java - 如何在android中实现手绘图像裁剪？
问题描述
我如何在Imageview.
使用下面的代码，我可以绘制手绘路径并且可以裁剪图像，但我面临一些其他问题
现在我到目前为止所尝试的
这是我的代码
使用画布裁剪图像的代码
public class SomeView extends View implements View.OnTouchListener {
private Paint paint;
int DIST = 2;
boolean flgPathDraw = true;
Point mfirstpoint = null;
boolean bfirstpoint = false;
Point mlastpoint = null;
Bitmap bitmap;
Context mContext;
public SomeView(Context c, Bitmap bitmap) {
super(c);
mContext = c;
this.bitmap = bitmap;
setFocusable(true);
setFocusableInTouchMode(true);
paint = new Paint(Paint.ANTI_ALIAS_FLAG);
paint.setStyle(Paint.Style.STROKE);
paint.setPathEffect(new DashPathEffect(new float[]{10, 20}, 0));
paint.setStrokeWidth(5);
paint.setColor(Color.RED);
paint.setStrokeJoin(Paint.Join.ROUND);
paint.setStrokeCap(Paint.Cap.ROUND);
this.setOnTouchListener(this);
points = new ArrayList<Point>();
bfirstpoint = false;
}
public SomeView(Context context, AttributeSet attrs) {
super(context, attrs);
mContext = context;
setFocusable(true);
setFocusableInTouchMode(true);
paint = new Paint(Paint.ANTI_ALIAS_FLAG);
paint.setStyle(Paint.Style.STROKE);
paint.setStrokeWidth(5);
paint.setColor(Color.RED);
points = new ArrayList<Point>();
bfirstpoint = false;
this.setOnTouchListener(this);
}
public void onDraw(Canvas canvas) {
/*Rect dest = new Rect(0, 0, getWidth(), getHeight());
paint.setFilterBitmap(true);
canvas.drawBitmap(bitmap, null, dest, paint);*/
canvas.drawBitmap(bitmap, 0, 0, null);
Path path = new Path();
boolean first = true;
for (int i = 0; i < points.size(); i += 2) {
Point point = points.get(i);
if (first) {
first = false;
path.moveTo(point.x, point.y);
} else if (i < points.size() - 1) {
Point next = points.get(i + 1);
path.quadTo(point.x, point.y, next.x, next.y);
} else {
mlastpoint = points.get(i);
path.lineTo(point.x, point.y);
}
}
canvas.drawPath(path, paint);
}
public boolean onTouch(View view, MotionEvent event) {
// if(event.getAction() != MotionEvent.ACTION_DOWN)
// return super.onTouchEvent(event);
Point point = new Point();
point.x = (int) event.getX();
point.y = (int) event.getY();
if (flgPathDraw) {
if (bfirstpoint) {
if (comparepoint(mfirstpoint, point)) {
// points.add(point);
points.add(mfirstpoint);
flgPathDraw = false;
showcropdialog();
} else {
points.add(point);
}
} else {
points.add(point);
}
if (!(bfirstpoint)) {
mfirstpoint = point;
bfirstpoint = true;
}
}
invalidate();
Log.e("Hi ==>", "Size: " + point.x + " " + point.y);
if (event.getAction() == MotionEvent.ACTION_UP) {
Log.d("Action up*****~~>>>>", "called");
mlastpoint = point;
if (flgPathDraw) {
if (points.size() > 12) {
if (!comparepoint(mfirstpoint, mlastpoint)) {
flgPathDraw = false;
points.add(mfirstpoint);
showcropdialog();
}
}
}
}
return true;
}
private boolean comparepoint(Point first, Point current) {
int left_range_x = (int) (current.x - 3);
int left_range_y = (int) (current.y - 3);
int right_range_x = (int) (current.x + 3);
int right_range_y = (int) (current.y + 3);
if ((left_range_x < first.x && first.x < right_range_x)
&& (left_range_y < first.y && first.y < right_range_y)) {
if (points.size() < 10) {
return false;
} else {
return true;
}
} else {
return false;
}
}
public void fillinPartofPath() {
Point point = new Point();
point.x = points.get(0).x;
point.y = points.get(0).y;
points.add(point);
invalidate();
}
public void resetView() {
points.clear();
paint.setColor(Color.WHITE);
paint.setStyle(Paint.Style.STROKE);
paint = new Paint(Paint.ANTI_ALIAS_FLAG);
paint.setStyle(Paint.Style.STROKE);
paint.setStrokeWidth(5);
paint.setColor(Color.RED);
points = new ArrayList<Point>();
bfirstpoint = false;
flgPathDraw = true;
invalidate();
}
private void showcropdialog() {
DialogInterface.OnClickListener dialogClickListener = new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int which) {
Intent intent;
switch (which) {
case DialogInterface.BUTTON_POSITIVE:
cropImage();
break;
case DialogInterface.BUTTON_NEGATIVE:
/*// No button clicked
intent = new Intent(mContext, DisplayCropActivity.class);
intent.putExtra("crop", false);
mContext.startActivity(intent);
bfirstpoint = false;*/
resetView();
break;
}
}
};
AlertDialog.Builder builder = new AlertDialog.Builder(mContext);
builder.setMessage("Do you Want to save Crop or Non-crop image?")
