VisualContext(this, this.factory);
ret.viewport = viewport;
ret.rootContext = rootContext;
ret.em = em;
ret.rem = rem;
ret.ex = ex;
ret.ch = ch;
ret.dpi = dpi;
ret.font = font;
ret.fontSize = fontSize;
ret.fontWeight = fontWeight;
ret.fontStyle = fontStyle;
ret.fontVariant = fontVariant;
ret.textDecoration = new ArrayList(textDecoration);
ret.color = color;
return ret;
}
//=========================================================================
public VisualContext getParentContext()
{
return parent;
}
public Viewport getViewport()
{
return viewport;
}
public void setViewport(Viewport viewport)
{
this.viewport = viewport;
}
public boolean isRootContext()
{
return (this == rootContext);
}
public void makeRootContext()
{
if (this.rootContext != null)
this.rootContext.rootContext = this; //the old root now points to us
this.rootContext = this; //we also point to us
}
/**
* The AWT font used for the box.
* @return current font
*/
public Font getFont()
{
return font;
}
/**
* Obtains the specified font size in pt.
* @return the font size in pt
*/
public double getFontSize()
{
return fontSize;
}
/**
* The font variant used for the box.
* @return normal or small-caps
*/
public String getFontVariant()
{
return fontVariant.toString();
}
/**
* Returns the text decoration used for the box.
* @return none or a string of space separated keywords underline, overline, line-through or blink
*/
public String getTextDecorationString()
{
if (textDecoration.isEmpty())
return "none";
else
{
StringBuilder ret = new StringBuilder();
for (CSSProperty.TextDecoration dec : textDecoration)
{
if (ret.length() > 0)
ret.append(' ');
ret.append(dec.toString());
}
return ret.toString();
}
}
/**
* Returns the text decoration used for the box.
* @return a list of TextDecoration values
*/
public List getTextDecoration()
{
return textDecoration;
}
/**
* The text color used for the box.
* @return color specification
*/
public Color getColor()
{
return color;
}
/**
* @return the em value of the context
*/
public double getEm()
{
return em;
}
/**
* @return the rem value of the context
*/
public double getRem()
{
return rem;
}
/**
* @return the ex value of the context
*/
public double getEx()
{
return ex;
}
/**
* @return the 'ch' value of the context
*/
public double getCh()
{
return ch;
}
/**
* @return the dpi value used in the context
*/
public double getDpi()
{
return dpi;
}
//=========================================================================
/**
* Updates the context according to the given element style. The properties that are not defined
* in the style are left unchanged.
* @param style the style data
*/
public void update(NodeData style)
{
//setup the font
String family = null;
CSSProperty.FontFamily ff = style.getProperty("font-family");
if (ff == null)
family = font.getFamily(); //use current
else if (ff == FontFamily.list_values)
{
TermList fmlspec = style.getValue(TermList.class, "font-family");
if (fmlspec == null)
family = font.getFamily();
else
family = getFontName(fmlspec);
}
else
{
if (factory != null)
family = factory.getConfig().getDefaultFont(ff.getAWTValue()); //try to translate to physical font
if (family == null)
family = ff.getAWTValue(); //could not translate - use as is
}
double size;
double psize = (parent == null) ? CSSUnits.medium_font : parent.getEm();
CSSProperty.FontSize fsize = style.getProperty("font-size");
if (fsize == null)
size = em;
else if (fsize == CSSProperty.FontSize.length || fsize == CSSProperty.FontSize.percentage)
{
TermLengthOrPercent lenspec = style.getValue(TermLengthOrPercent.class, "font-size");
if (lenspec != null)
{
em = psize;
size = pxLength(lenspec, psize); //pixels are ok here (java is fixed to 72 dpi for font sizes)
}
else
size = em;
}
else
size = CSSUnits.convertFontSize(psize, fsize);
fontSize = CSSUnits.points(size);
if (rootContext != null)
rem = rootContext.getEm();
else
rem = em; //we don't have a root context?
