在不使用ImageIO的情况下在Java中调整图像大小

Question

We have successfully resized the images by getting the JPEG thumbnail data, but there are certain images that doesn't have one.

The solution is just to resize the image to be able to create a thumbnail, but can only use Java 1.4 and below (hence I can't use ImageIO because the device doesn't support it)

Is there any solution to my problem on how to resize an image using ImageIO?

Answer 1

java.awt.Image.getScaledInstance(width, height, hints) returns a new, scaled instance of the Image.

The last parameter hints changes the scaling methods used, which will modify the resulting appearence. See the snippet below, taken directly from the JDK source.

 /**
 * Use the default image-scaling algorithm.
 * @since JDK1.1
 */
public static final int SCALE_DEFAULT = 1;

/**
 * Choose an image-scaling algorithm that gives higher priority
 * to scaling speed than smoothness of the scaled image.
 * @since JDK1.1
 */
public static final int SCALE_FAST = 2;

/**
 * Choose an image-scaling algorithm that gives higher priority
 * to image smoothness than scaling speed.
 * @since JDK1.1
 */
public static final int SCALE_SMOOTH = 4;

/**
 * Use the image scaling algorithm embodied in the
 * <code>ReplicateScaleFilter</code> class.
 * The <code>Image</code> object is free to substitute a different filter
 * that performs the same algorithm yet integrates more efficiently
 * into the imaging infrastructure supplied by the toolkit.
 * @see        java.awt.image.ReplicateScaleFilter
 * @since      JDK1.1
 */
public static final int SCALE_REPLICATE = 8;

/**
 * Use the Area Averaging image scaling algorithm.  The
 * image object is free to substitute a different filter that
 * performs the same algorithm yet integrates more efficiently
 * into the image infrastructure supplied by the toolkit.
 * @see java.awt.image.AreaAveragingScaleFilter
 * @since JDK1.1
 */
public static final int SCALE_AREA_AVERAGING = 16;

Answer 2

Try This code, Just put the size you want for Width and height and it will give you required image. Its shortest code I have found till now. works fine for me.

    Bitmap yourBitmap;
    Bitmap resized = Bitmap.createScaledBitmap(yourBitmap, newWidth, newHeight, true);