仅使用 API 将灰度图像绘制到另一个 BufferedImage 的 alpha 波段
Draw grayscale image to another BufferedImage's alpha band using API only
我有两个 BufferedImages：一个是 TYPE_INT_ARGB，另一个是 TYPE_BYTE_GRAY。如何仅使用 API 将整个彩色图像的 alpha 波段替换为灰度图像，而不干扰 RGB 值？
final int width = 200;
final int height = 200;
final BufferedImage colorImg = new BufferedImage(width, height, BufferedImage.TYPE_INT_ARGB);
final BufferedImage grayscaleImg = new BufferedImage(width, height, BufferedImage.TYPE_BYTE_GRAY);
Graphics2D g = colorImg.createGraphics();
// flip some mystical switches
// g.drawImage( grayscaleImg into colorImg's alpha band )
g.dispose();
我可以像这样屏蔽和复制字节来手动完成：
WritableRaster clrRaster = colorImg.getRaster();
DataBufferInt clrBuffer = (DataBufferInt) clrRaster.getDataBuffer();
int[] clrData = clrBuffer.getData();
WritableRaster grayRaster = grayscaleImg.getRaster();
DataBufferByte grayBuffer = (DataBufferByte) grayRaster.getDataBuffer();
byte[] grayData = grayBuffer.getData();
int pixel, alphaBits;
for(int i = 0; i < clrData.length; i++) {
pixel = clrData[i] & 0x00ffffff;
alphaBits = (int)grayData[i] << 24;
clrData[i] = pixel | alphaBits;
}
但是 API 方法是什么？
更新 #1
样本图像：输入灰度alpha，输入彩色猫，输出带洞的彩色猫。
生成的图像在输出颜色的 alpha 中具有灰度。在照片编辑器中查看生成的图像，您会看到中间的孔实际上是透明的。
private void injectAlphaIntoColor() {
try {
// BEWARE: this code does not check if both images are the same
// width and height. May get out of bounds exception if w&h are
// different.
BufferedImage cat = ImageIO.read(new File("s:/temp/cat5.png"));
BufferedImage gray = ImageIO.read(new File("s:/temp/layermask.png"));
// convert color cat to TYPE_INT_ARGB
BufferedImage color = new BufferedImage(cat.getWidth(), cat.getHeight(), BufferedImage.TYPE_INT_ARGB);
Graphics2D g = color.createGraphics();
g.drawImage(cat, 0, 0, null);
g.dispose();
final WritableRaster clrRaster = color.getRaster();
final DataBufferInt clrBuffer = (DataBufferInt) clrRaster.getDataBuffer();
final int[] clrData = clrBuffer.getData();
final WritableRaster grayRaster = gray.getRaster();
final DataBufferByte grayBuffer = (DataBufferByte) grayRaster.getDataBuffer();
final byte[] grayData = grayBuffer.getData();
int pixel, alphaBits;
// manually put each grayscale pixel into each color pixel's alpha
for(int i = 0; i < clrData.length; i++) {
pixel = clrData[i] & 0x00ffffff;
alphaBits = (int)grayData[i] << 24;
clrData[i] = pixel | alphaBits;
}
ImageIO.write(color, "png", new File("s:/temp/3rd_output.png"));
}
catch (IOException ex) {
System.out.println(ex.getMessage());
}
}
重申我原来的 objective，Java API 执行上述代码的方法是什么？
啊，你想用蒙版剪掉部分图像，我的坏人。
简单的解决方案 - 首先使用基于 alpha 的蒙版。但我假设你没有那个选项。我确实尝试找到可能做到这一点的解决方案，但相反，我偶然发现了 this example。
哪个能够产生您似乎正在寻找的结果
（蓝色为面板背景色）
核心功能用于...
public void applyGrayscaleMaskToAlpha(BufferedImage image, BufferedImage mask) {
int width = image.getWidth();
int height = image.getHeight();
int[] imagePixels = image.getRGB(0, 0, width, height, null, 0, width);
int[] maskPixels = mask.getRGB(0, 0, width, height, null, 0, width);
for (int i = 0; i < imagePixels.length; i++) {
int color = imagePixels[i] & 0x00ffffff; // Mask preexisting alpha
int alpha = maskPixels[i] << 24; // Shift blue to alpha
imagePixels[i] = color | alpha;
}
image.setRGB(0, 0, width, height, imagePixels, 0, width);
}
但是作为一个简单的可运行示例...
import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.EventQueue;
import java.awt.Graphics;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;
import javax.imageio.ImageIO;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.UIManager;
public class Test {
public static void main(String[] args) {
new Test();
}
public Test() {
EventQueue.invokeLater(new Runnable() {
@Override
public void run() {
try {
UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
} catch (Exception ex) {
}
JFrame frame = new JFrame("Testing");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setLayout(new BorderLayout());
frame.add(new TestPane());
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
});
}
public void applyGrayscaleMaskToAlpha(BufferedImage image, BufferedImage mask) {
int width = image.getWidth();
int height = image.getHeight();
int[] imagePixels = image.getRGB(0, 0, width, height, null, 0, width);
int[] maskPixels = mask.getRGB(0, 0, width, height, null, 0, width);
for (int i = 0; i < imagePixels.length; i++) {
int color = imagePixels[i] & 0x00ffffff; // Mask preexisting alpha
int alpha = maskPixels[i] << 24; // Shift blue to alpha
imagePixels[i] = color | alpha;
}
image.setRGB(0, 0, width, height, imagePixels, 0, width);
}
public class TestPane extends JPanel {
private BufferedImage master;
private BufferedImage mask;
public TestPane() {
setBackground(Color.BLUE);
try {
master = ImageIO.read(new File("..."));
mask = ImageIO.read(new File("..."));
applyGrayscaleMaskToAlpha(master, mask);
} catch (IOException exp) {
exp.printStackTrace();
}
}
@Override
public Dimension getPreferredSize() {
Dimension size = super.getPreferredSize();
if (master != null && mask != null) {
size = new Dimension(master.getWidth() + mask.getWidth(), Math.max(master.getHeight(), mask.getHeight()));
}
return size;
}
@Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
int x = (getWidth() - (master.getWidth() + mask.getWidth())) / 2;
int y = (getHeight() - master.getHeight()) / 2;
g.drawImage(master, x, y, this);
x += mask.getWidth();
y = (getHeight() - mask.getHeight()) / 2;
g.drawImage(mask, x, y, this);
}
}
}
抱歉造成混淆
已更新 - 没有“操纵数据缓冲区”
I was looking for the Java API way of doing the same job without manipuating the bits
好的，所以我也更喜欢从灰度图像生成基于 alpha 的图像的解决方案，它更适合整体 Graphics 2D API。所以，在阅读更多 of this question which keeps on giving 之后，我偶然发现了这个想法......
public static BufferedImage grayScaleToTransparency(BufferedImage master) {
ImageFilter filter = new RGBImageFilter() {
public final int filterRGB(int x, int y, int rgb) {
return (rgb << 16) & 0xFF000000;
}
};
ImageProducer ip = new FilteredImageSource(master.getSource(), filter);
Image img = Toolkit.getDefaultToolkit().createImage(ip);
BufferedImage buffer = createCompatibleImage(img.getWidth(null), img.getHeight(null), Transparency.TRANSLUCENT);
Graphics2D g2d = buffer.createGraphics();
g2d.drawImage(img, 0, 0, null);
g2d.dispose();
return buffer;
}
现在，可能无法使用 BufferedImageFilter 和 BufferedImageOp 来获取它，但我没有时间或经验来进一步研究它。
使用这种技术我能够生产...
