springboot使用GDAL获取tif文件的缩略图并转为base64
首先需要安装gdal：https://blog.csdn.net/qq_61950936/article/details/142880279?spm=1001.2014.3001.5501
然后是配置pom.xml文件：
<!--处理缩略图的--><dependency><groupId>org.gdal</groupId><artifactId>gdal</artifactId><version>3.9.0</version></dependency>
更新maven。
效果：
TiffThumbnailGenerator类：
package com.geofly.dataservicecenter.api.common.util;import java.awt.*;import org.gdal.gdal.Dataset;
import org.gdal.gdal.gdal;
import org.gdal.gdal.Band;
import org.gdal.gdalconst.gdalconstConstants;import java.awt.image.BufferedImage;
import javax.imageio.ImageIO;
import java.io.*;
import java.util.Base64;/*** @Description: 读取 tif文件的InputStream 并生成缩略图** @Auther: yanghaoxing* @Date: 2024/10/12*/
public class TiffThumbnailGenerator {static {System.loadLibrary("gdal");gdal.AllRegister();}// 将 InputStream 写入临时文件private static File inputStreamToFile(InputStream inputStream) throws IOException {File tempFile = File.createTempFile("tempTiff", ".tif");try (FileOutputStream out = new FileOutputStream(tempFile)) {byte[] buffer = new byte[1024];int bytesRead;while ((bytesRead = inputStream.read(buffer)) != -1) {out.write(buffer, 0, bytesRead);}}return tempFile;}/*** @Description: 传入InputStream，读取缩略图的BufferedImage** @Param: [inputStream, width, height]* @Return: java.awt.image.BufferedImage* @Author yanghaoxing* @Date 2024/10/12 16:25*/public static BufferedImage generateThumbnail(InputStream inputStream, int width, int height) throws IOException {File tiffFile = inputStreamToFile(inputStream);Dataset dataset = gdal.Open(tiffFile.getAbsolutePath(), gdalconstConstants.GA_ReadOnly);if (dataset == null) {// 无法打开 TIFF 文件return null;}int xSize = dataset.getRasterXSize();int ySize = dataset.getRasterYSize();// 读取三个波段（假设分别为 R、G、B）Band bandRed = dataset.GetRasterBand(1); // 红波段Band bandGreen = dataset.GetRasterBand(2); // 绿波段Band bandBlue = dataset.GetRasterBand(3); // 蓝波段// 分配数组来存储波段数据int[] redData = new int[xSize * ySize];int[] greenData = new int[xSize * ySize];int[] blueData = new int[xSize * ySize];// 读取波段数据bandRed.ReadRaster(0, 0, xSize, ySize, redData);bandGreen.ReadRaster(0, 0, xSize, ySize, greenData);bandBlue.ReadRaster(0, 0, xSize, ySize, blueData);// 创建 RGB 图像BufferedImage originalImage = new BufferedImage(xSize, ySize, BufferedImage.TYPE_INT_RGB);for (int y = 0; y < ySize; y++) {for (int x = 0; x < xSize; x++) {int r = redData[y * xSize + x];int g = greenData[y * xSize + x];int b = blueData[y * xSize + x];int rgb = (r << 16) | (g << 8) | b;originalImage.setRGB(x, y, rgb);}}// 先裁剪掉黑边BufferedImage croppedImage = cropBlackBorders(originalImage);// 然后缩放并居中图像BufferedImage resizedImage = resizeAndCenterImage(croppedImage, width, height);// 关闭数据集dataset.delete();return resizedImage;}// 缩放图片以适应指定大小并保持宽高比public static BufferedImage resizeAndCenterImage(BufferedImage originalImage, int targetWidth, int targetHeight) {int originalWidth = originalImage.getWidth();int originalHeight = originalImage.getHeight();// 计算缩放比例，保持宽高比double scaleFactor = Math.min((double) targetWidth / originalWidth, (double) targetHeight / originalHeight);int scaledWidth = (int) (originalWidth * scaleFactor);int scaledHeight = (int) (originalHeight * scaleFactor);// 创建一个新的目标图像（透明背景）BufferedImage resizedImage = new BufferedImage(targetWidth, targetHeight, BufferedImage.TYPE_INT_ARGB);// 在新图像上进行绘制Graphics2D g2d = resizedImage.createGraphics();g2d.setRenderingHint(RenderingHints.KEY_INTERPOLATION, RenderingHints.VALUE_INTERPOLATION_BICUBIC);g2d.