Java 如何加载位图图像并操作单个像素？
声明：本页面是StackOverFlow热门问题的中英对照翻译，遵循CC BY-SA 4.0协议，如果您需要使用它，必须同样遵循CC BY-SA许可，注明原文地址和作者信息，同时你必须将它归于原作者（不是我）：StackOverFlow
原文地址: http://stackoverflow.com/questions/16475482/
Warning: these are provided under cc-by-sa 4.0 license. You are free to use/share it, But you must attribute it to the original authors (not me):
StackOverFlow
How can I load a bitmap image and manipulate individual pixels?
提问by Joseph
I want to load a single large bitmap image from a file, run a function that manipulates individual pixels and then re save the bitmap.
我想从文件加载单个大位图图像，运行一个操作单个像素的函数，然后重新保存位图。
File formats can be either PNG or BMP, and the manipulating function is something simple such as:
文件格式可以是 PNG 或 BMP，操作功能很简单，例如：
if r=200,g=200,b=200 then +20 on all values, else -100 on all values
The trick is being able to load a bitmap and being able to read each pixel line by line
诀窍是能够加载位图并能够逐行读取每个像素
Is there standard library machinery in Java that can handle this I/O?
Java 中是否有可以处理此 I/O 的标准库机制？
(The bitmap will need to be several megapixels, I need to be able to handle millions of pixels)
（位图需要几百万像素，我需要能够处理数百万像素）
采纳答案by Joseph
Thanks to MadProgrammer I have an answer:
感谢 MadProgrammer 我有一个答案：
package image_test;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;
import javax.imageio.ImageIO;
public class Image_test {
public static void main(String[] args) {
BufferedImage img = null;
try {
img = ImageIO.read(new File("test.bmp"));
} catch (IOException e) {
}
int height = img.getHeight();
int width = img.getWidth();
int amountPixel = 0;
int amountBlackPixel = 0;
int rgb;
int red;
int green;
int blue;
double percentPixel = 0;
System.out.println(height + " " + width + " " + img.getRGB(30, 30));
for (int h = 1; h<height; h++)
{
for (int w = 1; w<width; w++)
{
amountPixel++;
rgb = img.getRGB(w, h);
red = (rgb >> 16 ) & 0x000000FF;
green = (rgb >> 8 ) & 0x000000FF;
blue = (rgb) & 0x000000FF;
if (red == 0 && green == 0 && blue == 0)
{
amountBlackPixel ++;
}
}
}
percentPixel = (double)amountBlackPixel / (double)amountPixel;
System.out.println("amount pixel: "+amountPixel);
System.out.println("amount black pixel: "+amountBlackPixel);
System.out.println("amount pixel black percent: "+percentPixel);
}
}
