BlackBerry平台图片缩放功能-Bitmap

public void scaleInto(Bitmap dst,  int filterType)

dst

filterType

Bitmap.FILTER_LANCZOS

Bitmap.FILTER_BOX

Bitmap.FILTER_BILINEAR

NullPointerException

IllegalArgumentException

IllegalArgumentException

Bitmap Scaling

testBitmap0 = Bitmap.getBitmapResource("rim.png");
// Create different scaled versions of the original bitmap
Bitmap scaledBitmap1 = new Bitmap(200, 50);
Bitmap scaledBitmap2 = new Bitmap(200, 75);
Bitmap scaledBitmap3 = new Bitmap(40, 60);
Bitmap scaledBitmap4 = new Bitmap(200, 50);
Bitmap scaledBitmap5 = new Bitmap(40, 60);
Bitmap scaledBitmap6 = new Bitmap(200, 40);

// Example 1. Scale the source bitmap and store it in another bitmap
testBitmap0.scaleInto(scaledBitmap1, Bitmap.FILTER_BILINEAR);

// Example 2. Copy fragments of the original bitmap into fragments of another bitmap
testBitmap0.scaleInto(0, 0, testBitmap0.getWidth(), testBitmap0.getHeight(), scaledBitmap2,
0, 0, 50, 50, Bitmap.FILTER_BILINEAR);
testBitmap0.scaleInto( 0, 0, 50, 50, scaledBitmap2, 75, 15, 50, 50, Bitmap.FILTER_BILINEAR);
testBitmap0.scaleInto(50, 0, 50, 50, scaledBitmap2, 150, 0, 50, 50, Bitmap.FILTER_BILINEAR);

// Example 3. Scale preserving the aspect ratio. Fit horizontally.
testBitmap0.scaleInto(scaledBitmap3, Bitmap.FILTER_BILINEAR, Bitmap.SCALE_TO_FIT);

// Example 4. Scale preserving the aspect ratio. Fit vertically.
testBitmap0.scaleInto(scaledBitmap4, Bitmap.FILTER_BILINEAR, Bitmap.SCALE_TO_FIT);

// Example 5. Scale preserving the aspect ratio. Fill vertically.
testBitmap0.scaleInto(scaledBitmap5, Bitmap.FILTER_BILINEAR, Bitmap.SCALE_TO_FILL);

// Example 6. Scale preserving the aspect ratio. Fill horizontally.
testBitmap0.scaleInto(scaledBitmap6, Bitmap.FILTER_BILINEAR, Bitmap.SCALE_TO_FILL);

各种图片缩放结果如下：

Bitmap.FILTER_LANCZOS

Bitmap.FILTER_BOX

Bitmap.FILTER_BILINEAR

public void scaleInto(Bitmap dst,int filterType,int iAspectRatioOption)

dst

filterType

Bitmap.FILTER_LANCZOS

Bitmap.FILTER_BOX

Bitmap.FILTER_BILINEAR

preserveAspectRatio

Bitmap.SCALE_STRETCH

Bitmap.SCALE_TO_FIT

Bitmap.SCALE_TO_FILL

NullPointerException

IllegalArgumentException

IllegalArgumentException

IllegalArgumentException

ScaleApplication 源代码如下：

package com.rim.samples.device.ui.bitmapscalingdemo;

import net.rim.device.api.system.*;import net.rim.device.api.ui.*;import net.rim.device.api.ui.container.*;import net.rim.device.api.ui.component.*;

/** *  A sample application to demonstrate Bitmap scaling */public class BitmapScalingDemo extends UiApplication{    /**     * Entry point for application     * @param args Command line arguments (not used)     */    public static void main(String[] args)    {        // Create a new instance of the application and make the currently        // running thread the application's event dispatch thread.        BitmapScalingDemo app = new BitmapScalingDemo();        app.enterEventDispatcher();           }

    /**     * Creates a new BitmapScalingDemo object     */    public BitmapScalingDemo()    {        pushScreen(new BitmapScalingDemoScreen());    }    

