Android图形图像处理：添加涂鸦文字

╰+攻爆jí腚メ 2024-02-19 17:31 160阅读 0赞

先看运行效果：

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3poYW5ncGhpbA_size_16_color_FFFFFF_t_70][]

关键的PaintView:

package com.zhangphil;
    
    import android.content.Context;
    import android.graphics.Canvas;
    import android.graphics.Color;
    import android.graphics.Paint;
    import android.graphics.Path;
    import android.util.AttributeSet;
    import android.view.MotionEvent;
    import android.view.View;
    
    import java.util.ArrayList;
    import java.util.List;
    
    public class PaintView extends View {
    
        public class DrawPath {
            Path path;
            Paint paint;
        }
    
        private Paint paint;
        private Path path;
        private float downX, downY;
        private float tempX, tempY;
        private int paintWidth = 10;
        private List<DrawPath> drawPathList;
        private List<DrawPath> savePathList;
    
        public PaintView(Context context) {
            this(context, null);
        }
    
        public PaintView(Context context, AttributeSet attrs) {
            this(context, attrs, 0);
        }
    
        public PaintView(Context context, AttributeSet attrs, int defStyleAttr) {
            super(context, attrs, defStyleAttr);
            drawPathList = new ArrayList<>();
            savePathList = new ArrayList<>();
            initPaint();
        }
    
        private void initPaint() {
            paint = new Paint();
            paint.setAntiAlias(true);
            paint.setStrokeWidth(paintWidth);
            paint.setStyle(Paint.Style.STROKE);
        }
    
        @Override
        protected void onDraw(Canvas canvas) {
            super.onDraw(canvas);
            if (drawPathList != null && !drawPathList.isEmpty()) {
                for (DrawPath drawPath : drawPathList) {
                    if (drawPath.path != null) {
                        canvas.drawPath(drawPath.path, drawPath.paint);
                    }
                }
            }
        }
    
        @Override
        public boolean onTouchEvent(MotionEvent event) {
            switch (event.getAction()) {
                case MotionEvent.ACTION_DOWN:
                    downX = event.getX();
                    downY = event.getY();
                    path = new Path();//每次手指下去都是一条新的路径
                    path.moveTo(downX, downY);
                    DrawPath drawPath = new DrawPath();
                    drawPath.paint = paint;
                    drawPath.path = path;
                    drawPathList.add(drawPath);
                    invalidate();
                    tempX = downX;
                    tempY = downY;
                    break;
                case MotionEvent.ACTION_MOVE:
                    float moveX = event.getX();
                    float moveY = event.getY();
                    path.quadTo(tempX, tempY, moveX, moveY);
                    invalidate();
                    tempX = moveX;
                    tempY = moveY;
                    break;
                case MotionEvent.ACTION_UP:
                    initPaint();//每次手指抬起都要重置下画笔,不然画笔会保存了之前的设置什么画笔的属性会引起bug
                    break;
            }
            return true;
        }
    
        /**
         * 撤销功能。
         */
        public void undo() {
            if (drawPathList != null && drawPathList.size() >= 1) {
                savePathList.add(drawPathList.get(drawPathList.size() - 1));
                drawPathList.remove(drawPathList.size() - 1);
                invalidate();
            }
        }
    
        /**
         * 反撤销功能。重新生效。
         */
        public void reundo() {
            if (savePathList != null && !savePathList.isEmpty()) {
                drawPathList.add(savePathList.get(savePathList.size() - 1));
                savePathList.remove(savePathList.size() - 1);
                invalidate();
            }
        }
    
        /**
         * 改变画笔颜色。
         *
         * @param color
         */
        public void resetPaintColor(int color) {
            paint.setColor(color);
        }
    
        /**
         * 放大就是改变画笔的宽度。线条变粗。
         */
        public void resetPaintWidth() {
            paintWidth += 2;
            paint.setStrokeWidth(paintWidth);
        }
    
        /**
         * 橡皮擦功能。
         * 原理是把画笔的颜色和view的背景颜色一样就,然后把画笔的宽度变大了,擦除的时候显得擦除范围大点。
         */
        public void eraser() {
            paint.setColor(Color.WHITE);//这是view背景的颜色
            paint.setStrokeWidth(paintWidth + 6);
        }
    }

