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Open HTML to PDF is a CSS 2.1 renderer written in Java. This artifact contains the core rendering and layout code.
/*
* {{{ header & license
* Copyright (c) 2006 Wisconsin Court System
*
* This program 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 2.1
* of the License, or (at your option) any later version.
*
* This program 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 this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
* }}}
*/
package com.openhtmltopdf.context;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
import org.w3c.dom.Element;
import com.openhtmltopdf.css.constants.IdentValue;
import com.openhtmltopdf.css.extend.ContentFunction;
import com.openhtmltopdf.css.parser.CSSPrimitiveValue;
import com.openhtmltopdf.css.parser.FSFunction;
import com.openhtmltopdf.css.parser.PropertyValue;
import com.openhtmltopdf.layout.CounterFunction;
import com.openhtmltopdf.layout.InlineBoxing;
import com.openhtmltopdf.layout.LayoutContext;
import com.openhtmltopdf.render.Box;
import com.openhtmltopdf.render.InlineBox;
import com.openhtmltopdf.render.InlineLayoutBox;
import com.openhtmltopdf.render.InlineText;
import com.openhtmltopdf.render.LineBox;
import com.openhtmltopdf.render.RenderingContext;
public class ContentFunctionFactory {
private final List _functions = new ArrayList<>();
public ContentFunctionFactory() {
_functions.add(new PageCounterFunction());
_functions.add(new PagesCounterFunction());
_functions.add(new TargetCounterFunction());
_functions.add(new TargetTextFunction());
_functions.add(new LeaderFunction());
_functions.add(new FsIfCutOffFunction());
}
public ContentFunction lookupFunction(LayoutContext c, FSFunction function) {
return _functions.stream()
.filter(f -> f.canHandle(c, function))
.findFirst().orElse(null);
}
public void registerFunction(ContentFunction function) {
_functions.add(function);
}
/**
* Content function which returns its argument if on a cut off page, else the empty string.
* Example:
* content: "Page " counter(page) -fs-if-cut-off(" continued") " of " counter(pages);
*/
private static class FsIfCutOffFunction extends ContentFunctionAbstract {
@Override
public String calculate(LayoutContext c, FSFunction function) {
return null;
}
@Override
public String calculate(RenderingContext c, FSFunction function, InlineText text) {
return c.getShadowPageNumber() >= 0 ?
function.getParameters().get(0).getStringValue() :
"";
}
@Override
public String getLayoutReplacementText() {
// Needs to be non-empty.
return "cont";
}
@Override
public boolean canHandle(LayoutContext c, FSFunction function) {
return function.getName().equals("-fs-if-cut-off") &&
function.getParameters().size() == 1 &&
function.getParameters().get(0).getPrimitiveType() == CSSPrimitiveValue.CSS_STRING;
}
}
private static abstract class PageNumberFunction extends ContentFunctionAbstract {
@Override
public String calculate(LayoutContext c, FSFunction function) {
return null;
}
@Override
public String getLayoutReplacementText() {
return "999";
}
protected IdentValue getListStyleType(FSFunction function) {
IdentValue result = IdentValue.DECIMAL;
List parameters = function.getParameters();
if (parameters.size() == 2) {
PropertyValue pValue = parameters.get(1);
IdentValue iValue = IdentValue.valueOf(pValue.getStringValue());
if (iValue != null) {
result = iValue;
}
}
return result;
}
protected boolean isCounter(FSFunction function, String counterName) {
if (function.getName().equals("counter")) {
List parameters = function.getParameters();
if (parameters.size() == 1 || parameters.size() == 2) {
PropertyValue param = parameters.get(0);
if (param.getPrimitiveType() != CSSPrimitiveValue.CSS_IDENT ||
! param.getStringValue().equals(counterName)) {
return false;
}
if (parameters.size() == 2) {
param = parameters.get(1);
return param.getPrimitiveType() == CSSPrimitiveValue.CSS_IDENT;
}
return true;
}
}
return false;
}
}
private static class PageCounterFunction extends PageNumberFunction {
@Override
public String calculate(RenderingContext c, FSFunction function, InlineText text) {
int value = c.getRootLayer().getRelativePageNo(c) + 1;
return CounterFunction.createCounterText(getListStyleType(function), value);
}
@Override
public boolean canHandle(LayoutContext c, FSFunction function) {
return c.isPrint() && isCounter(function, "page");
}
}
private static class PagesCounterFunction extends PageNumberFunction {
@Override
public String calculate(RenderingContext c, FSFunction function, InlineText text) {
int value = c.getRootLayer().getRelativePageCount(c);
return CounterFunction.createCounterText(getListStyleType(function), value);
}
@Override
public boolean canHandle(LayoutContext c, FSFunction function) {
return c.isPrint() && isCounter(function, "pages");
}
}
/**
* Partially implements target counter as specified here:
* http://www.w3.org/TR/2007/WD-css3-gcpm-20070504/#cross-references
*/
private static class TargetCounterFunction extends ContentFunctionAbstract {
@Override
public String calculate(RenderingContext c, FSFunction function, InlineText text) {
// Due to how BoxBuilder::wrapGeneratedContent works, it is likely the immediate
// parent of text is an anonymous InlineLayoutBox so we have to go up another
// level to the wrapper box which contains the element.
