I have nothing to do on weekends and use opencv to simply implement a tool class that can draw curves in mat, which is convenient for learning image processing related content.
The coordinate system itself is relatively simple. It is a conventional mathematical coordinate system. You can freely set the range of the coordinate system in the image, and the points to be drawn will be automatically mapped to the Mat. Because the annotations are relatively complete, the following is only a brief description of the usage and will not be explained in detail.
double mysqrt(double x) {
return sqrt(x);
}
double mysqare(double x, int a, int b) {
return x * x * a + b;
}
double myawx(double x, int a, int b) {
return x * a + b;
}
void testSurface() {
AxisSurface surface(cv::Size(960, 960), 10);
int axisRange = 50;
AxisRange range = {
cv::Point2d(-1 * axisRange, -1 * axisRange), cv::Point2d(axisRange, axisRange) };
surface.setRange(range);
auto func1 = std::bind(mysqrt, std::placeholders::_1);
AxisFunc<decltype(func1)> axisFunc1 = {
func1, -256, 256, 0.001, AxisColorRed, "f(x) = sqrt(x)"};
surface.draw(axisFunc1);
auto func2 = std::bind(mysqare, std::placeholders::_1, 2, -30);
AxisFunc<decltype(func2)> axisFunc2 = {
func2, -256, 256, 0.001, AxisColorBlue, "f(x) = 2x^2 - 30" };
surface.draw(axisFunc2);
auto func3 = std::bind(myawx, std::placeholders::_1, 1, 20);
AxisFunc<decltype(func3)> axisFunc3 = {
func3, -256, 256, 0.001, AxisColorBlue, "f(x) = x + 20" };
surface.draw(axisFunc3);
cv::Mat ret = surface.getSurface();
cv::namedWindow("");
cv::imshow("", ret);
cv::waitKey(0);
}
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002.jpg |
Implementation
#ifndef __AXIS_SURFACE_H__
#define __AXIS_SURFACE_H__
/*
* @brief 一个坐标系的实现，会将图像绘制到opencv的mat中，主要用来绘制函数曲线，函数曲线使用点来绘制
*/
#include <opencv/cv.h>
#include <opencv2/opencv.hpp>
#include <memory>
/*
* @brief 一些预设的颜色和方位
*/
#define AxisColorBlack cv::Scalar(0, 0, 0)
#define AxisColorWhite cv::Scalar(255, 255, 255)
#define AxisColorGray(x) cv::Scalar(int(x), int(x), int(x))
#define AxisColorRed cv::Scalar(0, 0, 255)
#define AxisColorGreen cv::Scalar(0, 255, 0)
#define AxisColorBlue cv::Scalar(255, 0, 0)
enum AxisTextLocation : int32_t {
AxisTextLocationTop,
AxisTextLocationTopRight,
AxisTextLocationRight,
AxisTextLocationBottomRight,
AxisTextLocationBottom,
AxisTextLocationBottomLeft,
AxisTextLocationLeft,
AxisTextLocationTopLeft,
};
/*
* @brief 坐标轴的边框的设置参数
* @param color 坐标轴边框的颜色
* @param type 绘制的线的类型
* @param width 宽度
*/
struct AxisLineParam {
cv::Scalar color;
cv::LineTypes type;
int32_t width;
};
/*
* @brief 画布中坐标轴的范围，正常的xy坐标轴，内部会将坐标映射到画布中，比如希望创建[-10,-10]->[10,10]大小的画布，分别设置两个点为[-10,-10] [10,10]即可
* @param leftBottom 坐标轴左下角坐标
* @param rightTop 坐标轴右下角坐标
*/
struct AxisRange {
cv::Point2d leftBottom;
cv::Point2d rightTop;
};
/*
* @brief 绘制的函数的参数，来描述希望绘制的函数曲线的具体参数，曲线使用点绘制的
* @pram func 函数模板，使用时使用std::bind绑定函数即可
