Android实现对图片的缩放剪切旋转存储

Posted 2021-01-26 ming

一、问题描述

　　在开发中，当我们需要的有一张大图片同时还需要一些小图片时，我们只需要通过代码对此图片进行不同比例的缩放即可，这样大大节约资源，减小了安装包的尺寸 。除缩放外，我们还经常对图片进行其他操作如裁剪、旋转、存储等。

　　这样我们可以编写对于图片进行处理的通用组件，方便开发。下面就分享一下对图片进行处理的组件BitmapUtil，案例界面：

二、技术点描述

　　1、通过BitmapFactory取得Bitmap

Bitmap bm=BitmapFactory.decodeStream(InputStream is );

　　2、Bimap的createBitmap()方法

Bitmap newbm = Bitmap.createBitmap( Bitmap s, int x, int y, int w, int h, Matrix m, boolean f);

　　该方法可实现位图的缩放、裁剪、旋转操作

　　参数说明：

Bitmap s：要处理的原始位图

int x ,y：起始位置坐标

int w：要截的图的宽度

int h：要截的图的宽度

Matrix m 矩阵，主要是用于平面的缩放、平移、旋转

boolean f：是否保证等比

返回值：返回处理后的Bitmap

三、BitmapUtil组件

　　可实现对图片进行按比例缩放、图片按比例裁剪、圆形图片处理等方法，实现功能如下：

1、readBitmapById（）方法

/**
     * 通过资源id转化成Bitmap
     * @param context
     * @param resId
     * @return
     */
    public static Bitmap readBitmapById(Context context, int resId){
        BitmapFactory.Options opt = new BitmapFactory.Options();
        opt.inPreferredConfig = Bitmap.Config.RGB_565;
        opt.inPurgeable = true;
        opt.inInputShareable = true;
        InputStream is = context.getResources().openRawResource(resId);
        return BitmapFactory.decodeStream(is, null, opt);
    }

2、scaleImage()方法，实现按指定宽高缩放图片

　　执行效果如图：

/**
* 缩放图片
     * @param bm 要缩放图片
     * @param newWidth 宽度
     * @param newHeight 高度
     * @return处理后的图片
     */
    public static  Bitmap  scaleImage(Bitmap bm, int newWidth, int newHeight){
        if (bm == null){
            return null;
        }
        int width = bm.getWidth();
        int height = bm.getHeight();
        float scaleWidth = ((float) newWidth) / width;
        float scaleHeight = ((float) newHeight) / height;
        Matrix matrix = new Matrix();
        matrix.postScale(scaleWidth, scaleHeight);
        Bitmap newbm = Bitmap.createBitmap(bm, 0, 0, width, height, matrix,true);
        if (bm != null & !bm.isRecycled()){
            bm.recycle();//销毁原图片
            bm = null;
        }
        return newbm;
    }

3、imageCrop()方法

 执行效果如图：

/**
     * 按照一定的宽高比例裁剪图片
     * @param bitmap 要裁剪的图片
     * @param num1 长边的比例
     * @param num2 短边的比例
     * @param isRecycled是否回收原图片
     * @return 裁剪后的图片
     */
    public static Bitmap  imageCrop(Bitmap bitmap, int num1, int num2, boolean isRecycled){
        if (bitmap == null){
            return null;
        }
        int w = bitmap.getWidth(); // 得到图片的宽，高
        int h = bitmap.getHeight();
        int retX, retY;
        int nw, nh;
        if (w > h){
            if (h > w * num2 / num1){
                nw = w;
                nh = w * num2 / num1;
                retX = 0;
                retY = (h - nh) / 2;
            } else{
                nw = h * num1 / num2;
                nh = h;
                retX = (w - nw) / 2;
                retY = 0;
            }
        } else{
            if (w > h * num2 / num1){
                nh = h;
                nw = h * num2 / num1;
                retY = 0;
                retX = (w - nw) / 2;
            } else{
                nh = w * num1 / num2;
                nw = w;
                retY = (h - nh) / 2;
                retX = 0;}
        }
        Bitmap bmp = Bitmap.createBitmap(bitmap, retX, retY, nw, nh, null,false);
        if (isRecycled && bitmap != null && !bitmap.equals(bmp)&& !bitmap.isRecycled()){
            bitmap.recycle();//回收原图片
            bitmap = null;
        }
        return bmp;
    }

4、toRoundCorner()实现将图片转圆角

 　　执行效果如图：

 

