安卓之图形绘制的应用场景以及各种技术优劣分析

public class MyView extends View {
    private Bitmap mBitmap;
    private Canvas mCanvas;
    private Paint mPaint;

    public MyView(Context context) {
        super(context);
        init();
    }

    private void init() {
        mBitmap = BitmapFactory.decodeResource(getResources(), R.drawable.my_image);
        mCanvas = new Canvas(mBitmap);
        mPaint = new Paint();
        mPaint.setColor(Color.RED);
        mPaint.setStyle(Paint.Style.FILL);
    }

    @Override
    protected void onDraw(Canvas canvas) {
        super.onDraw(canvas);
        mCanvas.drawRect(0, 0, mBitmap.getWidth(), mBitmap.getHeight(), mPaint);
    }
}

dependencies {
    implementation 'com.caverock:androidsvg-aar:1.4'
}

然后进行绘制
import android.graphics.Canvas;
import android.graphics.Paint;
import com.caverock.androidsvg.SVG;
import com.caverock.androidsvg.SVGParseException;

public class SvgToPathExample {

    public void drawSvgOnCanvas(Canvas canvas, String svgAssetPath) {
        try {
            // 加载SVG资源
            SVG svg = SVG.getFromResource(context.getResources(), R.drawable.your_svg_file);

            // 获取SVG的根元素，它包含了图形的所有路径信息
            SVGLength height = svg.getDocumentHeight();
            SVGLength width = svg.getDocumentWidth();

            // 创建一个足够大的画布区域来适应SVG大小
            canvas.save();
            canvas.translate(0, 0); // 调整坐标系以使SVG居中或放置在合适位置
            canvas.clipRect(0, 0, width.getValue(), height.getValue());

            // 将SVG中的所有路径转换并绘制到Canvas上
            for (SVGDrawable drawable : svg.getDrawableRoot().getChildren()) {
                if (drawable instanceof SVGShape) {
                    SVGShape shape = (SVGShape) drawable;
                    Path path = shape.getPath(); // 获取SVG形状的Path对象

                    // 创建Paint对象，并设置颜色、填充模式等属性
                    Paint paint = new Paint(Paint.ANTI_ALIAS_FLAG);
                    paint.setColor(Color.BLACK); // 设置颜色
                    paint.setStyle(Paint.Style.FILL); // 设置填充样式

                    // 在Canvas上绘制Path
                    canvas.drawPath(path, paint);
                }
            }

            canvas.restore();

        } catch (SVGParseException e) {
            e.printStackTrace();
        }
    }
}

// 使用示例：
drawSvgOnCanvas(yourCanvas, "your_svg_asset_path");

public class MyView extends View implements GLSurfaceView.Renderer {
    private Triangle mTriangle;
    private GLES20 mGLES20;

    public MyView(Context context) {
        super(context);
        init();
    }

    private void init() {
        mTriangle = new Triangle();
        mGLES20 = (GLES20) EGLContext.getEGL().getCurrentContext();
    }

    @Override
    public void onSurfaceCreated(GL10 unused, EGLConfig config) {
        mGLES20.glClearColor(0.0f, 0.0f, 0.0f, 1.0f);
    }

    @Override
    public void onDrawFrame(GL10 unused) {
        mGLES20.glClear(GLES20.GL_COLOR_BUFFER_BIT | GLES20.GL_DEPTH_BUFFER_BIT);
        mTriangle.draw();
    }
}

<vector xmlns:android="http://schemas.android.com/apk/res/android"
    android:width="24dp"
    android:height="24dp"
    android:viewportWidth="24.0"
    android:viewportHeight="24.0">
    <path
        android:fillColor="#FF000000"
        android:pathData="M12,2C6.48,2 2,6.48 2,12s4.48,10 10,10 10,-4.48 10,-10S17.52,2 12,2zM10,17l-5,-5 1.41,-1.41L10,14.17v-2.28l7.07,-7.07L19,8.5l-7.07,7.07v2.28L10,17z" />
</vector>

在XML布局文件中定义一个View:
<View  
    android:layout_width="200dp"  
    android:layout_height="200dp"  
android:background="@drawable/shape_drawable" />

在res/drawable目录下创建一个名为shape_drawable.xml的文件，并添加以下内容：
<shape xmlns:android="http://schemas.android.com/apk/res/android">  
    <gradient  
        android:startColor="#FF0000"  
        android:endColor="#0000FF"  
        android:angle="90" />  
    <solid android:color="#FFFFFF" />  
    <corners android:radius="10dp" />  
</shape>

// 导入所需的OpenCV库
import org.opencv.android.Utils;
import org.opencv.core.Core;
import org.opencv.core.CvType;
import org.opencv.core.Mat;
import org.opencv.core.Point;
import org.opencv.core.Rect;
import org.opencv.imgcodecs.Imgcodecs;
import org.opencv.imgproc.Imgproc;

// 在你的Activity或者自定义类中操作
public class OpenCVDrawExample extends AppCompatActivity {

    private Mat mRgba; // 声明一个Mat对象用于存储图像

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        // 创建一个空白图像
        mRgba = new Mat(480, 640, CvType.CV_8UC4); // 4通道图像，也可以用CV_8UC3创建3通道图像

        // 绘制一个矩形
        Point rectStartPoint = new Point(100, 100);
        Point rectEndPoint = new Point(300, 300);
        Rect rectangle = new Rect(rectStartPoint, rectEndPoint);

        Scalar color = new Scalar(0, 255, 0, 255); // 绿色填充（对于4通道）
        int thickness = 2; // 边框粗细
        int lineType = Imgproc.LINE_AA; // 抗锯齿线型

        Imgproc.rectangle(mRgba, rectangle.tl(), rectangle.br(), color, thickness, lineType);

        // 将结果显示到ImageView中（假设你有一个名为imageView的ImageView控件）
        ImageView imageView = findViewById(R.id.imageView);
        Bitmap bitmap = Bitmap.createBitmap(mRgba.cols(), mRgba.rows(), Bitmap.Config.ARGB_8888);
        Utils.matToBitmap(mRgba, bitmap);
        imageView.setImageBitmap(bitmap);
    }
}