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/*
This file is part of the iText (R) project.
Copyright (c) 1998-2024 Apryse Group NV
Authors: Apryse Software.
This program is offered under a commercial and under the AGPL license.
For commercial licensing, contact us at https://itextpdf.com/sales. For AGPL licensing, see below.
AGPL licensing:
This program is free software: you can redistribute it and/or modify
it under the terms of the GNU Affero General Public License as published by
the Free Software Foundation, either version 3 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 Affero General Public License for more details.
You should have received a copy of the GNU Affero General Public License
along with this program. If not, see .
*/
package com.itextpdf.kernel.pdf.canvas.parser.data;
import com.itextpdf.io.font.FontProgram;
import com.itextpdf.io.font.otf.GlyphLine;
import com.itextpdf.kernel.colors.Color;
import com.itextpdf.kernel.font.PdfFont;
import com.itextpdf.kernel.font.PdfType0Font;
import com.itextpdf.kernel.geom.LineSegment;
import com.itextpdf.kernel.geom.Matrix;
import com.itextpdf.kernel.geom.Vector;
import com.itextpdf.kernel.pdf.PdfName;
import com.itextpdf.kernel.pdf.PdfString;
import com.itextpdf.kernel.pdf.canvas.CanvasGraphicsState;
import com.itextpdf.kernel.pdf.canvas.CanvasTag;
import com.itextpdf.kernel.pdf.canvas.parser.PdfCanvasProcessor;
import com.itextpdf.kernel.pdf.canvas.parser.listener.IEventListener;
import java.io.UnsupportedEncodingException;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
import java.util.Stack;
/**
* Provides information and calculations needed by render listeners
* to display/evaluate text render operations.
*
* This is passed between the {@link PdfCanvasProcessor} and
* {@link IEventListener} objects as text rendering operations are
* discovered
*/
public class TextRenderInfo extends AbstractRenderInfo {
private final PdfString string;
private String text = null;
private final Matrix textToUserSpaceTransformMatrix;
private final Matrix textMatrix;
private float unscaledWidth = Float.NaN;
/**
* Hierarchy of nested canvas tags for the text from the most inner (nearest to text) tag to the most outer.
*/
private final List canvasTagHierarchy;
/**
* Creates a new TextRenderInfo object
*
* @param str the PDF string that should be displayed
* @param gs the graphics state (note: at this time, this is not immutable, so don't cache it)
* @param textMatrix the text matrix at the time of the render operation
* @param canvasTagHierarchy the marked content tags sequence, if available
*/
public TextRenderInfo(PdfString str, CanvasGraphicsState gs, Matrix textMatrix, Stack canvasTagHierarchy) {
super(gs);
this.string = str;
this.textToUserSpaceTransformMatrix = textMatrix.multiply(gs.getCtm());
this.textMatrix = textMatrix;
this.canvasTagHierarchy = Collections.unmodifiableList(new ArrayList<>(canvasTagHierarchy));
}
/**
* Used for creating sub-TextRenderInfos for each individual character.
*
* @param parent the parent TextRenderInfo
* @param str the content of a TextRenderInfo
* @param horizontalOffset the unscaled horizontal offset of the character that this TextRenderInfo represents
*/
private TextRenderInfo(TextRenderInfo parent, PdfString str, float horizontalOffset) {
super(parent.gs);
this.string = str;
Matrix offsetMatrix = new Matrix(horizontalOffset, 0);
this.textToUserSpaceTransformMatrix = offsetMatrix.multiply(parent.textToUserSpaceTransformMatrix);
this.textMatrix = offsetMatrix.multiply(parent.textMatrix);
this.canvasTagHierarchy = parent.canvasTagHierarchy;
}
/**
* Gets the text to be rendered according to canvas operators.
*
* @return the text to render
*/
public String getText() {
checkGraphicsState();
if (text == null) {
GlyphLine gl = gs.getFont().decodeIntoGlyphLine(string);
if (!isReversedChars()) {
text = gl.toUnicodeString(gl.start, gl.end);
} else {
StringBuilder sb = new StringBuilder(gl.end - gl.start);
for (int i = gl.end - 1; i >= gl.start; i--) {
sb.append(gl.get(i).getUnicodeChars());
}
text = sb.toString();
}
}
return text;
}
/**
* @return original PDF string
*/
public PdfString getPdfString() {
return string;
}
/**
* Gets original Text matrix.
