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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.
/*
* CSSDecoder.java
* Copyright (c) 2005-2007 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 em units etc.)
* @param c the visual contect to be assigned
*/
public CSSDecoder(VisualContext c)
{
context = c;
}
/**
* Returns the visual context of this decoder.
* @return the assigned visual context
*/
public VisualContext getContext()
{
return context;
}
/**
* Changes the visual context assigned to this decoder.
* @param c The new visual context to be assigned
*/
public void setContext(VisualContext c)
{
context = c;
}
/**
* Returns the length in pixels from a CSS definition. null values
* of the lengths are interpreted as zero.
* @param value The length or percentage value to be converted
* @param auto True, if the property is set to auto
* @param defval The length value to be used when the first one is null
* @param autoval The value to be used when "auto" is specified
* @param whole the length to be returned as 100% (in case of percentage values)
*/
public int getLength(TermLengthOrPercent value, boolean auto, TermLengthOrPercent defval, TermLengthOrPercent autoval, int whole)
{
TermLengthOrPercent val = value;
if (value == null) val = defval;
if (auto) val = autoval;
if (val != null)
return (int) context.pxLength(val, whole);
else
return 0;
}
/**
* Returns the length in pixels from a CSS definition
* @param value The length or percentage value to be converted
* @param auto True, if the property is set to auto
* @param defval The length value to be used when the first one is null
* @param autoval The value to be used when "auto" is specified
* @param whole the length to be returned as 100% (in case of percentage values)
*/
public int getLength(TermLengthOrPercent value, boolean auto, int defval, int autoval, int whole)
{
if (auto)
return autoval;
else if (value == null)
return defval;
else
return (int) context.pxLength(value, whole);
}
/**
* Computes the width and height of a replaced object based on the following properties:
*
* - Intrinsic width and height
* - The
width and height attributes
* - Effective style
*
* @param obj The replaced content object
* @param box The element box whose size should be computed
* @return A rectangle with the width and height set accordingly
*/
public static Rectangle computeReplacedObjectSize(ReplacedContent obj, ElementBox box)
{
int boxw; //resulting size
int boxh;
int intw; //intrinsic sizes
int inth;
float intr;
if (obj != null)
{
intw = obj.getIntrinsicWidth();
inth = obj.getIntrinsicHeight();
if (intw == 0 || inth == 0)
{
log.warn("Obtained a zero intrinsic width or height for " + obj.toString());
intw = inth = 1; //a fallback for avoiding zeros in ratios
}
intr = (float) intw / inth;
boxw = intw;
boxh = inth;
}
else
{
boxw = intw = 20; //some reasonable default values
boxh = inth = 20;
intr = 1.0f;
}
//total widths used for percentages
int twidth = box.getContainingBlock().getContentWidth();
int theight = box.getViewport().getContentHeight();
//try to use the attributes
Element el = box.getElement();
int atrw = -1;
int atrh = -1;
try {
if (!el.getAttribute("width").equals(""))
atrw = HTMLNorm.computeAttributeLength(el.getAttribute("width"), twidth);
} catch (NumberFormatException e) {
log.info("Invalid width value: " + el.getAttribute("width"));
}
try {
if (!el.getAttribute("height").equals(""))
atrh = HTMLNorm.computeAttributeLength(el.getAttribute("height"), theight);
} catch (NumberFormatException e) {
log.info("Invalid height value: " + el.getAttribute("width"));
}
//apply intrinsic ration when necessary
if (atrw == -1 && atrh == -1)
{
boxw = intw;
boxh = inth;
}
else if (atrw == -1)
{
boxw = Math.round(intr * atrh);
boxh = atrh;
}
else if (atrh == -1)
{
boxw = atrw;
boxh = Math.round(atrw / intr);
}
else
{
boxw = atrw;
boxh = atrh;
intr = (float) boxw / boxh; //new intrsinsic ratio is set explicitly
}
//compute dimensions from styles (styles should override the attributes)
CSSDecoder dec = new CSSDecoder(box.getVisualContext());
CSSProperty.Width width = box.getStyle().getProperty("width");
if (width == CSSProperty.Width.AUTO) width = null; //auto and null are equal for width
CSSProperty.Height height = box.getStyle().getProperty("height");
if (height == CSSProperty.Height.AUTO) height = null; //auto and null are equal for height
if (width == null && height != null)
{
//compute boxh, boxw is intrinsic
int autoh = Math.round(boxw / intr);
boxh = dec.getLength(box.getLengthValue("height"), height == CSSProperty.Height.AUTO, boxh, autoh, theight);
boxw = Math.round(intr * boxh);
}
else if (width != null && height == null)
{
//compute boxw, boxh is intrinsic
int autow = Math.round(intr * boxh);
boxw = dec.getLength(box.getLengthValue("width"), width == CSSProperty.Width.AUTO, boxw, autow, twidth);
boxh = Math.round(boxw / intr);
}
else
{
boxw = dec.getLength(box.getLengthValue("width"), width == CSSProperty.Width.AUTO, boxw, intw, twidth);
boxh = dec.getLength(box.getLengthValue("height"), height == CSSProperty.Height.AUTO, boxh, inth, theight);
}
return new Rectangle(boxw, boxh);
}
}