原图 |原始（灰度）蒙版 |基于 Alpha 的掩码 |屏蔽图像
同样，蓝色是面板的背景色。
import java.awt.AlphaComposite;
import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.EventQueue;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.GraphicsConfiguration;
import java.awt.GraphicsEnvironment;
import java.awt.Image;
import java.awt.RenderingHints;
import java.awt.Toolkit;
import java.awt.Transparency;
import java.awt.image.BufferedImage;
import java.awt.image.FilteredImageSource;
import java.awt.image.ImageFilter;
import java.awt.image.ImageProducer;
import java.awt.image.RGBImageFilter;
import java.io.File;
import java.io.IOException;
import javax.imageio.ImageIO;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.UIManager;
public class Test {
public static void main(String[] args) {
new Test();
}
public Test() {
EventQueue.invokeLater(new Runnable() {
@Override
public void run() {
try {
UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
} catch (Exception ex) {
}
JFrame frame = new JFrame("Testing");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setLayout(new BorderLayout());
frame.add(new TestPane());
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
});
}
public static GraphicsConfiguration getGraphicsConfiguration() {
return GraphicsEnvironment.getLocalGraphicsEnvironment().getDefaultScreenDevice().getDefaultConfiguration();
}
public static BufferedImage createCompatibleImage(int width, int height, int transparency) {
BufferedImage image = getGraphicsConfiguration().createCompatibleImage(width, height, transparency);
image.coerceData(true);
return image;
}
public static void applyQualityRenderingHints(Graphics2D g2d) {
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_DITHERING, RenderingHints.VALUE_DITHER_ENABLE);
g2d.setRenderingHint(RenderingHints.KEY_FRACTIONALMETRICS, RenderingHints.VALUE_FRACTIONALMETRICS_ON);
g2d.setRenderingHint(RenderingHints.KEY_INTERPOLATION, RenderingHints.VALUE_INTERPOLATION_BILINEAR);
g2d.setRenderingHint(RenderingHints.KEY_RENDERING, RenderingHints.VALUE_RENDER_QUALITY);
g2d.setRenderingHint(RenderingHints.KEY_STROKE_CONTROL, RenderingHints.VALUE_STROKE_PURE);
}
public static BufferedImage applyMask(BufferedImage master, BufferedImage mask) {
int imgWidth = master.getWidth();
int imgHeight = master.getHeight();
BufferedImage imgMask = createCompatibleImage(imgWidth, imgHeight, Transparency.TRANSLUCENT);
Graphics2D g2 = imgMask.createGraphics();
applyQualityRenderingHints(g2);
g2.drawImage(mask, 0, 0, null);
g2.setComposite(AlphaComposite.getInstance(AlphaComposite.SRC_IN, 1f));
g2.drawImage(master, 0, 0, null);
g2.dispose();
return imgMask;
}
public static BufferedImage grayScaleToTransparency(BufferedImage master) {
ImageFilter filter = new RGBImageFilter() {
public final int filterRGB(int x, int y, int rgb) {
return (rgb << 16) & 0xFF000000;
}
};
ImageProducer ip = new FilteredImageSource(master.getSource(), filter);
Image img = Toolkit.getDefaultToolkit().createImage(ip);
BufferedImage buffer = createCompatibleImage(img.getWidth(null), img.getHeight(null), Transparency.TRANSLUCENT);
Graphics2D g2d = buffer.createGraphics();
g2d.drawImage(img, 0, 0, null);
g2d.dispose();
return buffer;
}
public class TestPane extends JPanel {
private BufferedImage master;
private BufferedImage originalMask;
private BufferedImage alphaMask;
private BufferedImage masked;
public TestPane() {
setBackground(Color.BLUE);
try {
master = ImageIO.read(new File("/Users/swhitehead/Downloads/lIceL.png"));
originalMask = ImageIO.read(new File("/Users/swhitehead/Downloads/MXmFp.png"));
alphaMask = grayScaleToTransparency(originalMask);
masked = applyMask(master, alphaMask);
// tinted = tint(master, mask);
} catch (IOException exp) {
exp.printStackTrace();
}
}
protected int desiredWidth() {
return master.getWidth() + originalMask.getWidth() + alphaMask.getWidth() + masked.getWidth();
}
protected int desiredHeight() {
return Math.max(Math.max(Math.max(master.getHeight(), originalMask.getHeight()), alphaMask.getHeight()), masked.getHeight());
}
@Override
public Dimension getPreferredSize() {
Dimension size = super.getPreferredSize();
if (master != null && originalMask != null) {
size = new Dimension(desiredWidth(),
desiredHeight());
}
return size;
}
@Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
int x = (getWidth() - desiredWidth()) / 2;
int y = (getHeight() - master.getHeight()) / 2;
g.drawImage(master, x, y, this);
x += originalMask.getWidth();
y = (getHeight() - originalMask.getHeight()) / 2;
g.drawImage(originalMask, x, y, this);
x += alphaMask.getWidth();
y = (getHeight() - alphaMask.getHeight()) / 2;
g.drawImage(alphaMask, x, y, this);
x += masked.getWidth();
y = (getHeight() - masked.getHeight()) / 2;
g.drawImage(masked, x, y, this);
}
}
}
感谢@Hovercraft Full Of Eels 提出 BufferedImageOp 的建议，这导致了 BandCombineOp。当输入合适的矩阵时，class 可以操纵任何或所有波段。变亮、变暗、移动和复制条带，而无需访问 DataBuffer 或操作位。
如何将图像放入 alpha 波段
- 加载或绘制图像；这将成为 alpha 波段。图片
可以是彩色或灰度。
- 将图像转换为
BufferedImage.TYPE_BYTE_GRAY
- 将灰度转换为
BufferedImage.TYPE_INT_ARGB。颜色
条带将包含 near 个相同的灰度副本。
- 使用
BandCombineOp 将颜色波段复制到 alpha 波段。参见矩阵 toAlpha()。
这是 move/copy 编码位操作的更好方法，因为它在数学上很优雅，并且 API 可以利用视频加速硬件（如果存在并受 Java.)
示例 Java 应用程序：嵌入 alpha
包含一个应用程序来演示该过程。 Select 颜色源和 alpha 源，应用会将它们合成为一张图像。显示两个源图像、中间图像和合成图像是为了保持理智。右键单击任何图像以保存。
色源：猫
Alpha 来源：鸟
Alpha 源：复制到 Alpha 带的绿色带
复合
到 运行 应用程序：(1) 创建一个名为 embedalpha 的 JavaFX 项目，(2) 删除自动生成的内容。java文件，(3) 粘贴我的代码，(4) 运行.
要跟踪过程，请在方法 handleBuildComposite() 中放置一个断点。忽略 appendGallery()。 toAlpha() 复制乐队。
/*
Your use of any portion of the code constitutes your acceptance of full
responsibility for all wonderful and aweful outcomes.
*/
package embedalpha;
import java.awt.AlphaComposite;
import java.awt.Dimension;
import java.awt.Graphics2D;
import java.awt.RenderingHints;
import java.awt.Toolkit;
import java.awt.color.ColorSpace;
import java.awt.color.ICC_ColorSpace;
import java.awt.color.ICC_Profile;
import java.awt.image.BandCombineOp;
import java.awt.image.BufferedImage;
import java.awt.image.ColorConvertOp;
import java.io.File;
import javafx.application.Application;
import javafx.beans.property.IntegerProperty;
import javafx.beans.property.ObjectProperty;
import javafx.beans.property.SimpleIntegerProperty;
import javafx.beans.property.SimpleObjectProperty;
import javafx.collections.ListChangeListener;
import javafx.collections.ObservableList;
import javafx.embed.swing.SwingFXUtils;
import javafx.event.ActionEvent;
import javafx.geometry.Insets;
import javafx.geometry.Pos;
import javafx.scene.Node;
import javafx.scene.Scene;
import javafx.scene.canvas.Canvas;
import javafx.scene.canvas.GraphicsContext;
import javafx.scene.control.Alert;
import javafx.scene.control.Button;
import javafx.scene.control.ButtonType;
import javafx.scene.control.ScrollPane;
import javafx.scene.control.Tooltip;
import javafx.scene.image.Image;
import javafx.scene.image.WritableImage;
import javafx.scene.input.MouseButton;
import javafx.scene.input.MouseEvent;
import javafx.scene.layout.BorderPane;
import javafx.scene.layout.FlowPane;
import javafx.scene.layout.HBox;
import javafx.scene.paint.Color;
import javafx.scene.paint.ImagePattern;
import javafx.scene.paint.Paint;
import javafx.stage.FileChooser;
import javafx.stage.Stage;
import javax.imageio.ImageIO;
/**
* Demonstrate copying/moving a color band to the alpha band within the same
* image using only API. The specific method is toAlpha().