* @param startx 希望绘制的x坐标范围[startx, endx]
* @param endx 希望绘制的曲线的x坐标范围的结尾
* @param step 绘制曲线时x坐标的步进，即相邻两个点之间横坐标的差
* @param color 绘制的曲线的颜色
* @param desc 绘制曲线的描述
* @param radius 绘制曲线每个点的半径
*/
template<class Func>
struct AxisFunc {
Func func;
double startx;
double endx;
double step;
cv::Scalar color;
std::string desc;
double radius;
};
/*
* @brief 使用opencv绘制函数曲线，内部包含一个mat类，所有的内容都会绘制到mat中
* @param m_size 当前画布的大小，即Mat的实际大小
* @param m_border 坐标轴边界和mat边界之间的间距，四个边是等距的
* @param m_lineParam 绘制边框的线的参数
* @param m_range 当前画布中坐标轴的范围
* @param m_psurface 当前绘制的画面的mat
*/
class AxisSurface{
public:
AxisSurface(const cv::Size size = {
720, 480 }, const int32_t border = 20, const AxisLineParam& lineParam = {
AxisColorBlack, cv::LINE_8, 2 }) : m_size(size), m_border(border), m_lineParam(lineParam) {
m_psurface = std::make_shared<cv::Mat>(m_size.height, m_size.width, CV_8UC3, AxisColorWhite);
update(m_size, m_border, lineParam);
}
~AxisSurface() {
}
public:
void setRange(const AxisRange &range) {
if (!(m_range.leftBottom == range.leftBottom && m_range.rightTop == range.rightTop)) {
m_range = range;
clear(m_size, m_border, m_lineParam);
}
}
/*
* @brief 绘制函数曲线，以及函数的描述
*/
template<class Func>
void draw(const AxisFunc<Func> func) {
for (double x = func.startx; x <= func.endx; x += func.step) {
double y = func.func(x);
drawPoint(cv::Point2d(x, y), func.radius, func.color);
}
cv::Size textSize = cv::getTextSize(func.desc, cv::FONT_HERSHEY_SIMPLEX, 0.4, 1, nullptr);
double value = (textSize.height + 7) * (m_range.rightTop.y - m_range.leftBottom.y) / (m_size.height - 2.0 * m_border);
drawText(func.desc, cv::Point2d(m_range.leftBottom.x, m_range.rightTop.y - value * m_funcNumber++), cv::FONT_HERSHEY_SIMPLEX, 0.4, func.color, AxisTextLocationBottomRight);
update(m_size, m_border, m_lineParam);
}
cv::Mat getSurface() {
return (*m_psurface).clone();
}
/**
* @brief 仅仅更新坐标轴的参数
*/
void updateSetting(const int border, const AxisLineParam& lineParam) {
m_lineParam = lineParam;
m_border = border;
update(m_size, border, lineParam);
}
/**
* @brief 更新当前已经绘制的mat的参数，如果尺寸和当前存在的mat不同会清空已经绘制的内容
*/
void updateSetting(const cv::Size size, const int border, const AxisLineParam& lineParam) {
if (size.width == m_size.width && size.height == m_size.height) {
updateSetting(border, lineParam);
}
else {
clear(size, border, lineParam);
}
}
/*
* @brief 清空mat，参数为AxisSurface希望更新的参数
*/
void clear(const cv::Size size = {
-1, -1 }, const int border = -1, const AxisLineParam& lineParam = {
AxisColorBlack, cv::LINE_8, 2 }) {
if (!(size.width < 0 || size.height < 0 || border < 0)) {
m_size = size;
m_border = border;
}
m_psurface = std::make_shared<cv::Mat>(m_size, CV_8UC3, AxisColorWhite);
m_lineParam = lineParam;
m_funcNumber = 0;
update(m_size, border, lineParam);
}
private:
/*
* @brief 绘制坐标轴，基本参数就是surface的参数，不详述
*/
void update(const cv::Size &size, const int border, const AxisLineParam& lineParam) {
