android– 如何在上传到服务器之前减少图像文件大小

概述许多应用程序允许共享从图库中挑选的图像.他们上传原始图片文件吗？这是1-3MB？或者他们处理？在任何情况下,我如何从文件路径中获取图像,通过降低分辨率来减小其大小,并将其保存在其他地方并尝试上传？我试过了：Bitmapphoto=decodeSampledBitmapFromFile(filePath,DESIRED_WIDTH,

许多应用程序允许共享从图库中挑选的图像.

他们上传原始图片文件吗？这是1-3 MB？或者他们处理？

在任何情况下,我如何从文件路径中获取图像,通过降低分辨率来减小其大小,并将其保存在其他地方并尝试上传？

我试过了：

Bitmap photo = decodeSampledBitmapFromfile(filePath, DESIRED_WIDTH,                    DESIRED_HEIGHT);fileOutputStream out = new fileOutputStream(filePath);photo.compress(Bitmap.CompressFormat.JPEG, 100, out);public static Bitmap decodeSampledBitmapFromfile(String path, int reqWIDth,        int reqHeight) {    final BitmapFactory.Options options = new BitmapFactory.Options();    options.inJustDecodeBounds = true;    BitmapFactory.decodefile(path, options);    final int height = options.outHeight;    final int wIDth = options.outWIDth;    options.inPreferredConfig = Bitmap.Config.ARGB_8888;    int inSampleSize = 1;    if (height > reqHeight) {        inSampleSize = Math.round((float) height / (float) reqHeight);    }    int expecteDWIDth = wIDth / inSampleSize;    if (expecteDWIDth > reqWIDth) {        inSampleSize = Math.round((float) wIDth / (float) reqWIDth);    }    options.inSampleSize = inSampleSize;    options.inJustDecodeBounds = false;    return BitmapFactory.decodefile(path, options);}

但这是他们正确的方法吗？因为我看到的答案表明压缩 *** 作花费了相当多的时间here

解决方法:

这很有效试试这个

private String decodefile(String path,int DESIREDWIDTH, int DESIREDHEIGHT) {        String strMyImagePath = null;        Bitmap scaledBitmap = null;        try {            // Part 1: Decode image            Bitmap unscaledBitmap = ScalingUtilitIEs.decodefile(path, DESIREDWIDTH, DESIREDHEIGHT, ScalingLogic.FIT);            if (!(unscaledBitmap.getWIDth() <= DESIREDWIDTH && unscaledBitmap.getHeight() <= DESIREDHEIGHT)) {                // Part 2: Scale image                scaledBitmap = ScalingUtilitIEs.createScaledBitmap(unscaledBitmap, DESIREDWIDTH, DESIREDHEIGHT, ScalingLogic.FIT);            } else {                unscaledBitmap.recycle();                return path;            }            // Store to tmp file            String extr = Environment.getExternalStorageDirectory().toString();            file mFolder = new file(extr + "/TMMFolDER");            if (!mFolder.exists()) {                mFolder.mkdir();            }            String s = "tmp.png";            file f = new file(mFolder.getabsolutePath(), s);            strMyImagePath = f.getabsolutePath();            fileOutputStream fos = null;            try {                fos = new fileOutputStream(f);                scaledBitmap.compress(Bitmap.CompressFormat.JPEG, 75, fos);                fos.flush();                fos.close();            } catch (fileNotFoundException e) {                e.printstacktrace();            } catch (Exception e) {                e.printstacktrace();            }            scaledBitmap.recycle();        } catch (Throwable e) {        }        if (strMyImagePath == null) {            return path;        }        return strMyImagePath;    }

ScalingUtilitIEs.java

import androID.content.res.Resources;import androID.graphics.Bitmap;import androID.graphics.Bitmap.Config;import androID.graphics.BitmapFactory;import androID.graphics.BitmapFactory.Options;import androID.graphics.Canvas;import androID.graphics.Paint;import androID.graphics.Rect;/** * Class containing static utility methods for bitmap deCoding and scaling * * @author  */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;    }    public static Bitmap decodefile(String path, int dstWIDth, int dstHeight,            ScalingLogic scalingLogic) {        Options options = new Options();        options.inJustDecodeBounds = true;        BitmapFactory.decodefile(path, options);        options.inJustDecodeBounds = false;        options.inSampleSize = calculateSampleSize(options.outWIDth, options.outHeight, dstWIDth,                dstHeight, scalingLogic);        Bitmap unscaledBitmap = BitmapFactory.decodefile(path, 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);        }    }}

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