记一次图片处理过程
# thumbnailator 功能
# 1. 从现有图像创建高质量的缩略图
BufferedImage thumbnail = Thumbnails.of(originalImage)
.size(WIDTH, HEIGHT)
.asBufferedImage();
Thumbnails.of(new File("original.jpg"))
.size(160, 160)
.toFile(new File("thumbnail.jpg"));
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# 2. 可以在缩略图中嵌入水印(例如徽标)
Thumbnails.of(new File("original.jpg"))
.size(160, 160)
.rotate(90)
.watermark(Positions.BOTTOM_RIGHT, ImageIO.read(new File("watermark.png")), 0.5f)
.outputQuality(0.8)
.toFile(new File("image-with-watermark.jpg"));
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# 3. 水印的透明度是可调的，从透明(0%)到不透明(100%)
# 4. 支持图片旋转
BufferedImage originalImage = ImageIO.read(new File("original.jpg"));
BufferedImage thumbnail = Thumbnails.of(originalImage)
.size(200, 200)
.rotate(90)
.asBufferedImage();
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# 5. 编程过程简化
# 6. 支持批量操作
for (int i : new int[] {0, 90, 180, 270, 45}) {
Thumbnails.of(new File("coobird.png"))
.size(100, 100)
.rotate(i)
.toFile(new File("image-rotated-" + i + ".png"));
}
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# 7. 可直接操作网络图片
Thumbnails.of(new URL(card.getAvatarUrl()));
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# 扩展
# 1.ImageFilter 的扩展
# ImageFilter
public interface ImageFilter
{
/**
* Applies a image filtering operation on an image.
*
* @param img The image to apply the filtering on.
* @return The resulting image after applying this filter.
*/
public BufferedImage apply(BufferedImage img);
}
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# 将图片转化为圆形
private static final ImageFilter CUT_CIRCLE =
(bufferedImage) -> {
int width = bufferedImage.getWidth(), height = width;
BufferedImage circleBuffer = new BufferedImage(width, height, BufferedImage.TYPE_INT_ARGB);
Graphics2D g2 = circleBuffer.createGraphics();
g2.setClip(new Ellipse2D.Float(0, 0, width, width));
g2.drawImage(bufferedImage, 0, 0, width, height, null);
return circleBuffer;
};
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# 使用方式
BufferedImage avatar =
Thumbnails.of(new URL(card.getAvatarUrl()))
.size(315, 315)
.addFilter(CUT_CIRCLE)
.asBufferedImage();
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# 2.Position 的扩展
# Position 源码
public interface Position
{
/**
* Calculates the position of an object enclosed by an enclosing object.
*
* @param enclosingWidth The width of the enclosing object that is
* to contain the enclosed object.
* @param enclosingHeight The height of the enclosing object that is
* to contain the enclosed object.
* @param width The width of the object that is to be
* placed inside an enclosing object.
* @param height The height of the object that is to be
* placed inside an enclosing object.
* @param insetLeft The inset on the left-hand side of the
* object to be enclosed.
* @param insetRight The inset on the right-hand side of the
* object to be enclosed.
* @param insetTop The inset on the top side of the
* object to be enclosed.
* @param insetBottom The inset on the bottom side of the
* object to be enclosed.
* @return The position to place the object.
*/
public Point calculate(
int enclosingWidth, int enclosingHeight, int width, int height,
int insetLeft, int insetRight, int insetTop, int insetBottom
);
}
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# 自动设置水平居中,使用时只需指定垂直高度
public static class Horizontally implements Position {
private final int height;
public Horizontally(int height) {
this.height = height;
}
@Override
public Point calculate(
int enclosingWidth,
int enclosingHeight,
int width,
int height,
int insetLeft,
int insetRight,
int insetTop,
int insetBottom) {
int x = (enclosingWidth / 2)-(width / 2);
return new Point(x, this.height + insetTop);
}
}
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