文章目录
前言
opencv绘制形状与文字
一、绘制形状与文字的模板类：
1、Point模板类（二维）：
解析：为了描述图像中的点，opencv提供了由坐标“x”和“y”指定的 二维点 的模板类,该类的一个实例可以与C结构、CvPoint和CvPoint2D32f互换。有也是一个cast操作符，用于将点坐标转换为指定类型。从通过舍入将浮点坐标转换为整数坐标。通常，转换对每个坐标使用此操作
pt1 = pt2 + pt3;
pt1 = pt2 - pt3;
pt1 = pt2 * a;
pt1 = a * pt2;
pt1 = pt2 / a;
pt1 += pt2;
pt1 -= pt2;
pt1 *= a;
pt1 /= a;
double value = norm(pt); // L2 norm
pt1 == pt2;
pt1 != pt2;
为方便起见，定义了以下类型别名:
typedef Point_<int> Point2i;
typedef Point2i Point;
typedef Point_<float> Point2f;
typedef Point_<double> Point2d;
举例：
Point2f a(0.3f, 0.f), b(0.f, 0.4f);
Point pt = (a + b)*10.f;
cout << pt.x << ", " << pt.y << endl;
三维的点坐标，我们可以自行学习：
2、Scalar向量模板类：
解析：从Vec派生的4元素向量的模板类，从Vec\<_Tp, 4\> , Scalar\_ 和 Scalar派生而来，可以像典型的4元素一样使用向量。此外，还可以将它们转换为CvScalar。OpenCV传递像素值。
//进行实例化，直接使用color使用创建的像素值
Scalar color = Scalar(0, 150, 15);
3、Rect二维矩阵模板类：
解析：二维矩形的简明模板类；左上角的坐标开始，构建一个矩阵
OpenCV通常假定矩形的上边界和左边界是包含的，而右边界和下边界不相同。
//构造函数：
Rect_();
Rect_(_Tp _x, _Tp _y, _Tp _width, _Tp _height);
Rect_(const Rect_& r);
Rect_(Rect_&& r) CV_NOEXCEPT;
Rect_(const Point_<_Tp>& org, const Size_<_Tp>& sz);
Rect_(const Point_<_Tp>& pt1, const Point_<_Tp>& pt2);
//参数：
_Tp x；//左上角的x坐标
_Tp y；//左上角的y坐标
_Tp width；//矩形的宽度
_Tp height；//矩形的高度
矩形的其他操作：
-\f$\texttt{
rect} = \texttt{
rect} \pm \texttt{
point}\f$ （将矩形移动一定的偏移量）
-\f$\texttt{
rect} = \texttt{
rect} \pm \texttt{
size}\f$ 通过一定数量）
-rect+=point，rect-=point，rect+=size，rect-=size（增广运算）
-rect=rect1&rect2（矩形相交）
-rect=rect1 | rect2（包含rect1和rect2的最小面积矩形）
-rect&=rect1，rect |=rect1（及相应的增广运算）
-rect==rect1，rect！=rect1（矩形比较）
4、RNG类
解析：第一个窗体将状态设置为预定义值，在当前实现中等于2\*\*32-1。这个第二种形式将状态设置为指定值。如果通过state=0，构造函数使用上述默认值来避免奇异随机数序列，由全零组成。
构造函数：
RNG();
/** @overload
@param state 64-bit value used to initialize the RNG.
*/
RNG(uint64 state);
uniform()方法：
int uniform(int a, int b);
/** @overload */
float uniform(float a, float b);
/** @overload */
double uniform(double a, double b);
//返回[a，b）范围内均匀分布的整数随机数这些方法使用MWC算法进行状态转换，
//并返回下一个指定类型的均匀布随机数从输入参数类型，从范围[a，b]。
二、绘制形状与文字的函数：
1、line()函数：
简而言之：绘制从第一个点指向第二个点的箭头段。
void line(InputOutputArray img, Point pt1, Point pt2, const Scalar& color,
int thickness = 1, int lineType = LINE_8, int shift = 0);
/*
img 图像.
pt1 pt1箭头的起始点.
pt2 pt2箭头指向的点.
color 线条颜色.
thickness 线条厚度.
line_type line的类型.
