如何调整Android中的位图大小？-Java 学习之路

276

我从远程数据库中获取了一个Base64字符串的位图，（ encodedImage 是用Base64表示图像的字符串）：

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

好的，但是我必须在我的 ImageView 布局上显示之前调整此图像的大小 . 我必须将其调整为120x120 .

有人能告诉我调整大小的代码吗？

我找到的示例无法应用于base64字符串获取的位图 .

13 回答

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;
    }

回复于 2024-04-28T17:27:15+08:00

profileImage.setImageBitmap(
    Bitmap.createScaledBitmap(
        BitmapFactory.decodeByteArray(imageAsBytes, 0, imageAsBytes.length), 
        80, 80, false
    )
);

回复于 2024-04-28T17:27:15+08:00

在这种情况下有人问如何保持纵横比：

计算用于缩放的因子，并将其用于两个维度 . 假设您希望图像的高度为屏幕的20％

int scaleToUse = 20; // this will be our percentage
Bitmap bmp = BitmapFactory.decodeResource(
    context.getResources(), R.drawable.mypng);
int sizeY = screenResolution.y * scaleToUse / 100;
int sizeX = bmp.getWidth() * sizeY / bmp.getHeight();
Bitmap scaled = Bitmap.createScaledBitmap(bmp, sizeX, sizeY, false);

获得屏幕分辨率，你有这个解决方案：Get screen dimensions in pixels

回复于 2024-04-28T17:27:15+08:00

public Bitmap scaleBitmap(Bitmap mBitmap) {
        int ScaleSize = 250;//max Height or width to Scale
        int width = mBitmap.getWidth();
        int height = mBitmap.getHeight();
        float excessSizeRatio = width > height ? width / ScaleSize : height / ScaleSize;
         Bitmap bitmap = Bitmap.createBitmap(
                mBitmap, 0, 0,(int) (width/excessSizeRatio),(int) (height/excessSizeRatio));
        //mBitmap.recycle(); if you are not using mBitmap Obj
        return bitmap;
    }

回复于 2024-04-28T17:27:15+08:00

public Bitmap getResizedBitmap(Bitmap bm, int newWidth, int newHeight) {
    int width = bm.getWidth();
    int height = bm.getHeight();
    float scaleWidth = ((float) newWidth) / width;
    float scaleHeight = ((float) newHeight) / height;
    // CREATE A MATRIX FOR THE MANIPULATION
    Matrix matrix = new Matrix();
    // RESIZE THE BIT MAP
    matrix.postScale(scaleWidth, scaleHeight);

    // "RECREATE" THE NEW BITMAP
    Bitmap resizedBitmap = Bitmap.createBitmap(
        bm, 0, 0, width, height, matrix, false);
    bm.recycle();
    return resizedBitmap;
}

编辑：正如@aveschini所建议的那样，我已经为内存泄漏添加了 bm.recycle(); . 请注意，如果您将上一个对象用于其他目的，请相应处理 .

回复于 2024-04-28T17:27:15+08:00

位图根据任何显示大小调整大小

public Bitmap bitmapResize(Bitmap imageBitmap) {

    Bitmap bitmap = imageBitmap;
    float heightbmp = bitmap.getHeight();
    float widthbmp = bitmap.getWidth();

    // Get Screen width
    DisplayMetrics displaymetrics = new DisplayMetrics();
    this.getWindowManager().getDefaultDisplay().getMetrics(displaymetrics);
    float height = displaymetrics.heightPixels / 3;
    float width = displaymetrics.widthPixels / 3;

    int convertHeight = (int) hight, convertWidth = (int) width;

    // higher
    if (heightbmp > height) {
        convertHeight = (int) height - 20;
        bitmap = Bitmap.createScaledBitmap(bitmap, convertWidth,
                convertHighet, true);
    }

    // wider
    if (widthbmp > width) {
        convertWidth = (int) width - 20;
        bitmap = Bitmap.createScaledBitmap(bitmap, convertWidth,
                convertHeight, true);
    }

    return bitmap;
}

回复于 2024-04-28T17:27:15+08:00

471

如果您已有位图，则可以使用以下代码调整大小：

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

回复于 2024-04-28T17:27:15+08:00

101

从API 19开始，存在Bitmap setWidth（int width）和setHeight（int height） . http://developer.android.com/reference/android/graphics/Bitmap.html

回复于 2024-04-28T17:27:15+08:00

使用目标最大大小和宽度缩放位图，同时保持纵横比：

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);

回复于 2024-04-28T17:27:15+08:00

基于 aspect ratio 的比例：

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

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

使用height作为宽度的基本intead更改为：

int height = 480;
int width = Math.round(height * aspectRatio);

回复于 2024-04-28T17:27:15+08:00

试试这个：这个函数按比例调整位图大小 . 当最后一个参数设置为"X"时， newDimensionXorY 被视为s新宽度，当设置为"Y"时为新高度 .

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;
}

回复于 2024-04-28T17:27:15+08:00

更改：

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

至：

Bitmap b = BitmapFactory.decodeByteArray(imageAsBytes, 0, imageAsBytes.length)
profileImage.setImageBitmap(Bitmap.createScaledBitmap(b, 120, 120, false));

回复于 2024-04-28T17:27:15+08:00

252

试试这个代码：

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

我希望它有用 .

回复于 2024-04-28T17:27:15+08:00

如何调整Android中的位图大小？

13 回答

位图根据任何显示大小调整大小

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