*
* @author deskwarrior
* @see
*/
public class TheApp extends Application {
private final int NODE_SPACING = 5;
private final int TILE_SIZE = 40;
private final int APP_WIDTH;
private final int APP_HEIGHT;
private final ObjectProperty<BufferedImage> colorSource = new SimpleObjectProperty<>(this, "colorSource", null);
private final ObjectProperty<BufferedImage> alphaSource = new SimpleObjectProperty<>(this, "alphaSource", null);
private final Paint backgroundColor;
private final HBox gallery = new HBox(NODE_SPACING);
private final IntegerProperty gallerySize = new SimpleIntegerProperty(this, "gallerySize", 0);
private final Tooltip canvasTip = new Tooltip("Right-click to save image as PNG.");
private Canvas colorSourceCanvas = null;
private Canvas alphaSourceCanvas = null;
private final FileChooser openFC = new FileChooser();
private final FileChooser saveFC = new FileChooser();
private File lastDirectoryVisited = null;
private final RenderingHints colorHints = new RenderingHints(
RenderingHints.KEY_COLOR_RENDERING,
RenderingHints.VALUE_COLOR_RENDER_QUALITY);
private final ICC_ColorSpace grayColorSpace;
private final ICC_ColorSpace rgbColorSpace;
private final BorderPane root = new BorderPane();
private Stage stage = null;
public TheApp() {
Dimension screenSize = Toolkit.getDefaultToolkit().getScreenSize();
APP_WIDTH = screenSize.width;
APP_HEIGHT = screenSize.height * 2 / 3;
openFC.getExtensionFilters().addAll(
new FileChooser.ExtensionFilter("Image Files", "*.png", "*.jpg", "*.gif", "*.bmp"),
new FileChooser.ExtensionFilter("All Files", "*.*"));
saveFC.setTitle("Save image as PNG");
saveFC.getExtensionFilters().addAll(
new FileChooser.ExtensionFilter("Portable network graphics", "*.png"));
colorHints.put(RenderingHints.KEY_DITHERING, RenderingHints.VALUE_DITHER_ENABLE);
ICC_Profile grayProfile = ICC_Profile.getInstance(ColorSpace.CS_GRAY);
grayColorSpace = new ICC_ColorSpace(grayProfile);
ICC_Profile rgbProfile = ICC_Profile.getInstance(ColorSpace.CS_sRGB);
rgbColorSpace = new ICC_ColorSpace(rgbProfile);
Image tile = createCheckeredTile();
backgroundColor = new ImagePattern(tile, 0, 0, TILE_SIZE, TILE_SIZE, false);
}
/**
* Convert a BufferedImage to another color space.
*
* @param src cannot be TYPE_CUSTOM or null
* @param dstImageType valid BufferedImage types: TYPE_BYTE_GRAY,
* TYPE_INT_RGB, TYPE_INT_ARGB
* @return BufferedImage in the new color space. never null.
* @exception NullPointerException when src is null
* @exception IllegalArgumentException when dstImageType is not one of the
* three accepted types
*/
private BufferedImage toImageType(BufferedImage src, int dstImageType) {
BufferedImage dst;
if(src.getType() == dstImageType)
dst = src;
else {
ColorSpace dstColorSpace;
switch(dstImageType) {
case BufferedImage.TYPE_BYTE_GRAY:
dstColorSpace = grayColorSpace;
break;
case BufferedImage.TYPE_INT_RGB:
case BufferedImage.TYPE_INT_ARGB:
dstColorSpace = rgbColorSpace;
break;
default:
String msg = String.format("Conversion to BufferedImage type %d not supported.", dstImageType);
throw new IllegalArgumentException(msg);
}
/*
Using ColorConvertOp because the documentation promises images
with pre-multiplied alphas will be divided out.
Another possibility is dst.createGraphics().drawImage(src). Whether
drawImage() divides out premultiplied alphas is unknown to me, and
I don't feel like tracing the method to find out.
*/
ColorSpace srcColorSpace = src.getColorModel().getColorSpace();
ColorConvertOp op = new ColorConvertOp(srcColorSpace, dstColorSpace, colorHints);
dst = new BufferedImage(src.getWidth(), src.getHeight(), dstImageType);
op.filter(src, dst);
}
return dst;
}
/**
* Starting point for merging color source and alpha source into one image.
*
* @param e
*/
private void handleBuildComposite(ActionEvent e) {
try {
e.consume();
/*
Color source's RGB bands will become the composite's RGB bands.
If color source is ARGB then discard the alpha band to remove
any premultiplied alpha values.
If color source is grayscale then convert to RGB in preparation
for merge.
*/
final BufferedImage colorSourceRGB = toImageType(getColorSource(), BufferedImage.TYPE_INT_RGB);
appendGallery(colorSourceRGB, "Color source: RGB");
/*
One of alpha source's RGB bands will become the composite's alpha
band.
If alpha source is a color image, then convert to grayscale to get
R == G == B; at the expense of some information. If a color band
were copied to the alpha band without conversion, the resulting
alpha band wouldn't accurately represent the original color image
because R != G != B.
If alpha source is a grayscale image then no change.
*/
final BufferedImage alphaSourceGray = toImageType(getAlphaSource(), BufferedImage.TYPE_BYTE_GRAY);
appendGallery(alphaSourceGray, "Alpha source: grayscale");
/*
The objective of this app is to copy/move a color band into the
alpha band. Problem is grayscales don't have an alpha band. Convert
to ARGB to give it one.
*/
final BufferedImage alphaRGBA = toImageType(alphaSourceGray, BufferedImage.TYPE_INT_ARGB);
appendGallery(alphaRGBA, "Alpha source: grayscale to RGBA");
/*
Method toAlpha() is where the magic happens. Copy/move one of the
color bands into the alpha band.
*/
final BufferedImage trueAlpha = toAlpha(alphaRGBA);
appendGallery(trueAlpha, "Alpha source: Green to Alpha, RGB to white");
/*
Composite the color values with the alpha values into one image.
Copy colorSourceRGB's RGB into the composite's RGB.
Copy trueAlpha's alpha into the composite's alpha.
*/
BufferedImage colorPlusAlpha = toComposite(colorSourceRGB, trueAlpha);
appendGallery(colorPlusAlpha, "Color + alpha composite");
}
catch(Exception ex) {
final Alert dlg = new Alert(Alert.AlertType.ERROR, ex.getMessage(), ButtonType.CLOSE);
dlg.showAndWait();
}
}
/**
* Copy the green band into the alpha band.
*
* @param src presumed to be some type with an alpha band. You're screwed
* if it isn't.
* @return a BufferedImage with the green band in the alpha band, and
* the RGB bands set to white. Never null.
*/
private BufferedImage toAlpha(BufferedImage src) {
/*
This matrix specifies which band(s) to manipulate and how. The 3-ones
in the right-most column sets dst's RGB bands to white. The solitary
one in the bottom row will copy the green band into dst's alpha band.