.setPositiveButton("Crop", dialogClickListener)
.setNegativeButton("Non-crop", dialogClickListener).show()
.setCancelable(false);
}
}
裁剪位图的代码
public void cropImage() {
setContentView(R.layout.activity_picture_preview);
imageView = findViewById(R.id.image);
int widthOfscreen = 0;
int heightOfScreen = 0;
DisplayMetrics dm = new DisplayMetrics();
try {
getWindowManager().getDefaultDisplay().getMetrics(dm);
} catch (Exception ex) {
}
widthOfscreen = dm.widthPixels;
heightOfScreen = dm.heightPixels;
Bitmap bitmap2 = mBitmap;
Bitmap resultingImage = Bitmap.createBitmap(widthOfscreen,
heightOfScreen, bitmap2.getConfig());
Canvas canvas = new Canvas(resultingImage);
Paint paint = new Paint();
Path path = new Path();
for (int i = 0; i < points.size(); i++) {
path.lineTo(points.get(i).x, points.get(i).y);
}
canvas.drawPath(path, paint);
paint.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.SRC_IN));
canvas.drawBitmap(bitmap2, 0, 0, paint);
imageView.setImageBitmap(resultingImage);
}
这是我使用上面的代码得到的结果
这是我的预期输出
请检查下面的屏幕截图是否相同
我在上面的代码中面临的以下问题
- 无法使用画布全屏设置位图
- 如果我在画布中全屏设置位图，则图像正在拉伸
- 如何为裁剪的位图设置透明背景
- 无法为裁剪的图像添加边框
- 图像裁剪的结果不符合预期
这是我迄今为止尝试过的其他一些帖子
以上帖子均无助于实现我的例外输出
如果需要更多信息，请告诉我。提前致谢。您的努力将不胜感激。
解决方案
一般来说，您的代码看起来不错，但我有几点意见：
- 无法使用画布全屏设置位图
如果我在画布中将位图设置为全屏而不是图像正在拉伸
您选择的图像部分需要放置在较小的位图中，以便布局 XML 可以根据需要对其进行定位。您正在创建全屏位图。有关详细信息，请参阅以下演示。如何为裁剪的位图设置透明背景
我不清楚问题是什么。无法为裁剪的图像添加边框
- 图像裁剪的结果与预期不符
见下文。
这是一个使用您的代码的小型演示应用程序。您没有提供MCVE，因此出于演示目的，我将以下内容放在一起。除了让应用程序运行之外，我认为唯一的变化是在MainActivity.java. 边框宽度从用户绘制的剪切路径开始，向内到达剪切位置。如果您想在不丢失任何像素的情况下实际构图切口，则需要扩展路径以容纳我任意设置为 20 像素的帧。
我还必须创建使用的布局，所以你可能想看看那些。它们张贴在下面。
这是带有代码的演示视频：
MainActivity.java
public class MainActivity extends AppCompatActivity {
private Bitmap mBitmap;
private SomeView mSomeView;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
mBitmap = BitmapFactory.decodeResource(getResources(), R.drawable.dog);
mSomeView = new SomeView(this, mBitmap);
LinearLayout layout = findViewById(R.id.layout);
LinearLayout.LayoutParams lp =
new LinearLayout.LayoutParams(LinearLayout.LayoutParams.WRAP_CONTENT,
LinearLayout.LayoutParams.WRAP_CONTENT);
layout.addView(mSomeView, lp);
}
public void cropImage() {
setContentView(R.layout.activity_picture_preview);
ImageView imageView = findViewById(R.id.image);
Bitmap fullScreenBitmap =
Bitmap.createBitmap(mSomeView.getWidth(), mSomeView.getHeight(), mBitmap.getConfig());
Canvas canvas = new Canvas(fullScreenBitmap);
Path path = new Path();
List<Point> points = mSomeView.getPoints();
for (int i = 0; i < points.size(); i++) {
path.lineTo(points.get(i).x, points.get(i).y);
}
// Cut out the selected portion of the image...