const int axisWidth = lineParam.width;
cv::Scalar color = lineParam.color;
cv::LineTypes lineType = lineParam.type;
//绘制坐标轴
double startx = m_range.leftBottom.x, endx = m_range.rightTop.x;
double starty = m_range.leftBottom.y, endy = m_range.rightTop.y;
{
int awidth = 1;
drawLine(cv::Point2d(startx, 0), cv::Point2d(endx, 0), AxisColorGray(128), awidth, lineType);
drawLine(cv::Point2d(0, starty), cv::Point2d(0, endy), AxisColorGray(128), awidth, lineType);
drawCircle(cv::Point2d(0, 0), 3, AxisColorBlack, -1);
}
{
//绘制边界
cv::Point2d leftDown = {
startx, starty }, leftUp = {
startx, endy }, rightUp = {
endx, endy }, rightDown = {
endx, starty };
//下方的线
drawLine(leftDown, rightDown, color, axisWidth, lineType);
//左侧的线
drawLine(leftDown, leftUp, color, axisWidth, lineType);
//右边的线
drawLine(rightDown, rightUp, color, axisWidth, lineType);
//顶部的线
drawLine(rightUp, leftUp, color, axisWidth, lineType);
}
{
float textSize = 0.5;
cv::Scalar textColor = AxisColorBlack;
int textFont = cv::FONT_HERSHEY_SIMPLEX;
int gap = 5;
drawText("0", cv::Point2d(0, 0), textFont, textSize, textColor, AxisTextLocationBottomRight, 2);
drawText(std::to_string(int(endy)), cv::Point2d(0, endy), textFont, textSize, textColor, AxisTextLocationBottomRight, gap);
drawText(std::to_string(int(startx)), cv::Point2d(startx, 0), textFont, textSize, textColor, AxisTextLocationBottomRight, gap);
drawText(std::to_string(int(starty)), cv::Point2d(0, starty), textFont, textSize, textColor, AxisTextLocationTopRight, gap);
if (endx != 0) {
//防止m_range.rightTop的x坐标为0时，会绘制两个0
drawText(std::to_string(int(endx)), cv::Point2d(endx, 0), textFont, textSize, textColor, AxisTextLocationBottomLeft, gap);
}
}
}
private:
//绘制相关的函数，传入的最表示数学上常规的坐标系，x和y分别向右向上增长，如果绘制的坐标超过边界会略过
/*
* @brief 绘制圆，基本参数和opencv相同，只是做了坐标映射
*/
void drawCircle(cv::Point2d center, int radius, const cv::Scalar& color, int thickness = 1 , int lineType = cv::LINE_8 , int shift = 0 ) {
cv::Point2d pt(pointMap(center));
if (pt.x < m_border || pt.x > m_size.width - m_border || pt.y < m_border || pt.y > m_size.height - m_border) {
return;
}
cv::circle(*m_psurface, pt, radius, color, thickness, lineType, shift);
}
/*
* @brief 绘制实心圆，基本参数和opencv相同，只是做了坐标映射
*/
void drawPoint(cv::Point2d center, int radius, const cv::Scalar& color, int lineType = cv::LINE_8, int shift = 0) {
drawCircle(center, radius, color, -1, lineType, shift);
}
/*
* @brief 绘制线，基本参数和opencv相同，只是做了坐标映射
*/
void drawLine(cv::Point2d pt1, cv::Point pt2, const cv::Scalar& color, int thickness = 1, int lineType = cv::LINE_8, int shift = 0) {
cv::Point2d point1(pointMap(pt1)), point2(pointMap(pt2));
if (point1.x < m_border || point1.x > m_size.width - m_border || point1.y < m_border || point1.y > m_size.height - m_border) {
return;
}
if (point2.x < m_border || point2.x > m_size.width - m_border || point2.y < m_border || point2.y > m_size.height - m_border) {