Footnote: when the grayscale was converted to ARGB I expected the RGB
bands to be identical. After some testing the bands were found to be
*near* identical; it seems a color conversion from grayscale to
RGB is not as simple as a bulk memory copy. The differences are low
enough that no one would've noticed a difference had the either the
red or blue band been chosen over the green band.
*/
final float[][] matrix = new float[][] {
{0, 0, 0, 1},
{0, 0, 0, 1},
{0, 0, 0, 1},
{0, 1, 0, 0}};
BandCombineOp op = new BandCombineOp(matrix, null);
BufferedImage dst = new BufferedImage(src.getWidth(), src.getHeight(), src.getType());
op.filter(src.getRaster(), dst.getRaster());
return dst;
}
/**
* Composite color's RGB bands with alpha's alpha band into one image.
*
* @param color anything except BufferedImage.TYPE_CUSTOM and null.
* @param alpha anything with an alpha band otherwise very bad
* @return a BufferedImage of the two inputs. never null.
*/
private BufferedImage toComposite(BufferedImage color, BufferedImage alpha) {
final int width = Math.max(color.getWidth(), alpha.getWidth());
final int height = Math.max(color.getHeight(), alpha.getHeight());
final BufferedImage dst = new BufferedImage(width, height, BufferedImage.TYPE_INT_ARGB);
Graphics2D g = dst.createGraphics();
g.drawImage(color, null, 0, 0);
/*
AlphaComposite.DST_IN ignores alpha's RGB bands and copies just the
alpha band.
*/
g.setComposite(AlphaComposite.getInstance(AlphaComposite.DST_IN));
g.drawImage(alpha, null, 0, 0);
g.dispose();
return dst;
}
private Image createCheckeredTile() {
final Canvas can = new Canvas(TILE_SIZE, TILE_SIZE);
final GraphicsContext gc = can.getGraphicsContext2D();
final int haf = TILE_SIZE / 2;
gc.setFill(Color.DARKGRAY);
gc.fillRect(0, 0, haf, haf); // top-left
gc.fillRect(haf, haf, haf, haf); // bottom-right
gc.setFill(Color.DIMGREY);
gc.fillRect(haf, 0, haf, haf); // top-right
gc.fillRect(0, haf, haf, haf); // bottom-left
WritableImage snapshot = can.snapshot(null, null);
return snapshot;
}
private void loadImage(String title, ObjectProperty<BufferedImage> imageObj) {
try {
openFC.setTitle(title);
openFC.setInitialDirectory(lastDirectoryVisited);
File filePath = openFC.showOpenDialog(stage);
if(filePath != null) {
lastDirectoryVisited = filePath.getParentFile();
BufferedImage image = ImageIO.read(filePath);
imageObj.set(image);
}
}
catch(Exception ex) {
final Alert dlg = new Alert(Alert.AlertType.ERROR, ex.getMessage(), ButtonType.CLOSE);
dlg.showAndWait();
}
}
private void saveImage(MouseEvent e) {
try {
if(e.getButton() == MouseButton.SECONDARY) {
e.consume();
saveFC.setInitialDirectory(lastDirectoryVisited);
File filePath = saveFC.showSaveDialog(stage);
if(filePath != null) {
lastDirectoryVisited = filePath.getParentFile();
Canvas canvas = (Canvas) e.getSource();
BufferedImage img = (BufferedImage) canvas.getUserData();
ImageIO.write(img, "png", filePath);
}
}
}
catch(Exception ex) {
final Alert dlg = new Alert(Alert.AlertType.ERROR, ex.getMessage(), ButtonType.CLOSE);
dlg.showAndWait();
}
}
private Canvas appendGallery(BufferedImage src, String desc) {
final int width = src.getWidth();
final int height = src.getHeight();
final Canvas canvas = new Canvas(width, height);
canvas.setUserData(src);
Tooltip.install(canvas, canvasTip);
canvas.setOnMouseReleased(this::saveImage);
final GraphicsContext gc = canvas.getGraphicsContext2D();
final Image image = SwingFXUtils.toFXImage(src, null);
gc.setFill(backgroundColor);
gc.fillRect(0, 0, width, height);
gc.drawImage(image, 0, 0);
String desc2 = desc != null && !desc.isEmpty() ? desc : "?";
if(src.isAlphaPremultiplied())
desc2 += ", premultiplied alpha";
gc.setStroke(Color.LIME);
gc.strokeText(desc2, 5, 20);
gallery.getChildren().add(canvas);
return canvas;
}
private boolean neitherColorNorAlpha(Node n) {
boolean colorOrAlpha =
((colorSourceCanvas != null) && (n == colorSourceCanvas)) ||
((alphaSourceCanvas != null) && (n == alphaSourceCanvas));
return !colorOrAlpha;
}
private void setupMenu() {
Button loadColorSource = new Button("Load color source ...");
loadColorSource.setTooltip(new Tooltip("The image's color values will become the composite's color values."));
loadColorSource.setOnAction((e) -> {
e.consume();
loadImage(loadColorSource.getText(), colorSource);
colorSourceCanvas = appendGallery(getColorSource(), "Color source");
});
Button loadAlphaSource = new Button("Load alpha source ...");
loadAlphaSource.setTooltip(new Tooltip("The image's color values will become the composite's alpha values."));
loadAlphaSource.setOnAction((e) -> {
e.consume();
loadImage(loadAlphaSource.getText(), alphaSource);
alphaSourceCanvas = appendGallery(getAlphaSource(), "Alpha source");
});
Button buildComposite = new Button("Build composite");
buildComposite.setTooltip(new Tooltip("Merge color and alpha into one image."));
buildComposite.setOnAction(this::handleBuildComposite);
buildComposite.disableProperty().bind(colorSource.isNull().or(alphaSource.isNull()));
Button clearGallery = new Button("Clear gallery");
clearGallery.setTooltip(new Tooltip("Keep the current color source and alpha source; discard other images."));
clearGallery.disableProperty().bind(gallerySize.lessThanOrEqualTo(2));
clearGallery.setOnAction((e) -> {
e.consume();
gallery.getChildren().removeIf(this::neitherColorNorAlpha);
});
FlowPane parent = new FlowPane(NODE_SPACING, NODE_SPACING);
parent.setAlignment(Pos.CENTER);
parent.getChildren().addAll(loadColorSource, loadAlphaSource, buildComposite, clearGallery);
parent.setPadding(new Insets(NODE_SPACING));
root.setTop(parent);
}
private void setupGallery() {
gallery.setPadding(new Insets(NODE_SPACING));
ObservableList<Node> children = gallery.getChildren();
children.addListener(new ListChangeListener<Node>() {
@Override
public void onChanged(ListChangeListener.Change c) {
setGallerySize(children.size());
}
});
ScrollPane scroll = new ScrollPane(gallery);
scroll.setPannable(true);
scroll.setStyle("-fx-background-color: transparent;");
root.setCenter(scroll);
}
@Override
public void start(Stage primaryStage) {
stage = primaryStage;
setupMenu();
setupGallery();
Scene scene = new Scene(root, APP_WIDTH, APP_HEIGHT);
stage.setTitle("Embed alpha");
stage.setScene(scene);
stage.setResizable(true);
stage.show();
}
public int getGallerySize() {
return gallerySize.get();
}
public void setGallerySize(int value) {
gallerySize.set(value);
}
public IntegerProperty gallerySizeProperty() {
return gallerySize;
}
public BufferedImage getAlphaSource() {
return alphaSource.get();
}
public void setAlphaSource(BufferedImage value) {
alphaSource.set(value);
}
public ObjectProperty alphaSourceProperty() {
return alphaSource;
}
public BufferedImage getColorSource() {
return colorSource.get();
}
public void setColorSource(BufferedImage value) {
colorSource.set(value);
}
public ObjectProperty colorSourceProperty() {
return colorSource;
}
/**
* @param args the command line arguments
*/
public static void main(String[] args) {
launch(args);
}
}
我有两个 BufferedImages：一个是 TYPE_INT_ARGB，另一个是 TYPE_BYTE_GRAY。如何仅使用 API 将整个彩色图像的 alpha 波段替换为灰度图像，而不干扰 RGB 值？
final int width = 200;
final int height = 200;
final BufferedImage colorImg = new BufferedImage(width, height, BufferedImage.TYPE_INT_ARGB);
final BufferedImage grayscaleImg = new BufferedImage(width, height, BufferedImage.TYPE_BYTE_GRAY);
Graphics2D g = colorImg.createGraphics();
// flip some mystical switches
// g.drawImage( grayscaleImg into colorImg's alpha band )
g.dispose();
我可以像这样屏蔽和复制字节来手动完成：
WritableRaster clrRaster = colorImg.getRaster();
DataBufferInt clrBuffer = (DataBufferInt) clrRaster.getDataBuffer();
int[] clrData = clrBuffer.getData();
WritableRaster grayRaster = grayscaleImg.getRaster();
DataBufferByte grayBuffer = (DataBufferByte) grayRaster.getDataBuffer();
byte[] grayData = grayBuffer.getData();
int pixel, alphaBits;
for(int i = 0; i < clrData.length; i++) {
pixel = clrData[i] & 0x00ffffff;
alphaBits = (int)grayData[i] << 24;
clrData[i] = pixel | alphaBits;
}
但是 API 方法是什么？
更新 #1
样本图像：输入灰度alpha，输入彩色猫，输出带洞的彩色猫。
生成的图像在输出颜色的 alpha 中具有灰度。在照片编辑器中查看生成的图像，您会看到中间的孔实际上是透明的。
private void injectAlphaIntoColor() {
try {
// BEWARE: this code does not check if both images are the same
// width and height. May get out of bounds exception if w&h are
// different.
