保存在ImageView中时，从自定义相机拍摄的图像会拉伸 [英] Taking image from custom camera is stretched when save in ImageView

问题描述

我正在使用此代码将图片保存在Imageview中，但是在imageview中进行dsave时会拉伸图像.相机预览是完美的，然后单击右图像，但是当我在imageview中设置该图像时，该图像将被拉伸.

I am using this code to save pic in Imageview but the image is stretched when dsave in imageview. Camera preview is prefect and click right image but when i set that image in imageview the image is stetched.

    public void onPicTaken(byte[] data) {

    if (data != null) {
        int screenWidth = getResources().getDisplayMetrics().widthPixels;
        int screenHeight = getResources().getDisplayMetrics().heightPixels;
        Bitmap bm = BitmapFactory.decodeByteArray(data, 0, (data != null) ? data.length : 0);

        if (getResources().getConfiguration().orientation == Configuration.ORIENTATION_PORTRAIT) {
            // Notice that width and height are reversed
            Bitmap scaled = Bitmap.createScaledBitmap(bm, screenHeight, screenWidth, true);
            int w = scaled.getWidth();
            int h = scaled.getHeight();
            // Setting post rotate to 90
            Matrix mtx = new Matrix();
            mtx.postRotate(90);
            // Rotating Bitmap
            bm = Bitmap.createBitmap(scaled, 0, 0, w, h, mtx, true);
        }else{// LANDSCAPE MODE
            //No need to reverse width and height
            Bitmap scaled = Bitmap.createScaledBitmap(bm, screenWidth,screenHeight , true);
            bm=scaled;
        }
        ivCaptureImagePreview.setImageBitmap(bm);
        ivCaptureImagePreview.setVisibility(View.VISIBLE);
    }

}

推荐答案

使用以下类来创建缩放的位图

Use following class for creating scaled bitmap

public class ScalingUtilities 
{
     /**
     * Utility function for decoding an image resource. The decoded bitmap will
     * be optimized for further scaling to the requested destination dimensions
     * and scaling logic.
     *
     * @param res The resources object containing the image data
     * @param resId The resource id of the image data
     * @param dstWidth Width of destination area
     * @param dstHeight Height of destination area
     * @param scalingLogic Logic to use to avoid image stretching
     * @return Decoded bitmap
     */
    public static Bitmap decodeResource(Resources res, int resId, int dstWidth, int dstHeight,
            ScalingLogic scalingLogic) {
        Options options = new Options();
        options.inJustDecodeBounds = true;
        BitmapFactory.decodeResource(res, resId, options);
        options.inJustDecodeBounds = false;
        options.inSampleSize = calculateSampleSize(options.outWidth, options.outHeight, dstWidth,
                dstHeight, scalingLogic);
        Bitmap unscaledBitmap = BitmapFactory.decodeResource(res, resId, options);

        return unscaledBitmap;
    }

    /**
     * Utility function for creating a scaled version of an existing bitmap
     *
     * @param unscaledBitmap Bitmap to scale
     * @param dstWidth Wanted width of destination bitmap
     * @param dstHeight Wanted height of destination bitmap
     * @param scalingLogic Logic to use to avoid image stretching
     * @return New scaled bitmap object
     */
    public static Bitmap createScaledBitmap(Bitmap unscaledBitmap, int dstWidth, int dstHeight,
            ScalingLogic scalingLogic) {
        Rect srcRect = calculateSrcRect(unscaledBitmap.getWidth(), unscaledBitmap.getHeight(),
                dstWidth, dstHeight, scalingLogic);
        Rect dstRect = calculateDstRect(unscaledBitmap.getWidth(), unscaledBitmap.getHeight(),
                dstWidth, dstHeight, scalingLogic);
        Bitmap scaledBitmap = Bitmap.createBitmap(dstRect.width(), dstRect.height(),
                Config.ARGB_8888);
        Canvas canvas = new Canvas(scaledBitmap);
        canvas.drawBitmap(unscaledBitmap, srcRect, dstRect, new Paint(Paint.FILTER_BITMAP_FLAG));

        return scaledBitmap;
    }

    /**
     * ScalingLogic defines how scaling should be carried out if source and
     * destination image has different aspect ratio.
     *
     * CROP: Scales the image the minimum amount while making sure that at least
     * one of the two dimensions fit inside the requested destination area.
     * Parts of the source image will be cropped to realize this.
     *
     * FIT: Scales the image the minimum amount while making sure both
     * dimensions fit inside the requested destination area. The resulting
     * destination dimensions might be adjusted to a smaller size than
     * requested.
     */
    public static enum ScalingLogic {
        CROP, FIT
    }