shift Number of fractional bits in the point coordinates.点坐标中小数位数的移位
tipLength 相对于箭头长度的箭头尖端长度
*/
line()函数线的类型：
enum LineTypes {
FILLED = -1,
LINE_4 = 4, //!< 4-connected line
LINE_8 = 8, //!< 8-connected line
LINE_AA = 16 //!< antialiased line抗锯齿
};
2、rectangle()函数：
简而言之：绘制简单的、粗的或填充的右矩形。rectangle绘制一个矩形轮廓或两个对角的填充矩形是pt1和pt2。
rectangle()函数的多态：
CV_EXPORTS_W void rectangle(InputOutputArray img, Point pt1, Point pt2,
const Scalar& color, int thickness = 1,
int lineType = LINE_8, int shift = 0);
/*use `rec` parameter as alternative specification of the drawn rectangle: `r.tl() and
r.br()-Point(1,1)` are opposite corners*/
CV_EXPORTS_W void rectangle(InputOutputArray img, Rect rec,
const Scalar& color, int thickness = 1,
int lineType = LINE_8, int shift = 0);
/** @example samples/cpp/tutorial_code/ImgProc/basic_drawing/Drawing_2.cpp
An example using drawing functions*/
3、ellipse()函数：
简而言之，绘制简单或粗的椭圆弧或填充椭圆扇区。eliple绘制椭圆轮廓、填充椭圆和椭圆，圆弧或实心椭圆扇形。采用分段线性曲线逼近椭圆弧边界。
ellipse()函数的多态：
CV_EXPORTS_W void ellipse(InputOutputArray img, Point center, Size axes,
double angle, double startAngle, double endAngle,
const Scalar& color, int thickness = 1,
int lineType = LINE_8, int shift = 0);
CV_EXPORTS_W void ellipse(InputOutputArray img, const RotatedRect& box, const Scalar& color,
int thickness = 1, int lineType = LINE_8);
4、circle()函数：
简而言之：画了一个圆。circle用给定的圆心和半径绘制一个简单的或填充的圆。
circle()函数的构造：
CV_EXPORTS_W void circle(InputOutputArray img, Point center, int radius,
const Scalar& color, int thickness = 1,
int lineType = LINE_8, int shift = 0);
5、fillPoly()函数：
简而言之：填充凸多边形，fillconverxpoly绘制一个填充的凸多边形。这个函数比函数#fillPoly。它不仅可以填充凸多边形，而且可以填充任何单调多边形自相交，即轮廓与每条水平线（扫描线）相交的多边形最多两次（不过，其顶部和/或底部边缘可能是水平的）。
fillPoly()函数的构造：
CV_EXPORTS void fillPoly(InputOutputArray img, const Point** pts,
const int* npts, int ncontours,
const Scalar& color, int lineType = LINE_8, int shift = 0,
Point offset = Point() );
三、在图像上绘制形状和文字：
1、绘制线条：
代码块：
#include <opencv2/opencv.hpp>
#include <iostream>
using namespace std;
using namespace cv;
Mat bgImage;
const char* dravdemo_win = "draw shapes and text demo!!!";
void Myline() {
Point p1 = Point(0, 0);
Point p2;
p2.x = bgImage.cols;
p2.y = bgImage.rows;
Scalar color = Scalar(0, 0, 255);
line(bgImage, p1, p2, color, 1, LINE_4);
}
int main() {
bgImage = imread("D:\\Myfile\\素材照片\\opencv素材照片\\4.jpg");
if (!bgImage.data) {
cout << "could not load image..." << endl;
return 0;
}
Myline();
namedWindow(dravdemo_win, WINDOW_AUTOSIZE);
imshow(dravdemo_win, bgImage);
waitKey(0);
return 0;
}
运行结果：
2、绘制矩形
代码块：
#include <opencv2/opencv.hpp>
#include <iostream>
using namespace std;
using namespace cv;
Mat bgImage;
const char* dravdemo_win = "draw shapes and text demo!!!";
void MyRectangle() {
Rect rect = Rect(66, 25, 73, 72);
Scalar color = Scalar(255, 0, 0);
rectangle(bgImage, rect, color, 2, LINE_8);
rect= Rect(142, 60, 55, 60);
color = Scalar(0, 255, 0);
rectangle(bgImage, rect, color, 2, LINE_8);
rect = Rect(210, 62, 55, 55);