BufferedImage cat = ImageIO.read(new File("s:/temp/cat5.png"));
BufferedImage gray = ImageIO.read(new File("s:/temp/layermask.png"));
// convert color cat to TYPE_INT_ARGB
BufferedImage color = new BufferedImage(cat.getWidth(), cat.getHeight(), BufferedImage.TYPE_INT_ARGB);
Graphics2D g = color.createGraphics();
g.drawImage(cat, 0, 0, null);
g.dispose();
final WritableRaster clrRaster = color.getRaster();
final DataBufferInt clrBuffer = (DataBufferInt) clrRaster.getDataBuffer();
final int[] clrData = clrBuffer.getData();
final WritableRaster grayRaster = gray.getRaster();
final DataBufferByte grayBuffer = (DataBufferByte) grayRaster.getDataBuffer();
final byte[] grayData = grayBuffer.getData();
int pixel, alphaBits;
// manually put each grayscale pixel into each color pixel's alpha
for(int i = 0; i < clrData.length; i++) {
pixel = clrData[i] & 0x00ffffff;
alphaBits = (int)grayData[i] << 24;
clrData[i] = pixel | alphaBits;
}
ImageIO.write(color, "png", new File("s:/temp/3rd_output.png"));
}
catch (IOException ex) {
System.out.println(ex.getMessage());
}
}
重申我原来的 objective，Java API 执行上述代码的方法是什么？
啊，你想用蒙版剪掉部分图像，我的坏人。
简单的解决方案 - 首先使用基于 alpha 的蒙版。但我假设你没有那个选项。我确实尝试找到可能做到这一点的解决方案，但相反，我偶然发现了 this example。
哪个能够产生您似乎正在寻找的结果
（蓝色为面板背景色）
核心功能用于...
public void applyGrayscaleMaskToAlpha(BufferedImage image, BufferedImage mask) {
int width = image.getWidth();
int height = image.getHeight();
int[] imagePixels = image.getRGB(0, 0, width, height, null, 0, width);
int[] maskPixels = mask.getRGB(0, 0, width, height, null, 0, width);
for (int i = 0; i < imagePixels.length; i++) {
int color = imagePixels[i] & 0x00ffffff; // Mask preexisting alpha
int alpha = maskPixels[i] << 24; // Shift blue to alpha
imagePixels[i] = color | alpha;
}
image.setRGB(0, 0, width, height, imagePixels, 0, width);
}
但是作为一个简单的可运行示例...
import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.EventQueue;
import java.awt.Graphics;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;
import javax.imageio.ImageIO;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.UIManager;
public class Test {
public static void main(String[] args) {
new Test();
}
public Test() {
EventQueue.invokeLater(new Runnable() {
@Override
public void run() {
try {
UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
} catch (Exception ex) {
}
JFrame frame = new JFrame("Testing");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setLayout(new BorderLayout());
frame.add(new TestPane());
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
});
}
public void applyGrayscaleMaskToAlpha(BufferedImage image, BufferedImage mask) {
int width = image.getWidth();
int height = image.getHeight();
int[] imagePixels = image.getRGB(0, 0, width, height, null, 0, width);
int[] maskPixels = mask.getRGB(0, 0, width, height, null, 0, width);
for (int i = 0; i < imagePixels.length; i++) {
int color = imagePixels[i] & 0x00ffffff; // Mask preexisting alpha
int alpha = maskPixels[i] << 24; // Shift blue to alpha
imagePixels[i] = color | alpha;
}
image.setRGB(0, 0, width, height, imagePixels, 0, width);
}
public class TestPane extends JPanel {
private BufferedImage master;
private BufferedImage mask;
public TestPane() {
setBackground(Color.BLUE);
try {
master = ImageIO.read(new File("..."));
mask = ImageIO.read(new File("..."));
applyGrayscaleMaskToAlpha(master, mask);
} catch (IOException exp) {
exp.printStackTrace();
}
}
@Override
public Dimension getPreferredSize() {
Dimension size = super.getPreferredSize();
if (master != null && mask != null) {
size = new Dimension(master.getWidth() + mask.getWidth(), Math.max(master.getHeight(), mask.getHeight()));
}
return size;
}
@Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
int x = (getWidth() - (master.getWidth() + mask.getWidth())) / 2;
int y = (getHeight() - master.getHeight()) / 2;
g.drawImage(master, x, y, this);
x += mask.getWidth();
y = (getHeight() - mask.getHeight()) / 2;
g.drawImage(mask, x, y, this);
}
}
}
抱歉造成混淆
已更新 - 没有“操纵数据缓冲区”
I was looking for the Java API way of doing the same job without manipuating the bits
好的，所以我也更喜欢从灰度图像生成基于 alpha 的图像的解决方案，它更适合整体 Graphics 2D API。所以，在阅读更多 of this question which keeps on giving 之后，我偶然发现了这个想法......
public static BufferedImage grayScaleToTransparency(BufferedImage master) {
ImageFilter filter = new RGBImageFilter() {
public final int filterRGB(int x, int y, int rgb) {
return (rgb << 16) & 0xFF000000;
}
};
ImageProducer ip = new FilteredImageSource(master.getSource(), filter);
Image img = Toolkit.getDefaultToolkit().createImage(ip);
BufferedImage buffer = createCompatibleImage(img.getWidth(null), img.getHeight(null), Transparency.TRANSLUCENT);
Graphics2D g2d = buffer.createGraphics();
g2d.drawImage(img, 0, 0, null);
g2d.dispose();
return buffer;
}
现在，可能无法使用 BufferedImageFilter 和 BufferedImageOp 来获取它，但我没有时间或经验来进一步研究它。
使用这种技术我能够生产...
