itext7 study notes-Chapter 2 Practice &example

Others 2020-10-28 02:43:34 views: null

    For the examples in this chapter, please refer to the blog post I translated: itext7 study notes-Chapter 2 , which has a detailed explanation. If you don't understand, you can comment or send a private message to me!

Example 1: Simple coordinate system

    Simply draw an x ​​and y axis coordinate system, the code is as follows:

import com.itextpdf.kernel.geom.PageSize;
import com.itextpdf.kernel.pdf.PdfDocument;
import com.itextpdf.kernel.pdf.PdfPage;
import com.itextpdf.kernel.pdf.PdfWriter;
import com.itextpdf.kernel.pdf.canvas.PdfCanvas;
import com.itextpdf.kernel.pdf.canvas.PdfCanvasConstants;

import java.io.File;
import java.io.IOException;

public class C02E01_Axes {

    public static final String DEST = "results/chapter02/axes.pdf";

    public static void main(String args[]) throws IOException {
        File file = new File(DEST);
        file.getParentFile().mkdirs();
        new C02E01_Axes().createPdf(DEST);
    }

    public void createPdf(String dest) throws IOException {

        //Initialize PDF document
        PdfDocument pdf = new PdfDocument(new PdfWriter(dest));

        PageSize ps = PageSize.A4.rotate();
        PdfPage page = pdf.addNewPage(ps);

        PdfCanvas canvas = new PdfCanvas(page);
        //Replace the origin of the coordinate system to the center of the page
        canvas.concatMatrix(1, 0, 0, 1, ps.getWidth() / 2, ps.getHeight() / 2);

        C02E01_Axes.drawAxes(canvas, ps);

        //Close document
        pdf.close();

    }

    public static void drawAxes(PdfCanvas canvas, PageSize ps) {
        //Draw X axis
        canvas.moveTo(-(ps.getWidth() / 2 - 15), 0)
                .lineTo(ps.getWidth() / 2 - 15, 0)
                .stroke();

        //Draw X axis arrow
        canvas.setLineJoinStyle(PdfCanvasConstants.LineJoinStyle.ROUND)
                .moveTo(ps.getWidth() / 2 - 25, -10)
                .lineTo(ps.getWidth() / 2 - 15, 0)
                .lineTo(ps.getWidth() / 2 - 25, 10).stroke()
                .setLineJoinStyle(PdfCanvasConstants.LineJoinStyle.MITER);

        //Draw Y axis
        canvas.moveTo(0, -(ps.getHeight() / 2 - 15))
                .lineTo(0, ps.getHeight() / 2 - 15)
                .stroke();

        //Draw Y axis arrow
        canvas.saveState()
                .setLineJoinStyle(PdfCanvasConstants.LineJoinStyle.ROUND)
                .moveTo(-10, ps.getHeight() / 2 - 25)
                .lineTo(0, ps.getHeight() / 2 - 15)
                .lineTo(10, ps.getHeight() / 2 - 25).stroke()
                .restoreState();

        //Draw X serif
        for (int i = -((int) ps.getWidth() / 2 - 61); i < ((int) ps.getWidth() / 2 - 60); i += 40) {
    
    
            canvas.moveTo(i, 5).lineTo(i, -5);
        }
        //Draw Y serif
        for (int j = -((int) ps.getHeight() / 2 - 57); j < ((int) ps.getHeight() / 2 - 56); j += 40) {
    
    
            canvas.moveTo(5, j).lineTo(-5, j);
        }
        canvas.stroke();
    }
}

Example 2: Coordinate system and grid lines

    On the basis of the coordinate system, divide the coordinate system and draw grid lines. The code is as follows:

import com.itextpdf.kernel.color.Color;
import com.itextpdf.kernel.color.DeviceCmyk;
import com.itextpdf.kernel.geom.PageSize;
import com.itextpdf.kernel.pdf.PdfDocument;
import com.itextpdf.kernel.pdf.PdfPage;
import com.itextpdf.kernel.pdf.PdfWriter;
import com.itextpdf.kernel.pdf.canvas.PdfCanvas;

import java.io.File;
import java.io.IOException;

public class C02E02_GridLines {

    public static final String DEST = "results/chapter02/grid_lines.pdf";

    public static void main(String args[]) throws IOException {
        File file = new File(DEST);
        file.getParentFile().mkdirs();
        new C02E02_GridLines().createPdf(DEST);
    }

    public void createPdf(String dest) throws IOException {

        //Initialize PDF document
        PdfDocument pdf = new PdfDocument(new PdfWriter(dest));

