简单的java图片缩放代码

/**
* @param source: source image file
* @param output: output image file
* @param mode: 0 ratio,1 maxWidth,2 maxHeight,3 maxSide
* @param maxSide: maxWidth, maxHeight or maxSide, different by mode
* @param ratio: ratio if resized by ratio
*/
public static void resizeImage(File source, File output, int mode, Integer maxSide, Double ratio)
throws IOException {
// read image
Image sourceImage = ImageIO.read(source);
// resize image
BufferedImage outputImage = getResizeImage(sourceImage, mode, maxSide, ratio);
// wirite image to file
wirteImageToFile(outputImage, output);
}
/**
* @param source: source image
* @param mode: 0 ratio,1 maxWidth,2 maxHeight,3 maxSide
* @param maxSide: maxWidth, maxHeight or maxSide, different by mode
* @param ratio: ratio if resized by ratio
*/
public static BufferedImage getResizeImage(Image source, int mode, Integer maxSide, Double ratio) {
int srcImageWidth = source.getWidth(null);
int srcImageHeight = source.getHeight(null);
int width = 0, height = 0;
switch (mode) {
case 0:
// resize by ratio
width = (int) (srcImageWidth * ratio);
height = (int) (srcImageHeight * ratio);
break;
case 1:
// resize by max width
width = maxSide;
height = new BigDecimal(srcImageHeight).divide(new BigDecimal(srcImageWidth), 5, RoundingMode.HALF_EVEN)
.multiply(new BigDecimal(width)).intValue();
break;
case 2:
// resize by max height
height = maxSide;
width = new BigDecimal(srcImageWidth).divide(new BigDecimal(srcImageHeight), 5, RoundingMode.HALF_EVEN)
.multiply(new BigDecimal(height)).intValue();
break;
case 3:
// resize by max side(between width and height)
if (srcImageWidth > srcImageHeight) {
width = maxSide;
height = maxSide * srcImageHeight / srcImageWidth;
} else {
width = maxSide * srcImageWidth / srcImageHeight;
height = maxSide;
}
break;
}
BufferedImage t