import android.content.Context;
import android.content.res.Resources;
import android.graphics.Bitmap;
import android.graphics.Canvas;
import android.graphics.Matrix;
import android.graphics.PointF;
import android.graphics.RectF;
import android.graphics.drawable.Drawable;
import android.util.AttributeSet;
import android.util.DisplayMetrics;
import android.view.MotionEvent;
import android.view.ScaleGestureDetector;
import android.view.View;
import android.widget.ImageView;
import androidx.appcompat.widget.AppCompatImageView;
/**
* Created by TU on 2019/8/26.
* 可以拖动和缩放
*/
public class PhotoView extends AppCompatImageView implements View.OnTouchListener,
ScaleGestureDetector.OnScaleGestureListener{
private static final String TAG = PhotoView.class.getSimpleName();
//最大缩放比例
private static final float MAX_SCALE = 4.0f;
//最小缩放比例
private static float MIN_SCALE = 1.0f;
//matrix array
private static final float MATRIX_ARR[] = new float[9];
private static final class Mode {
// 初始状态
private static final int NONE = 0;
//托动
private static final int DRAG = 1;
//缩放
private static final int ZOOM = 2;
}
//当前状态
private int mMode = Mode.NONE;
//缩放手势
private ScaleGestureDetector mScaleDetector;
//矩阵
private Matrix mMatrix = new Matrix();
//托动时手指按下的点
private PointF mPrevPointF = new PointF();
//截取的圆框的半径
private int mRadius;
//第一次
private boolean firstTime = true;
public PhotoView(Context context) {
this(context, null);
}
public PhotoView(Context context, AttributeSet attrs) {
this(context, attrs, 0);
}
public PhotoView(Context context, AttributeSet attrs, int defStyleAttr) {
super(context, attrs, defStyleAttr);
mScaleDetector = new ScaleGestureDetector(context, this);
mRadius = getRadius(getContext());
// 必须设置才能触发
setOnTouchListener(this);
setScaleType(ImageView.ScaleType.MATRIX);
}
/**
* 初始化
*/
private void init() {
Drawable drawable = getDrawable();
if (drawable == null) {
//throw new IllegalArgumentException("drawable can not be null");
return;
}
initScale();
}
/**
* 初始化缩放比例
*/
private void initScale() {
if (firstTime) {
Drawable drawable = getDrawable();
int width = getWidth();
int height = getHeight();
//初始化
int dw = drawable.getIntrinsicWidth();
int dh = drawable.getIntrinsicHeight();
float scaleX = 1.0f;
float scaleY = 1.0f;
//是否已经做过缩放处理
boolean isScaled = false;
if (width < getDiameter()) {
scaleX = getDiameter() * 1.0f / width;
isScaled = true;
}
if (height < getDiameter()) {
scaleY = getDiameter() * 1.0f / height;
isScaled = true;
}
float scale = Math.max(scaleX, scaleY);
if (isScaled) {
MIN_SCALE = scale;
} else {
MIN_SCALE = Math.max((getDiameter() * 1.0f) / dw, getDiameter() * 1.0f / dh) + 0.01f;
}
mMatrix.postScale(scale, scale, getWidth() / 2, getHeight() / 2);
mMatrix.postTranslate((width - dw) / 2, (height - dh) / 2);
setImageMatrix(mMatrix);
firstTime = false;
}
}
@Override
public boolean onScale(ScaleGestureDetector detector) {
float scale = getScale();
float scaleFactor = detector.getScaleFactor();
if ((scale >= MIN_SCALE && scaleFactor > 1.0f) ||
(scale <= MAX_SCALE && scaleFactor < 1.0f)) {
if (scale * scaleFactor <= MIN_SCALE) {
scaleFactor = MIN_SCALE / scale;
} else if (scale * scaleFactor >= MAX_SCALE) {
scaleFactor = MAX_SCALE / scale;
}
mMatrix.postScale(scaleFactor, scaleFactor, detector.getFocusX(), detector.getFocusY());
checkTrans();
setImageMatrix(mMatrix);
}
return true;
}
@Override
public boolean onScaleBegin(ScaleGestureDetector detector) {
