public class picture {
// todo auto-generated constructor stub
public static void resizepng(string fromfile, string tofile, int outputwidth, int outputheight,boolean proportion) {
try {
file f2 = new file(fromfile);
bufferedimage bi2 = imageio.read(f2);
int newwidth;
int newheight;
// 判断是否是等比缩放
if (proportion == true) {
// 为等比缩放计算输出的图片宽度及高度
double rate1 = ((double) bi2.getwidth(null)) / (double) outputwidth + 0.1;
double rate2 = ((double) bi2.getheight(null)) / (double) outputheight + 0.1;
// 根据缩放比率大的进行缩放控制
double rate = rate1 < rate2 ? rate1 : rate2;
newwidth = (int) (((double) bi2.getwidth(null)) / rate);
newheight = (int) (((double) bi2.getheight(null)) / rate);
} else {
newwidth = outputwidth; // 输出的图片宽度
newheight = outputheight; // 输出的图片高度
}
bufferedimage to = new bufferedimage(newwidth, newheight,
bufferedimage.type_int_rgb);
graphics2d g2d = to.creategraphics();
to = g2d.getdeviceconfiguration().createcompatibleimage(newwidth,newheight,
transparency.translucent);
g2d.dispose();
g2d = to.creategraphics();
image from = bi2.getscaledinstance(newwidth, newheight, bi2.scale_area_averaging);
g2d.drawimage(from, 0, 0, null);
g2d.dispose();
imageio.write(to, "png", new file(tofile));
} catch (ioexception e) {
e.printstacktrace();
}
}
public static void main(string[] args) throws ioexception {
system.out.println("start");
resizepng("c:\\documents and settings\\administrator\\桌面\\8d9e9c82d158ccbf8b31059319d8bc3eb035414e.jpg", "c:\\documents and settings\\administrator\\桌面\\ell.png",200, 100,true);
system.out.println("ok");
}
}
更多解决java压缩图片透明背景变黑色的问题。