Element hrefElement = text.getParent().getElement() == null ?
text.getParent().getParent().getElement() :
text.getParent().getElement();
String uri = hrefElement.getAttribute("href");
if (uri != null && uri.startsWith("#")) {
String anchor = uri.substring(1);
Box target = c.getBoxById(anchor);
if (target != null) {
int pageNo = c.getRootLayer().getRelativePageNo(c, target.getAbsY());
IdentValue counterStyle = IdentValue.DECIMAL; // default type
List params = function != null ? function.getParameters() : Collections.emptyList();
if (params.size() > 2) {
IdentValue iValue = IdentValue.valueOf(params.get(2).getStringValue());
if (iValue != null) {
counterStyle = iValue;
}
}
return CounterFunction.createCounterText(counterStyle, pageNo + 1);
}
}
return "";
}
@Override
public String calculate(LayoutContext c, FSFunction function) {
return null;
}
@Override
public String getLayoutReplacementText() {
return "999";
}
@Override
public boolean canHandle(LayoutContext c, FSFunction function) {
if (c.isPrint() && function.getName().equals("target-counter")) {
List parameters = function.getParameters();
if (parameters.size() == 2 || parameters.size() == 3) {
FSFunction f = parameters.get(0).getFunction();
if (f == null ||
f.getParameters().size() != 1 ||
f.getParameters().get(0).getPrimitiveType() != CSSPrimitiveValue.CSS_IDENT ||
! f.getParameters().get(0).getStringValue().equals("href")) {
return false;
}
PropertyValue param = parameters.get(1);
return param.getPrimitiveType() == CSSPrimitiveValue.CSS_IDENT &&
param.getStringValue().equals("page");
}
}
return false;
}
}
/**
* https://www.w3.org/TR/css-gcpm-3/#target-text
* https://www.w3.org/TR/css-values-3/#attr-notation
*
* We support target-text(attr(xxx)) and target-text(attr(xxx url))
* where xxx is an attribute name and url is the
* type returned (only url is supported as the second param).
*
* Limitations:
* The value returned from the attribute must start with hash (#), it
* is not resolved to an absolute url.
* We only support returning the content of the target element, not a specific pseudo element.
*/
private static class TargetTextFunction extends ContentFunctionAbstract {
@Override
public boolean isCalculableAtLayout() {
return true;
}
@Override
public String calculate(RenderingContext c, FSFunction function, InlineText text) {
// FIXME: Not sure this method is used any longer.
// Prefer getPostBoxingLayoutReplacementText below.
// Due to how BoxBuilder::wrapGeneratedContent works, it is likely the immediate
// parent of text is an anonymous InlineLayoutBox so we have to go up another
// level to the wrapper box which contains the element.
Element hrefElement = text.getParent().getElement() == null ?
text.getParent().getParent().getElement() :
text.getParent().getElement();
// We want to get xxx in target-text(attr(xxx))
// Default to href.
String attribute =
function.getParameters().isEmpty() ||
function.getParameters().get(0).getFunction() == null ||
!"attr".equals(function.getParameters().get(0).getFunction().getName()) ||
function.getParameters().get(0).getFunction().getParameters().isEmpty() ?
"href" : function.getParameters().get(0).getFunction().getParameters().get(0).getStringValue();
String uri = hrefElement.getAttribute(attribute);
if (uri != null && uri.startsWith("#")) {
String anchor = uri.substring(1);
Box target = c.getBoxById(anchor);
if (target != null) {
StringBuilder strBuilder = new StringBuilder();
target.collectText(c, strBuilder);
return strBuilder.toString();
}
}
return "";
}
@Override
public String calculate(LayoutContext c, FSFunction function) {
return null;
}
@Override
public String getLayoutReplacementText() {
return "ABCABC";
}
@Override
public String getPostBoxingLayoutReplacementText(
LayoutContext c, Element hrefElement, FSFunction function) {
if (hrefElement == null) {
return "";
}
// We want to get xxx in target-text(attr(xxx))
// Default to href.
String attribute =
function.getParameters().isEmpty() ||
function.getParameters().get(0).getFunction() == null ||
!"attr".equals(function.getParameters().get(0).getFunction().getName()) ||
function.getParameters().get(0).getFunction().getParameters().isEmpty() ?