return;
}
cv::line(*m_psurface, point1, point2, color, thickness, lineType, shift);
}
/*
* @brief 绘制文字，opencv默认绘制文字的坐标是文字的左下角，这里提供参数来配置文字具体绘制在哪个方向
* @param text 文字具体内容
* @param org 绘制文字的坐标
* @param fontFact 文字字体类型
* @param fontScale 文字大小
* @param color 文字颜色
* @param location 文字绘制位置相对于org的位置
* @param gap 绘制文字是x和y方向相对于org的距离
* @param thickness 文字的线的宽度
* @param lineType 文字的线的类型
*/
void drawText(const std::string &text, const cv::Point2d org, int fontFace, double fontScale, cv::Scalar color = AxisColorBlack, const AxisTextLocation location = AxisTextLocationTopRight, int gap= 5, int thickness = 1, int lineType = cv::LINE_8) {
cv::Point2d point1(pointMap(org));
if (point1.x < m_border || point1.x > m_size.width - m_border || point1.y < m_border || point1.y > m_size.height - m_border) {
return;
}
{
//根据文字的大小和方向计算具体绘制的位置
cv::Size textSize = cv::getTextSize(text, fontFace, fontScale, thickness, nullptr);
switch (location) {
case AxisTextLocationTop:
{
point1 = cv::Point2d(point1.x - textSize.width / 2, point1.y - gap);
}
break;
case AxisTextLocationTopRight:
{
point1 = cv::Point2d(point1.x, point1.y - gap);
}
break;
case AxisTextLocationRight:
{
point1 = cv::Point2d(point1.x + gap, point1.y + textSize.height / 2);
}
break;
case AxisTextLocationBottomRight:
{
point1 = cv::Point2d(point1.x + gap, point1.y + textSize.height + gap);
}
break;
case AxisTextLocationBottom:
{
point1 = cv::Point2d(point1.x - textSize.width / 2, point1.y + textSize.height + gap);
}
break;
case AxisTextLocationBottomLeft:
{
point1 = cv::Point2d(point1.x - textSize.width - gap, point1.y + textSize.height + gap);
}
break;
case AxisTextLocationLeft:
{
point1 = cv::Point2d(point1.x - textSize.width - gap, point1.y + textSize.height / 2);
}
break;
case AxisTextLocationTopLeft:
{
point1 = cv::Point2d(point1.x - textSize.width - gap, point1.y + gap);
}
break;
default:
break;
}
}
cv::putText(*m_psurface, text, point1, fontFace, fontScale, color, thickness, lineType);
}
/*
* @brief 将数学坐标系上的坐标映射到画布上的真实坐标
* @param 希望映射的xy坐标轴上的坐标
*/
cv::Point2d pointMap(const cv::Point2d &pt) {
cv::Size2d canvSize(m_range.rightTop.x - m_range.leftBottom.x, m_range.rightTop.y - m_range.leftBottom.y);
cv::Size2d matSize(m_size.width - 2 * m_border, m_size.height - 2 * m_border);
cv::Point2d canvDistance(pt.x - m_range.leftBottom.x, pt.y - m_range.leftBottom.y);
cv::Point2d matDistance(matSize.width * 1.0 / canvSize.width * canvDistance.x, matSize.height * 1.0 / canvSize.height * canvDistance.y);
return cv::Point2d(m_border + matDistance.x, m_size.height - m_border - matDistance.y);
}
private:
cv::Size2d m_size = {
720, 480};
int32_t m_border = 30;
AxisLineParam m_lineParam = {
AxisColorBlack, cv::LINE_8, 3};
AxisRange m_range = {
{
-128, -128}, {
128, 128} };
std::shared_ptr<cv::Mat> m_psurface;
int32_t m_funcNumber = 0;
};
#endif //__AXIS_SURFACE_H__