We 've stumbled upon several issues with EmfMetafile rendering of metafiles copied from MS Office.

1. How are the dimensions of default rendered image computed? EmfMetafile.createDefaultRendering() returns large rendered images under circumstances we have not been able to pinpoint.
2. Does EmfMetafile.createScaledRendering(int w, int h, java.awt.RenderingHints hints) execution time and memory consumption depend on width/height, and if so, how? 
   
   We need to create a rendered image from EMF
1. fast (to be used for a paste function)
2. not using a lot of memory
3. Using the following code we want to render an EnhMetafile with certain dimensions :
   
   RenderedImage rendImg = null;
   try {
   
    ByteArrayInputStream bis = new ByteArrayInputStream(contents);
    EmfMetafile emf = new EmfMetafile(bis);
   
    float ratio = emf.getWidth()/emf.getHeight();
    final double MilliMetersPerInch = 25.4;
    int renderWidth = (int) ((width*toolkit.getScreenResolution())/MilliMetersPerInch);
    height = (int) (renderWidth/ratio);
   
    RenderingHints hints = new RenderingHints(RenderingHints.KEY_RENDERING, RenderingHints.VALUE_RENDER_SPEED);
    rendImg = emf.createScaledRendering(renderWidth, height, hints);
    
   } catch (MetafilesException e) {
    // TODO Auto-generated catch block
    e.printStackTrace();
   }
   
    ByteArrayOutputStream bos = new ByteArrayOutputStream();
    try {
     ImageIO.write(rendImg, "png", bos);
    } catch (IOException e) {
     // TODO Auto-generated catch block
     e.printStackTrace();
    }
    
   Unfortunately ImageIO fails with the following stack trace :
   
   !STACK 0
   java.lang.ArrayIndexOutOfBoundsException: Coordinate out of bounds!
    at java.awt.image.SinglePixelPackedSampleModel.getPixels(Unknown Source)
    at java.awt.image.Raster.getPixels(Unknown Source)
    at com.sun.imageio.plugins.png.PNGImageWriter.encodePass(Unknown Source)
    at com.sun.imageio.plugins.png.PNGImageWriter.write_IDAT(Unknown Source)
    at com.sun.imageio.plugins.png.PNGImageWriter.write(Unknown Source)
    at javax.imageio.ImageWriter.write(Unknown Source)
    at javax.imageio.ImageIO.write(Unknown Source)
    at javax.imageio.ImageIO.write(Unknown Source)
    
   This does not happen if we use emf.createDefaultRendering().
   Why would PNGImageWriter fail with this image, but not the default rendered? Is this a bug?
   
   

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Sakis Kotisis

Senior Software Engineer

SciGen Technologies, Inc.

Office: +30 25410 25801

Hello,

 

I have forwarded your questions to technical team, it will answer you as soon as possible.

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Many Thanks and Kind Regards,

Shakeel Faiz
Support Developer
Aspose Sialkot Team
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Hello Sakis,

Coordinates of metafiles can start from negative value. In this case the only right way to render it is using code provided in our demo. It uses AffineTransform for translating coordinates. You only need change scale factor there.

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Alexey Zhilin
Team Leader
Aspose Tyumen Team
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