Android：實用的圖片處理(壓縮、旋轉、放大或縮小、圖片上印字、加水印、圖片驗證碼)

這些天一直爲android程序如何壓縮圖片煩惱，上網找了不少資料，整理了一下，通過測試，都是可用的，

/** 
     * 壓縮圖片 
     * @param bitmap 源圖片 
     * @param width 想要的寬度 
     * @param height 想要的高度 
     * @param isAdjust 是否自動調整尺寸, true圖片就不會拉伸，false嚴格按照你的尺寸壓縮 
     * @return Bitmap 
     */  
    public Bitmap reduce(Bitmap bitmap, int width, int height, boolean isAdjust) {  
        // 若是想要的寬度和高度都比源圖片小，就不壓縮了，直接返回原圖  
        if (bitmap.getWidth() < width && bitmap.getHeight() < height) {return bitmap;}  
        // 根據想要的尺寸精確計算壓縮比例, 方法詳解：public BigDecimal divide(BigDecimal divisor, int scale, int roundingMode);  
        // scale表示要保留的小數位, roundingMode表示如何處理多餘的小數位，BigDecimal.ROUND_DOWN表示自動捨棄  
        float sx = new BigDecimal(width).divide(new BigDecimal(bitmap.getWidth()), 4, BigDecimal.ROUND_DOWN).floatValue();  
        float sy = new BigDecimal(height).divide(new BigDecimal(bitmap.getHeight()), 4, BigDecimal.ROUND_DOWN).floatValue();  
        if (isAdjust) {// 若是想自動調整比例，不至於圖片會拉伸  
            sx = (sx < sy ? sx : sy);sy = sx;// 哪一個比例小一點，就用哪一個比例  
        }  
        Matrix matrix = new Matrix();  
        matrix.postScale(sx, sy);// 調用api中的方法進行壓縮，就大功告成了  
        return Bitmap.createBitmap(bitmap, 0, 0, bitmap.getWidth(), bitmap.getHeight(), matrix, true);

旋轉圖片：

/** 
     * 旋轉圖片 
     * @param bitmap 源圖片 
     * @param angle 旋轉角度(90爲順時針旋轉,-90爲逆時針旋轉) 
     * @return Bitmap 
     */  
    public Bitmap rotate(Bitmap bitmap, float angle) {  
        Matrix matrix = new Matrix();    
        matrix.postRotate(angle);  
        return Bitmap.createBitmap(bitmap, 0, 0, bitmap.getWidth(), bitmap.getHeight(), matrix, true);  
    }

放大或縮小圖片：

/** 
     * 放大或縮小圖片 
     * @param bitmap 源圖片 
     * @param ratio 放大或縮小的倍數，大於1表示放大，小於1表示縮小 
     * @return Bitmap 
     */  
    public Bitmap zoom(Bitmap bitmap, float ratio) {  
        if (ratio < 0f) {return bitmap;}  
        Matrix matrix = new Matrix();  
        matrix.postScale(ratio, ratio);  
        return Bitmap.createBitmap(bitmap, 0, 0, bitmap.getWidth(), bitmap.getHeight(), matrix, true);  
    }

在圖片上印字：

/** 
     * 在圖片上印字 
     * @param bitmap 源圖片 
     * @param text 印上去的字 
     * @param param 字體參數分別爲：顏色,大小,是否加粗,起點x,起點y; 好比：{color : 0xFF000000, size : 30, bold : true, x : 20, y : 20} 
     * @return Bitmap 
     */  
    public Bitmap printWord(Bitmap bitmap, String text, Map<String, Object> param) {  
        if (ToolUtil.get().isBlank(text) || null == param) {return bitmap;}  
        Bitmap newBitmap = Bitmap.createBitmap(bitmap.getWidth(), bitmap.getHeight(), Config.ARGB_8888);  
        Canvas canvas = new Canvas(newBitmap);  
        canvas.drawBitmap(bitmap, 0, 0, null);canvas.save(Canvas.ALL_SAVE_FLAG);canvas.restore();  
        Paint paint = new Paint();  
        paint.setColor(null != param.get("color") ? (Integer) param.get("color") : Color.BLACK);  
        paint.setTextSize(null != param.get("size") ? (Integer) param.get("size") : 20);  
        paint.setFakeBoldText(null != param.get("bold") ? (Boolean) param.get("bold") : false);  
        canvas.drawText(text, null != param.get("x") ? (Integer) param.get("x") : 0, null != param.get("y") ? (Integer) param.get("y") : 0, paint);  
        canvas.save(Canvas.ALL_SAVE_FLAG);canvas.restore();  
        return newBitmap;  
    }