CSSProperty.FontWeight weight = style.getProperty("font-weight");
if (weight != null) fontWeight = weight;
CSSProperty.FontStyle fstyle = style.getProperty("font-style");
if (fstyle != null) fontStyle = fstyle;
int fs = Font.PLAIN;
if (representsBold(fontWeight))
fs = Font.BOLD;
if (fontStyle == CSSProperty.FontStyle.ITALIC || fontStyle == CSSProperty.FontStyle.OBLIQUE)
fs = fs | Font.ITALIC;
font = new Font(family, fs, (int) Math.round(size));
em = size;
CSSProperty.FontVariant variant = style.getProperty("font-variant");
if (variant != null) fontVariant = variant;
CSSProperty.TextDecoration decor = style.getProperty("text-decoration");
textDecoration.clear();
if (decor != null)
{
if (decor == TextDecoration.list_values)
{
TermList list = style.getValue(TermList.class, "text-decoration");
for (Term t : list)
{
if (t.getValue() instanceof CSSProperty.TextDecoration)
textDecoration.add((CSSProperty.TextDecoration) t.getValue());
}
}
else if (decor != TextDecoration.NONE)
textDecoration.add(decor);
}
//color
TermColor clr = style.getValue(TermColor.class, "color");
if (clr != null) color = clr.getValue();
}
/**
* Updates a Graphics according to this context
* @param g Graphics to be updated
*/
public void updateGraphics(Graphics2D g)
{
g.setFont(font);
g.setColor(color);
g.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_OFF);
g.setRenderingHint(RenderingHints.KEY_TEXT_ANTIALIASING, RenderingHints.VALUE_TEXT_ANTIALIAS_ON);
}
/**
* Updates this context according to the given style. Moreover given Graphics is updated
* to this style and used for taking the font metrics.
* @param style the style data to be used
* @param g Graphics to be updated and used
*/
public void updateForGraphics(NodeData style, Graphics2D g)
{
if (style != null) update(style);
updateGraphics(g);
fm = g.getFontMetrics();
//update the width units
//em has been updated in update()
FontRenderContext frc = new FontRenderContext(null, false, false);
TextLayout layout = new TextLayout("x", font, frc);
ex = layout.getBounds().getHeight();
ch = fm.charWidth('0');
}
//-----------------------------------------------------------------------
/**
* Computes current text line height.
* @return the height of the normal text line in pixels
*/
public int getFontHeight()
{
return fm.getHeight();
}
/**
* Obtains the maximal distance from the line top to the baseline
* for the current font.
* @return the baseline y offset.
*/
public int getBaselineOffset()
{
return fm.getAscent();
}
/**
* Converts a length from a CSS length or percentage to 'pt'.
* @param spec the CSS length specification
* @param whole the value that corresponds to 100%. It is used only when spec is a percentage.
* @return the length in 'pt'
*/
public double ptLength(TermLengthOrPercent spec, double whole)
{
float nval = spec.getValue();
if (spec.isPercentage())
return (whole * nval) / 100;
else
{
TermLength.Unit unit = spec.getUnit();
double ret = 0;
if (unit == TermLength.Unit.pt)
{
ret = nval;
}
else if (unit == TermLength.Unit.in)
{
ret = nval * 72;
}
else if (unit == TermLength.Unit.cm)
{
ret = (nval * 72) / 2.54;
}
else if (unit == TermLength.Unit.mm)
{
ret = (nval * 72) / 25.4;
}
else if (unit == TermLength.Unit.pc)
{
ret = nval * 12;
}
else if (unit == TermLength.Unit.px)
{
ret = (nval * 72) / dpi;
}
else if (unit == TermLength.Unit.em)
{
ret = (em * nval * 72) / dpi; //em is in pixels
}
else if (unit == TermLength.Unit.rem)
{
ret = (rem * nval * 72) / dpi;
}
else if (unit == TermLength.Unit.ex)
{
ret = (ex * nval * 72) / dpi;
}
else if (unit == TermLength.Unit.ch)
{
ret = (ch * nval * 72) / dpi;
}
else if (unit == TermLength.Unit.vw)
{
return (viewport.getVisibleRect().getWidth() * nval * 72) / (100.0 * dpi);
}
else if (unit == TermLength.Unit.vh)
{
return (viewport.getVisibleRect().getHeight() * nval * 72) / (100.0 * dpi);
}
else if (unit == TermLength.Unit.vmin)
{
return (Math.min(viewport.getVisibleRect().getWidth(), viewport.getVisibleRect().getHeight()) * nval * 72) / (100.0 * dpi);
}
else if (unit == TermLength.Unit.vmax)
{
return (Math.max(viewport.getVisibleRect().getWidth(), viewport.getVisibleRect().getHeight()) * nval * 72) / (100.0 * dpi);
}
return ret;
}
}
/**
* Converts a length from a CSS length to 'pt'. Percentages are always evaluated to 0.
