Scaling an image down over a large range is inherently dangerous (from the point of view of quality), especially using a single step.
The recommended method is to use a divide and conquer method. Basically, you scale the image down in steps of 50% until you reach your desired size.
So, I took the original image of 650×748 and scaled it down to fit within a 60×60 region (52×60).
Divide and conquer compared to one step…
public class TestImageResize {
public static void main(String[] args) {
new TestImageResize();
}
public TestImageResize() {
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 ScalePane());
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
});
}
public class ScalePane extends JPanel {
private BufferedImage original;
private BufferedImage scaled;
public ScalePane() {
try {
original = ImageIO.read(new File("path/to/master.jpg"));
scaled = getScaledInstanceToFit(original, new Dimension(60, 60));
ImageIO.write(scaled, "jpg", new File("scaled.jpg"));
BufferedImage image = new BufferedImage(52, 60, BufferedImage.TYPE_INT_RGB);
Graphics2D g2d = image.createGraphics();
g2d.setRenderingHint(RenderingHints.KEY_INTERPOLATION, RenderingHints.VALUE_INTERPOLATION_BILINEAR);
g2d.setRenderingHint(RenderingHints.KEY_RENDERING, RenderingHints.VALUE_RENDER_QUALITY);
g2d.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
g2d.drawImage(original, 0, 0, 52, 60, this);
g2d.dispose();
ImageIO.write(image, "jpg", new File("test.jpg"));
} catch (IOException ex) {
ex.printStackTrace();
}
}
@Override
public Dimension getPreferredSize() {
Dimension size = super.getPreferredSize();
if (original != null) {
if (scaled != null) {
size.width = original.getWidth() + scaled.getWidth();
size.height = original.getHeight();
} else {
size.width = original.getWidth();
size.height = original.getHeight();
}
}
return size;
}
@Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
Graphics2D g2d = (Graphics2D) g.create();
g2d.setRenderingHint(RenderingHints.KEY_INTERPOLATION, RenderingHints.VALUE_INTERPOLATION_BILINEAR);
g2d.setRenderingHint(RenderingHints.KEY_RENDERING, RenderingHints.VALUE_RENDER_QUALITY);
g2d.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
if (original != null) {
int x = 0;
int y = (getHeight() - original.getHeight()) / 2;;
if (scaled != null) {
x = (getWidth() - (original.getWidth() + scaled.getWidth())) / 2;
} else {
x = (getWidth() - original.getWidth()) / 2;
}
g2d.drawImage(original, x, y, this);
if (scaled != null) {
x += original.getWidth();
y = (getHeight() - scaled.getHeight()) / 2;
g2d.drawImage(scaled, x, y, this);
}
}
g2d.dispose();
}
public BufferedImage getScaledInstanceToFit(BufferedImage img, Dimension size) {
float scaleFactor = getScaleFactorToFit(img, size);
return getScaledInstance(img, scaleFactor);
}
public float getScaleFactorToFit(BufferedImage img, Dimension size) {
float scale = 1f;
if (img != null) {
int imageWidth = img.getWidth();
int imageHeight = img.getHeight();
scale = getScaleFactorToFit(new Dimension(imageWidth, imageHeight), size);
}
return scale;
}
public float getScaleFactorToFit(Dimension original, Dimension toFit) {
float scale = 1f;
if (original != null && toFit != null) {
float dScaleWidth = getScaleFactor(original.width, toFit.width);
float dScaleHeight = getScaleFactor(original.height, toFit.height);
scale = Math.min(dScaleHeight, dScaleWidth);
}
return scale;
}
public float getScaleFactor(int iMasterSize, int iTargetSize) {
float scale = 1;
if (iMasterSize > iTargetSize) {
scale = (float) iTargetSize / (float) iMasterSize;
} else {
scale = (float) iTargetSize / (float) iMasterSize;
}
return scale;
}
public BufferedImage getScaledInstance(BufferedImage img, double dScaleFactor) {
BufferedImage imgBuffer = null;
imgBuffer = getScaledInstance(img, dScaleFactor, RenderingHints.VALUE_INTERPOLATION_BILINEAR, true);
return imgBuffer;
}
protected BufferedImage getScaledInstance(BufferedImage img, double dScaleFactor, Object hint, boolean higherQuality) {
int targetWidth = (int) Math.round(img.getWidth() * dScaleFactor);
int targetHeight = (int) Math.round(img.getHeight() * dScaleFactor);
int type = (img.getTransparency() == Transparency.OPAQUE)
? BufferedImage.TYPE_INT_RGB : BufferedImage.TYPE_INT_ARGB;
BufferedImage ret = (BufferedImage) img;
if (targetHeight > 0 || targetWidth > 0) {
int w, h;
if (higherQuality) {
w = img.getWidth();
h = img.getHeight();
} else {
w = targetWidth;
h = targetHeight;
}
do {
if (higherQuality && w > targetWidth) {
w /= 2;
if (w < targetWidth) {
w = targetWidth;
}
}
if (higherQuality && h > targetHeight) {
h /= 2;
if (h < targetHeight) {
h = targetHeight;
}
}
BufferedImage tmp = new BufferedImage(Math.max(w, 1), Math.max(h, 1), type);
Graphics2D g2 = tmp.createGraphics();
g2.setRenderingHint(RenderingHints.KEY_INTERPOLATION, hint);
g2.drawImage(ret, 0, 0, w, h, null);
g2.dispose();
ret = tmp;
} while (w != targetWidth || h != targetHeight);
} else {
ret = new BufferedImage(1, 1, type);
}
return ret;
}
}
}
You may, also, find The Perils of Image.getScaledInstance() of interest.