java graphics2d旋转_JAVA用Graphics2D实现图片旋转，缩放，合成
第一步：读入文件
public BufferedImage loadImageLocal(String path) {
try {
return ImageIO.read(new File(path));
} catch (IOException e) {
e.printStackTrace();
}
return null;
}
第二步：缩放文件
/**
*
* @param mini 贴图
* @param Scale 缩放比例
* @return
*/
public BufferedImage modifyImageScale(BufferedImage mini,double Scale) {
int w = (int)Math.round(mini.getWidth()*Scale);
int h = (int)Math.round(mini.getHeight()*Scale);
//设置生成图片宽*高，色彩
BufferedImage bi = new BufferedImage(w, h, BufferedImage.TYPE_INT_RGB);
//创建画布
Graphics2D g2 = bi.createGraphics()；
//设置图片透明 注********：只有png格式的图片才能设置背景透明，jpg设置图片颜色变的乱七八糟
bi = g2.getDeviceConfiguration().createCompatibleImage(w, h, Transparency.TRANSLUCENT);
//重新创建画布
g2 = bi.createGraphics();
//画图
g2.drawImage(mini, 0,0,w,h, null);
//关闭资源
g2.dispose();
return bi;
}
第三步：旋转文件
/**
*
* @param mini 贴图
* @param ratio 旋转角度
* @return
*/
public BufferedImage modifyImageRatio(BufferedImage mini,int ratio) {
int src_width = mini.getWidth();
int src_height = mini.getHeight();
//针对图片旋转重新计算图的宽*高
Rectangle rect_des = CalcRotatedSize(new Rectangle(new Dimension(
src_width, src_height)), ratio);
//设置生成图片的宽*高，色彩度
BufferedImage res = new BufferedImage(rect_des.width, rect_des.height,BufferedImage.TYPE_INT_RGB);
//创建画布
Graphics2D g2 = res.createGraphics();
res = g2.getDeviceConfiguration().createCompatibleImage(rect_des.width, rect_des.height, Transparency.TRANSLUCENT);
g2 = res.createGraphics();
//重新设定原点坐标
g2.translate((rect_des.width - src_width) / 2,
(rect_des.height - src_height) / 2);
//执行图片旋转，rotate里包含了translate，并还原了原点坐标
g2.rotate(Math.toRadians(ratio), src_width / 2, src_height / 2);
g2.drawImage(mini, null, null);
g2.dispose();
return res;
}
private Rectangle CalcRotatedSize(Rectangle src, int angel) {
if (angel >= 90) {
if(angel / 90 % 2 == 1){
int temp = src.height;
src.height = src.width;
src.width = temp;
}
angel = angel % 90;
}
double r = Math.sqrt(src.height * src.height + src.width * src.width) / 2;
double len = 2 * Math.sin(Math.toRadians(angel) / 2) * r;
double angel_alpha = (Math.PI - Math.toRadians(angel)) / 2;
double angel_dalta_width = Math.atan((double) src.height / src.width);
double angel_dalta_height = Math.atan((double) src.width / src.height);
int len_dalta_width = (int) (len * Math.cos(Math.PI - angel_alpha
- angel_dalta_width));
int len_dalta_height = (int) (len * Math.cos(Math.PI - angel_alpha
- angel_dalta_height));
int des_width = src.width + len_dalta_width * 2;
int des_height = src.height + len_dalta_height * 2;
return new Rectangle(new Dimension(des_width, des_height));
}
第四步：合成文件
/**
*
* @param mini 贴图
* @param big 底图
* @param indexX x坐标位置
* @param indexY y坐标位置
* @return
*/
public BufferedImage modifyImagetogeter(BufferedImage mini, BufferedImage big,Integer indexX,Integer indexY) {
try {
int w =mini.getWidth();
int h =mini.getHeight();
System.out.println(w+" , "+h);
Graphics2D g = big.createGraphics();
g.drawImage(mini, indexX, indexY, w,h, null);
g.dispose();
} catch (Exception e) {
System.out.println(e.getMessage());
}
return big;
}
第五步：导出文件
public void writeImageLocal(String newPath, BufferedImage newImg) {
if (newPath != null && newImg != null) {
try {
File outputfile = new File(newPath);
ImageIO.write(newImg, "png", outputfile);
} catch (IOException e) {
System.out.println(e.getMessage());
}
}
}