How to Resize a Bitmap in Android?

2018-12-31 05:52发布

I have a bitmap taken of a Base64 String from my remote database, (encodedImage is the string representing the image with Base64):

profileImage = (ImageView)findViewById(R.id.profileImage);

byte[] imageAsBytes=null;
try {
    imageAsBytes = Base64.decode(encodedImage.getBytes());
} catch (IOException e) {e.printStackTrace();}

profileImage.setImageBitmap(
    BitmapFactory.decodeByteArray(imageAsBytes, 0, imageAsBytes.length)
);

profileImage is my ImageView

Ok, but I have to resize this image before showing it on my ImageView of my layout. I have to resize it to 120x120.

Can someone tell me the code to resize it?

The examples I found could not be applied to a base64 string obtained bitmap.

13条回答
十年一品温如言
2楼-- · 2018-12-31 06:13

Scale based on aspect ratio:

float aspectRatio = yourSelectedImage.getWidth() / 
    (float) yourSelectedImage.getHeight();
int width = 480;
int height = Math.round(width / aspectRatio);

yourSelectedImage = Bitmap.createScaledBitmap(
    yourSelectedImage, width, height, false);

To use height as base intead of width change to:

int height = 480;
int width = Math.round(height * aspectRatio);
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琉璃瓶的回忆
3楼-- · 2018-12-31 06:13

Scale a bitmap with a target maximum size and width, while maintaining aspect ratio:

int maxHeight = 2000;
int maxWidth = 2000;    
float scale = Math.min(((float)maxHeight / bitmap.getWidth()), ((float)maxWidth / bitmap.getHeight()));

Matrix matrix = new Matrix();
matrix.postScale(scale, scale);

bitmap = Bitmap.createBitmap(bitmap, 0, 0, bitmap.getWidth(), bitmap.getHeight(), matrix, true);
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深知你不懂我心
4楼-- · 2018-12-31 06:15

try this this code :

BitmapDrawable drawable = (BitmapDrawable) imgview.getDrawable();
Bitmap bmp = drawable.getBitmap();
Bitmap b = Bitmap.createScaledBitmap(bmp, 120, 120, false);

I hope it's useful.

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与君花间醉酒
5楼-- · 2018-12-31 06:18

Try this: This function resizes a bitmap proportionally. When the last parameter is set to "X" the newDimensionXorY is treated as s new width and when set to "Y" a new height.

public Bitmap getProportionalBitmap(Bitmap bitmap, 
                                    int newDimensionXorY, 
                                    String XorY) {
    if (bitmap == null) {
        return null;
    }

    float xyRatio = 0;
    int newWidth = 0;
    int newHeight = 0;

    if (XorY.toLowerCase().equals("x")) {
        xyRatio = (float) newDimensionXorY / bitmap.getWidth();
        newHeight = (int) (bitmap.getHeight() * xyRatio);
        bitmap = Bitmap.createScaledBitmap(
            bitmap, newDimensionXorY, newHeight, true);
    } else if (XorY.toLowerCase().equals("y")) {
        xyRatio = (float) newDimensionXorY / bitmap.getHeight();
        newWidth = (int) (bitmap.getWidth() * xyRatio);
        bitmap = Bitmap.createScaledBitmap(
            bitmap, newWidth, newDimensionXorY, true);
    }
    return bitmap;
}
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梦醉为红颜
6楼-- · 2018-12-31 06:26
public static Bitmap resizeBitmapByScale(
            Bitmap bitmap, float scale, boolean recycle) {
        int width = Math.round(bitmap.getWidth() * scale);
        int height = Math.round(bitmap.getHeight() * scale);
        if (width == bitmap.getWidth()
                && height == bitmap.getHeight()) return bitmap;
        Bitmap target = Bitmap.createBitmap(width, height, getConfig(bitmap));
        Canvas canvas = new Canvas(target);
        canvas.scale(scale, scale);
        Paint paint = new Paint(Paint.FILTER_BITMAP_FLAG | Paint.DITHER_FLAG);
        canvas.drawBitmap(bitmap, 0, 0, paint);
        if (recycle) bitmap.recycle();
        return target;
    }
    private static Bitmap.Config getConfig(Bitmap bitmap) {
        Bitmap.Config config = bitmap.getConfig();
        if (config == null) {
            config = Bitmap.Config.ARGB_8888;
        }
        return config;
    }
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裙下三千臣
7楼-- · 2018-12-31 06:27

If you already have a bitmap, you could use the following code to resize:

Bitmap originalBitmap = <original initialization>;
Bitmap resizedBitmap = Bitmap.createScaledBitmap(
    originalBitmap, newWidth, newHeight, false);
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