[英]JAI Change JPEG Resolution
我在使用Java JAI(Java高级映像)API将JPEG图像的分辨率从比如说1024x800更改为512x400时遇到困难。
我玩弄了API,并不断收到流或java.lang.OutOfMemory
异常。
有工作实例的任何人。
这是一个使用JAI的
public void resize(String filename, RenderedOp image, double wScale, double hScale)
{
// now resize the image
ParameterBlock pb = new ParameterBlock();
pb.addSource(image); // The source image
pb.add(wScale); // The xScale
pb.add(hScale); // The yScale
pb.add(0.0F); // The x translation
pb.add(0.0F); // The y translation
RenderingHints hints = new RenderingHints(RenderingHints.KEY_RENDERING, RenderingHints.VALUE_RENDER_QUALITY);
RenderedOp resizedImage = JAI.create("SubsampleAverage", pb, hints);
// lastly, write the newly-resized image to an
// output stream, in a specific encoding
try
{
FileOutputStream fos = new FileOutputStream(new File(filename));
JAI.create("encode", resizedImage, fos, getImageType(filename), null);
}
catch (FileNotFoundException e)
{
}
}
这是一个工作示例,按“原样”提供,不提供任何担保:)
BufferedImage scaleImage(BufferedImage sourceImage, int scaledWidth) {
float scale = scaledWidth / (float) sourceImage.getWidth();
int scaledHeight = (int) (sourceImage.getHeight() * scale);
Image scaledImage = sourceImage.getScaledInstance(
scaledWidth,
scaledHeight,
Image.SCALE_AREA_AVERAGING
);
BufferedImage bufferedImage = new BufferedImage(
scaledImage.getWidth(null),
scaledImage.getHeight(null),
BufferedImage.TYPE_INT_RGB
);
Graphics g = bufferedImage.createGraphics();
g.drawImage(scaledImage, 0, 0, null);
g.dispose();
return bufferedImage;
}
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