Convert WMF to PNG/BMP/JPG

Question

How can I convert one WMF file to PNG/BMP/JPG format with custom output resolution?

Example: Take WMF file and outputs PNG file with 2000x2000 px.

Thanks in advance.

Electrician

The only way to reliably convert this format is by using the Windows' GDI API, what is your operating system ? I've seen an online converter (zamzar.com) that seems to handle the format, but I'm not sure how well. – Rate

Im using Ubuntu with Java 6 – Electrician

Then you will need to luck, i.e., your WMF files are simple and don't use newer API calls from GDI(+). – Rate

Answer 1

You can use the excelent Batik ( http://xmlgraphics.apache.org/batik/ ) lib to achieve this. But you will need to follow this steps:

1. Convert the WMF file to SVG using the WMFTranscoder
2. Convert the SVG to JGP using the JPGTranscoder

WMF >> SVG >> JPG

Here is a discussion on coderanch about it: http://www.coderanch.com/t/422868/java/java/converting-WMF-Windows-Meta-File

Attendant

Interesting, does it guarantee that it always work even using a operating system different than Windows ? In that case, does it also fully support the newer WMF formats: EMF and EMF+ ? – Rate

Ah, now I see a footnote on its page: "Windows Metafiles (WMF) are supported through classes in Apache Batik. At the moment, support for this format is experimental and may not always work as expected." – Rate

@mmgp, yeah it works on Linux too, last year i did something like this and it works perfect. About the newer WMF format i dont know, i've only used the WMF exported by autocad. – Attendant

@mmgp, sometimes batik cant convert some objects and gives warnings, but this is best way that i can find to do this conversion... – Attendant

There is the unoconv tool which might be better, there is also libgdiplus from Mono which might be better too. – Rate

Answer 2

WMF, EMF and EMF+ are integral parts of slideshows, therefore I've developed a renderer for those as part of Apache POI. As for the upcoming POI-4.1.2 this is still work in progress - if you have any rendering issues, please upload your file in a new bug report in our bugzilla.

The main description can be found in the POI documentation.

Here is an excerpt:

#1 - Use PPTX2PNG via file or stdin

For file system access, you need to save your slideshow/WMF/EMF/EMF+ first to disc and then call PPTX2PNG.main() with the corresponding parameters.

for stdin access, you need to redirect System.in before:

/* the file content */
InputStream is = ...;
/* Save and set System.in */
InputStream oldIn = System.in;
try {
    System.setIn(is);
    String[] args = {
        "-format", "png", // png,gif,jpg,svg or null for test
        "-outdir", new File("out/").getCanonicalPath(),
        "-outfile", "export.png",
        "-fixside", "long",
        "-scale", "800",
        "-ignoreParse",
        "stdin"
    };
    PPTX2PNG.main(args);
} finally {
    System.setIn(oldIn);
}

#2 - Render WMF / EMF / EMF+ via the *Picture classes

File f = samples.getFile("santa.wmf");
try (FileInputStream fis = new FileInputStream(f)) {
    // for WMF
    HwmfPicture wmf = new HwmfPicture(fis);
    // for EMF / EMF+
    HemfPicture emf = new HemfPicture(fis);
    Dimension dim = wmf.getSize();
    int width = Units.pointsToPixel(dim.getWidth());
    // keep aspect ratio for height
    int height = Units.pointsToPixel(dim.getHeight());
    double max = Math.max(width, height);
    if (max > 1500) {
    width *= 1500/max;
    height *= 1500/max;
    }
    BufferedImage bufImg = new BufferedImage(width, height, BufferedImage.TYPE_INT_ARGB);
    Graphics2D g = bufImg.createGraphics();
    g.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
    g.setRenderingHint(RenderingHints.KEY_RENDERING, RenderingHints.VALUE_RENDER_QUALITY);
    g.setRenderingHint(RenderingHints.KEY_INTERPOLATION, RenderingHints.VALUE_INTERPOLATION_BICUBIC);
    g.setRenderingHint(RenderingHints.KEY_FRACTIONALMETRICS, RenderingHints.VALUE_FRACTIONALMETRICS_ON);
    wmf.draw(g, new Rectangle2D.Double(0,0,width,height));
    g.dispose();
    ImageIO.write(bufImg, "PNG", new File("bla.png"));
}

Christcross

This worked beautifully for me. Just as a note, I had to pull in the poi-scratchpad artifact (as opposed to just "poi") to get the classes under the org.apache.poi.hemf package. – Richter

Answer 3

You can use different tools for this format. You can choose for example GIMP. In Java you have a library for converting WMF files.

Backsight

Answer 4

I wrote a walkaround here, for Java I learned that I can run shell command following answers in this question. For WMF, convert it to EMF first following this answer.

Sanmiguel