uCrop图片裁剪

uCrop使用

github地址

https://github.com/Yalantis/uCrop
然后clone或下载到本地，运行之。

效果预览

app/build.gradle

compile 'com.yalantis:ucrop:1.5.0'

AndroidManifest.xml

1 <activity
2     android:name="com.yalantis.ucrop.UCropActivity"
3     android:screenOrientation="portrait"
4     android:theme="@style/Theme.AppCompat.Light.NoActionBar" />

这里theme可以改成自己的

配置uCrop

 1  /**
 2   * 启动裁剪
 3   * @param activity 上下文
 4   * @param sourceFilePath 需要裁剪图片的绝对路径
 5   * @param requestCode 比如：UCrop.REQUEST_CROP
 6   * @param aspectRatioX 裁剪图片宽高比
 7   * @param aspectRatioY 裁剪图片宽高比
 8   * @return
 9   */
10 public static String startUCrop(Activity activity, String sourceFilePath, 
11     int requestCode, float aspectRatioX, float aspectRatioY) {
12     Uri sourceUri = Uri.fromFile(new File(sourceFilePath));
13     File outDir = Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_PICTURES);
14     if (!outDir.exists()) {
15         outDir.mkdirs();
16     }
17     File outFile = new File(outDir, System.currentTimeMillis() + ".jpg");
18     //裁剪后图片的绝对路径
19     String cameraScalePath = outFile.getAbsolutePath();
20     Uri destinationUri = Uri.fromFile(outFile);
21     //初始化，第一个参数：需要裁剪的图片；第二个参数：裁剪后图片
22     UCrop uCrop = UCrop.of(sourceUri, destinationUri);
23     //初始化UCrop配置
24     UCrop.Options options = new UCrop.Options();
25     //设置裁剪图片可操作的手势
26     options.setAllowedGestures(UCropActivity.SCALE, UCropActivity.ROTATE, UCropActivity.ALL);
27     //是否隐藏底部容器，默认显示
28     options.setHideBottomControls(true);
29     //设置toolbar颜色
30     options.setToolbarColor(ActivityCompat.getColor(activity, R.color.colorPrimary));
31     //设置状态栏颜色
32     options.setStatusBarColor(ActivityCompat.getColor(activity, R.color.colorPrimary));
33     //是否能调整裁剪框
34     options.setFreeStyleCropEnabled(true);
35     //UCrop配置
36     uCrop.withOptions(options);
37     //设置裁剪图片的宽高比，比如16：9
38     uCrop.withAspectRatio(aspectRatioX, aspectRatioY);
39     //uCrop.useSourceImageAspectRatio();
40     //跳转裁剪页面
41     uCrop.start(activity, requestCode);
42     return cameraScalePath;
43 }

其他配置

 1 //设置Toolbar标题
 2 void setToolbarTitle(@Nullable String text)
 3 //设置裁剪的图片格式
 4 void setCompressionFormat(@NonNull Bitmap.CompressFormat format)
 5 //设置裁剪的图片质量，取值0-100
 6 void setCompressionQuality(@IntRange(from = 0) int compressQuality)
 7 //设置最多缩放的比例尺
 8 void setMaxScaleMultiplier(@FloatRange(from = 1.0, fromInclusive = false) float maxScaleMultiplier)
 9 //动画时间
10 void setImageToCropBoundsAnimDuration(@IntRange(from = 100) int durationMillis)
11 //设置图片压缩最大值
12 void setMaxBitmapSize(@IntRange(from = 100) int maxBitmapSize)
13 //是否显示椭圆裁剪框阴影
14 void setOvalDimmedLayer(boolean isOval) 
15 //设置椭圆裁剪框阴影颜色
16 void setDimmedLayerColor(@ColorInt int color)
17 //是否显示裁剪框
18 void setShowCropFrame(boolean show)
19 //设置裁剪框边的宽度
20 void setCropFrameStrokeWidth(@IntRange(from = 0) int width)
21 //是否显示裁剪框网格
22 void setShowCropGrid(boolean show) 
23 //设置裁剪框网格颜色
24 void setCropGridColor(@ColorInt int color)
25 //设置裁剪框网格宽
26 void setCropGridStrokeWidth(@IntRange(from = 0) int width)