/**
     *图片转圆角 
     * @param bitmap需要转的bitmap
     * @param pixels转圆角的弧度
     * @return 转圆角的bitmap
     */
    public static Bitmap toRoundCorner(Bitmap bitmap, int pixels)    {
        Bitmap output = Bitmap.createBitmap(bitmap.getWidth(),
                bitmap.getHeight(), Config.ARGB_8888);
        Canvas canvas = new Canvas(output);
        final int color = 0xff424242;
        final Paint paint = new Paint();
        final Rect rect = new Rect(0, 0, bitmap.getWidth(), bitmap.getHeight());
        final RectF rectF = new RectF(rect);
        final float roundPx = pixels;
        paint.setAntiAlias(true);
        canvas.drawARGB(0, 0, 0, 0);
        paint.setColor(color);
        canvas.drawRoundRect(rectF, roundPx, roundPx, paint);
        paint.setXfermode(new PorterDuffXfermode(Mode.SRC_IN));
        canvas.drawBitmap(bitmap, rect, rect, paint);
        if (bitmap != null && !bitmap.isRecycled())
        {
            bitmap.recycle();
        }
        return output;
    }

5、toRoundBitmap（）方法将图像裁剪成圆形

 　　执行效果如图：

public static Bitmap toRoundBitmap(Bitmap bitmap){
if (bitmap == null){
            return null;
        }
        int width = bitmap.getWidth();
        int height = bitmap.getHeight();
        float roundPx;
        float left, top, right, bottom, dst_left, dst_top, dst_right, dst_bottom;
        if (width <= height){
            roundPx = width / 2;
            top = 0;
            bottom = width;
            left = 0;
            right = width;
            height = width;
            dst_left = 0;
            dst_top = 0;
            dst_right = width;
            dst_bottom = width;
        } else{
            roundPx = height / 2;
            float clip = (width - height) / 2;
            left = clip;
            right = width - clip;
            top = 0;
            bottom = height;
            width = height;
            dst_left = 0;
            dst_top = 0;
            dst_right = height;
            dst_bottom = height;
        }

        Bitmap output = Bitmap.createBitmap(width, height, Config.ARGB_8888);
        Canvas canvas = new Canvas(output);
        final int color = 0xff424242;
        final Paint paint = new Paint();
        final Rect src = new Rect((int) left, (int) top, (int) right,
                (int) bottom);
        final Rect dst = new Rect((int) dst_left, (int) dst_top,
                (int) dst_right, (int) dst_bottom);
        final RectF rectF = new RectF(dst);
        paint.setAntiAlias(true);
        canvas.drawARGB(0, 0, 0, 0);
        paint.setColor(color);
        canvas.drawRoundRect(rectF, roundPx, roundPx, paint);
        paint.setXfermode(new PorterDuffXfermode(Mode.SRC_IN));
        canvas.drawBitmap(bitmap, src, dst, paint);
        if (bitmap != null && !bitmap.isRecycled()){
            bitmap.recycle();
            bitmap = null;
        }
        return output;
    }

6、rotaingImageView()方法，实现旋转图片

 执行效果如图：

/**
     * 旋转图片
     * @param angle 旋转角度
     * @param bitmap 要处理的Bitmap
     * @return 处理后的Bitmap
     */
    public static Bitmap rotaingImageView(int angle, Bitmap bitmap)
    {
        // 旋转图片 动作
        Matrix matrix = new Matrix();
        matrix.postRotate(angle);
        // 创建新的图片
        Bitmap resizedBitmap = Bitmap.createBitmap(bitmap, 0, 0,
                bitmap.getWidth(), bitmap.getHeight(), matrix, true);
        if (resizedBitmap != bitmap && bitmap != null && !bitmap.isRecycled()){
            bitmap.recycle();
            bitmap = null;
        }
        return resizedBitmap;
        }

7、saveBmpToSd()实现将保存Bitmap到sdcard

        public static boolean saveBmpToSd(String dir, Bitmap bm, String filename,
            int quantity, boolean recyle) {
        boolean ret = true;
        if (bm == null) {
            return false;}
        File dirPath = new File(dir);
        if (!exists(dir)) {
            dirPath.mkdirs();
        }
        if (!dir.endsWith(File.separator)) {
            dir += File.separator;
        }
        File file = new File(dir + filename);
        OutputStream outStream = null;
        try {
            file.createNewFile();
            outStream = new FileOutputStream(file);
            bm.compress(Bitmap.CompressFormat.JPEG, quantity, outStream);
        } catch (Exception e) {
            e.printStackTrace();
            ret = false;
        } finally {
            try {
                if (outStream != null) outStream.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
            if (recyle && !bm.isRecycled()) {
                bm.recycle();
                bm = null;
            }
        }
        return ret;
    }

作者：杰瑞教育
出处：http://www.cnblogs.com/jerehedu/ 
本文版权归烟台杰瑞教育科技有限公司和博客园共有，欢迎转载，但未经作者同意必须保留此段声明，且在文章页面明显位置给出原文连接，否则保留追究法律责任的权利。