JAVA实现多张PNG生成GIF图片
2018-12-05 本文已影响0人
shiguangfeixu
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多张PNG图片生成GIF图片算法（可抽帧压缩）
/**
* 生成GIF图片
* @param files 原始PNG图片
* @param isPressed 是否被压缩，默认true
* @return
*/
public static File generatePreview(File[] files, Boolean isPressed) {
try {
BufferedImage[] images = null;
if(isPressed)
images = parseCompressed(files);
else
images = parse(files);
Path path = Files.createTempFile("preview_", ".gif");
System.out.println(path);
AnimatedGifEncoder encoder = new AnimatedGifEncoder();
// 设置循环模式，0为无限循环 这里没有使用源文件的播放次数
encoder.setRepeat(0);
encoder.start(new FileOutputStream(path.toFile()));
int count = 1;
//采样频率，数字越大，文件越小，丢失的帧越多，设置为1可保持原帧
int frequency = 2;
for (BufferedImage image : images) {
if((++count)%frequency==0){
encoder.setDelay(50*frequency);
encoder.addFrame(image);
}
}
encoder.finish();
System.out.print("GIF创建成功： ");
return path.toFile();
} catch (IOException e) {
System.out.println("failed to generate preview file");
throw new RuntimeException("failed to generate preview file");
}
}
把PNG素材压缩并转成BufferedImage
/**
* 把PNG素材压缩并转成BufferedImage
*
* @param files png文件
* @return BufferedImage[]
*/
private static BufferedImage[] parseCompressed(File[] files) {
BufferedImage[] bi = new BufferedImage[files.length];
try {
for (int index = 0; index < files.length; index++) {
bi[index] = CompressPic.compressPic(ImageIO.read(files[index]));
}
} catch (IOException e) {
System.out.println("fail to parse template");
throw new RuntimeException("fail to parse template", e);
}
return bi;
}
对PNG图片进行等比压缩处理
/**
* 对图片进行压缩处理
* @param img
* @return
*/
public static BufferedImage compressPic(BufferedImage img) {
BufferedImage imgCompressed = null;
try {
if (img.getWidth(null) == -1) {
//打印错误日志
System.out.println("图片格式错误！");
return imgCompressed;
} else {
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) img.getWidth(null))
/ (double) outputWidth * 1.0;
double rate2 = ((double) img.getHeight(null))
/ (double) outputHeight * 1.0;
// 根据缩放比率大的进行缩放控制
double rate = rate1 > rate2 ? rate1 : rate2;
newWidth = (int) (((double) img.getWidth(null)) / rate);
newHeight = (int) (((double) img.getHeight(null)) / rate);
} else {
newWidth = outputWidth; // 输出的图片宽度
newHeight = outputHeight; // 输出的图片高度
}
imgCompressed = new BufferedImage(newWidth, newHeight, BufferedImage.TYPE_INT_RGB);
/*
* Image.SCALE_SMOOTH 的缩略算法 生成缩略图片的平滑度的优先级比速度高 生成的图片质量比较好 但速度慢
*/
imgCompressed.getGraphics().drawImage(img.getScaledInstance(newWidth, newHeight, Image.SCALE_SMOOTH)
, 0, 0, null);
}
} catch (Exception ex) {
ex.printStackTrace();
}
return imgCompressed;
}
单张图片压缩算法（与上述方法无关）
/**
* 压缩图片
* @param file
* @param qality 参数qality是取值0~1范围内 代表压缩的程度
* @return
* @throws IOException
*/
public static File compressPictureByQality(File file, float qality) throws IOException {
BufferedImage src = null;
FileOutputStream out = null;
ImageWriter imgWrier;
ImageWriteParam imgWriteParams;
System.out.println("开始设定压缩图片参数");
// 指定写图片的方式为 jpg
imgWrier = ImageIO.getImageWritersByFormatName("png").next();
imgWriteParams = new javax.imageio.plugins.jpeg.JPEGImageWriteParam(
null);
// 要使用压缩，必须指定压缩方式为MODE_EXPLICIT
imgWriteParams.setCompressionMode(imgWriteParams.MODE_EXPLICIT);
// 这里指定压缩的程度，参数qality是取值0~1范围内，
imgWriteParams.setCompressionQuality(qality);
imgWriteParams.setProgressiveMode(imgWriteParams.MODE_DISABLED);
ColorModel colorModel =ImageIO.read(file).getColorModel();// ColorModel.getRGBdefault();
imgWriteParams.setDestinationType(new javax.imageio.ImageTypeSpecifier(
colorModel, colorModel.createCompatibleSampleModel(32, 32)));
System.out.println("结束设定压缩图片参数");
if (!file.exists()) {
System.out.println("Not Found Img File,文件不存在");
throw new FileNotFoundException("Not Found Img File,文件不存在");
} else {
System.out.println("图片转换前大小"+file.length()/1024+"kb");
src = ImageIO.read(file);
out = new FileOutputStream(file);
imgWrier.reset();
// 必须先指定 out值，才能调用write方法, ImageOutputStream可以通过任何
// OutputStream构造
imgWrier.setOutput(ImageIO.createImageOutputStream(out));
// 调用write方法，就可以向输入流写图片
imgWrier.write(null, new IIOImage(src, null, null),
imgWriteParams);
out.flush();
out.close();
System.out.println("图片转换后大小"+file.length()/1024+"kb");
return file;
}
}