onActivityResult

经过裁剪，返回结果，这里我一般只需要裁剪后的图片绝对路径（调用上面startUCrop，即返回图片路径），然后调接口上传服务器。

1 @Override
2 public void onActivityResult(int requestCode, int resultCode, Intent data) {
3     if (resultCode == RESULT_OK && requestCode == UCrop.REQUEST_CROP) {
4         final Uri resultUri = UCrop.getOutput(data);
5     } else if (resultCode == UCrop.RESULT_ERROR) {
6         final Throwable cropError = UCrop.getError(data);
7     }
8 }

uCrop源码浅析

uCrop源码能学习的东西有很多，比如左右滑的标尺，不过我们这里源码浅析只关注裁剪部分。

类关系

首先有个大概了解：

GestureCropImageView：负责监听各种手势
CropImageView：主要完成图片裁剪工作，和判断裁剪图片是否充满裁剪框
TransformImageView：负责图片旋转、缩放、位移操作

入口

由上面的效果图可知，点击右上角，调用裁剪操作，代码如下：

 1 @Override
 2 public boolean onOptionsItemSelected(MenuItem item) {
 3     if (item.getItemId() == R.id.menu_crop) {
 4         cropAndSaveImage();
 5     }
 6     return super.onOptionsItemSelected(item);
 7 }
 8 //裁剪和保存图片
 9 protected void cropAndSaveImage() {
10     ……
11     mGestureCropImageView.cropAndSaveImage(mCompressFormat, mCompressQuality, new BitmapCropCallback() {
12         @Override
13         public void onBitmapCropped(@NonNull Uri resultUri) {
14             setResultUri(resultUri, mGestureCropImageView.getTargetAspectRatio());
15             finish();
16         }
17         @Override
18         public void onCropFailure(@NonNull Throwable t) {
19             setResultError(t);
20             finish();
21         }
22     });
23 }

这里调用了GestureCropImageView&cropAndSaveImage方法，如下：

 1 /**
 2  * @param compressFormat  图片压缩格式
 3  * @param compressQuality 图片压缩质量
 4  * @param cropCallback    图片压缩回调
 5  */
 6 public void cropAndSaveImage(@NonNull Bitmap.CompressFormat compressFormat, int                                             compressQuality,@Nullable BitmapCropCallback cropCallback) {
 7     //取消所有动画
 8     cancelAllAnimations();
 9     //判断裁剪图片是否充满裁剪框
10     setImageToWrapCropBounds(false);
11     //进行裁剪
12     new BitmapCropTask(getViewBitmap(), mCropRect, RectUtils.trapToRect(mCurrentImageCorners),
13             getCurrentScale(), getCurrentAngle(),
14             mMaxResultImageSizeX, mMaxResultImageSizeY,
15             compressFormat, compressQuality,
16             getImageInputPath(), getImageOutputPath(),
17             cropCallback).execute();
18 }

