Scaled Bitmap Maintaining Aspect Ratio

Scaled Bitmap maintaining aspect ratio

What about this:

Bitmap background = Bitmap.createBitmap((int)width, (int)height, Config.ARGB_8888);

float originalWidth = originalImage.getWidth(); 
float originalHeight = originalImage.getHeight();

Canvas canvas = new Canvas(background);

float scale = width / originalWidth;

float xTranslation = 0.0f;
float yTranslation = (height - originalHeight * scale) / 2.0f;

Matrix transformation = new Matrix();
transformation.postTranslate(xTranslation, yTranslation);
transformation.preScale(scale, scale);

Paint paint = new Paint();
paint.setFilterBitmap(true);

canvas.drawBitmap(originalImage, transformation, paint);

return background;

I added a paint to filter the scaled bitmap.

Scale Bitmap maintaining aspect ratio and fitting both width and height

Based on Streets of Boston's answer, I made this method that scales and returns any Bitmap to a desired width and height, fitting both dimensions (no blank space!). It automatically adapts to more horizontal or more vertical images.

public Bitmap resizeBitmapFitXY(int width, int height, Bitmap bitmap){
    Bitmap background = Bitmap.createBitmap(width, height, Bitmap.Config.ARGB_8888);
    float originalWidth = bitmap.getWidth(), originalHeight = bitmap.getHeight();
    Canvas canvas = new Canvas(background);
    float scale, xTranslation = 0.0f, yTranslation = 0.0f;
    if (originalWidth > originalHeight) {
        scale = height/originalHeight;
        xTranslation = (width - originalWidth * scale)/2.0f;
    }
    else {
        scale = width / originalWidth;
        yTranslation = (height - originalHeight * scale)/2.0f;
    }
    Matrix transformation = new Matrix();
    transformation.postTranslate(xTranslation, yTranslation);
    transformation.preScale(scale, scale);
    Paint paint = new Paint();
    paint.setFilterBitmap(true);
    canvas.drawBitmap(bitmap, transformation, paint);
    return background;
}

Android resize bitmap keeping aspect ratio

You should try using a transformation matrix built for ScaleToFit.CENTER. For example:

Matrix m = new Matrix();
m.setRectToRect(new RectF(0, 0, b.getWidth(), b.getHeight()), new RectF(0, 0, reqWidth, reqHeight), Matrix.ScaleToFit.CENTER);
return Bitmap.createBitmap(b, 0, 0, b.getWidth(), b.getHeight(), m, true);

Scale bitmap to specific size, keeping aspect ratio and filling the rest with 0 alpha pixels

I managed to solve it using this function:

Bitmap resizeBitmap(Bitmap image, int destWidth, int destHeight) {
    Bitmap background = Bitmap.createBitmap(destWidth, destHeight, Bitmap.Config.ARGB_8888);
    float originalWidth = image.getWidth();
    float originalHeight = image.getHeight();
    Canvas canvas = new Canvas(background);

    float scaleX = (float) 1280 / originalWidth;
    float scaleY = (float) 720 / originalHeight;

    float xTranslation = 0.0f;
    float yTranslation = 0.0f;
    float scale = 1;

    if (scaleX < scaleY) { // Scale on X, translate on Y
        scale = scaleX;
        yTranslation = (destHeight - originalHeight * scale) / 2.0f;
    } else { // Scale on Y, translate on X
        scale = scaleY;
        xTranslation = (destWidth - originalWidth * scale) / 2.0f;
    }

    Matrix transformation = new Matrix();
    transformation.postTranslate(xTranslation, yTranslation);
    transformation.preScale(scale, scale);
    Paint paint = new Paint();
    paint.setFilterBitmap(true);
    canvas.drawBitmap(image, transformation, paint);
    return background;
}

Resizing a bitmap to a fixed value but without changing the aspect ratio

Try this, calculate the ratio and then rescale.

private Bitmap scaleBitmap(Bitmap bm) {
    int width = bm.getWidth();
    int height = bm.getHeight();

    Log.v("Pictures", "Width and height are " + width + "--" + height);

    if (width > height) {
        // landscape
        float ratio = (float) width / maxWidth;
        width = maxWidth;
        height = (int)(height / ratio);
    } else if (height > width) {
        // portrait
        float ratio = (float) height / maxHeight;
        height = maxHeight;
        width = (int)(width / ratio);
    } else {
        // square
        height = maxHeight;
        width = maxWidth;
    }

    Log.v("Pictures", "after scaling Width and height are " + width + "--" + height);

    bm = Bitmap.createScaledBitmap(bm, width, height, true);
    return bm;
}