ImageUtil (jsm-frame 1.1 API)

java.lang.Object
- com.jsmframe.utils.ImageUtil

```
public class ImageUtil
extends Object
```
Utilities methods for image manipulation. It does not support writting of GIF images, but it can read from. GIF images will be saved as PNG.

版本:

$Id: ImageUtils.java,v 1.22 2007/07/28 14:17:12 rafaelsteil Exp $

作者:

Rafael Steil

字段概要

字段
限定符和类型字段和说明

static String IMAGE_GIF

static String IMAGE_JPEG

static String IMAGE_PNG

字段
限定符和类型	字段和说明
`static String`	`IMAGE_GIF`
`static String`	`IMAGE_JPEG`
`static String`	`IMAGE_PNG`

构造器概要

构造器
构造器和说明

ImageUtil()

构造器
构造器和说明
`ImageUtil()`

方法概要

All Methods Static Methods Concrete Methods
限定符和类型	方法和说明
`static void`	`addText(String destImage, String text)`
`static void`	`compressImage(String imagePath, float quality)`
`static BufferedImage`	`createHeadlessBufferedImage(BufferedImage image, String ext, int width, int height)` Creates a `BufferedImage` from an `Image`.
`static BufferedImage`	`createHeadlessSmoothBufferedImage(BufferedImage source, String ext, int width, int height)` Creates a `BufferedImage` from an `Image`.
`static void`	`cutImage(InputStream input, OutputStream out, int x, int y, int width, int height, String imageType)`
`static void`	`cutJPG(InputStream input, OutputStream out, int x, int y, int width, int height)`
`static void`	`cutPNG(InputStream input, OutputStream out, int x, int y, int width, int height)`
`static Graphics2D`	`drawAL(int sx, int sy, int ex, int ey, Graphics2D g2)`
`static boolean`	`fromBase64(String imgStr, String imgFilePath)` 字符串进行Base64解码并生成图片
`static String`	`getImageExtension(String imagePath)`
`static int`	`getLength(String text)` 获取字符长度，一个汉字作为 1 个字符, 一个英文字母作为 0.5 个字符
`static String`	`getSuffix(String fileName, String defaultExt)`
`static boolean`	`hasAlpha(Image image)` Determines if the image has transparent pixels.
`static void`	`pressImage(String targetImg, String waterImg, int x, int y, float alpha)` 添加图片水印
`static void`	`pressText(String targetImg, String pressText, String fontName, int fontStyle, int fontSize, Color color, int x, int y, float alpha)` 添加文字水印
`static void`	`resize(String filePath, int height, int width, boolean bb)` 图片缩放
`static BufferedImage`	`resizeImage(BufferedImage image, String ext, int maxWidth, int maxHeight)` Resizes an image.
`static BufferedImage`	`resizeImage(String imgName, String ext, int maxWidth, int maxHeight)` Resizes an image
`static BufferedImage`	`rotate(BufferedImage image, int degree, Color bgcolor)`
`static InputStream`	`rotateImg(BufferedImage image, int degree, Color bgcolor)`
`static void`	`saveCompressedImage(BufferedImage image, String toFileName, String ext)` Compress and save an image to the disk.
`static boolean`	`saveImage(BufferedImage image, String toFileName, String ext)` Saves an image to the disk.
`static void`	`scaleByWidth(String filePath, int newWidth)`
`static String`	`toBase64(String imgFilePath)` 将图片文件 Base64 String

从类继承的方法 java.lang.Object
equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

字段详细资料
- IMAGE_JPEG
```
public static final String IMAGE_JPEG
```
  另请参阅:
  
  常量字段值
- IMAGE_PNG
```
public static final String IMAGE_PNG
```
  另请参阅:
  
  常量字段值
- IMAGE_GIF
```
public static final String IMAGE_GIF
```
  另请参阅:
  
  常量字段值

构造器详细资料
- ImageUtil
```
public ImageUtil()
```

方法详细资料

resizeImage

public static BufferedImage resizeImage(String imgName,
                                        String ext,
                                        int maxWidth,
                                        int maxHeight)
                                 throws IOException

Resizes an image

参数:: imgName - The image name to resize. Must be the complet path to the file; type - int; maxWidth - The image's max width; maxHeight - The image's max height
返回:: A resized BufferedImage
抛出:: IOException

resizeImage

public static BufferedImage resizeImage(BufferedImage image,
                                        String ext,
                                        int maxWidth,
                                        int maxHeight)

Resizes an image.

参数:: image - The image to resize; maxWidth - The image's max width; maxHeight - The image's max height; type - int
返回:: A resized BufferedImage

saveImage
```
public static boolean saveImage(BufferedImage image,
                                String toFileName,
                                String ext)
                         throws IOException
```
Saves an image to the disk.

参数:

image - The image to save

toFileName - The filename to use

type - The image type. Use ImageUtils.IMAGE_JPEG to save as JPEG images, or ImageUtils.IMAGE_PNG to save as PNG.

返回:

false if no appropriate writer is found

抛出:

IOException

saveCompressedImage
```
public static void saveCompressedImage(BufferedImage image,
                                       String toFileName,
                                       String ext)
                                throws IOException
```
Compress and save an image to the disk. Currently this method only supports JPEG images.

参数:

image - The image to save

toFileName - The filename to use

type - The image type. Use ImageUtils.IMAGE_JPEG to save as JPEG images, or ImageUtils.IMAGE_PNG to save as PNG.