裁剪之前

setImageToWrapCropBounds

裁剪之前，先判断裁剪图片是否充满裁剪框，如果没有，进行移动和缩放让其充满。

 1 public void setImageToWrapCropBounds(boolean animate) {
 2     //mBitmapLaidOut图片加载OK，isImageWrapCropBounds()检查图片是否充满裁剪框
 3     if (mBitmapLaidOut && !isImageWrapCropBounds()) {
 4         //当前图片中心X点
 5         float currentX = mCurrentImageCenter[0];
 6         //当前图片中心Y点
 7         float currentY = mCurrentImageCenter[1];
 8         //当前图片缩放值
 9         float currentScale = getCurrentScale();
10         //差量
11         float deltaX = mCropRect.centerX() - currentX;
12         float deltaY = mCropRect.centerY() - currentY;
13         float deltaScale = 0;
14         //临时矩阵重置
15         mTempMatrix.reset();
16         //临时矩阵移动
17         mTempMatrix.setTranslate(deltaX, deltaY);
18         //复制到新的数组
19         final float[] tempCurrentImageCorners = Arrays.copyOf(mCurrentImageCorners, mCurrentImageCorners.length);
20         //将此矩阵应用于二维点的数组，并编写转换后的指向数组的点
21         mTempMatrix.mapPoints(tempCurrentImageCorners);
22         //再检查图片是否充满裁剪框
23         boolean willImageWrapCropBoundsAfterTranslate = isImageWrapCropBounds(tempCurrentImageCorners);
24         if (willImageWrapCropBoundsAfterTranslate) {
25             //图片缩进的数组
26             final float[] imageIndents = calculateImageIndents();
27             deltaX = -(imageIndents[0] + imageIndents[2]);
28             deltaY = -(imageIndents[1] + imageIndents[3]);
29         } else {
30             RectF tempCropRect = new RectF(mCropRect);
31             mTempMatrix.reset();
32             mTempMatrix.setRotate(getCurrentAngle());
33             mTempMatrix.mapRect(tempCropRect);
34             //获取裁剪图片的边
35             final float[] currentImageSides = RectUtils.getRectSidesFromCorners(mCurrentImageCorners);
36             deltaScale = Math.max(tempCropRect.width() / currentImageSides[0],
37                     tempCropRect.height() / currentImageSides[1]);
38             deltaScale = deltaScale * currentScale - currentScale;
39         }
40         if (animate) {
41             //移动或缩放图片（有动画效果）
42             post(mWrapCropBoundsRunnable = new WrapCropBoundsRunnable(
43                     CropImageView.this, mImageToWrapCropBoundsAnimDuration, currentX, currentY, deltaX, deltaY,
44                     currentScale, deltaScale, willImageWrapCropBoundsAfterTranslate));
45         } else {
46             //移动图片
47             postTranslate(deltaX, deltaY);
48             if (!willImageWrapCropBoundsAfterTranslate) {
49                 //缩放图片
50                 zoomInImage(currentScale + deltaScale, mCropRect.centerX(), mCropRect.centerY());
51             }
52         }
53     }
54 }

进行裁剪

裁剪放到了异步，即BitmapCropTask继承AsyncTask，先设置原始图片resizeScale值，然后通过ExifInterface保存新的图片，即裁剪后的图片