Paint paint = new Paint();
canvas.drawPath(path, paint);
paint.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.SRC_IN));
canvas.drawBitmap(mBitmap, 0, 0, paint);
// Frame the cut out portion...
paint.setColor(Color.WHITE);
paint.setStyle(Paint.Style.STROKE);
paint.setStrokeWidth(10f);
canvas.drawPath(path, paint);
// Create a bitmap with just the cropped area.
Region region = new Region();
Region clip = new Region(0, 0, fullScreenBitmap.getWidth(), fullScreenBitmap.getHeight());
region.setPath(path, clip);
Rect bounds = region.getBounds();
Bitmap croppedBitmap =
Bitmap.createBitmap(fullScreenBitmap, bounds.left, bounds.top,
bounds.width(), bounds.height());
imageView.setImageBitmap(croppedBitmap);
}
}
SomeView.java
我不认为这个类有任何实质性的变化。
public class SomeView extends View implements View.OnTouchListener {
private Paint paint;
private List<Point> points;
int DIST = 2;
boolean flgPathDraw = true;
Point mfirstpoint = null;
boolean bfirstpoint = false;
Point mlastpoint = null;
Bitmap bitmap;
Context mContext;
public SomeView(Context c, Bitmap bitmap) {
super(c);
mContext = c;
this.bitmap = bitmap;
setFocusable(true);
setFocusableInTouchMode(true);
paint = new Paint(Paint.ANTI_ALIAS_FLAG);
paint.setStyle(Paint.Style.STROKE);
paint.setPathEffect(new DashPathEffect(new float[]{10, 20}, 0));
paint.setStrokeWidth(5);
paint.setColor(Color.RED);
paint.setStrokeJoin(Paint.Join.ROUND);
paint.setStrokeCap(Paint.Cap.ROUND);
this.setOnTouchListener(this);
points = new ArrayList<Point>();
bfirstpoint = false;
}
public SomeView(Context context, AttributeSet attrs) {
super(context, attrs);
mContext = context;
setFocusable(true);
setFocusableInTouchMode(true);
paint = new Paint(Paint.ANTI_ALIAS_FLAG);
paint.setStyle(Paint.Style.STROKE);
paint.setStrokeWidth(5);
paint.setColor(Color.RED);
points = new ArrayList<Point>();
bfirstpoint = false;
this.setOnTouchListener(this);
}
public void onDraw(Canvas canvas) {
/*Rect dest = new Rect(0, 0, getWidth(), getHeight());
paint.setFilterBitmap(true); canvas.drawBitmap(bitmap, null, dest, paint);*/
canvas.drawBitmap(bitmap, 0, 0, null);
Path path = new Path();
boolean first = true;
for (int i = 0; i < points.size(); i += 2) {
Point point = points.get(i);
if (first) {
first = false;
path.moveTo(point.x, point.y);
} else if (i < points.size() - 1) {
Point next = points.get(i + 1);
path.quadTo(point.x, point.y, next.x, next.y);
} else {
mlastpoint = points.get(i);
path.lineTo(point.x, point.y);
}
}
canvas.drawPath(path, paint);
}
public boolean onTouch(View view, MotionEvent event) {
// if(event.getAction() != MotionEvent.ACTION_DOWN)
// return super.onTouchEvent(event);
Point point = new Point();
point.x = (int) event.getX();
point.y = (int) event.getY();
if (flgPathDraw) {
if (bfirstpoint) {
if (comparepoint(mfirstpoint, point)) {
// points.add(point);
points.add(mfirstpoint);
flgPathDraw = false;
showcropdialog();
} else {
points.add(point);
}
} else {
points.add(point);
}
if (!(bfirstpoint)) {
mfirstpoint = point;
bfirstpoint = true;
}
}
invalidate();
Log.e("Hi ==>", "Size: " + point.x + " " + point.y);
if (event.getAction() == MotionEvent.ACTION_UP) {
Log.d("Action up*****~~>>>>", "called");
mlastpoint = point;
if (flgPathDraw) {
if (points.size() > 12) {
