Java 创建调整大小的图像和视频缩略图
我正在努力使自己的生活更舒适 -任何类型图像的缩略图。(拇指插入.jpg) -最中间帧的视频缩略图 我已经看到了一些其他的问题和谷歌,但不能使任何一个工作良好 e、 g 使用了此代码,但无法创建高质量的缩略图Java 创建调整大小的图像和视频缩略图,java,Java,我正在努力使自己的生活更舒适 -任何类型图像的缩略图。(拇指插入.jpg) -最中间帧的视频缩略图 我已经看到了一些其他的问题和谷歌,但不能使任何一个工作良好 e、 g 使用了此代码,但无法创建高质量的缩略图 package main; import java.awt.Graphics2D; import java.awt.image.BufferedImage; import java.io.File; import javax.imageio.ImageIO; public cla
package main;
import java.awt.Graphics2D;
import java.awt.image.BufferedImage;
import java.io.File;
import javax.imageio.ImageIO;
public class Main implements Serializable {
public static void main(String[] args) throws FileNotFoundException, IOException {
Main fac = new Main();
fac.run("C:\\Users\\Masood-Ahmad\\Desktop\\tempSnaps");
}
public void run(String folder) {
File dir = new File(folder);
for (File file : dir.listFiles()) {
createThumbnail(file);
}
}
private void createThumbnail(File file) {
try {
// BufferedImage is the best (Toolkit images are less flexible)
BufferedImage img = ImageIO.read(file);
BufferedImage thumb = createEmptyThumbnail();
// BufferedImage has a Graphics2D
Graphics2D g2d = (Graphics2D) thumb.getGraphics();
//**Edit-------------**
g2d.setRenderingHint(RenderingHints.KEY_ALPHA_INTERPOLATION, RenderingHints.VALUE_ALPHA_INTERPOLATION_QUALITY);
g2d.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
g2d.setRenderingHint(RenderingHints.KEY_COLOR_RENDERING, RenderingHints.VALUE_COLOR_RENDER_QUALITY);
g2d.setRenderingHint(RenderingHints.KEY_RENDERING, RenderingHints.VALUE_RENDER_QUALITY);
g2d.setRenderingHint(RenderingHints.KEY_DITHERING, RenderingHints.VALUE_DITHER_ENABLE);
g2d.setRenderingHint(RenderingHints.KEY_FRACTIONALMETRICS, RenderingHints.VALUE_FRACTIONALMETRICS_ON);
g2d.setRenderingHint(RenderingHints.KEY_DITHERING, RenderingHints.VALUE_DITHER_ENABLE);
g2d.setRenderingHint(RenderingHints.KEY_STROKE_CONTROL, RenderingHints.VALUE_STROKE_NORMALIZE);
//**Edit end----------------**
g2d.drawImage(img, 0, 0,
thumb.getWidth() - 1,
thumb.getHeight() - 1,
0, 0,
img.getWidth() - 1,
img.getHeight() - 1,
null);
g2d.dispose();
ImageIO.write(thumb, "JPG", createOutputFile(file));
} catch (Exception e) {
e.printStackTrace();
}
}
private File createOutputFile(File inputFile) {
// You'll want something better than this...
return new File(inputFile.getAbsolutePath()
+ ".thumb.png");
}
private BufferedImage createEmptyThumbnail() {
return new BufferedImage(200, 200,
BufferedImage.TYPE_INT_RGB);
}
您可能需要使用插值——请参见
java.awt.RenderingHints
和Graphics2D.setRenderingHint()
。这将有助于渲染质量更好的缩略图
package main;
import java.awt.Graphics2D;
import java.awt.image.BufferedImage;
import java.io.File;
import javax.imageio.ImageIO;
public class Main implements Serializable {
public static void main(String[] args) throws FileNotFoundException, IOException {
Main fac = new Main();
fac.run("C:\\Users\\Masood-Ahmad\\Desktop\\tempSnaps");
}
public void run(String folder) {
File dir = new File(folder);
for (File file : dir.listFiles()) {
createThumbnail(file);
}
}
private void createThumbnail(File file) {
try {
// BufferedImage is the best (Toolkit images are less flexible)
BufferedImage img = ImageIO.read(file);
BufferedImage thumb = createEmptyThumbnail();
// BufferedImage has a Graphics2D
Graphics2D g2d = (Graphics2D) thumb.getGraphics();
//**Edit-------------**
g2d.setRenderingHint(RenderingHints.KEY_ALPHA_INTERPOLATION, RenderingHints.VALUE_ALPHA_INTERPOLATION_QUALITY);
g2d.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
g2d.setRenderingHint(RenderingHints.KEY_COLOR_RENDERING, RenderingHints.VALUE_COLOR_RENDER_QUALITY);
g2d.setRenderingHint(RenderingHints.KEY_RENDERING, RenderingHints.VALUE_RENDER_QUALITY);
g2d.setRenderingHint(RenderingHints.KEY_DITHERING, RenderingHints.VALUE_DITHER_ENABLE);
g2d.setRenderingHint(RenderingHints.KEY_FRACTIONALMETRICS, RenderingHints.VALUE_FRACTIONALMETRICS_ON);
g2d.setRenderingHint(RenderingHints.KEY_DITHERING, RenderingHints.VALUE_DITHER_ENABLE);
g2d.setRenderingHint(RenderingHints.KEY_STROKE_CONTROL, RenderingHints.VALUE_STROKE_NORMALIZE);
//**Edit end----------------**
g2d.drawImage(img, 0, 0,
thumb.getWidth() - 1,
thumb.getHeight() - 1,
0, 0,
img.getWidth() - 1,
img.getHeight() - 1,
null);
g2d.dispose();
ImageIO.write(thumb, "JPG", createOutputFile(file));
} catch (Exception e) {
e.printStackTrace();
}
}
private File createOutputFile(File inputFile) {
// You'll want something better than this...
return new File(inputFile.getAbsolutePath()
+ ".thumb.png");
}
private BufferedImage createEmptyThumbnail() {
return new BufferedImage(200, 200,
BufferedImage.TYPE_INT_RGB);
}
使用Java生成缩略图存在一些问题——大型图形可能会消耗大量内存,一些不寻常的图像可能无法读取,并且支持的格式有限
对于更广泛的图像兼容性和格式支持,调用外部程序(如image Magick)可以提供更好的可移植性。请参见
Runtime.exec()
。我想向您推荐Image Magick,因为它可以产生良好的输出。迭代缩放,每次将分辨率减半,直到接近目标分辨率,然后一次性完成剩余部分。我说的插值!使用RenderingHints。按一下INTERPOLATION
键并将其设置为VALUE\u INTERPOLATION\u BICUBIC
,您已经设置了所有其他可能的提示,但不是实际需要的提示。我认为您对drawImage()
的调用应该使用thumb和image width&height,而不是width-1和height-1。几何边界通常是低包容、高排斥的,因此它们的差异与它们测量的像素数相同。谢谢,非常好,尽管有渲染提示。关键点_插值并将其设置为值_插值_双三次生成与以前相同的结果(或者没有明显的变化,我觉得拇指很小,100*100,但效果还是不错)