原图 |原始（灰度）蒙版 |基于 Alpha 的掩码 |屏蔽图像
同样，蓝色是面板的背景色。
import java.awt.AlphaComposite;
import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.EventQueue;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.GraphicsConfiguration;
import java.awt.GraphicsEnvironment;
import java.awt.Image;
import java.awt.RenderingHints;
import java.awt.Toolkit;
import java.awt.Transparency;
import java.awt.image.BufferedImage;
import java.awt.image.FilteredImageSource;
import java.awt.image.ImageFilter;
import java.awt.image.ImageProducer;
import java.awt.image.RGBImageFilter;
import java.io.File;
import java.io.IOException;
import javax.imageio.ImageIO;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.UIManager;
public class Test {
public static void main(String[] args) {
new Test();
}
public Test() {
EventQueue.invokeLater(new Runnable() {
@Override
public void run() {
try {
UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
} catch (Exception ex) {
}
JFrame frame = new JFrame("Testing");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setLayout(new BorderLayout());
frame.add(new TestPane());
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
});
}
public static GraphicsConfiguration getGraphicsConfiguration() {
return GraphicsEnvironment.getLocalGraphicsEnvironment().getDefaultScreenDevice().getDefaultConfiguration();
}
public static BufferedImage createCompatibleImage(int width, int height, int transparency) {
BufferedImage image = getGraphicsConfiguration().createCompatibleImage(width, height, transparency);
image.coerceData(true);
return image;
}
public static void applyQualityRenderingHints(Graphics2D g2d) {
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_DITHERING, RenderingHints.VALUE_DITHER_ENABLE);
g2d.setRenderingHint(RenderingHints.KEY_FRACTIONALMETRICS, RenderingHints.VALUE_FRACTIONALMETRICS_ON);
g2d.setRenderingHint(RenderingHints.KEY_INTERPOLATION, RenderingHints.VALUE_INTERPOLATION_BILINEAR);
g2d.setRenderingHint(RenderingHints.KEY_RENDERING, RenderingHints.VALUE_RENDER_QUALITY);
g2d.setRenderingHint(RenderingHints.KEY_STROKE_CONTROL, RenderingHints.VALUE_STROKE_PURE);
}
public static BufferedImage applyMask(BufferedImage master, BufferedImage mask) {
int imgWidth = master.getWidth();
int imgHeight = master.getHeight();
BufferedImage imgMask = createCompatibleImage(imgWidth, imgHeight, Transparency.TRANSLUCENT);
Graphics2D g2 = imgMask.createGraphics();
applyQualityRenderingHints(g2);
g2.drawImage(mask, 0, 0, null);
g2.setComposite(AlphaComposite.getInstance(AlphaComposite.SRC_IN, 1f));
g2.drawImage(master, 0, 0, null);
g2.dispose();
return imgMask;
}
public static BufferedImage grayScaleToTransparency(BufferedImage master) {
ImageFilter filter = new RGBImageFilter() {
public final int filterRGB(int x, int y, int rgb) {
return (rgb << 16) & 0xFF000000;
}
};
ImageProducer ip = new FilteredImageSource(master.getSource(), filter);
Image img = Toolkit.getDefaultToolkit().createImage(ip);
BufferedImage buffer = createCompatibleImage(img.getWidth(null), img.getHeight(null), Transparency.TRANSLUCENT);
Graphics2D g2d = buffer.createGraphics();
g2d.drawImage(img, 0, 0, null);
g2d.dispose();
return buffer;
}
public class TestPane extends JPanel {
private BufferedImage master;
private BufferedImage originalMask;
private BufferedImage alphaMask;
private BufferedImage masked;
public TestPane() {
setBackground(Color.BLUE);
try {
master = ImageIO.read(new File("/Users/swhitehead/Downloads/lIceL.png"));
originalMask = ImageIO.read(new File("/Users/swhitehead/Downloads/MXmFp.png"));
alphaMask = grayScaleToTransparency(originalMask);
masked = applyMask(master, alphaMask);
// tinted = tint(master, mask);
} catch (IOException exp) {
exp.printStackTrace();
}
}
protected int desiredWidth() {
return master.getWidth() + originalMask.getWidth() + alphaMask.getWidth() + masked.getWidth();
}
protected int desiredHeight() {
return Math.max(Math.max(Math.max(master.getHeight(), originalMask.getHeight()), alphaMask.getHeight()), masked.getHeight());
}
@Override
public Dimension getPreferredSize() {
Dimension size = super.getPreferredSize();
if (master != null && originalMask != null) {
size = new Dimension(desiredWidth(),
desiredHeight());
}
return size;
}
@Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
int x = (getWidth() - desiredWidth()) / 2;
int y = (getHeight() - master.getHeight()) / 2;
g.drawImage(master, x, y, this);
x += originalMask.getWidth();
y = (getHeight() - originalMask.getHeight()) / 2;
g.drawImage(originalMask, x, y, this);
x += alphaMask.getWidth();
y = (getHeight() - alphaMask.getHeight()) / 2;
g.drawImage(alphaMask, x, y, this);
x += masked.getWidth();
y = (getHeight() - masked.getHeight()) / 2;
g.drawImage(masked, x, y, this);
}
}
}
感谢@Hovercraft Full Of Eels 提出 BufferedImageOp 的建议，这导致了 BandCombineOp。当输入合适的矩阵时，class 可以操纵任何或所有波段。变亮、变暗、移动和复制条带，而无需访问 DataBuffer 或操作位。
如何将图像放入 alpha 波段
- 加载或绘制图像；这将成为 alpha 波段。图片 可以是彩色或灰度。
- 将图像转换为
BufferedImage.TYPE_BYTE_GRAY - 将灰度转换为
BufferedImage.TYPE_INT_ARGB。颜色 条带将包含 near 个相同的灰度副本。 - 使用
BandCombineOp将颜色波段复制到 alpha 波段。参见矩阵toAlpha()。
这是 move/copy 编码位操作的更好方法，因为它在数学上很优雅，并且 API 可以利用视频加速硬件（如果存在并受 Java.)
示例 Java 应用程序：嵌入 alpha
包含一个应用程序来演示该过程。 Select 颜色源和 alpha 源，应用会将它们合成为一张图像。显示两个源图像、中间图像和合成图像是为了保持理智。右键单击任何图像以保存。
色源：猫
Alpha 来源：鸟
Alpha 源：复制到 Alpha 带的绿色带
复合
到 运行 应用程序：(1) 创建一个名为 embedalpha 的 JavaFX 项目，(2) 删除自动生成的内容。java文件，(3) 粘贴我的代码，(4) 运行.
要跟踪过程，请在方法 handleBuildComposite() 中放置一个断点。忽略 appendGallery()。 toAlpha() 复制乐队。
/*
Your use of any portion of the code constitutes your acceptance of full
responsibility for all wonderful and aweful outcomes.
*/
package embedalpha;
import java.awt.AlphaComposite;
import java.awt.Dimension;
import java.awt.Graphics2D;
import java.awt.RenderingHints;
import java.awt.Toolkit;
import java.awt.color.ColorSpace;
import java.awt.color.ICC_ColorSpace;
import java.awt.color.ICC_Profile;
import java.awt.image.BandCombineOp;
import java.awt.image.BufferedImage;
import java.awt.image.ColorConvertOp;
import java.io.File;
import javafx.application.Application;
import javafx.beans.property.IntegerProperty;
import javafx.beans.property.ObjectProperty;
import javafx.beans.property.SimpleIntegerProperty;
import javafx.beans.property.SimpleObjectProperty;
import javafx.collections.ListChangeListener;
import javafx.collections.ObservableList;
import javafx.embed.swing.SwingFXUtils;
import javafx.event.ActionEvent;
import javafx.geometry.Insets;
import javafx.geometry.Pos;
import javafx.scene.Node;
import javafx.scene.Scene;
import javafx.scene.canvas.Canvas;
import javafx.scene.canvas.GraphicsContext;
import javafx.scene.control.Alert;
import javafx.scene.control.Button;
import javafx.scene.control.ButtonType;
import javafx.scene.control.ScrollPane;
import javafx.scene.control.Tooltip;
import javafx.scene.image.Image;
import javafx.scene.image.WritableImage;
import javafx.scene.input.MouseButton;
import javafx.scene.input.MouseEvent;
import javafx.scene.layout.BorderPane;
import javafx.scene.layout.FlowPane;
import javafx.scene.layout.HBox;
import javafx.scene.paint.Color;
import javafx.scene.paint.ImagePattern;
import javafx.scene.paint.Paint;
import javafx.stage.FileChooser;
import javafx.stage.Stage;
import javax.imageio.ImageIO;
/**
* Demonstrate copying/moving a color band to the alpha band within the same
* image using only API. The specific method is toAlpha().