"href" : function.getParameters().get(0).getFunction().getParameters().get(0).getStringValue();
String uri = hrefElement.getAttribute(attribute);
if (uri.startsWith("#")) {
String href = uri.substring(1);
Object target = c.getLayoutBox(href);
if (target == null) {
return "";
} else if (target instanceof Box) {
Box box = (Box) target;
StringBuilder strBuilder = new StringBuilder();
box.collectLayoutText(c, strBuilder);
return strBuilder.toString();
} else if (target instanceof InlineBox) {
InlineBox ib = (InlineBox) target;
return ib.getText();
}
}
return "";
}
@Override
public boolean canHandle(LayoutContext c, FSFunction function) {
if (c.isPrint() && function.getName().equals("target-text")) {
List parameters = function.getParameters();
if(parameters.size() == 1) {
FSFunction f = parameters.get(0).getFunction();
return "attr".equals(f.getName()) &&
(f.getParameters().size() == 1 ||
(f.getParameters().size() == 2 && "url".equals(f.getParameters().get(1).getStringValue())));
}
}
return false;
}
}
/**
* Partially implements leaders as specified here:
* http://www.w3.org/TR/2007/WD-css3-gcpm-20070504/#leaders
*/
public static class LeaderFunction extends ContentFunctionAbstract {
@Override
public String calculate(RenderingContext c, FSFunction function, InlineText text) {
InlineLayoutBox iB = text.getParent();
LineBox lineBox = iB.getLineBox();
// There might be a dynamic function (target-counter, counter, etc)
// after this function.
// Because the leader should fill up the line, we need the correct
// width and must first compute the dynamic function.
boolean dynamic = false;
boolean dynamic2 = false;
Box wrapperBox = iB.getParent();
List children = null;
// The type of wrapperBox will depend on the CSS display property
// of the pseudo element where the content property using this function exists.
// See BoxBuilder#wrapGeneratedContent.
if (wrapperBox instanceof InlineLayoutBox) {
children = ((InlineLayoutBox) wrapperBox).getInlineChildren();
} else {
children = wrapperBox.getChildren();
}
for (Object child : children) {
if (child == iB) {
// Don't call InlineLayoutBox::lookForDynamicFunctions on this box
// as we will arrive back here and end up as a stack overflow.
// Instead set the dynamic flag so we resolve subsequent dynamic functions.
dynamic = true;
} else if (child instanceof InlineLayoutBox) {
// This forces the computation of dynamic functions.
// NOTE: We do not evaluate other leaders as this would
// cause a battle with this leader and that leader ending in a
// stack overflow or worse an endless loop.
((InlineLayoutBox)child).lookForDynamicFunctions(c, false);
}
}
// We also have to evaluate subsequent dynamic functions at the line level
// in the case that we are in the ::before and subsequent functions are in ::after.
if (dynamic) {
for (Box child : lineBox.getChildren()) {
if (wrapperBox == child) {
dynamic2 = true;
} else if (dynamic2 && child instanceof InlineLayoutBox) {
((InlineLayoutBox)child).lookForDynamicFunctions(c, false);
}
}
}
if (dynamic) {
// Re-calculate the width of the line after subsequent dynamic functions
// have been calculated.
int totalLineWidth = InlineBoxing.positionHorizontally(c, lineBox, 0);
lineBox.setContentWidth(totalLineWidth);
}
// Get leader value and value width
PropertyValue param = function.getParameters().get(0);
String value = param.getStringValue();
if (param.getPrimitiveType() == CSSPrimitiveValue.CSS_IDENT) {
if (value.equals("dotted")) {
value = ". ";
} else if (value.equals("solid")) {
value = "_";
} else if (value.equals("space")) {
value = " ";
}
}
// Compute value width using 100x string to get more precise width.
// Otherwise there might be a small gap at the right side. This is
// necessary because a TextRenderer usually use double/float for width.
StringBuilder tmp = new StringBuilder(100 * value.length());
for (int i = 0; i < 100; i++) {
tmp.append(value);
}
float valueWidth = c.getTextRenderer().getWidth(c.getFontContext(),
iB.getStyle().getFSFont(c), tmp.toString()) / 100f;
int spaceWidth = c.getTextRenderer().getWidth(c.getFontContext(),
iB.getStyle().getFSFont(c), " ");
// compute leader width and necessary count of values
int leaderWidth = iB.getContainingBlockWidth() - iB.getLineBox().getWidth() + text.getWidth();
int count = (int) ((leaderWidth - (2 * spaceWidth)) / valueWidth);
// build leader string
StringBuilder buf = new StringBuilder(count * value.length() + 2);
buf.append(' ');
for (int i = 0; i < count; i++) {
buf.append(value);
}
buf.append(' ');
String leaderString = buf.toString();
// set left margin to ensure that the leader is right aligned (for TOC)
int leaderStringWidth = c.getTextRenderer().getWidth(c.getFontContext(),
iB.getStyle().getFSFont(c), leaderString);
iB.setMarginLeft(c, leaderWidth - leaderStringWidth);
return leaderString;
}
@Override
public String calculate(LayoutContext c, FSFunction function) {
return null;
}
@Override
public String getLayoutReplacementText() {
return " . ";
}
@Override
public boolean canHandle(LayoutContext c, FSFunction function) {
if (c.isPrint() && function.getName().equals("leader")) {
List parameters = function.getParameters();
if (parameters.size() == 1) {
PropertyValue param = parameters.get(0);
return param.getPrimitiveType() == CSSPrimitiveValue.CSS_STRING ||
(param.getPrimitiveType() == CSSPrimitiveValue.CSS_IDENT &&
(param.getStringValue().equals("dotted") ||
param.getStringValue().equals("solid") ||
param.getStringValue().equals("space")));
}
}
return false;
}
}
}