        PageSize ps = PageSize.A4.rotate();
        PdfPage page = pdf.addNewPage(ps);

        PdfCanvas canvas = new PdfCanvas(page);
        //Replace the origin of the coordinate system to the center of the page
        canvas.concatMatrix(1, 0, 0, 1, ps.getWidth() / 2, ps.getHeight() / 2);

        Color grayColor = new DeviceCmyk(0.f, 0.f, 0.f, 0.875f);
        Color greenColor = new DeviceCmyk(1.f, 0.f, 1.f, 0.176f);
        Color blueColor = new DeviceCmyk(1.f, 0.156f, 0.f, 0.118f);

        canvas.setLineWidth(0.5f).setStrokeColor(blueColor);

        //Draw horizontal grid lines
        for (int i = -((int) ps.getHeight() / 2 - 57); i < ((int) ps.getHeight() / 2 - 56); i += 40) {
    
    
            canvas.moveTo(-(ps.getWidth() / 2 - 15), i)
                    .lineTo(ps.getWidth() / 2 - 15, i);
        }
        //Draw vertical grid lines
        for (int j = -((int) ps.getWidth() / 2 - 61); j < ((int) ps.getWidth() / 2 - 60); j += 40) {
    
    
            canvas.moveTo(j, -(ps.getHeight() / 2 - 15))
                    .lineTo(j, ps.getHeight() / 2 - 15);
        }
        canvas.stroke();

        //Draw axes
        canvas.setLineWidth(3).setStrokeColor(grayColor);
        C02E01_Axes.drawAxes(canvas, ps);

        //Draw plot
        canvas.setLineWidth(2).setStrokeColor(greenColor)
                .setLineDash(10, 10, 8)
                .moveTo(-(ps.getWidth() / 2 - 15), -(ps.getHeight() / 2 - 15))
                .lineTo(ps.getWidth() / 2 - 15, ps.getHeight() / 2 - 15).stroke();

        //Close document
        pdf.close();

    }
}

Example 3: Paragraphs of text and fonts

    Here we simply display the beginning text of the Star Wars 5 Empire Strikes Back, the code is as follows:

import com.itextpdf.io.font.FontConstants;
import com.itextpdf.kernel.font.PdfFontFactory;
import com.itextpdf.kernel.geom.PageSize;
import com.itextpdf.kernel.pdf.PdfDocument;
import com.itextpdf.kernel.pdf.PdfPage;
import com.itextpdf.kernel.pdf.PdfWriter;
import com.itextpdf.kernel.pdf.canvas.PdfCanvas;

import java.io.File;
import java.io.IOException;
import java.util.ArrayList;
import java.util.List;

public class C02E03_StarWars {

    public static final String DEST = "results/chapter02/star_wars.pdf";

    public static void main(String args[]) throws IOException {
        File file = new File(DEST);
        file.getParentFile().mkdirs();
        new C02E03_StarWars().createPdf(DEST);
    }

    public void createPdf(String dest) throws IOException {

        //Initialize PDF document
        PdfDocument pdf = new PdfDocument(new PdfWriter(dest));

        //Add new page
        PageSize ps = PageSize.A4;
        PdfPage page = pdf.addNewPage(ps);

        PdfCanvas canvas = new PdfCanvas(page);

        List<String> text = new ArrayList();
        text.add("         Episode V         ");
        text.add("  THE EMPIRE STRIKES BACK  ");
        text.add("It is a dark time for the");
        text.add("Rebellion. Although the Death");
        text.add("Star has been destroyed,");
        text.add("Imperial troops have driven the");
        text.add("Rebel forces from their hidden");
        text.add("base and pursued them across");
        text.add("the galaxy.");
        text.add("Evading the dreaded Imperial");
        text.add("Starfleet, a group of freedom");
        text.add("fighters led by Luke Skywalker");
        text.add("has established a new secret");
        text.add("base on the remote ice world");
        text.add("of Hoth...");