color = Scalar(0, 0, 255);
rectangle(bgImage, rect, color, 2, LINE_8);
}
int main() {
bgImage = imread("D:\\Myfile\\素材照片\\opencv素材照片\\8.jpg");
if (!bgImage.data) {
cout << "could not load image..." << endl;
return 0;
}
MyRectangle();
namedWindow(dravdemo_win, WINDOW_AUTOSIZE);
imshow(dravdemo_win, bgImage);
waitKey(0);
return 0;
}
运行结果：
3、绘制椭圆与圆
代码块：
#include <opencv2/opencv.hpp>
#include <iostream>
using namespace std;
using namespace cv;
Mat bgImage;
const char* dravdemo_win = "draw shapes and text demo!!!";
void MyEllipse() {
Scalar color = Scalar(0, 255, 255);
ellipse(bgImage, Point(bgImage.cols / 2, bgImage.rows / 2), Size(bgImage.cols / 4, bgImage.rows / 4), 90, 0, 360, color, 2, LINE_8);
}
void MyCircle() {
Scalar color = Scalar(255, 0, 255);
circle(bgImage, Point(bgImage.cols / 2, bgImage.rows / 2), 30, color, 2, LINE_8);
}
int main() {
bgImage = imread("D:\\Myfile\\素材照片\\opencv素材照片\\8.jpg");
if (!bgImage.data) {
cout << "could not load image..." << endl;
return 0;
}
MyEllipse();
MyCircle();
namedWindow(dravdemo_win, WINDOW_AUTOSIZE);
imshow(dravdemo_win, bgImage);
waitKey(0);
return 0;
}
运行结果：
4、绘制凸多边形
代码块：
#include <opencv2/opencv.hpp>
#include <iostream>
using namespace std;
using namespace cv;
Mat bgImage;
const char* dravdemo_win = "draw shapes and text demo!!!";
void MyPolygon() {
Point pts[1][5];
pts[0][0] = Point(10, 10);
pts[0][1] = Point(10, 40);
pts[0][2] = Point(200, 200);
pts[0][3] = Point(200, 10);
pts[0][4] = Point(10, 10);
const Point* ppts[] = {
pts[0] };
int npt[] = {
5 };
Scalar color = Scalar(0, 150, 15);
fillPoly(bgImage, ppts, npt, 1, color, 8);
}
int main() {
bgImage = imread("D:\\Myfile\\素材照片\\opencv素材照片\\4.jpg");
if (!bgImage.data) {
cout << "could not load image..." << endl;
return 0;
}
MyPolygon();
namedWindow(dravdemo_win, WINDOW_AUTOSIZE);
imshow(dravdemo_win, bgImage);
waitKey(0);
return 0;
}
运行结果：
5、写文字
代码块：
#include <opencv2/opencv.hpp>
#include <iostream>
using namespace std;
using namespace cv;
int main() {
Mat bgImage;
const char* dravdemo_win = "draw shapes and text demo!!!";
bgImage = imread("D:\\Myfile\\素材照片\\opencv素材照片\\6.jpg");
if (!bgImage.data) {
cout << "could not load image..." << endl;
return 0;
}
putText(bgImage, "Hello five-size-seven!", Point(10, 20), FONT_HERSHEY_DUPLEX, 1.0, Scalar(120, 255, 120), 1, 4); namedWindow(dravdemo_win, WINDOW_AUTOSIZE);
namedWindow(dravdemo_win, WINDOW_AUTOSIZE);
imshow(dravdemo_win, bgImage);
waitKey(0);
return 0;
}
运行结果：
6、绘制随机线条
代码块：
#include <opencv2/opencv.hpp>
#include <iostream>
using namespace std;
using namespace cv;
Mat bgImage;
const char* dravdemo_win = "draw shapes and text demo!!!";
void RandomLineDemo() {
RNG rng(12345);
Point pt1;
Point pt2;
namedWindow("Randow_new_image", WINDOW_AUTOSIZE);
Mat new_bgImage = Mat::zeros(bgImage.size(), bgImage.type());
for (int i = 0; i < 100000; i++) {
pt1.x = rng.uniform(0, bgImage.cols);
pt2.x = rng.uniform(0, bgImage.cols);