    /**     * MainScreen class for the BitmapScalingDemo application     */    static class BitmapScalingDemoScreen extends MainScreen    {        private static String LABEL_X = " x ";               /**         * Creates a new BitmapScalingDemoScreen object         */        BitmapScalingDemoScreen()        {            setTitle("Bitmap Scaling Demo");                                    // Create a Bitmap from a project resource            Bitmap bitmapOrig = Bitmap.getBitmapResource("rim.png");                                  // Create a Bitmap of arbitrary size            int scaledX = 175;            int scaledY = 50;            Bitmap bitmapScaled = new Bitmap(scaledX, scaledY);                       // Scale the original Bitmap into the new Bitmap using            // a Lanczos filter.                       bitmapOrig.scaleInto(bitmapScaled, Bitmap.FILTER_LANCZOS);                                             // Display the original Bitmap on the screen            BitmapField bitmapFieldOrig = new BitmapField(bitmapOrig, Field.FOCUSABLE);            StringBuffer strBuff = new StringBuffer("Original - ");            strBuff.append(bitmapOrig.getWidth());            strBuff.append(LABEL_X);            strBuff.append(bitmapOrig.getHeight());                       add(new LabelField(strBuff.toString()));            add(bitmapFieldOrig);                       add(new SeparatorField());                       // Display the scaled Bitmap on the screen            BitmapField bitmapFieldScaled1 = new BitmapField(bitmapScaled, Field.FOCUSABLE);            strBuff.delete(0, strBuff.length());            strBuff.append("/nScaled - ");            strBuff.append(bitmapScaled.getWidth());            strBuff.append(LABEL_X);            strBuff.append(bitmapScaled.getHeight());            strBuff.append(" - FILTER_LANCZOS - Aspect ratio not preserved");            add(new LabelField(strBuff.toString()));            add(bitmapFieldScaled1);                       add(new SeparatorField());                       // Redefine the scaled Bitmap            bitmapScaled = new Bitmap(scaledX, scaledY);                                  // Scale the original Bitmap into the new Bitmap using            // a bilinear filter and maintaining aspect ratio.                       bitmapOrig.scaleInto(bitmapScaled, Bitmap.FILTER_BILINEAR, Bitmap.SCALE_TO_FILL);                                             // Display the newly scaled Bitmap on the screen                       BitmapField bitmapFieldScaled2 = new BitmapField(bitmapScaled, Field.FOCUSABLE);            strBuff.delete(0, strBuff.length());            strBuff.append("/nScaled - ");            strBuff.append(bitmapScaled.getWidth());            strBuff.append(LABEL_X);            strBuff.append(bitmapScaled.getHeight());            strBuff.append(" - FILTER_BILINEAR - Aspect ratio preserved");                      add(new LabelField(strBuff.toString()));            add(bitmapFieldScaled2);                       add(new SeparatorField());                                // Redefine the scaled Bitmap            bitmapScaled = new Bitmap(scaledX, scaledY);                       // Calculate fragment dimensions                     int fragmentWidth = bitmapOrig.getWidth() >> 1; // >> 1 equivalent to / 2                       int fragmentHeight = bitmapOrig.getHeight() >> 1; // >> 1 equivalent to / 2                       // Scale a fragment of the original Bitmap into the new Bitmap            // using a box filter.            bitmapOrig.scaleInto(0, 0, fragmentWidth, fragmentHeight, bitmapScaled, 0, 0, bitmapScaled.getWidth(), bitmapScaled.getHeight(), Bitmap.FILTER_BOX);                       // Display the newly scaled Bitmap on the screen                       BitmapField bitmapFieldScaled3 = new BitmapField(bitmapScaled, Field.FOCUSABLE);                       strBuff.delete(0, strBuff.length());            strBuff.append("/nScaled fragment ");            strBuff.append(fragmentWidth);            strBuff.append(LABEL_X);            strBuff.append(fragmentHeight);            strBuff.append(" into ");            strBuff.append(bitmapScaled.getWidth());            strBuff.append(LABEL_X);            strBuff.append(bitmapScaled.getHeight());            strBuff.append(" - FILTER_BOX");                                 add(new LabelField(strBuff.toString()));            add(bitmapFieldScaled3);        }           }}