建立logo(給圖片加水印), ：

/** 
     * 建立logo(給圖片加水印),  
     * @param bitmaps 原圖片和水印圖片 
     * @param left 左邊起點座標 
     * @param top 頂部起點座標t 
     * @return Bitmap 
     */  
    public Bitmap createLogo(Bitmap[] bitmaps, int left, int top) {  
        Bitmap newBitmap = Bitmap.createBitmap(bitmaps[0].getWidth(), bitmaps[0].getHeight(), Config.ARGB_8888);  
        Canvas canvas = new Canvas(newBitmap);  
        for (int i = 0; i < bitmaps.length; i++) {  
            if (i == 0) {  
                canvas.drawBitmap(bitmaps[0], 0, 0, null);  
            } else {  
                canvas.drawBitmap(bitmaps[i], left, top, null);  
            }  
            canvas.save(Canvas.ALL_SAVE_FLAG);canvas.restore();  
        }  
        return newBitmap;  
    }

產生一個4位隨機數字的圖片驗證碼：

private int width = 140, height = 40, codeLen = 4;  
    private String checkCode = "";  
    private Random random = new Random();  
      
    /** 
     * 產生一個4位隨機數字的圖片驗證碼 
     * @return Bitmap 
     */  
    public Bitmap createCode() {  
        checkCode = "";  
        String[] chars = { "0", "1", "2", "3", "4", "5", "6", "7", "8", "9" };  
        for (int i = 0; i < codeLen; i++) {checkCode += chars[random.nextInt(chars.length)];}  
        Bitmap bitmap = Bitmap.createBitmap(width, height, Config.ARGB_8888);  
        Canvas canvas = new Canvas(bitmap);canvas.drawColor(Color.WHITE);  
        Paint paint = new Paint();paint.setTextSize(30);paint.setColor(Color.BLUE);  
        for (int i = 0; i < checkCode.length(); i++) {  
            paint.setColor(randomColor(1));paint.setFakeBoldText(random.nextBoolean());  
            float skewX = random.nextInt(11) / 10;  
            paint.setTextSkewX(random.nextBoolean() ? skewX : -skewX);  
            int x = width / codeLen * i + random.nextInt(10);  
            canvas.drawText(String.valueOf(checkCode.charAt(i)), x, 28, paint);  
        }  
        for (int i = 0; i < 3; i++) {drawLine(canvas, paint);}  
        for (int i = 0; i < 255; i++) {drawPoints(canvas, paint);}  
        canvas.save(Canvas.ALL_SAVE_FLAG);canvas.restore();  
        return bitmap;  
    }  
      
    /** 
     * 得到一個隨機的顏色 
     * @param rate 
     * @return  
     */  
    public int randomColor(int rate) {  
        int red = random.nextInt(256) / rate, green = random.nextInt(256) / rate, blue = random.nextInt(256) / rate;  
        return Color.rgb(red, green, blue);  
    }  
  
    /** 
     * 畫隨機線條 
     * @param canvas 
     * @param paint 
     */  
    public void drawLine(Canvas canvas, Paint paint) {  
        int startX = random.nextInt(width), startY = random.nextInt(height);  
        int stopX = random.nextInt(width), stopY = random.nextInt(height);  
        paint.setStrokeWidth(1);paint.setColor(randomColor(1));  
        canvas.drawLine(startX, startY, stopX, stopY, paint);  
    }  
  
    /** 
     * 畫隨機干擾點 
     * @param canvas 
     * @param paint 
     */  
    public void drawPoints(Canvas canvas, Paint paint) {  
        int stopX = random.nextInt(width), stopY = random.nextInt(height);  
        paint.setStrokeWidth(1);  
        paint.setColor(randomColor(1));  
        canvas.drawPoint(stopX, stopY, paint);  
    }  
      
    /** 
     * 返回真實驗證碼字符串 
     * @return String 
     */  
    public String getCheckCode() {  
        return checkCode;  
    }