* @param spec the CSS length specification
* @return font size in 'pt'
*/
public double ptLength(TermLengthOrPercent spec)
{
return ptLength(spec, 0);
}
/**
* Converts a length from a CSS length or percentage to 'px'.
* @param spec the CSS length specification
* @param whole the value that corresponds to 100%. It is used only when spec is a percentage.
* @return the length in 'px'
*/
public double pxLength(TermLengthOrPercent spec, double whole)
{
float nval = spec.getValue();
if (spec.isPercentage())
return (whole * nval) / 100;
else
{
TermLength.Unit unit = spec.getUnit();
double ret = 0;
if (unit == TermLength.Unit.pt)
{
ret = (nval * dpi) / 72;
}
else if (unit == TermLength.Unit.in)
{
ret = nval * dpi;
}
else if (unit == TermLength.Unit.cm)
{
ret = (nval * dpi) / 2.54;
}
else if (unit == TermLength.Unit.mm)
{
ret = (nval * dpi) / 25.4;
}
else if (unit == TermLength.Unit.pc)
{
ret = (nval * 12 * dpi) / 72;
}
else if (unit == TermLength.Unit.px)
{
ret = nval;
}
else if (unit == TermLength.Unit.em)
{
ret = em * nval; //em is in pixels
}
else if (unit == TermLength.Unit.rem)
{
ret = rem * nval; //em is in pixels
}
else if (unit == TermLength.Unit.ex)
{
ret = ex * nval;
}
else if (unit == TermLength.Unit.ch)
{
ret = ch * nval;
}
else if (unit == TermLength.Unit.vw)
{
return viewport.getVisibleRect().getWidth() * nval / 100.0;
}
else if (unit == TermLength.Unit.vh)
{
return viewport.getVisibleRect().getHeight() * nval / 100.0;
}
else if (unit == TermLength.Unit.vmin)
{
return Math.min(viewport.getVisibleRect().getWidth(), viewport.getVisibleRect().getHeight()) * nval / 100.0;
}
else if (unit == TermLength.Unit.vmax)
{
return Math.max(viewport.getVisibleRect().getWidth(), viewport.getVisibleRect().getHeight()) * nval / 100.0;
}
return ret;
}
}
/**
* Converts a length from a CSS length to 'px'. Percentages are always evaluated to 0.
* @param spec the CSS length specification
* @return font size in 'px'
*/
public double pxLength(TermLengthOrPercent spec)
{
return pxLength(spec, 0);
}
/**
* Converts the weight value to bold / not bold
* @param weight a CSS weight
* @return true if the given weight corresponds to bold
*/
public boolean representsBold(CSSProperty.FontWeight weight)
{
if (weight == CSSProperty.FontWeight.BOLD ||
weight == CSSProperty.FontWeight.BOLDER ||
weight == CSSProperty.FontWeight.numeric_600 ||
weight == CSSProperty.FontWeight.numeric_700 ||
weight == CSSProperty.FontWeight.numeric_800 ||
weight == CSSProperty.FontWeight.numeric_900)
{
return true;
}
else
return false;
}
/**
* Scans a list of font definitions and chooses the first one that is available
* @param list of terms obtained from the font-family property
* @return a font name string according to java.awt.Font
*/
public String getFontName(TermList list)
{
String avail[] = GraphicsEnvironment.getLocalGraphicsEnvironment().getAvailableFontFamilyNames();
for (Term term : list)
{
Object value = term.getValue();
if (value instanceof CSSProperty.FontFamily)
return ((CSSProperty.FontFamily) value).getAWTValue();
else
{
String name = fontAvailable(value.toString(), avail);
if (name != null) return name;
}
}
//nothing found, use Serif
return java.awt.Font.SERIF;
}
/** Returns true if the font family is available.
* @return The exact name of the font family or null if it's not available
*/
private String fontAvailable(String family, String[] avail)
{
for (int i = 0; i < avail.length; i++)
if (avail[i].equalsIgnoreCase(family)) return avail[i];
return null;
}
/**
* Creates a new java Color instance according to a CSS specification rgb(r,g,b)
* @param spec the CSS color specification
* @return the Color instance
*/
public Color getColor(String spec)
{
if (spec.startsWith("rgb("))
{
String s = spec.substring(4, spec.length() - 1);
String[] lst = s.split(",");
try {
int r = Integer.parseInt(lst[0].trim());
int g = Integer.parseInt(lst[1].trim());
int b = Integer.parseInt(lst[2].trim());
return new Color(r, g, b);
} catch (NumberFormatException e) {
return null;
}
}
else
return null;
}
}