剩下的就是使用。写一个xml布局：

<?xml version="1.0" encoding="utf-8"?>
    <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
        android:id="@+id/activity_main"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:background="#ffffff">
    
        <RelativeLayout
            android:id="@+id/rl_left"
            android:layout_width="100dp"
            android:layout_height="match_parent">
    
            <Button
                android:id="@+id/btn_undo"
                android:layout_width="match_parent"
                android:layout_height="60dp"
                android:text="撤销" />
    
            <Button
                android:id="@+id/btn_do"
                android:layout_width="match_parent"
                android:layout_height="60dp"
                android:layout_below="@id/btn_undo"
                android:text="反撤销" />
    
            <Button
                android:id="@+id/btn_red"
                android:layout_width="match_parent"
                android:layout_height="60dp"
                android:layout_below="@id/btn_do"
                android:text="红色" />
    
            <Button
                android:id="@+id/btn_blue"
                android:layout_width="match_parent"
                android:layout_height="60dp"
                android:layout_below="@id/btn_red"
                android:text="蓝色" />
    
            <Button
                android:id="@+id/btn_green"
                android:layout_width="match_parent"
                android:layout_height="60dp"
                android:layout_below="@id/btn_blue"
                android:text="绿色" />
    
            <Button
                android:id="@+id/btn_scral"
                android:layout_width="match_parent"
                android:layout_height="60dp"
                android:layout_below="@id/btn_green"
                android:text="放大" />
    
            <Button
                android:id="@+id/btn_eraser"
                android:layout_width="match_parent"
                android:layout_height="60dp"
                android:layout_below="@id/btn_scral"
                android:text="橡皮擦" />
        </RelativeLayout>
    
        <com.zhangphil.PaintView
            android:id="@+id/paint_view"
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:layout_toRightOf="@id/rl_left" />
    </RelativeLayout>

测试的Activity：

package zhangphil.test;
    
    import android.graphics.Color;
    import android.support.v7.app.AppCompatActivity;
    import android.os.Bundle;
    import android.view.View;
    import android.widget.Button;
    
    import com.zhangphil.PaintView;
    
    public class DrawActivity extends AppCompatActivity implements View.OnClickListener {
        private Button btnUndo;
        private Button btnDo;
        private Button btnRed;
        private Button btnBlue;
        private Button btnGreen;
        private Button btnScral; //放大。
        private Button btnEraser; //橡皮擦。
        private PaintView paintView;
    
        @Override
        protected void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            setContentView(R.layout.activity_main);
            initView();
            initListener();
        }
    
        private void initListener() {
            btnUndo.setOnClickListener(this);
            btnDo.setOnClickListener(this);
            btnRed.setOnClickListener(this);
            btnBlue.setOnClickListener(this);
            btnGreen.setOnClickListener(this);
            btnScral.setOnClickListener(this);
            btnEraser.setOnClickListener(this);
        }
    
        private void initView() {
            paintView = (findViewById(R.id.paint_view));
            btnUndo = findViewById(R.id.btn_undo);
            btnDo = findViewById(R.id.btn_do);
            btnRed = findViewById(R.id.btn_red);
            btnBlue = findViewById(R.id.btn_blue);
            btnGreen = findViewById(R.id.btn_green);
            btnScral = findViewById(R.id.btn_scral);
            btnEraser =  findViewById(R.id.btn_eraser);
        }
    
        @Override
        public void onClick(View v) {
            switch (v.getId()) {
                case R.id.btn_undo:
                    paintView.undo();
                    return;
                case R.id.btn_do:
                    paintView.reundo();
                    return;
                case R.id.btn_red:
                    paintView.resetPaintColor(Color.RED);
                    return;
                case R.id.btn_green:
                    paintView.resetPaintColor(Color.GREEN);
                    return;
                case R.id.btn_blue:
                    paintView.resetPaintColor(Color.BLUE);
                    return;
                case R.id.btn_scral:
                    paintView.resetPaintWidth();
                    break;
                case R.id.btn_eraser:
                    paintView.eraser();
                    break;
            }
        }
    }

[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3poYW5ncGhpbA_size_16_color_FFFFFF_t_70]: https://image.dandelioncloud.cn/pgy_files/images/2024/01/29/0927d9f2b9594b42aa59329f6d97a5b1.png