opencv ppt效果_opencv几何图形画法-优快云博客

本文详细介绍了如何使用OpenCV的Java接口来绘制几何图形，包括画线、画圆、画椭圆和画矩形。通过提供的代码示例和效果展示，读者可以学习到如何设置图形的颜色、粗细以及定位等属性。

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opencv几何图形画法

本文目的

目的：学习使用opencv的几何图形画法
语言：java
版本：opencv-410
简介：使用org.opencv.imgproc.Imgproc进行几何图形绘画

画线
画椭圆
画圆
画矩形
画多边形

分解介绍

画线

使用opencv画线，只用了它的一个line函数，
Imgproc.line(img,start,end,new Scalar(0,255,0),thickness,linetype,shift);
函数有几个参数：
第一个是一个Mat对象，代表要在哪个图形上画线
start,end代表线的起始点和结束点坐标（点使用Point）
第四个参数是画线的颜色，这里使用RGB表示法
第五个参数thickness代表了线的粗细
第六个参数linetype代表了线型

public static void drawLine(Mat img,Point start,Point end){
        int thickness = 2;
        int linetype = 8;
        int shift = 0;
        Imgproc.line(img,start,end,new Scalar(0,255,0),thickness,linetype,shift);

    }

画圆

核心几个参数：
1.center定义了圆心的位置
2.第三个参数定义了圆半径
3.其他几个参数同上

private static void drawCircle(Mat mat,Point center){
        Imgproc.circle(mat,center,width/2,new Scalar(255,0,0));
    }

画椭圆

核心几个参数：
1.第二个参数定义了椭圆圆心位置
2.第三个参数定义了椭圆长半径和短半径的长度
3.第四个参数定义了椭圆的旋转角度

private static void drawEclipse(Mat img,double angle){
        int thickness = 2;
        int linetype = 8;
        int shift = 0;
        Imgproc.ellipse(img,
                new Point(width/2,width/2),
                new Size(width/4,width/16),
                angle,0.0,360,
                new Scalar(255,0,0),
                thickness,linetype,shift);
    }

画矩形框

核心参数：
start,end代表了画矩形时从哪个点到哪个对角点

public static void drawRect(Mat img,Point start,Point end){
        int thickness = 2;
        int linetype = 8;
        int shift = 0;
        Imgproc.rectangle(img,start,end,new Scalar(0,0,255));
    }

代码

package com.joe.vision.machine.vision.samples;

import org.opencv.core.*;
import org.opencv.highgui.HighGui;
import org.opencv.imgproc.Imgproc;

import java.util.ArrayList;
import java.util.List;

/**
 * 几何形状画法
 */
public class GeometricDrawingTest {
    static {
        System.loadLibrary(Core.NATIVE_LIBRARY_NAME);
    }

    static int width  = 400;

    public static void main(String[] args){
        String win1 = "window1";
        String win2 = "window2";
        Mat win1_img = Mat.zeros(new Size(width,width), CvType.CV_8UC3);
        Mat win2_img = Mat.zeros(new Size(width,width), CvType.CV_8UC3);

        //画椭圆
        drawEclipse(win1_img,90);
        drawEclipse(win1_img,0);
        drawEclipse(win1_img,-45);
        drawEclipse(win1_img,45);

        //画线
        drawLine(win1_img,new Point(width/2,width/2),new Point(width,width/2));

        //画圆
        drawCircle(win1_img,new Point(width/2,width/2));

        //画矩形块
        drawRect(win1_img,new Point(width/4,width/4),new Point(width/2,width/2));

        //画多边形
        //
        drawPolygon(win1_img);

        HighGui.imshow(win1,win1_img);
        HighGui.waitKey();
        System.exit(0);
    }

    private static void drawCircle(Mat mat,Point center){
        Imgproc.circle(mat,center,width/2,new Scalar(255,0,0));
    }

    /**
     * 画椭圆
     * @param img
     * @param angle
     */
    private static void drawEclipse(Mat img,double angle){
        int thickness = 2;
        int linetype = 8;
        int shift = 0;
        Imgproc.ellipse(img,
                new Point(width/2,width/2),
                new Size(width/4,width/16),
                angle,0.0,360,
                new Scalar(255,0,0),
                thickness,linetype,shift);
    }

    public static void drawLine(Mat img,Point start,Point end){
        int thickness = 2;
        int linetype = 8;
        int shift = 0;
        Imgproc.line(img,start,end,new Scalar(0,255,0),thickness,linetype,shift);

    }

    public static void drawRect(Mat img,Point start,Point end){
        int thickness = 2;
        int linetype = 8;
        int shift = 0;
        Imgproc.rectangle(img,start,end,new Scalar(0,0,255));
    }

    private static void drawPolygon( Mat img ) {
        int lineType = 8;
        int shift = 0;
        Point[] rook_points = new Point[20];
        rook_points[0]  = new Point(     width/4, 7*width/8   );
        rook_points[1]  = new Point(   3*width/4, 7*width/8   );
        rook_points[2]  = new Point(   3*width/4, 13*width/16 );
        rook_points[3]  = new Point( 11*width/16, 13*width/16 );
        rook_points[4]  = new Point( 19*width/32, 3*width/8   );
        rook_points[5]  = new Point(   3*width/4, 3*width/8   );
        rook_points[6]  = new Point(   3*width/4, width/8     );
        rook_points[7]  = new Point( 26*width/40, width/8     );
        rook_points[8]  = new Point( 26*width/40, width/4     );
        rook_points[9]  = new Point( 22*width/40, width/4     );
        rook_points[10] = new Point( 22*width/40, width/8     );
        rook_points[11] = new Point( 18*width/40, width/8     );
        rook_points[12] = new Point( 18*width/40, width/4     );
        rook_points[13] = new Point( 14*width/40, width/4     );
        rook_points[14] = new Point( 14*width/40, width/8     );
        rook_points[15] = new Point(     width/4, width/8     );
        rook_points[16] = new Point(     width/4, 3*width/8   );
        rook_points[17] = new Point( 13*width/32, 3*width/8   );
        rook_points[18] = new Point(  5*width/16, 13*width/16 );
        rook_points[19] = new Point(     width/4, 13*width/16 );
        MatOfPoint matPt = new MatOfPoint();
        matPt.fromArray(rook_points);
        List<MatOfPoint> ppt = new ArrayList<MatOfPoint>();
        ppt.add(matPt);
        Imgproc.fillPoly(img,
                ppt,
                new Scalar( 255, 255, 255 ),
                lineType,
                shift,
                new Point(0,0) );
    }

}