if (!comparepoint(mfirstpoint, mlastpoint)) {
flgPathDraw = false;
points.add(mfirstpoint);
showcropdialog();
}
}
}
}
return true;
}
private boolean comparepoint(Point first, Point current) {
int left_range_x = (int) (current.x - 3);
int left_range_y = (int) (current.y - 3);
int right_range_x = (int) (current.x + 3);
int right_range_y = (int) (current.y + 3);
if ((left_range_x < first.x && first.x < right_range_x)
&& (left_range_y < first.y && first.y < right_range_y)) {
if (points.size() < 10) {
return false;
} else {
return true;
}
} else {
return false;
}
}
public void fillinPartofPath() {
Point point = new Point();
point.x = points.get(0).x;
point.y = points.get(0).y;
points.add(point);
invalidate();
}
public void resetView() {
points.clear();
paint.setColor(Color.WHITE);
paint.setStyle(Paint.Style.STROKE);
paint = new Paint(Paint.ANTI_ALIAS_FLAG);
paint.setStyle(Paint.Style.STROKE);
paint.setStrokeWidth(5);
paint.setColor(Color.RED);
points = new ArrayList<Point>();
bfirstpoint = false;
flgPathDraw = true;
invalidate();
}
private void showcropdialog() {
DialogInterface.OnClickListener dialogClickListener = new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int which) {
Intent intent;
switch (which) {
case DialogInterface.BUTTON_POSITIVE:
((MainActivity) mContext).cropImage();
break;
case DialogInterface.BUTTON_NEGATIVE:
/*// No button clicked
intent = new Intent(mContext, DisplayCropActivity.class); intent.putExtra("crop", false); mContext.startActivity(intent);
bfirstpoint = false;*/ resetView();
break;
}
}
};
AlertDialog.Builder builder = new AlertDialog.Builder(mContext);
builder.setMessage("Do you Want to save Crop or Non-crop image?")
.setPositiveButton("Crop", dialogClickListener)
.setNegativeButton("Non-crop", dialogClickListener).show()
.setCancelable(false);
}
public List<Point> getPoints() {
return points;
}
}
activity_main.xml
<LinearLayout
android:id="@+id/layout"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
tools:context=".MainActivity"/>
activity_picture_preview.xml
<android.support.constraint.ConstraintLayout x
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="@color/colorPrimary">
<ImageView
android:id="@+id/image"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:adjustViewBounds="true"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
tools:srcCompat="@drawable/dog" />
</android.support.constraint.ConstraintLayout>
如果要创建具有 100px 边框的裁剪位图，请使用以下代码cropImage()：
// Create a bitmap with just the cropped area.
Region region = new Region();
Region clip = new Region(0, 0, fullScreenBitmap.getWidth(), fullScreenBitmap.getHeight());
region.setPath(path, clip);
Rect sourceBounds = region.getBounds();
Rect destBounds =
new Rect(CROPPED_MARGIN, CROPPED_MARGIN, sourceBounds.width() + CROPPED_MARGIN,
sourceBounds.height() + CROPPED_MARGIN);
Bitmap croppedBitmap =
Bitmap.createBitmap(sourceBounds.width() + CROPPED_MARGIN * 2,
sourceBounds.height() + CROPPED_MARGIN * 2, mBitmap.getConfig());
canvas.setBitmap(croppedBitmap);
canvas.drawBitmap(fullScreenBitmap, sourceBounds, destBounds, null);
imageView.setImageBitmap(croppedBitmap);
// Add as member variable.
private static final int CROPPED_MARGIN = 100;
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