*
* @return text matrix.
*/
public Matrix getTextMatrix() {
return textMatrix;
}
/**
* Checks if the text belongs to a marked content sequence
* with a given mcid.
*
* @param mcid a marked content id
* @return true if the text is marked with this id
*/
public boolean hasMcid(int mcid) {
return hasMcid(mcid, false);
}
/**
* Checks if the text belongs to a marked content sequence
* with a given mcid.
*
* @param mcid a marked content id
* @param checkTheTopmostLevelOnly indicates whether to check the topmost level of marked content stack only
* @return true if the text is marked with this id
*/
public boolean hasMcid(int mcid, boolean checkTheTopmostLevelOnly) {
if (checkTheTopmostLevelOnly) {
if (canvasTagHierarchy != null) {
int infoMcid = getMcid();
return infoMcid != -1 && infoMcid == mcid;
}
} else {
for (CanvasTag tag : canvasTagHierarchy) {
if (tag.hasMcid())
if (tag.getMcid() == mcid)
return true;
}
}
return false;
}
/**
* Gets the marked-content identifier associated with this {@link TextRenderInfo} instance
*
* @return associated marked-content identifier or -1 in case content is unmarked
*/
public int getMcid() {
for (CanvasTag tag : canvasTagHierarchy) {
if (tag.hasMcid()) {
return tag.getMcid();
}
}
return -1;
}
/**
* Gets the baseline for the text (i.e. the line that the text 'sits' on)
* This value includes the Rise of the draw operation - see {@link #getRise()} for the amount added by Rise
*
* @return the baseline line segment
*/
public LineSegment getBaseline() {
checkGraphicsState();
return getUnscaledBaselineWithOffset(0 + gs.getTextRise()).transformBy(textToUserSpaceTransformMatrix);
}
public LineSegment getUnscaledBaseline() {
checkGraphicsState();
return getUnscaledBaselineWithOffset(0 + gs.getTextRise());
}
/**
* Gets the ascent line for the text (i.e. the line that represents the topmost extent that a string of the current font could have).
* This value includes the Rise of the draw operation - see {@link #getRise()} for the amount added by Rise.
*
* @return a LineSegment instance
*/
public LineSegment getAscentLine() {
checkGraphicsState();
return getUnscaledBaselineWithOffset(getAscentDescent()[0] + gs.getTextRise()).transformBy(textToUserSpaceTransformMatrix);
}
/**
* Gets the descent line for the text (i.e. the line that represents the bottom most extent that a string of the current font could have).
* This value includes the Rise of the draw operation - see {@link #getRise()} for the amount added by Rise.
*
* @return a LineSegment instance
*/
public LineSegment getDescentLine() {
checkGraphicsState();
return getUnscaledBaselineWithOffset(getAscentDescent()[1] + gs.getTextRise()).transformBy(textToUserSpaceTransformMatrix);
}
/**
* Getter for the font
*
* @return the font
*/
public PdfFont getFont() {
checkGraphicsState();
return gs.getFont();
}
/**
* The rise represents how far above the nominal baseline the text should be rendered. The {@link #getBaseline()}, {@link #getAscentLine()} and {@link #getDescentLine()} methods already include Rise.
* This method is exposed to allow listeners to determine if an explicit rise was involved in the computation of the baseline (this might be useful, for example, for identifying superscript rendering)
*
* @return The Rise for the text draw operation, in user space units (Ts value, scaled to user space)
*/
public float getRise() {
checkGraphicsState();
// optimize the common case
if (gs.getTextRise() == 0) return 0;
return convertHeightFromTextSpaceToUserSpace(gs.getTextRise());
}
/**
* Provides detail useful if a listener needs access to the position of each individual glyph in the text render operation
*
* @return A list of {@link TextRenderInfo} objects that represent each glyph used in the draw operation. The next effect is if there was a separate Tj opertion for each character in the rendered string
*/
public List getCharacterRenderInfos() {
checkGraphicsState();
List rslt = new ArrayList<>(string.getValue().length());
PdfString[] strings = splitString(string);
float totalWidth = 0;
for (PdfString str : strings) {
float[] widthAndWordSpacing = getWidthAndWordSpacing(str);
TextRenderInfo subInfo = new TextRenderInfo(this, str, totalWidth);
rslt.add(subInfo);
totalWidth += (widthAndWordSpacing[0] * gs.getFontSize() + gs.getCharSpacing() + widthAndWordSpacing[1]) * (gs.getHorizontalScaling() / 100f);
}
for (TextRenderInfo tri : rslt)
tri.getUnscaledWidth();
return rslt;
}
/**
* @return The width, in user space units, of a single space character in the current font
*/
public float getSingleSpaceWidth() {
return convertWidthFromTextSpaceToUserSpace(getUnscaledFontSpaceWidth());
}
/**
* @return the text render mode that should be used for the text. From the
* PDF specification, this means:
*
*
0 = Fill text
*
1 = Stroke text
*
2 = Fill, then stroke text
*
3 = Invisible
*
4 = Fill text and add to path for clipping
*
5 = Stroke text and add to path for clipping
*
6 = Fill, then stroke text and add to path for clipping
*
7 = Add text to padd for clipping
*
*/
public int getTextRenderMode() {
checkGraphicsState();
return gs.getTextRenderingMode();
}
/**
* @return the current fill color.