    /**
     * Calculate optimal down-sampling factor given the dimensions of a source
     * image, the dimensions of a destination area and a scaling logic.
     *
     * @param srcWidth Width of source image
     * @param srcHeight Height of source image
     * @param dstWidth Width of destination area
     * @param dstHeight Height of destination area
     * @param scalingLogic Logic to use to avoid image stretching
     * @return Optimal down scaling sample size for decoding
     */
    public static int calculateSampleSize(int srcWidth, int srcHeight, int dstWidth, int dstHeight,
            ScalingLogic scalingLogic) {
        if (scalingLogic == ScalingLogic.FIT) {
            final float srcAspect = (float)srcWidth / (float)srcHeight;
            final float dstAspect = (float)dstWidth / (float)dstHeight;

            if (srcAspect > dstAspect) {
                return srcWidth / dstWidth;
            } else {
                return srcHeight / dstHeight;
            }
        } else {
            final float srcAspect = (float)srcWidth / (float)srcHeight;
            final float dstAspect = (float)dstWidth / (float)dstHeight;

            if (srcAspect > dstAspect) {
                return srcHeight / dstHeight;
            } else {
                return srcWidth / dstWidth;
            }
        }
    }

    /**
     * Calculates source rectangle for scaling bitmap
     *
     * @param srcWidth Width of source image
     * @param srcHeight Height of source image
     * @param dstWidth Width of destination area
     * @param dstHeight Height of destination area
     * @param scalingLogic Logic to use to avoid image stretching
     * @return Optimal source rectangle
     */
    public static Rect calculateSrcRect(int srcWidth, int srcHeight, int dstWidth, int dstHeight,
            ScalingLogic scalingLogic) {
        if (scalingLogic == ScalingLogic.CROP) {
            final float srcAspect = (float)srcWidth / (float)srcHeight;
            final float dstAspect = (float)dstWidth / (float)dstHeight;

            if (srcAspect > dstAspect) {
                final int srcRectWidth = (int)(srcHeight * dstAspect);
                final int srcRectLeft = (srcWidth - srcRectWidth) / 2;
                return new Rect(srcRectLeft, 0, srcRectLeft + srcRectWidth, srcHeight);
            } else {
                final int srcRectHeight = (int)(srcWidth / dstAspect);
                final int scrRectTop = (int)(srcHeight - srcRectHeight) / 2;
                return new Rect(0, scrRectTop, srcWidth, scrRectTop + srcRectHeight);
            }
        } else {
            return new Rect(0, 0, srcWidth, srcHeight);
        }
    }

    /**
     * Calculates destination rectangle for scaling bitmap
     *
     * @param srcWidth Width of source image
     * @param srcHeight Height of source image
     * @param dstWidth Width of destination area
     * @param dstHeight Height of destination area
     * @param scalingLogic Logic to use to avoid image stretching
     * @return Optimal destination rectangle
     */
    public static Rect calculateDstRect(int srcWidth, int srcHeight, int dstWidth, int dstHeight,
            ScalingLogic scalingLogic) {
        if (scalingLogic == ScalingLogic.FIT) {
            final float srcAspect = (float)srcWidth / (float)srcHeight;
            final float dstAspect = (float)dstWidth / (float)dstHeight;

            if (srcAspect > dstAspect) {
                return new Rect(0, 0, dstWidth, (int)(dstWidth / srcAspect));
            } else {
                return new Rect(0, 0, (int)(dstHeight * srcAspect), dstHeight);
            }
        } else {
            return new Rect(0, 0, dstWidth, dstHeight);
        }
    }


}

并在下面的函数中使用此类

and use this class in your function as below

public void onPicTaken(byte[] data) {

    if (data != null) {
        int screenWidth = getResources().getDisplayMetrics().widthPixels;
        int screenHeight = getResources().getDisplayMetrics().heightPixels;
        Bitmap bm = BitmapFactory.decodeByteArray(data, 0, (data != null) ? data.length : 0);

        if (getResources().getConfiguration().orientation == Configuration.ORIENTATION_PORTRAIT) {
            // Notice that width and height are reversed
            Bitmap scaled = ScalingUtilities.createScaledBitmap(bm, screenHeight, screenWidth, ScalingLogic.FIT);
            int w = scaled.getWidth();
            int h = scaled.getHeight();
            // Setting post rotate to 90
            Matrix mtx = new Matrix();
            mtx.postRotate(90);
            // Rotating Bitmap
            bm = Bitmap.createBitmap(scaled, 0, 0, w, h, mtx, true);
        }else{// LANDSCAPE MODE
            //No need to reverse width and height
            Bitmap scaled = ScalingUtilities.createScaledBitmap(bm, screenHeight, screenWidth, ScalingLogic.FIT);
            bm=scaled;
        }
        ivCaptureImagePreview.setImageBitmap(bm);
        ivCaptureImagePreview.setVisibility(View.VISIBLE);
    }

}

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