Write text to image in multiple fonts with wrapping in java

Question

I am trying to create an image with a given text and style. eg;

" textStyle(Offer ends 25/12/2016. Exclusions Apply., disclaimer) textStyle(See Details,underline) "

In above line i am splitting and creating a map that stores the first parameter of textStyle block as key and second parameter as value where second param defines the style to be applied on first param. Hence an entry of map will look like .

Now when i iterate over this map to write the text to image i check if the text is overflowing the width. If yes then it breaks the text and adds it to next line in the horizontal center. So for example lets say i am trying to write "Offer ends 25/12/2016. Exclusions Apply." with Arial and font size 12. While writing i find that i can write till "Offer ends 23/12/2016. " only and "Exclusions apply" has to go in next line. But it writes the text in horizontal center neglecting that as there is space left horizontally i can write "See Details" too in the same line.

Please help. Below is the code what i have tried. I have also tried creating a JTextPane and then converting it to image but this cannot be an option as it first creates the frame, makes it visible, writes it and then disposes it. And most of the times i was getting Nullpointer exception on SwingUtilities.invokeAndWait.

Actual : https://i.stack.imgur.com/47fFk.jpg Expected https://i.stack.imgur.com/xiRhd.jpg

public static BufferedImage getTextImage(String textWithoutStyle, Map<String, String> textToThemeMap, Properties prop, int height, int width) {

    BufferedImage img = new BufferedImage(width,height,BufferedImage.TYPE_4BYTE_ABGR);
    Graphics2D g2d = img.createGraphics();
    g2d.setPaint(Color.WHITE);
    FontMetrics fm = g2d.getFontMetrics();
    Map<String, Font> textToFontMap = new LinkedHashMap<String, Font>();


    for(Map.Entry<String, String> entry : textToThemeMap.entrySet()) {

        if(StringUtils.isNotBlank(entry.getKey()) && StringUtils.isNotBlank(entry.getValue())) {

            Font font = getFont(prop, entry.getValue().trim());
            g2d.setFont(font);
            fm = g2d.getFontMetrics();

            String string = entry.getKey();
            char[] chars = null;
            int i = 0, pixelWidth = 0;
            List<String> newTextList = new ArrayList<String>();


            if(fm.stringWidth(string) > (width - 10)) {
                chars = string.toCharArray();
                for (i = 0; i < chars.length; i++) {

                    pixelWidth = pixelWidth + fm.charWidth(chars[i]);
                    if(pixelWidth >= (width - 10)) {
                        break;
                    }
                }

                String newString = WordUtils.wrap(string, i, "\n",false);

                String[] splitString = newString.split("\n");
                for(String str : splitString) {
                    newTextList.add(str);
                    textToFontMap.put(string, font);
                }
            } else {
                newTextList.add(string);
                textToFontMap.put(string, font);
            }

        }
    }

    Font font  = new Font("Arial", Font.BOLD, 14);
    int spaceOfLineHeight = (textToFontMap.size() - 1) * 7;
    int spaceOfText = textToFontMap.size() * font.getSize();
    int totalSpace = spaceOfLineHeight + spaceOfText ;
    int marginRemaining = height - totalSpace;

    int tempHt = marginRemaining / 2 + 10;
    String txt = null;

    for(Map.Entry<String, Font> entry : textToFontMap.entrySet()) {

        txt = entry.getKey();
        font = entry.getValue();
        g2d.setFont(font);
        fm = g2d.getFontMetrics();


        int x = (width - fm.stringWidth(txt)) / 2;
        int y = tempHt;

        g2d.drawString(txt, x, y);
        tempHt = tempHt + fm.getHeight();
    }

   // g2d.drawString(text.getIterator(), 0, (int)lm.getAscent() + lm.getHeight());
   // g2d.dispose();

    return img;
}



// Code with JTextPane ------------------------------------------
public static BufferedImage getTextImage(final Map < String, String > textToThemeMap, final Properties prop, final int height, final int width) throws Exception {

    JFrame f = new JFrame();
    f.setSize(width, height);

    final StyleContext sc = new StyleContext();
    DefaultStyledDocument doc = new DefaultStyledDocument(sc);
    final JTextPane pane = new JTextPane(doc);
    pane.setSize(width, height);


    // Build the styles
    final Paragraph[] content = new Paragraph[1];
    Run[] runArray = new Run[textToThemeMap.size()];

    int i = 0;
    for (Map.Entry < String, String > entry: textToThemeMap.entrySet()) {

        if (StringUtils.isNotBlank(entry.getValue().trim()) && StringUtils.isNotBlank(entry.getKey().trim())) {
            Run run = new Run(entry.getValue().trim(), entry.getKey());
            runArray[i++] = run;
        }
    }

    content[0] = new Paragraph(null, runArray);

    /*createDocumentStyles(sc, prop,textToThemeMap.values());
    addText(pane, sc, sc.getStyle("default"), content);
    pane.setEditable(false);*/

    try {
        SwingUtilities.invokeAndWait(new Runnable() {
            public void run() {
                try {
                    createDocumentStyles(sc, prop, textToThemeMap.values());
                } catch (MalformedURLException e) {
                    //e.printStackTrace();
                }
                addText(pane, sc, sc.getStyle("default"), content);
                pane.setEditable(false);
            }
        });
    } catch (Exception e) {
        System.out.println("Exception when constructing document: " + e);

    }

    f.getContentPane().add(pane);
    f.setVisible(true);
    f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

    BufferedImage img = new BufferedImage(width, height, BufferedImage.TYPE_4BYTE_ABGR);
    Graphics2D gd = img.createGraphics();
    f.paint(gd);

    f.dispose();

    /*ImageIO.write(img, "png", new File("C:\\Users\\spande0\\Desktop\\a.png"));
    System.out.println("done");*/

    return img;
}

Answer 1

I suspect the issue is in your 'Y' computation.

int spaceOfLineHeight = (newTextList.size() - 1) * 7;
int spaceOfText = newTextList.size() * font.getSize();
int totalSpace = spaceOfLineHeight + spaceOfText;
int marginRemaining = height - totalSpace;

int tempHt = marginRemaining / 2 + 10;

You have to keep the height occupied by the previous lines, and add it to the current 'Y'.

At the moment, for all the lines, the 'Y' values is same.

Declare prevHeight outside the for loop. and then do the following.

int tempHt = marginRemaining / 2 + 10;
tempHT += prevHeight;
prevHeight = tempHeight

Based on the comments, I will suggest you to break down your function into two smaller functions.

// Loop through the strings and find out how lines are split and calculate the X, Y 
// This function will give the expected lines

splitLinesAndComputeResult

// Just render the lines
renderLines