*/
public Color getFillColor() {
checkGraphicsState();
return gs.getFillColor();
}
/**
* @return the current stroke color.
*/
public Color getStrokeColor() {
checkGraphicsState();
return gs.getStrokeColor();
}
public float getFontSize() {
checkGraphicsState();
return gs.getFontSize();
}
public float getHorizontalScaling() {
checkGraphicsState();
return gs.getHorizontalScaling();
}
public float getCharSpacing() {
checkGraphicsState();
return gs.getCharSpacing();
}
public float getWordSpacing() {
checkGraphicsState();
return gs.getWordSpacing();
}
public float getLeading() {
checkGraphicsState();
return gs.getLeading();
}
/**
* Gets /ActualText tag entry value if this text chunk is marked content.
*
* @return /ActualText value or null if none found
*/
public String getActualText() {
String lastActualText = null;
for (CanvasTag tag : canvasTagHierarchy) {
lastActualText = tag.getActualText();
if (lastActualText != null) {
break;
}
}
return lastActualText;
}
/**
* Gets /E tag (expansion text) entry value if this text chunk is marked content.
*
* @return /E value or null if none found
*/
public String getExpansionText() {
String expansionText = null;
for (CanvasTag tag : canvasTagHierarchy) {
expansionText = tag.getExpansionText();
if (expansionText != null) {
break;
}
}
return expansionText;
}
/**
* Determines if the text represented by this {@link TextRenderInfo} instance is written in a text showing operator
* wrapped by /ReversedChars marked content sequence
*
* @return true if this text block lies within /ReversedChars block, false otherwise
*/
public boolean isReversedChars() {
for (CanvasTag tag : canvasTagHierarchy) {
if (tag != null) {
if (PdfName.ReversedChars.equals(tag.getRole())) {
return true;
}
}
}
return false;
}
/**
* Gets hierarchy of the canvas tags that wraps given text.
*
* @return list of the wrapping canvas tags. The first tag is the innermost (nearest to the text).
*/
public List getCanvasTagHierarchy() {
return canvasTagHierarchy;
}
/**
* @return the unscaled (i.e. in Text space) width of the text
*/
public float getUnscaledWidth() {
if (Float.isNaN(unscaledWidth))
unscaledWidth = getPdfStringWidth(string, false);
return unscaledWidth;
}
private LineSegment getUnscaledBaselineWithOffset(float yOffset) {
checkGraphicsState();
// we need to correct the width so we don't have an extra character and word spaces at the end. The extra character and word spaces
// are important for tracking relative text coordinate systems, but should not be part of the baseline
String unicodeStr = string.toUnicodeString();
float correctedUnscaledWidth = getUnscaledWidth() - (gs.getCharSpacing() +
(unicodeStr.length() > 0 && unicodeStr.charAt(unicodeStr.length() - 1) == ' ' ? gs.getWordSpacing() : 0)) * (gs.getHorizontalScaling() / 100f);
return new LineSegment(new Vector(0, yOffset, 1), new Vector(correctedUnscaledWidth, yOffset, 1));
}
/**
* @param width the width, in text space
* @return the width in user space
*/
private float convertWidthFromTextSpaceToUserSpace(float width) {
LineSegment textSpace = new LineSegment(new Vector(0, 0, 1), new Vector(width, 0, 1));
LineSegment userSpace = textSpace.transformBy(textToUserSpaceTransformMatrix);
return userSpace.getLength();
}
/**
* @param height the height, in text space
* @return the height in user space
*/
private float convertHeightFromTextSpaceToUserSpace(float height) {
LineSegment textSpace = new LineSegment(new Vector(0, 0, 1), new Vector(0, height, 1));
LineSegment userSpace = textSpace.transformBy(textToUserSpaceTransformMatrix);
return userSpace.getLength();
}
/**
* Calculates the width of a space character in text space units.