抛出:

IOException

compressImage

public static void compressImage(String imagePath,
                                 float quality)
                          throws IOException

抛出:: IOException

getSuffix

public static String getSuffix(String fileName,
                               String defaultExt)

createHeadlessBufferedImage
```
public static BufferedImage createHeadlessBufferedImage(BufferedImage image,
                                                        String ext,
                                                        int width,
                                                        int height)
```
Creates a BufferedImage from an Image. This method can function on a completely headless system. This especially includes Linux and Unix systems that do not have the X11 libraries installed, which are required for the AWT subsystem to operate. This method uses nearest neighbor approximation, so it's quite fast. Unfortunately, the result is nowhere near as nice looking as the createHeadlessSmoothBufferedImage method.

参数:

image - The image to convert

w - The desired image width

h - The desired image height

type - int

返回:

The converted image

createHeadlessSmoothBufferedImage
```
public static BufferedImage createHeadlessSmoothBufferedImage(BufferedImage source,
                                                              String ext,
                                                              int width,
                                                              int height)
```
Creates a BufferedImage from an Image. This method can function on a completely headless system. This especially includes Linux and Unix systems that do not have the X11 libraries installed, which are required for the AWT subsystem to operate. The resulting image will be smoothly scaled using bilinear filtering.

参数:

source - The image to convert

w - The desired image width

h - The desired image height

type - int

返回:

The converted image

hasAlpha
```
public static boolean hasAlpha(Image image)
```
Determines if the image has transparent pixels.

参数:

image - The image to check for transparent pixel.s

返回:

true of false, according to the result

pressImage
```
public static final void pressImage(String targetImg,
                                    String waterImg,
                                    int x,
                                    int y,
                                    float alpha)
```
添加图片水印

参数:

targetImg - 目标图片路径，如：C://myPictrue//1.jpg

waterImg - 水印图片路径，如：C://myPictrue//logo.png

x - 水印图片距离目标图片左侧的偏移量，如果x<0, 则在正中间

y - 水印图片距离目标图片上侧的偏移量，如果y<0, 则在正中间

alpha - 透明度(0.0 -- 1.0, 0.0为完全透明，1.0为完全不透明)

pressText
```
public static void pressText(String targetImg,
                             String pressText,
                             String fontName,
                             int fontStyle,
                             int fontSize,
                             Color color,
                             int x,
                             int y,
                             float alpha)
```
添加文字水印

参数:

targetImg - 目标图片路径，如：C://myPictrue//1.jpg

pressText - 水印文字，如：中国证券网

fontName - 字体名称，如：宋体

fontStyle - 字体样式，如：粗体和斜体(Font.BOLD|Font.ITALIC)

fontSize - 字体大小，单位为像素

color - 字体颜色

x - 水印文字距离目标图片左侧的偏移量，如果x<0, 则在正中间

y - 水印文字距离目标图片上侧的偏移量，如果y<0, 则在正中间

alpha - 透明度(0.0 -- 1.0, 0.0为完全透明，1.0为完全不透明)

getLength
```
public static int getLength(String text)
```
获取字符长度，一个汉字作为 1 个字符, 一个英文字母作为 0.5 个字符

参数:

text -

返回:

字符长度，如：text="中国",返回 2；text="test",返回 2；text="中国ABC",返回 4.

resize

public static void resize(String filePath,
                          int height,
                          int width,
                          boolean bb)

图片缩放

参数:: filePath - 图片路径; height - 高度; width - 宽度; bb - 比例不对时是否需要补白

scaleByWidth

public static void scaleByWidth(String filePath,
                                int newWidth)

rotate

public static BufferedImage rotate(BufferedImage image,
                                   int degree,
                                   Color bgcolor)
                            throws IOException

抛出:: IOException

rotateImg

public static InputStream rotateImg(BufferedImage image,
                                    int degree,
                                    Color bgcolor)
                             throws IOException

抛出:: IOException

drawAL

public static Graphics2D drawAL(int sx,
                                int sy,
                                int ex,
                                int ey,
                                Graphics2D g2)

addText

public static void addText(String destImage,
                           String text)
                    throws IOException

抛出:: IOException

toBase64
```
public static String toBase64(String imgFilePath)
```
将图片文件 Base64 String

参数:

imgFilePath -

返回:

fromBase64

public static boolean fromBase64(String imgStr,
                                 String imgFilePath)

字符串进行Base64解码并生成图片

参数:: imgStr -; imgFilePath -
返回:

cutJPG

public static void cutJPG(InputStream input,
                          OutputStream out,
                          int x,
                          int y,
                          int width,
                          int height)

cutPNG

public static void cutPNG(InputStream input,
                          OutputStream out,
                          int x,
                          int y,
                          int width,
                          int height)

cutImage

public static void cutImage(InputStream input,
                            OutputStream out,
                            int x,
                            int y,
                            int width,
                            int height,
                            String imageType)

getImageExtension

public static String getImageExtension(String imagePath)

类 ImageUtil

字段概要

构造器概要

方法概要

从类继承的方法 java.lang.Object

字段详细资料

IMAGE_JPEG

IMAGE_PNG

IMAGE_GIF

构造器详细资料

ImageUtil

方法详细资料

resizeImage

resizeImage

saveImage

saveCompressedImage

compressImage

getSuffix

createHeadlessBufferedImage

createHeadlessSmoothBufferedImage

hasAlpha

pressImage

pressText

getLength

resize

scaleByWidth

rotate

rotateImg

drawAL

addText

toBase64

fromBase64

cutJPG

cutPNG

cutImage

getImageExtension