mMode = Mode.ZOOM;
return true;
}
@Override
public void onScaleEnd(ScaleGestureDetector detector) {
mMode = Mode.NONE;
}
@Override
public boolean onTouch(View v, MotionEvent event) {
if (getDrawable() == null) {
return false;
}
mScaleDetector.onTouchEvent(event);
switch (event.getAction() & MotionEvent.ACTION_MASK) {
case MotionEvent.ACTION_DOWN:
mMode = Mode.DRAG;
mPrevPointF.set(event.getX(), event.getY());
break;
case MotionEvent.ACTION_UP:
mMode = Mode.NONE;
break;
case MotionEvent.ACTION_MOVE:
if (mMode == Mode.DRAG && event.getPointerCount() == 1) {
float x = event.getX();
float y = event.getY();
float dx = event.getX() - mPrevPointF.x;
float dy = event.getY() - mPrevPointF.y;
RectF rectF = getMatrixRectF();
// 如果宽度小于屏幕宽度，则禁止左右移动
if (rectF.width() <= getDiameter()) {
dx = 0;
}
// 如果高度小雨屏幕高度，则禁止上下移动
if (rectF.height() <= getDiameter()) {
dy = 0;
}
mMatrix.postTranslate(dx, dy);
checkTrans();
//边界判断
setImageMatrix(mMatrix);
mPrevPointF.set(x, y);
}
break;
}
return true;
}
/**
* 移动边界检查
*/
private void checkTrans() {
RectF rect = getMatrixRectF();
float deltaX = 0;
float deltaY = 0;
int width = getWidth();
int height = getHeight();
int horizontalPadding = (width - getDiameter()) / 2;
int verticalPadding = (height - getDiameter()) / 2;
// 如果宽或高大于屏幕，则控制范围 ; 这里的0.001是因为精度丢失会产生问题
if (rect.width() + 0.01 >= getDiameter()) {
if (rect.left > horizontalPadding) {
deltaX = -rect.left + horizontalPadding;
}
if (rect.right < width - horizontalPadding) {
deltaX = width - horizontalPadding - rect.right;
}
}
if (rect.height() + 0.01 >= getDiameter()) {
if (rect.top > verticalPadding) {
deltaY = -rect.top + verticalPadding;
}
if (rect.bottom < height - verticalPadding) {
deltaY = height - verticalPadding - rect.bottom;
}
}
mMatrix.postTranslate(deltaX, deltaY);
}
/**
* 得到直径
*/
public int getDiameter() {
return mRadius * 2;
}
/**
* 获得缩放值
*
* @return
*/
private float getScale() {
return getMatrixValue(Matrix.MSCALE_X);
}
private float getMatrixValue(int index) {
mMatrix.getValues(MATRIX_ARR);
return MATRIX_ARR[index];
}
/**
* 获得Matrix的RectF
*/
private RectF getMatrixRectF() {
Matrix matrix = mMatrix;
RectF rect = new RectF();
Drawable d = getDrawable();
if (null != d) {
rect.set(0, 0, d.getIntrinsicWidth(), d.getIntrinsicHeight());
matrix.mapRect(rect);
}
return rect;
}
@Override
protected void onDraw(Canvas canvas) {
super.onDraw(canvas);
init();
}
/**
* 截取图片
*
* @return
*/
Bitmap clip() {
Bitmap bitmap = Bitmap.createBitmap(getWidth(), getHeight(), Bitmap.Config.ARGB_8888);
Canvas canvas = new Canvas(bitmap);
draw(canvas);
int x = (getWidth() - getDiameter()) / 2;
int y = (getHeight() - getDiameter()) / 2;
return Bitmap.createBitmap(bitmap, x, y, getDiameter(), getDiameter());
}
public static int getWidth(Context context) {
Resources resources = context.getApplicationContext().getResources();
DisplayMetrics dm = resources.getDisplayMetrics();
float density = dm.density;
int width = dm.widthPixels;
return width;
}
public static int getHeight(Context context) {
Resources resources = context.getApplicationContext().getResources();
DisplayMetrics dm = resources.getDisplayMetrics();
float density = dm.density;
int height = dm.heightPixels;
return height;
}
public static int getRadius(Context context) {
return Math.min(getWidth(context), getHeight(context)) / 4;
}
}
直接cv使用-。-
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