  1 public class BitmapCropTask extends AsyncTask<Void, Void, Throwable> {
  2     
  3     ……
  4     /**
  5      * @param viewBitmap          裁剪图片bitmap
  6      * @param cropRect            裁剪矩形
  7      * @param currentImageRect    当前图片矩形
  8      * @param currentScale        当前图片缩放值
  9      * @param currentAngle        当前图片角度
 10      * @param maxResultImageSizeX 图片裁剪后最大宽值
 11      * @param maxResultImageSizeY 图片裁剪后最大高值
 12      * @param compressFormat      图片裁剪的格式
 13      * @param compressQuality     图片裁剪的质量
 14      * @param imageInputPath      裁剪图片路径
 15      * @param imageOutputPath     图片裁剪后路径
 16      * @param cropCallback        裁剪回调
 17      */
 18     public BitmapCropTask(@Nullable Bitmap viewBitmap,
 19                           @NonNull RectF cropRect, @NonNull RectF currentImageRect,
 20                           float currentScale, float currentAngle,
 21                           int maxResultImageSizeX, int maxResultImageSizeY,
 22                           @NonNull Bitmap.CompressFormat compressFormat, int compressQuality,
 23                           @NonNull String imageInputPath, @NonNull String imageOutputPath,
 24                           @Nullable BitmapCropCallback cropCallback) {
 25       ……
 26     }
 27     @Override
 28     @Nullable
 29     protected Throwable doInBackground(Void... params) {
 30         if (mViewBitmap == null || mViewBitmap.isRecycled()) {
 31             return new NullPointerException("ViewBitmap is null or already recycled");
 32         }
 33         if (mCurrentImageRect.isEmpty()) {
 34             return new NullPointerException("CurrentImageRect is empty");
 35         }
 36         //设置resizeScale值
 37         float resizeScale = resize();
 38         try {
 39             //裁剪
 40             crop(resizeScale);
 41             //回收
 42             mViewBitmap.recycle();
 43             mViewBitmap = null;
 44         } catch (Throwable throwable) {
 45             return throwable;
 46         }
 47         return null;
 48     }
 49     private float resize() {
 50         //初始Options
 51         final BitmapFactory.Options options = new BitmapFactory.Options();
 52         //查询该位图，而无需分配存储器，可获取outHeight(图片原始高度)和 outWidth(图片的原始宽度)
 53         options.inJustDecodeBounds = true;
 54         //裁剪图片解码
 55         BitmapFactory.decodeFile(mImageInputPath, options);
 56         //原始图片和裁剪后图片比值
 57         float scaleX = options.outWidth / mViewBitmap.getWidth();
 58         float scaleY = options.outHeight / mViewBitmap.getHeight();
 59         float resizeScale = Math.min(scaleX, scaleY);
 60         mCurrentScale /= resizeScale;
 61         //初始化值为1
 62         resizeScale = 1;
 63         if (mMaxResultImageSizeX > 0 && mMaxResultImageSizeY > 0) {
 64             float cropWidth = mCropRect.width() / mCurrentScale;
 65             float cropHeight = mCropRect.height() / mCurrentScale;
 66             if (cropWidth > mMaxResultImageSizeX || cropHeight > mMaxResultImageSizeY) {
 67                 scaleX = mMaxResultImageSizeX / cropWidth;
 68                 scaleY = mMaxResultImageSizeY / cropHeight;
 69                 //设置resizeScale，如果是2就是高度和宽度都是原始的一半
 70                 resizeScale = Math.min(scaleX, scaleY);
 71                 mCurrentScale /= resizeScale;
 72             }
 73         }
 74         return resizeScale;
 75     }
 76     private boolean crop(float resizeScale) throws IOException {
 77         //ExifInterface这个接口提供了图片文件的旋转，gps，时间等信息，从原始图片读出Exif标签
 78         ExifInterface originalExif = new ExifInterface(mImageInputPath);
 79         int top = Math.round((mCropRect.top - mCurrentImageRect.top) / mCurrentScale);
 80         int left = Math.round((mCropRect.left - mCurrentImageRect.left) / mCurrentScale);
 81         int width = Math.round(mCropRect.width() / mCurrentScale);
 82         int height = Math.round(mCropRect.height() / mCurrentScale);
 83         //复制图片
 84         boolean cropped = cropCImg(mImageInputPath, mImageOutputPath,
 85                 left, top, width, height, mCurrentAngle, resizeScale,
 86                 mCompressFormat.ordinal(), mCompressQuality);
 87         if (cropped) {
 88             //拿到裁剪后图片
 89             copyExif(originalExif, width, height);
 90         }
 91         return cropped;
 92     }
 93     @SuppressWarnings("JniMissingFunction")
 94     native public boolean cropCImg(String inputPath, String outputPath,
 95                                    int left, int top, int width, int height, float angle, float resizeScale,
 96                                    int format, int quality) throws IOException, OutOfMemoryError;
 97     /**
 98      * @param originalExif 原始图片Exif
 99      * @param width        裁剪后图片宽
100      * @param height       裁剪后图片高
101      * @throws IOException 是否异常
102      */
103     public void copyExif(ExifInterface originalExif, int width, int height) throws IOException {
104         //Exif标签数组
105         String[] attributes = new String[]{
106                 ExifInterface.TAG_APERTURE,
107                 ……
108         };
109         //指定裁剪后图片路径，初始化新的ExifInterface
110         ExifInterface newExif = new ExifInterface(mImageOutputPath);
111         String value;
112         for (String attribute : attributes) {
113             value = originalExif.getAttribute(attribute);
114             if (!TextUtils.isEmpty(value)) {
115                 //设置Exif标签
116                 newExif.setAttribute(attribute, value);
117             }
118         }
119         newExif.setAttribute(ExifInterface.TAG_IMAGE_WIDTH, String.valueOf(width));
120         newExif.setAttribute(ExifInterface.TAG_IMAGE_LENGTH, String.valueOf(height));
121         newExif.setAttribute(ExifInterface.TAG_ORIENTATION, "0");
122         //保存
123         newExif.saveAttributes();
124     }
125     @Override
126     protected void onPostExecute(@Nullable Throwable t) {
127         if (mCropCallback != null) {
128             if (t == null) {
129                 //接口回调，over
130                 mCropCallback.onBitmapCropped(Uri.fromFile(new File(mImageOutputPath)));
131             } else {
132                 mCropCallback.onCropFailure(t);
133             }
134         }
135     }
136 }

总结

uCrop功能强大，对于我来说，有很多东西值得学习，难点如Rect包含问题（其实这块还不是很理解），新知识如ExifInterface操作图片，BitmapFactory显示图片的知识点温故等，还有自定义左右滑的标尺，都是不错的学习源码。抛砖引玉至此，over。