Memory efficient jpeg crop?
Hi,
I need to do 2 things with some big jpeg images:
1) get its height/width
2) create a crop, extract some part of the image.
I'd like to know if you know any way (or library) that could create a crop (a 300x300 subimage) out of a jpeg image. It is absoluely necessary that the process be memory efficient.
Loading the whole image into memory takes , well, too much RAM.
Any solution?
BTW, this is what I do today to get the image size and the crop:
// load image
BufferedImage image = ImageIO.read(fileOriginal);
int bigWidth = image.getWidth();
int bigHeight = image.getHeight();
// create crop
BufferedImage detail =new BufferedImage(imageWidth, imageHeight, BufferedImage.TYPE_INT_RGB);
Graphics2D g = detail.createGraphics();
g.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
g.setRenderingHint(RenderingHints.KEY_COLOR_RENDERING, RenderingHints.VALUE_COLOR_RENDER_QUALITY);
g.setRenderingHint(RenderingHints.KEY_DITHERING, RenderingHints.VALUE_DITHER_DISABLE);
g.setRenderingHint(RenderingHints.KEY_FRACTIONALMETRICS, RenderingHints.VALUE_FRACTIONALMETRICS_ON);
g.setRenderingHint(RenderingHints.KEY_INTERPOLATION, RenderingHints.VALUE_INTERPOLATION_BICUBIC);
g.setRenderingHint(RenderingHints.KEY_RENDERING, RenderingHints.VALUE_RENDER_QUALITY);
g.drawImage(image, 0, 0, imageWidth, imageHeight,null);
//... some code to get x, y ...
detail = detail.getSubimage(x, y, edge, edge);
// save thumbnail image to file
out =new BufferedOutputStream(new FileOutputStream(file));
JPEGImageEncoder encoder = JPEGCodec.createJPEGEncoder(out);
JPEGEncodeParam param = encoder.getDefaultJPEGEncodeParam(detail);
param.setQuality(compressionRatio,false);
encoder.setJPEGEncodeParam(param);
encoder.encode(detail);
