Matrix
Matrix
- 什么是Matrix
- 实际应用
什么是Matrix
Matrix 就是矩阵的意思，我们通常使用它进行一些图片的变化操作
平移、缩放、旋转、错切、水印等效果
常用api
Matrix 三种动作 pre 、post 、set
pre代表之前有操作，乖乖排队
post代表插队到第一个
set代表设置，替换之前所有
{
0,0,1
1,0,0
1,0,0
}
{
MSCALE_X MSKEW_X MTRANS_X
MSKEW_Y MSCALE_Y MTRANS_Y
MPERSP_0 MPERSP_1 MPERSP_2
}
平移Translate 通过改变矩阵 MTRANS_X、MTRANS_Y
preTranslate(float dx,float dy)
postTranslate(float dx,float dy)
setTranslate(float dx,float dy)
扭曲变幻 Skew 通过 MSKEW_X、MSKEW_Y
preSkew(float kx,float ky)
preSkew(float kx,float ky,float px,float,py)
…
点(x,y)通过Skew(dx,dy,px,py)变幻之后的坐标 kx*(y-py)+px , ky*(x-px)+py
旋转 Rotate 通过 MSCALE_X、MSKEW_X、MSCALE_Y、MSKEW_Y
preRotate(float degrees)
preRotate(float degrees, float dx,float dy)
…
degrees 旋转度数 dx,dy旋转角度通过这个设置缩放
缩放Scale 通过矩阵 MSCALE_X、MSCALE_Y
preRotate(float dx,float,dy)
…
实际应用
XML
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
tools:context=".MainActivity">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="horizontal"
android:padding="10dp">
<Button
android:id="@+id/bt1"
android:layout_width="0dp"
android:layout_height="match_parent"
android:layout_weight="1"
android:onClick="onClick"
android:text="平移" />
<Button
android:id="@+id/bt2"
android:layout_width="0dp"
android:layout_height="match_parent"
android:layout_weight="1"
android:onClick="onClick"
android:text="缩放" />
<Button
android:id="@+id/bt3"
android:layout_width="0dp"
android:layout_height="match_parent"
android:layout_weight="1"
android:onClick="onClick"
android:text="错切" />
<Button
android:id="@+id/bt4"
android:layout_width="0dp"
android:layout_height="match_parent"
android:layout_weight="1"
android:onClick="onClick"
android:text="水印" />
</LinearLayout>
<com.example.matrix.MatrixView
android:id="@+id/mv"
android:layout_width="match_parent"
android:layout_height="match_parent" />
<!--图片缩放-->
<com.github.chrisbanes.photoview.PhotoView
android:src="@drawable/a"
android:layout_width="match_parent"
android:layout_height="match_parent" />
</LinearLayout>MatrixView
package com.example.matrix;
import android.annotation.SuppressLint;
import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Matrix;
import android.graphics.Paint;
import android.graphics.PointF;
import android.util.AttributeSet;
import android.view.MotionEvent;
import com.github.chrisbanes.photoview.PhotoView;
@SuppressLint("AppCompatCustomView")
public class MatrixView extends PhotoView {
private Bitmap bitmap;
private Matrix matrix;
private Paint paint;
public MatrixView(Context context) {
super(context);
initBitmap();
}
public MatrixView(Context context, AttributeSet attrs) {
super(context, attrs);
initBitmap();
}
private void initBitmap() {
bitmap = BitmapFactory.decodeResource(getResources(), R.drawable.a);
matrix = new Matrix();
paint = new Paint(Paint.ANTI_ALIAS_FLAG);
paint.setColor(Color.RED);
paint.setStyle(Paint.Style.STROKE);
paint.setStrokeWidth(5);
paint.setTextSize(70);
}
@Override
protected void onDraw(Canvas canvas) {
super.onDraw(canvas);
canvas.drawBitmap(bitmap, matrix, paint);
}
public void scale() {
matrix.reset();
matrix.preScale(2, 2, 0, 0);
invalidate();
}
public void translate() {
matrix.reset();
matrix.preTranslate(200, 200);
invalidate();
}
public void skew() {
matrix.reset();
matrix.preSkew(1, 0, 0, 0);
invalidate();
}
public void addMark(Bitmap oldBitmap) {
Bitmap bitmap = Bitmap.createBitmap(oldBitmap.getWidth(), oldBitmap.getHeight(), Bitmap.Config.ARGB_8888);
Canvas canvas = new Canvas(bitmap);
canvas.drawBitmap(oldBitmap, matrix, paint);
canvas.drawText("赵旭辉", 0, 70, paint);
canvas.save();
this.bitmap = bitmap;
invalidate();
}
private PointF mPointF;
@Override
public boolean dispatchTouchEvent(MotionEvent event) {
if (event.getAction() == MotionEvent.ACTION_DOWN) {
//获取手指位置
if (mPointF == null) {
mPointF = new PointF();
}
mPointF.x = event.getX();
mPointF.y = event.getY();
} else if (event.getAction() == MotionEvent.ACTION_MOVE) {
float indexX = event.getRawX() - mPointF.x/2;
float indexY = event.getRawY() - mPointF.y/2;
matrix.reset();
matrix.preTranslate(indexX, indexY);
invalidate();
} else if (event.getAction() == MotionEvent.ACTION_UP) {
}
return true;
}
}
MainActivity
package com.example.matrix;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.os.Bundle;
import android.view.View;
import androidx.appcompat.app.AppCompatActivity;
public class MainActivity extends AppCompatActivity implements View.OnClickListener {
private MatrixView mv;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
mv = findViewById(R.id.mv);
}
@Override
public void onClick(View v) {
switch (v.getId()) {
case R.id.bt1:
mv.translate();
break;
case R.id.bt2:
mv.scale();
break;
case R.id.bt3:
mv.skew();
break;
case R.id.bt4:
Bitmap bitmap = BitmapFactory.decodeResource(getResources(), R.drawable.a);
mv.addMark(bitmap);
break;
}
}
}