        //Replace the origin of the coordinate system to the top left corner
        canvas.concatMatrix(1, 0, 0, 1, 0, ps.getHeight());
        canvas.beginText()
                .setFontAndSize(PdfFontFactory.createFont(FontConstants.COURIER_BOLD), 14)
                .setLeading(14 * 1.2f)
                .moveText(70, -40);
        for (String s : text) {
            //Add text and move to the next line
            canvas.newlineShowText(s);
        }
        canvas.endText();

        //Close document
        pdf.close();

    }
}

Example 4: Cool text effects

    We add cool effects based on the third example, the code is as follows:

import com.itextpdf.io.font.FontConstants;
import com.itextpdf.kernel.color.Color;
import com.itextpdf.kernel.color.DeviceCmyk;
import com.itextpdf.kernel.font.PdfFontFactory;
import com.itextpdf.kernel.geom.PageSize;
import com.itextpdf.kernel.pdf.PdfDocument;
import com.itextpdf.kernel.pdf.PdfPage;
import com.itextpdf.kernel.pdf.PdfWriter;
import com.itextpdf.kernel.pdf.canvas.PdfCanvas;

import java.io.File;
import java.io.IOException;
import java.util.ArrayList;
import java.util.List;


public class C02E04_StarWarsCrawl {

    public static final String DEST = "results/chapter02/star_wars_crawl.pdf";

    public static void main(String args[]) throws IOException {
        File file = new File(DEST);
        file.getParentFile().mkdirs();
        new C02E04_StarWarsCrawl().createPdf(DEST);
    }

    public void createPdf(String dest) throws IOException {

        List<String> text = new ArrayList();
        text.add("            Episode V      ");
        text.add("    THE EMPIRE STRIKES BACK  ");
        text.add("It is a dark time for the");
        text.add("Rebellion. Although the Death");
        text.add("Star has been destroyed,");
        text.add("Imperial troops have driven the");
        text.add("Rebel forces from their hidden");
        text.add("base and pursued them across");
        text.add("the galaxy.");
        text.add("Evading the dreaded Imperial");
        text.add("Starfleet, a group of freedom");
        text.add("fighters led by Luke Skywalker");
        text.add("has established a new secret");
        text.add("base on the remote ice world");
        text.add("of Hoth...");

        int maxStringWidth = 0;
        for (String fragment : text) {
            if (fragment.length() > maxStringWidth) maxStringWidth = fragment.length();
        }

        //Initialize PDF document
        PdfDocument pdf = new PdfDocument(new PdfWriter(dest));

        //Add new page
        PageSize ps = PageSize.A4;
        PdfPage page = pdf.addNewPage(ps);

        PdfCanvas canvas = new PdfCanvas(page);

        //Set black background
        canvas.rectangle(0, 0, ps.getWidth(), ps.getHeight())
                .setColor(Color.BLACK, true)
                .fill();

        //Replace the origin of the coordinate system to the top left corner
        canvas.concatMatrix(1, 0, 0, 1, 0, ps.getHeight());
        Color yellowColor = new DeviceCmyk(0.f, 0.0537f, 0.769f, 0.051f);
        float lineHeight = 5;
        float yOffset = -40;
        canvas.beginText()
                .setFontAndSize(PdfFontFactory.createFont(FontConstants.COURIER_BOLD), 1)
                .setColor(yellowColor, true);
        for (int j = 0; j < text.size(); j++) {
    
    
            String line = text.get(j);
            float xOffset = ps.getWidth() / 2 - 45 - 8 * j;
            float fontSizeCoeff = 6 + j;
            float lineSpacing = (lineHeight + j) * j / 1.5f;
            int stringWidth = line.length();
            for (int i = 0; i < stringWidth; i++) {
    
    
                float angle = (maxStringWidth / 2 - i) / 2f;
                float charXOffset = (4 + (float) j / 2) * i;
                canvas.setTextMatrix(fontSizeCoeff, 0,
                        angle, fontSizeCoeff / 1.5f,
                        xOffset + charXOffset, yOffset - lineSpacing)
                        .showText(String.valueOf(line.charAt(i)));
            }
        }
        canvas.endText();

        //Close document
        pdf.close();

    }
}

Example code download

    The code for this chapter can be downloaded at the following address (IDEA project): iText7-Chapter 2 Source Code Project

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Origin blog.csdn.net/u012397189/article/details/77119609
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