Android 圖片操作，Image實戰

平時有很多時候會涉及到圖片的操作，如獲取縮圖，裁剪圖片，旋轉圖片，獲取尺寸，改變大學，drawable與bitmap相互轉換等問題。本文給打擊總結一些常用的操作，比較基礎但是實用。

一，drawable與bitmap相互轉換

drawable資源轉換為bitmap物件

/**
     * 將已有的drawable資源轉換為bitmap物件
     */
    public static Bitmap drawableToBitamp(Drawable drawable)
    {
        BitmapDrawable bd = (BitmapDrawable) drawable;
        Bitmap bitmap = bd.getBitmap();
        return bitmap;
    }

或者

/**
     * 將已有的drawable資源轉換為bitmap物件,方式二
     */
    public static Bitmap drawable2Bitamp(Drawable drawable)
    {
        int w = drawable.getIntrinsicWidth();
        int h = drawable.getIntrinsicHeight();
        //System.out.println("Drawable轉Bitmap");
        Bitmap.Config config =
                drawable.getOpacity() != PixelFormat.OPAQUE ? Bitmap.Config.ARGB_8888
                        : Bitmap.Config.RGB_565;
        Bitmap bitmap = Bitmap.createBitmap(w,h,config);
        //注意，下面三行程式碼要用到，否在在View或者surfaceview裡的canvas.drawBitmap會看不到圖
        Canvas canvas = new Canvas(bitmap);
        drawable.setBounds(0, 0, w, h);
        drawable.draw(canvas);
        return bitmap;
    }

Bitmap轉化為drawable

/** 
     * Bitmap轉化為drawable 
     */  
    public static Drawable bitmap2Drawable(Bitmap bitmap) {  
        return new BitmapDrawable(bitmap);  
    }  

二，縮放圖片到指定的大小

 //圖片縮放到指定的寬高
    public static Bitmap zoomBitmap(Bitmap bitmap, int width, int height) {
        int w = bitmap.getWidth();
        int h = bitmap.getHeight();
        Matrix matrix = new Matrix();
        float scaleWidth = ((float) width / w);
        float scaleHeight = ((float) height / h);
        matrix.postScale(scaleWidth, scaleHeight);
        Bitmap newbmp = Bitmap.createBitmap(bitmap, 0, 0, w, h, matrix, true);
        return newbmp;
    }

三，儲存bitmap到本地

    //將bitmap儲存到sdcard中
    public static File saveBitmapToSDCard(Bitmap photoBitmap,String path,String photoName){
        if (FileUtils.isSDCardAvailable()) {
            File dir = new File(path);
            if (!dir.exists()){
                dir.mkdirs();
            }
            File photoFile = new File(path , photoName + ".jpg");
            FileOutputStream fileOutputStream = null;
            try {
                fileOutputStream = new FileOutputStream(photoFile);
                if (photoBitmap != null) {
                    if (photoBitmap.compress(Bitmap.CompressFormat.JPEG, 100, fileOutputStream)) {
                        fileOutputStream.flush();
                        //fileOutputStream.close();
                        return photoFile;
                    }
                }
            } catch (FileNotFoundException e) {
                photoFile.delete();
                e.printStackTrace();
            } catch (Exception e) {
                photoFile.delete();
                e.printStackTrace();
            } finally{
                try {
                    if (fileOutputStream!=null)
                    fileOutputStream.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }
        return null;
    }

四，把bitmap轉換成String

 /**
     * 把bitmap轉換成String
     */
    public static String bitmapToString(String filePath) {
        Bitmap bm = getSmallBitmap(filePath);
        ByteArrayOutputStream baos = new ByteArrayOutputStream();
        bm.compress(Bitmap.CompressFormat.JPEG, 40, baos);
        byte[] b = baos.toByteArray();
        return Base64.encodeToString(b, Base64.DEFAULT);
    }

五，計算圖片的縮放值

    /**
     * 計算圖片的縮放值
     * @return
     */
    public static int calculateInSampleSize(BitmapFactory.Options options,
            int reqWidth, int reqHeight) {
        final int height = options.outHeight;
        final int width = options.outWidth;
        int inSampleSize = 1;
        if (height > reqHeight || width > reqWidth) {
            // Calculate ratios of height and width to requested height andwidth
            final int heightRatio = Math.round((float) height / (float) reqHeight);
            final int widthRatio = Math.round((float) width / (float) reqWidth);
            // Choose the smallest ratio as inSampleSize value, this will guarantee
            // a final image with both dimensions larger than or equal to the requested height and width.
            inSampleSize = heightRatio < widthRatio ? heightRatio : widthRatio;
        }
        return inSampleSize;
    }

六，根據路徑獲得圖片並返回壓縮的bitmap

    /**
     * 根據路徑獲得圖片並壓縮，返回bitmap用於顯示
     */
    public static Bitmap getSmallBitmap(String filePath) {
        final BitmapFactory.Options options = new BitmapFactory.Options();
        options.inJustDecodeBounds = true;
        BitmapFactory.decodeFile(filePath, options);
        // Calculate inSampleSize
        options.inSampleSize = calculateInSampleSize(options, 480, 800);
        // Decode bitmap with inSampleSize set
        options.inJustDecodeBounds = false;
        return BitmapFactory.decodeFile(filePath, options);
    }

七，判斷照片角度

    /**
     * 判斷照片角度
     * @param path
     * @return
     */
    public static int readPictureDegree(String path) {
        int degree = 0;
        try {
            ExifInterface exifInterface = new ExifInterface(path);
            int orientation = exifInterface.getAttributeInt(
                    ExifInterface.TAG_ORIENTATION,
                    ExifInterface.ORIENTATION_NORMAL);
            switch (orientation) {
                case ExifInterface.ORIENTATION_ROTATE_90:
                    degree = 90;
                    break;
                case ExifInterface.ORIENTATION_ROTATE_180:
                    degree = 180;
                    break;
                case ExifInterface.ORIENTATION_ROTATE_270:
                    degree = 270;
                    break;
            }
        } catch (IOException e) {
            e.printStackTrace();
        }
        return degree;
    }

八，旋轉照片

    /**
     * 旋轉照片
     * @param bitmap
     * @param degress
     * @return
     */
    public static Bitmap rotateBitmap(Bitmap bitmap,int degress) {
        if (bitmap != null) {
            Matrix m = new Matrix();
            m.postRotate(degress);
            bitmap = Bitmap.createBitmap(bitmap, 0, 0, bitmap.getWidth(),
                    bitmap.getHeight(), m, true);
            return bitmap;
        }
        return bitmap;
    }

九，處理手機相片的角度旋轉

 /**
     * 壓縮圖片，處理某些手機拍照角度旋轉的問題
     */
    public static String compressImage(String filePath, String targetPath, int quality)  {
        Bitmap bm = getSmallBitmap(filePath);
        int degree = readPictureDegree(filePath);
        if(degree!=0){//旋轉照片角度
            bm=rotateBitmap(bm,degree);
        }
        File outputFile=new File(targetPath);
        try {
            if (!outputFile.exists()) {
                outputFile.getParentFile().mkdirs();
                outputFile.createNewFile();
            }else{
                outputFile.delete();
            }
            FileOutputStream out = new FileOutputStream(outputFile);
            bm.compress(Bitmap.CompressFormat.JPEG, quality, out);
        }catch (Exception e){
            LogUtils.debug(TAG,"compressImage error"+e.toString());
        }
        return outputFile.getPath();
    }

未完待續，歡迎交流，杜乾，Dusan，Q 291902259。