在java中自动裁剪图片的白色边框最简单的方法是什么?先谢谢你...
发布于 2012-05-21 11:40:10
如果你想让白色的部分不可见,最好的方法是使用图像滤镜并使白色像素透明,它是由@PhiLho提供的discussed here,带有一些很好的示例,如果你想调整图像的大小,使它的边框不会有白色,你可以用四个简单的循环来做,这个小方法,我为你写的这个小方法做到了,注意它只裁剪图像的上半部分,你可以写剩下的部分,
private Image getCroppedImage(String address) throws IOException{
BufferedImage source = ImageIO.read(new File(address)) ;
boolean flag = false ;
int upperBorder = -1 ;
do{
upperBorder ++ ;
for (int c1 =0 ; c1 < source.getWidth() ; c1++){
if(source.getRGB(c1, upperBorder) != Color.white.getRGB() ){
flag = true;
break ;
}
}
if (upperBorder >= source.getHeight())
flag = true ;
}while(!flag) ;
BufferedImage destination = new BufferedImage(source.getWidth(), source.getHeight() - upperBorder, BufferedImage.TYPE_INT_ARGB) ;
destination.getGraphics().drawImage(source, 0, upperBorder*-1, null) ;
return destination ;
}
发布于 2012-09-29 02:57:59
这是一种裁剪所有4个边的方法,使用左上角像素的颜色作为基线,并允许容忍颜色变化,这样图像中的噪声就不会使裁剪变得无用
public BufferedImage getCroppedImage(BufferedImage source, double tolerance) {
// Get our top-left pixel color as our "baseline" for cropping
int baseColor = source.getRGB(0, 0);
int width = source.getWidth();
int height = source.getHeight();
int topY = Integer.MAX_VALUE, topX = Integer.MAX_VALUE;
int bottomY = -1, bottomX = -1;
for(int y=0; y<height; y++) {
for(int x=0; x<width; x++) {
if (colorWithinTolerance(baseColor, source.getRGB(x, y), tolerance)) {
if (x < topX) topX = x;
if (y < topY) topY = y;
if (x > bottomX) bottomX = x;
if (y > bottomY) bottomY = y;
}
}
}
BufferedImage destination = new BufferedImage( (bottomX-topX+1),
(bottomY-topY+1), BufferedImage.TYPE_INT_ARGB);
destination.getGraphics().drawImage(source, 0, 0,
destination.getWidth(), destination.getHeight(),
topX, topY, bottomX, bottomY, null);
return destination;
}
private boolean colorWithinTolerance(int a, int b, double tolerance) {
int aAlpha = (int)((a & 0xFF000000) >>> 24); // Alpha level
int aRed = (int)((a & 0x00FF0000) >>> 16); // Red level
int aGreen = (int)((a & 0x0000FF00) >>> 8); // Green level
int aBlue = (int)(a & 0x000000FF); // Blue level
int bAlpha = (int)((b & 0xFF000000) >>> 24); // Alpha level
int bRed = (int)((b & 0x00FF0000) >>> 16); // Red level
int bGreen = (int)((b & 0x0000FF00) >>> 8); // Green level
int bBlue = (int)(b & 0x000000FF); // Blue level
double distance = Math.sqrt((aAlpha-bAlpha)*(aAlpha-bAlpha) +
(aRed-bRed)*(aRed-bRed) +
(aGreen-bGreen)*(aGreen-bGreen) +
(aBlue-bBlue)*(aBlue-bBlue));
// 510.0 is the maximum distance between two colors
// (0,0,0,0 -> 255,255,255,255)
double percentAway = distance / 510.0d;
return (percentAway > tolerance);
}
发布于 2017-09-29 03:30:32
这里是另一个例子
private static BufferedImage autoCrop(BufferedImage sourceImage) {
int left = 0;
int right = 0;
int top = 0;
int bottom = 0;
boolean firstFind = true;
for (int x = 0; x < sourceImage.getWidth(); x++) {
for (int y = 0; y < sourceImage.getWidth(); y++) {
// pixel is not empty
if (sourceImage.getRGB(x, y) != 0) {
// we walk from left to right, thus x can be applied as left on first finding
if (firstFind) {
left = x;
}
// update right on each finding, because x can grow only
right = x;
// on first find apply y as top
if (firstFind) {
top = y;
} else {
// on each further find apply y to top only if a lower has been found
top = Math.min(top, y);
}
// on first find apply y as bottom
if (bottom == 0) {
bottom = y;
} else {
// on each further find apply y to bottom only if a higher has been found
bottom = Math.max(bottom, y);
}
firstFind = false;
}
}
}
return sourceImage.getSubimage(left, top, right - left, bottom - top);
}
https://stackoverflow.com/questions/10678015
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