*
* @author deskwarrior
* @see
*/
public class TheApp extends Application {
private final int NODE_SPACING = 5;
private final int TILE_SIZE = 40;
private final int APP_WIDTH;
private final int APP_HEIGHT;
private final ObjectProperty<BufferedImage> colorSource = new SimpleObjectProperty<>(this, "colorSource", null);
private final ObjectProperty<BufferedImage> alphaSource = new SimpleObjectProperty<>(this, "alphaSource", null);
private final Paint backgroundColor;
private final HBox gallery = new HBox(NODE_SPACING);
private final IntegerProperty gallerySize = new SimpleIntegerProperty(this, "gallerySize", 0);
private final Tooltip canvasTip = new Tooltip("Right-click to save image as PNG.");
private Canvas colorSourceCanvas = null;
private Canvas alphaSourceCanvas = null;
private final FileChooser openFC = new FileChooser();
private final FileChooser saveFC = new FileChooser();
private File lastDirectoryVisited = null;
private final RenderingHints colorHints = new RenderingHints(
RenderingHints.KEY_COLOR_RENDERING,
RenderingHints.VALUE_COLOR_RENDER_QUALITY);
private final ICC_ColorSpace grayColorSpace;
private final ICC_ColorSpace rgbColorSpace;
private final BorderPane root = new BorderPane();
private Stage stage = null;
public TheApp() {
Dimension screenSize = Toolkit.getDefaultToolkit().getScreenSize();
APP_WIDTH = screenSize.width;
APP_HEIGHT = screenSize.height * 2 / 3;
openFC.getExtensionFilters().addAll(
new FileChooser.ExtensionFilter("Image Files", "*.png", "*.jpg", "*.gif", "*.bmp"),
new FileChooser.ExtensionFilter("All Files", "*.*"));
saveFC.setTitle("Save image as PNG");
saveFC.getExtensionFilters().addAll(
new FileChooser.ExtensionFilter("Portable network graphics", "*.png"));
colorHints.put(RenderingHints.KEY_DITHERING, RenderingHints.VALUE_DITHER_ENABLE);
ICC_Profile grayProfile = ICC_Profile.getInstance(ColorSpace.CS_GRAY);
grayColorSpace = new ICC_ColorSpace(grayProfile);
ICC_Profile rgbProfile = ICC_Profile.getInstance(ColorSpace.CS_sRGB);
rgbColorSpace = new ICC_ColorSpace(rgbProfile);
Image tile = createCheckeredTile();
backgroundColor = new ImagePattern(tile, 0, 0, TILE_SIZE, TILE_SIZE, false);
}
/**
* Convert a BufferedImage to another color space.
*
* @param src cannot be TYPE_CUSTOM or null
* @param dstImageType valid BufferedImage types: TYPE_BYTE_GRAY,
* TYPE_INT_RGB, TYPE_INT_ARGB
* @return BufferedImage in the new color space. never null.
* @exception NullPointerException when src is null
* @exception IllegalArgumentException when dstImageType is not one of the
* three accepted types
*/
private BufferedImage toImageType(BufferedImage src, int dstImageType) {
BufferedImage dst;
if(src.getType() == dstImageType)
dst = src;
else {
ColorSpace dstColorSpace;
switch(dstImageType) {
case BufferedImage.TYPE_BYTE_GRAY:
dstColorSpace = grayColorSpace;
break;
case BufferedImage.TYPE_INT_RGB:
case BufferedImage.TYPE_INT_ARGB:
dstColorSpace = rgbColorSpace;
break;
default:
String msg = String.format("Conversion to BufferedImage type %d not supported.", dstImageType);
throw new IllegalArgumentException(msg);
}
/*
Using ColorConvertOp because the documentation promises images
with pre-multiplied alphas will be divided out.
Another possibility is dst.createGraphics().drawImage(src). Whether
drawImage() divides out premultiplied alphas is unknown to me, and
I don't feel like tracing the method to find out.
*/
ColorSpace srcColorSpace = src.getColorModel().getColorSpace();
ColorConvertOp op = new ColorConvertOp(srcColorSpace, dstColorSpace, colorHints);
dst = new BufferedImage(src.getWidth(), src.getHeight(), dstImageType);
op.filter(src, dst);
}
return dst;
}
/**
* Starting point for merging color source and alpha source into one image.
*
* @param e
*/
private void handleBuildComposite(ActionEvent e) {
try {
e.consume();
/*
Color source's RGB bands will become the composite's RGB bands.
If color source is ARGB then discard the alpha band to remove
any premultiplied alpha values.
If color source is grayscale then convert to RGB in preparation
for merge.
*/
final BufferedImage colorSourceRGB = toImageType(getColorSource(), BufferedImage.TYPE_INT_RGB);
appendGallery(colorSourceRGB, "Color source: RGB");
/*
One of alpha source's RGB bands will become the composite's alpha
band.
If alpha source is a color image, then convert to grayscale to get
R == G == B; at the expense of some information. If a color band
were copied to the alpha band without conversion, the resulting
alpha band wouldn't accurately represent the original color image
because R != G != B.
If alpha source is a grayscale image then no change.
*/
final BufferedImage alphaSourceGray = toImageType(getAlphaSource(), BufferedImage.TYPE_BYTE_GRAY);
appendGallery(alphaSourceGray, "Alpha source: grayscale");
/*
The objective of this app is to copy/move a color band into the
alpha band. Problem is grayscales don't have an alpha band. Convert
to ARGB to give it one.
*/
final BufferedImage alphaRGBA = toImageType(alphaSourceGray, BufferedImage.TYPE_INT_ARGB);
appendGallery(alphaRGBA, "Alpha source: grayscale to RGBA");
/*
Method toAlpha() is where the magic happens. Copy/move one of the
color bands into the alpha band.
*/
final BufferedImage trueAlpha = toAlpha(alphaRGBA);
appendGallery(trueAlpha, "Alpha source: Green to Alpha, RGB to white");
/*
Composite the color values with the alpha values into one image.
Copy colorSourceRGB's RGB into the composite's RGB.
Copy trueAlpha's alpha into the composite's alpha.
*/
BufferedImage colorPlusAlpha = toComposite(colorSourceRGB, trueAlpha);
appendGallery(colorPlusAlpha, "Color + alpha composite");
}
catch(Exception ex) {
final Alert dlg = new Alert(Alert.AlertType.ERROR, ex.getMessage(), ButtonType.CLOSE);
dlg.showAndWait();
}
}
/**
* Copy the green band into the alpha band.
*
* @param src presumed to be some type with an alpha band. You're screwed
* if it isn't.
* @return a BufferedImage with the green band in the alpha band, and
* the RGB bands set to white. Never null.
*/
private BufferedImage toAlpha(BufferedImage src) {
/*
This matrix specifies which band(s) to manipulate and how. The 3-ones
in the right-most column sets dst's RGB bands to white. The solitary
one in the bottom row will copy the green band into dst's alpha band.