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);g2d.setRenderingHint(RenderingHints.KEY_RENDERING, RenderingHints.VALUE_RENDER_QUALITY);// 计算居中位置int x = (targetWidth - scaledWidth) / 2;int y = (targetHeight - scaledHeight) / 2;// 填充透明背景并绘制缩放后的图像g2d.drawImage(originalImage, x, y, scaledWidth, scaledHeight, null);g2d.dispose();return resizedImage;}// 裁剪黑边（裁剪掉纯黑的区域）public static BufferedImage cropBlackBorders(BufferedImage image) {int width = image.getWidth();int height = image.getHeight();int top = 0, bottom = height - 1, left = 0, right = width - 1;boolean foundTop = false, foundBottom = false, foundLeft = false, foundRight = false;// 检测上边界for (int y = 0; y < height && !foundTop; y++) {for (int x = 0; x < width; x++) {if (!isBlack(image.getRGB(x, y))) {top = y;foundTop = true;break;}}}// 检测下边界for (int y = height - 1; y >= 0 && !foundBottom; y--) {for (int x = 0; x < width; x++) {if (!isBlack(image.getRGB(x, y))) {bottom = y;foundBottom = true;break;}}}// 检测左边界for (int x = 0; x < width && !foundLeft; x++) {for (int y = 0; y < height; y++) {if (!isBlack(image.getRGB(x, y))) {left = x;foundLeft = true;break;}}}// 检测右边界for (int x = width - 1; x >= 0 && !foundRight; x--) {for (int y = 0; y < height; y++) {if (!isBlack(image.getRGB(x, y))) {right = x;foundRight = true;break;}}}// 裁剪图像return image.getSubimage(left, top, right - left + 1, bottom - top + 1);}// 判断一个像素是否是黑色（你可以根据需要调整黑色的判断标准）private static boolean isBlack(int rgb) {Color color = new Color(rgb);// 理论上应该是：color.getRed() == 0 && color.getGreen() == 0 && color.getBlue() == 0; 但是目前测试数据的黑边是色值是：1,1,0// 白边也去掉return (color.getRed() == 1 && color.getGreen() == 1 && color.getBlue() == 0) ||(color.getRed() == 0 && color.getGreen() == 0 && color.getBlue() == 0) ||(color.getRed() == 255 && color.getGreen() == 255 && color.getBlue() == 255);}// 将 BufferedImage 转换为 Base64 字符串public static String bufferedImageToBase64(BufferedImage image, String format) throws IOException {if (image == null) {return null;}ByteArrayOutputStream outputStream = new ByteArrayOutputStream();ImageIO.write(image, format, outputStream);byte[] imageBytes = outputStream.toByteArray();String base64Image = Base64.getEncoder().encodeToString(imageBytes);outputStream.close();return base64Image;}/*** @Description: 将BufferedImage写入指定路径** @Param: [thumbnail, outputFilePath]* @Return: void* @Author yanghaoxing* @Date 2024/10/12 16:24*/public static void saveThumbnailToFile(BufferedImage thumbnail, String outputFilePath) throws IOException {File outputfile = new File(outputFilePath);ImageIO.write(thumbnail, "png", outputfile);}
}使用：
/*** @Description: 根据文件id获取该tif图的缩略图** @Param: [fileId]* @Return: String base64Image* @Author yanghaoxing* @Date 2024/10/12 10:24*/private String getTiffImageBuffered(List<String> fileIds) {int width = 255, height = 255;FileDownloadVo fileDownloadVo = uploadService.getFile(fileIds.get(0));if (fileDownloadVo != null && fileDownloadVo.getFileStream() != null) {InputStream inputStream = fileDownloadVo.getFileStream();try {// 传入InputStream，读取缩略图的BufferedImageBufferedImage bufferedImage = TiffThumbnailGenerator.generateThumbnail(inputStream, width, height);// 转为base64格式String base64Image = TiffThumbnailGenerator.bufferedImageToBase64(bufferedImage, "png");return base64Image != null ? "data:image/png;base64," + base64Image : null;} catch (IOException e) {return null;}}return null;}
