help with creating dynamic text on a jsp

[paries]

Hello,
I am trying to create dynamic text on a JSP
I am following the example

http://today.java.net/pub/a/today/2004/04/22/images.html

(Dynamic Text section.)
I have that part working just fine. The problem i am having is how to create the text image with a transparent background

Thanks

 

[jwenting]

there's libraries that will create an Image out of a String.
You can then save that Image as a gif or png with the desired transparancy settings using appropriate libraries for that.

I'll leave the searching for those libraries to you (I know they exist but have forgotten where).

 

[prosper]

only netscape can see this png with color red as the transparent color, I don't know why

<%@ page import="java.io.*" %>
<%@ page import="java.awt.*"
%><%@ page import="java.awt.geom.*"
%><%@ page import="java.awt.image.*"
%><%@ page import="java.awt.font.*"
%><%@ page import="java.io.*"
%><%@ page import="org.joshy.*"
%><%@ page import="javax.swing.*"
%><%@ page import="javax.imageio.*"%>
<%@ page import="com.sun.media.jai.codec.*"

%>
<%
    try {
    
        // configure all of the parameters
        String text = "ABC abc XYZ xyz";
        if(request.getParameter("text") != null) {
            text = request.getParameter("text");
        }
        String font_file = "dungeon.ttf";
        if(request.getParameter("font-file") != null) {
            font_file = request.getParameter("font-file");
        }
        font_file = request.getRealPath(font_file);
        float size = 20.0f;
        if(request.getParameter("size") != null) {
            size = Float.parseFloat(request.getParameter("size"));
        }

        Color background = Color.white;
        if(request.getParameter("background") != null) {
            background = new Color(Integer.parseInt(request.getParameter("background"),16));
        }
        Color color = Color.black;
        if(request.getParameter("color") != null) {
            color = new Color(Integer.parseInt(request.getParameter("color"),16));
        }
        
        Font font = Font.createFont(Font.TRUETYPE_FONT,new FileInputStream(font_file));
        font = font.deriveFont(size);
        BufferedImage buffer = new BufferedImage(1,1,BufferedImage.TYPE_INT_RGB);
        Graphics2D g2 = buffer.createGraphics();
        g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING,RenderingHints.VALUE_ANTIALIAS_ON);
        FontRenderContext fc = g2.getFontRenderContext();
        Rectangle2D bounds = font.getStringBounds(text,fc);
        
        // calculate the size of the text
        int width = (int) bounds.getWidth();
        int height = (int) bounds.getHeight();
        
        // prepare some output
        buffer = new BufferedImage(width,height,BufferedImage.TYPE_INT_RGB);
        g2 = buffer.createGraphics();
        g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING,RenderingHints.VALUE_ANTIALIAS_OFF);
        g2.setFont(font);
        
        // actually do the drawing
        g2.setColor(new Color(255,0,0));
        g2.fillRect(0,0,width,height);
        g2.setColor(color);
        g2.drawString(text,0,(int)-bounds.getY());
        
        // set the content type and get the output stream
        response.setContentType("image/png");
        OutputStream sos = response.getOutputStream();

        // output the image as png
	PNGEncodeParam param = new PNGEncodeParam.RGB();
	//param.setBitDepth(8);
((PNGEncodeParam.RGB)param).setTransparentRGB(new int[]{255,0,0});
             ImageEncoder enc = ImageCodec.createImageEncoder("PNG",sos,param);
;
             enc.encode(buffer);
             sos.close();
    } catch (Exception ex) {
        System.out.println(ex);
    }
%>

 

[prosper]

change the content of text.jsp to my modified version