pt1.y = rng.uniform(0, bgImage.rows);
pt2.y = rng.uniform(0, bgImage.rows);
Scalar color = Scalar(rng.uniform(0, 255), rng.uniform(0, 255), rng.uniform(0, 255));
if (waitKey(50) > 0)break;
line(new_bgImage, pt1, pt2, color, 1, 8);
imshow("Randow_new_image", new_bgImage);
}
}
int main() {
bgImage = imread("D:\\Myfile\\素材照片\\opencv素材照片\\4.jpg");
if (!bgImage.data) {
cout << "could not load image..." << endl;
return 0;
}
RandomLineDemo();
namedWindow(dravdemo_win, WINDOW_AUTOSIZE);
imshow(dravdemo_win, bgImage);
waitKey(0);
return 0;
}
运行结果：
四、总代码块
#include <opencv2/opencv.hpp>
#include <iostream>
using namespace std;
using namespace cv;
Mat bgImage;
const char* dravdemo_win = "draw shapes and text demo!!!";
void Myline() {
Point p1 = Point(0, 0);
Point p2;
p2.x = bgImage.cols;
p2.y = bgImage.rows;
Scalar color = Scalar(0, 0, 255);
line(bgImage, p1, p2, color, 1, LINE_8);
}
void MyRectangle() {
Rect rect = Rect(66, 25, 73, 72);
Scalar color = Scalar(255, 0, 0);
rectangle(bgImage, rect, color, 2, LINE_8);
rect= Rect(142, 60, 55, 60);
color = Scalar(0, 255, 0);
rectangle(bgImage, rect, color, 2, LINE_8);
rect = Rect(210, 62, 55, 55);
color = Scalar(0, 0, 255);
rectangle(bgImage, rect, color, 2, LINE_8);
}
void MyEllipse() {
Scalar color = Scalar(0, 255, 255);
ellipse(bgImage, Point(bgImage.cols / 2, bgImage.rows / 2), Size(bgImage.cols / 4, bgImage.rows / 4), 90, 0, 360, color, 2, LINE_8);
}
void MyCircle() {
Scalar color = Scalar(255, 0, 255);
circle(bgImage, Point(bgImage.cols / 2, bgImage.rows / 2), 30, color, 2, LINE_8);
}
void MyPolygon() {
Point pts[1][5];
pts[0][0] = Point(10, 10);
pts[0][1] = Point(10, 40);
pts[0][2] = Point(20, 20);
pts[0][3] = Point(20, 10);
pts[0][4] = Point(10, 10);
const Point* ppts[] = {
pts[0] };
int npt[] = {
5 };
Scalar color = Scalar(0, 150, 15);
fillPoly(bgImage, ppts, npt, 1, color, 8);
}
void RandomLineDemo() {
RNG rng(12345);
Point pt1;
Point pt2;
namedWindow("Randow_new_image", WINDOW_AUTOSIZE);
Mat new_bgImage = Mat::zeros(bgImage.size(), bgImage.type());
for (int i = 0; i < 100000; i++) {
pt1.x = rng.uniform(0, bgImage.cols);
pt2.x = rng.uniform(0, bgImage.cols);
pt1.y = rng.uniform(0, bgImage.rows);
pt2.y = rng.uniform(0, bgImage.rows);
Scalar color = Scalar(rng.uniform(0, 255), rng.uniform(0, 255), rng.uniform(0, 255));
if (waitKey(50) > 0)break;
line(new_bgImage, pt1, pt2, color, 1, 8);
imshow("Randow_new_image", new_bgImage);
}
}
int main() {
bgImage = imread("D:\\Myfile\\素材照片\\opencv素材照片\\8.jpg");
if (!bgImage.data) {
cout << "could not load image..." << endl;
return 0;
}
Myline();
MyRectangle();
MyEllipse();
MyCircle();
MyPolygon();
//RandomLineDemo();
putText(bgImage, "Hello Opencv", Point(10, 20), FONT_HERSHEY_PLAIN, 1.0, Scalar(120, 120, 120), 1, 4); namedWindow(dravdemo_win, WINDOW_AUTOSIZE);
namedWindow(dravdemo_win, WINDOW_AUTOSIZE);
imshow(dravdemo_win, bgImage);
waitKey(0);
return 0;
}
运行结果：
总结
本文讲述了如何绘画形状和文字，已经创建随机线条
如有错误，敬请指正！