*
* @return the width of a single space character in text space units
*/
private float getUnscaledFontSpaceWidth() {
checkGraphicsState();
char spaceChar = ' ';
int charWidth = gs.getFont().getWidth(spaceChar);
if (charWidth == 0) {
charWidth = gs.getFont().getFontProgram().getAvgWidth();
}
final float charWidthInGlyphSpace = FontProgram.convertTextSpaceToGlyphSpace(charWidth);
return (charWidthInGlyphSpace * gs.getFontSize() + gs.getCharSpacing() + gs.getWordSpacing())
* gs.getHorizontalScaling() / 100F;
}
/**
* Gets the width of a PDF string in text space units
*
* @param string the string that needs measuring
* @return the width of a String in text space units
*/
private float getPdfStringWidth(PdfString string, boolean singleCharString) {
checkGraphicsState();
if (singleCharString) {
float[] widthAndWordSpacing = getWidthAndWordSpacing(string);
return (float)(((double)widthAndWordSpacing[0] * (double)gs.getFontSize() + (double)gs.getCharSpacing()
+ (double)widthAndWordSpacing[1]) * (double)gs.getHorizontalScaling() / 100f);
} else {
float totalWidth = 0;
for (PdfString str : splitString(string)) {
totalWidth += getPdfStringWidth(str, true);
}
return totalWidth;
}
}
/**
* Calculates width and word spacing of a single character PDF string.
* IMPORTANT: Shall ONLY be used for a single character pdf strings.
*
* @param string a character to calculate width.
* @return array of 2 items: first item is a character width, second item is a calculated word spacing.
*/
private float[] getWidthAndWordSpacing(PdfString string) {
checkGraphicsState();
return new float[] {
FontProgram.convertTextSpaceToGlyphSpace(gs.getFont().getContentWidth(string)),
" ".equals(string.getValue()) ? gs.getWordSpacing() : 0,
};
}
/**
* Converts a single character string to char code.
*
* @param string single character string to convert to.
* @return char code.
*/
private int getCharCode(String string) {
try {
byte[] b = string.getBytes("UTF-16BE");
int value = 0;
for (int i = 0; i < b.length - 1; i++) {
value += b[i] & 0xff;
value <<= 8;
}
if (b.length > 0) {
value += b[b.length - 1] & 0xff;
}
return value;
} catch (UnsupportedEncodingException e) {
}
return 0;
}
/**
* Split PDF string into array of single character PDF strings.
*
* @param string PDF string to be split.
* @return split PDF string.
*/
private PdfString[] splitString(PdfString string) {
checkGraphicsState();
PdfFont font = gs.getFont();
if (font instanceof PdfType0Font) {
// Number of bytes forming one glyph can be arbitrary from [1; 4] range
List strings = new ArrayList<>();
GlyphLine glyphLine = gs.getFont().decodeIntoGlyphLine(string);
for (int i = glyphLine.start; i < glyphLine.end; i++) {
strings.add(new PdfString(gs.getFont().convertToBytes(glyphLine.get(i))));
}
return strings.toArray(new PdfString[strings.size()]);
} else {
// One byte corresponds to one character
PdfString[] strings = new PdfString[string.getValue().length()];
for (int i = 0; i < string.getValue().length(); i++) {
strings[i] = new PdfString(string.getValue().substring(i, i + 1), string.getEncoding());
}
return strings;
}
}
private float[] getAscentDescent() {
checkGraphicsState();
float ascent = gs.getFont().getFontProgram().getFontMetrics().getTypoAscender();
float descent = gs.getFont().getFontProgram().getFontMetrics().getTypoDescender();
// If descent is positive, we consider it a bug and fix it
if (descent > 0) {
descent = -descent;
}
final float scale = (ascent - descent < 700) ? (ascent - descent) : FontProgram.UNITS_NORMALIZATION;
descent = descent / scale * gs.getFontSize();
ascent = ascent / scale * gs.getFontSize();
return new float[]{ascent, descent};
}
}