Footnote: when the grayscale was converted to ARGB I expected the RGB
bands to be identical. After some testing the bands were found to be
*near* identical; it seems a color conversion from grayscale to
RGB is not as simple as a bulk memory copy. The differences are low
enough that no one would've noticed a difference had the either the
red or blue band been chosen over the green band.
*/
final float[][] matrix = new float[][] {
{0, 0, 0, 1},
{0, 0, 0, 1},
{0, 0, 0, 1},
{0, 1, 0, 0}};
BandCombineOp op = new BandCombineOp(matrix, null);
BufferedImage dst = new BufferedImage(src.getWidth(), src.getHeight(), src.getType());
op.filter(src.getRaster(), dst.getRaster());
return dst;
}
/**
* Composite color's RGB bands with alpha's alpha band into one image.
*
* @param color anything except BufferedImage.TYPE_CUSTOM and null.
* @param alpha anything with an alpha band otherwise very bad
* @return a BufferedImage of the two inputs. never null.
*/
private BufferedImage toComposite(BufferedImage color, BufferedImage alpha) {
final int width = Math.max(color.getWidth(), alpha.getWidth());
final int height = Math.max(color.getHeight(), alpha.getHeight());
final BufferedImage dst = new BufferedImage(width, height, BufferedImage.TYPE_INT_ARGB);
Graphics2D g = dst.createGraphics();
g.drawImage(color, null, 0, 0);
/*
AlphaComposite.DST_IN ignores alpha's RGB bands and copies just the
alpha band.
*/
g.setComposite(AlphaComposite.getInstance(AlphaComposite.DST_IN));
g.drawImage(alpha, null, 0, 0);
g.dispose();
return dst;
}
private Image createCheckeredTile() {
final Canvas can = new Canvas(TILE_SIZE, TILE_SIZE);
final GraphicsContext gc = can.getGraphicsContext2D();
final int haf = TILE_SIZE / 2;
gc.setFill(Color.DARKGRAY);
gc.fillRect(0, 0, haf, haf); // top-left
gc.fillRect(haf, haf, haf, haf); // bottom-right
gc.setFill(Color.DIMGREY);
gc.fillRect(haf, 0, haf, haf); // top-right
gc.fillRect(0, haf, haf, haf); // bottom-left
WritableImage snapshot = can.snapshot(null, null);
return snapshot;
}
private void loadImage(String title, ObjectProperty<BufferedImage> imageObj) {
try {
openFC.setTitle(title);
openFC.setInitialDirectory(lastDirectoryVisited);
File filePath = openFC.showOpenDialog(stage);
if(filePath != null) {
lastDirectoryVisited = filePath.getParentFile();
BufferedImage image = ImageIO.read(filePath);
imageObj.set(image);
}
}
catch(Exception ex) {
final Alert dlg = new Alert(Alert.AlertType.ERROR, ex.getMessage(), ButtonType.CLOSE);
dlg.showAndWait();
}
}
private void saveImage(MouseEvent e) {
try {
if(e.getButton() == MouseButton.SECONDARY) {
e.consume();
saveFC.setInitialDirectory(lastDirectoryVisited);
File filePath = saveFC.showSaveDialog(stage);
if(filePath != null) {
lastDirectoryVisited = filePath.getParentFile();
Canvas canvas = (Canvas) e.getSource();
BufferedImage img = (BufferedImage) canvas.getUserData();
ImageIO.write(img, "png", filePath);
}
}
}
catch(Exception ex) {
final Alert dlg = new Alert(Alert.AlertType.ERROR, ex.getMessage(), ButtonType.CLOSE);
dlg.showAndWait();
}
}
private Canvas appendGallery(BufferedImage src, String desc) {
final int width = src.getWidth();
final int height = src.getHeight();
final Canvas canvas = new Canvas(width, height);
canvas.setUserData(src);
Tooltip.install(canvas, canvasTip);
canvas.setOnMouseReleased(this::saveImage);
final GraphicsContext gc = canvas.getGraphicsContext2D();
final Image image = SwingFXUtils.toFXImage(src, null);
gc.setFill(backgroundColor);
gc.fillRect(0, 0, width, height);
gc.drawImage(image, 0, 0);
String desc2 = desc != null && !desc.isEmpty() ? desc : "?";
if(src.isAlphaPremultiplied())
desc2 += ", premultiplied alpha";
gc.setStroke(Color.LIME);
gc.strokeText(desc2, 5, 20);
gallery.getChildren().add(canvas);
return canvas;
}
private boolean neitherColorNorAlpha(Node n) {
boolean colorOrAlpha =
((colorSourceCanvas != null) && (n == colorSourceCanvas)) ||
((alphaSourceCanvas != null) && (n == alphaSourceCanvas));
return !colorOrAlpha;
}
private void setupMenu() {
Button loadColorSource = new Button("Load color source ...");
loadColorSource.setTooltip(new Tooltip("The image's color values will become the composite's color values."));
loadColorSource.setOnAction((e) -> {
e.consume();
loadImage(loadColorSource.getText(), colorSource);
colorSourceCanvas = appendGallery(getColorSource(), "Color source");
});
Button loadAlphaSource = new Button("Load alpha source ...");
loadAlphaSource.setTooltip(new Tooltip("The image's color values will become the composite's alpha values."));
loadAlphaSource.setOnAction((e) -> {
e.consume();
loadImage(loadAlphaSource.getText(), alphaSource);
alphaSourceCanvas = appendGallery(getAlphaSource(), "Alpha source");
});
Button buildComposite = new Button("Build composite");
buildComposite.setTooltip(new Tooltip("Merge color and alpha into one image."));
buildComposite.setOnAction(this::handleBuildComposite);
buildComposite.disableProperty().bind(colorSource.isNull().or(alphaSource.isNull()));
Button clearGallery = new Button("Clear gallery");
clearGallery.setTooltip(new Tooltip("Keep the current color source and alpha source; discard other images."));
clearGallery.disableProperty().bind(gallerySize.lessThanOrEqualTo(2));
clearGallery.setOnAction((e) -> {
e.consume();
gallery.getChildren().removeIf(this::neitherColorNorAlpha);
});
FlowPane parent = new FlowPane(NODE_SPACING, NODE_SPACING);
parent.setAlignment(Pos.CENTER);
parent.getChildren().addAll(loadColorSource, loadAlphaSource, buildComposite, clearGallery);
parent.setPadding(new Insets(NODE_SPACING));
root.setTop(parent);
}
private void setupGallery() {
gallery.setPadding(new Insets(NODE_SPACING));
ObservableList<Node> children = gallery.getChildren();
children.addListener(new ListChangeListener<Node>() {
@Override
public void onChanged(ListChangeListener.Change c) {
setGallerySize(children.size());
}
});
ScrollPane scroll = new ScrollPane(gallery);
scroll.setPannable(true);
scroll.setStyle("-fx-background-color: transparent;");
root.setCenter(scroll);
}
@Override
public void start(Stage primaryStage) {
stage = primaryStage;
setupMenu();
setupGallery();
Scene scene = new Scene(root, APP_WIDTH, APP_HEIGHT);
stage.setTitle("Embed alpha");
stage.setScene(scene);
stage.setResizable(true);
stage.show();
}
public int getGallerySize() {
return gallerySize.get();
}
public void setGallerySize(int value) {
gallerySize.set(value);
}
public IntegerProperty gallerySizeProperty() {
return gallerySize;
}
public BufferedImage getAlphaSource() {
return alphaSource.get();
}
public void setAlphaSource(BufferedImage value) {
alphaSource.set(value);
}
public ObjectProperty alphaSourceProperty() {
return alphaSource;
}
public BufferedImage getColorSource() {
return colorSource.get();
}
public void setColorSource(BufferedImage value) {
colorSource.set(value);
}
public ObjectProperty colorSourceProperty() {
return colorSource;
}
/**
* @param args the command line arguments
*/
public static void main(String[] args) {
launch(args);
}
}