[英]Drawing filled polygon using mouse events in open cv using python
I am trying to draw a polygon between the coordinates which would be obtained by clicking by mouse events.我正在尝试在通过鼠标事件单击获得的坐标之间绘制一个多边形。
The first click should define the starting point of the polygon.第一次点击应该定义多边形的起点。 Each additional click should sketch a line segment from the previous click.每次额外的点击都应该从上一次点击中绘制一条线段。 When whole clicked points sketch the polygon, inside of the polygon should be filled.当全部点击的点绘制多边形时,多边形内部应该被填充。
Can someone please suggest how to draw polygons between the points I click on the image?有人可以建议如何在我单击图像的点之间绘制多边形吗? I am considering cv2.polylines
function, however I have no idea how to integrate that with SetMouseCallback
function.我正在考虑cv2.polylines
函数,但是我不知道如何将它与SetMouseCallback
函数集成。
To make the user interface more intuitive (since it would be very difficult for the user to click exactly in the same spot as the starting point), let's use the following actions:为了使用户界面更直观(因为用户很难准确地单击与起点相同的位置),让我们使用以下操作:
We will need several variables to keep track of our progress:我们将需要几个变量来跟踪我们的进度:
(x, y)
每个点都是一个元组(x, y)
We will use a mouse callback to update those variables periodically when the appropriate mouse events occur:当适当的鼠标事件发生时,我们将使用鼠标回调来定期更新这些变量:
EVENT_MOUSEMOVE
-- mouse has moved, update the current position EVENT_MOUSEMOVE
-- 鼠标已经移动,更新当前位置EVENT_LBUTTONDOWN
-- user pressed the left mouse button, add current position to list of points EVENT_LBUTTONDOWN
-- 用户按下鼠标左键,将当前位置添加到点列表EVENT_RBUTTONDOWN
-- user pressed the right mouse button, mark data entry as complete EVENT_RBUTTONDOWN
-- 用户按下鼠标右键,将数据输入标记为完成Finally, we will have a function implementing the display loop.最后,我们将有一个实现显示循环的函数。
This function will first create a named window, draw a blank canvas, and set up the mouse callback.此函数将首先创建一个命名窗口,绘制一个空白画布,并设置鼠标回调。 Then it will repeatedly keep updating the screen by:然后它将通过以下方式反复更新屏幕:
cv2.polyline
输入点时,使用cv2.polyline
绘制连接线段cv2.line
.使用cv2.line
以不同的颜色绘制从最后输入的点指向当前位置的当前线段。Once the data entry process is complete, the function will draw the final filled polygon and a clean canvas image, show it, and when the user presses a key return the final image.数据输入过程完成后,该函数将绘制最终填充的多边形和干净的画布图像,并显示它,并在用户按下某个键时返回最终图像。
import numpy as np
import cv2
# ============================================================================
CANVAS_SIZE = (600,800)
FINAL_LINE_COLOR = (255, 255, 255)
WORKING_LINE_COLOR = (127, 127, 127)
# ============================================================================
class PolygonDrawer(object):
def __init__(self, window_name):
self.window_name = window_name # Name for our window
self.done = False # Flag signalling we're done
self.current = (0, 0) # Current position, so we can draw the line-in-progress
self.points = [] # List of points defining our polygon
def on_mouse(self, event, x, y, buttons, user_param):
# Mouse callback that gets called for every mouse event (i.e. moving, clicking, etc.)
if self.done: # Nothing more to do
return
if event == cv2.EVENT_MOUSEMOVE:
# We want to be able to draw the line-in-progress, so update current mouse position
self.current = (x, y)
elif event == cv2.EVENT_LBUTTONDOWN:
# Left click means adding a point at current position to the list of points
print("Adding point #%d with position(%d,%d)" % (len(self.points), x, y))
self.points.append((x, y))
elif event == cv2.EVENT_RBUTTONDOWN:
# Right click means we're done
print("Completing polygon with %d points." % len(self.points))
self.done = True
def run(self):
# Let's create our working window and set a mouse callback to handle events
cv2.namedWindow(self.window_name, flags=cv2.CV_WINDOW_AUTOSIZE)
cv2.imshow(self.window_name, np.zeros(CANVAS_SIZE, np.uint8))
cv2.waitKey(1)
cv2.cv.SetMouseCallback(self.window_name, self.on_mouse)
while(not self.done):
# This is our drawing loop, we just continuously draw new images
# and show them in the named window
canvas = np.zeros(CANVAS_SIZE, np.uint8)
if (len(self.points) > 0):
# Draw all the current polygon segments
cv2.polylines(canvas, np.array([self.points]), False, FINAL_LINE_COLOR, 1)
# And also show what the current segment would look like
cv2.line(canvas, self.points[-1], self.current, WORKING_LINE_COLOR)
# Update the window
cv2.imshow(self.window_name, canvas)
# And wait 50ms before next iteration (this will pump window messages meanwhile)
if cv2.waitKey(50) == 27: # ESC hit
self.done = True
# User finised entering the polygon points, so let's make the final drawing
canvas = np.zeros(CANVAS_SIZE, np.uint8)
# of a filled polygon
if (len(self.points) > 0):
cv2.fillPoly(canvas, np.array([self.points]), FINAL_LINE_COLOR)
# And show it
cv2.imshow(self.window_name, canvas)
# Waiting for the user to press any key
cv2.waitKey()
cv2.destroyWindow(self.window_name)
return canvas
# ============================================================================
if __name__ == "__main__":
pd = PolygonDrawer("Polygon")
image = pd.run()
cv2.imwrite("polygon.png", image)
print("Polygon = %s" % pd.points)
Drawing in progress, we have 5 points entered, and the current segment is being shown as a darker line pointing to the current position of the mouse:绘图正在进行中,我们输入了 5 个点,当前线段显示为指向鼠标当前位置的深色线:
Drawing is complete, and the program is showing the whole polygon filled:绘图完成,程序显示整个多边形已填充:
Adding point #0 with position(257,144)
Adding point #1 with position(657,263)
Adding point #2 with position(519,478)
Adding point #3 with position(283,383)
Adding point #4 with position(399,126)
Adding point #5 with position(142,286)
Adding point #6 with position(165,38)
Completing polygon with 7 points.
Polygon = [(257, 144), (657, 263), (519, 478), (283, 383), (399, 126), (142, 286), (165, 38)]
Same Code as above but with C++.与上面相同的代码,但使用 C++。 Take an image as input rather than canvas将图像作为输入而不是画布
#include <boost/shared_ptr.hpp>
#include <opencv2/opencv.hpp>
cv::Scalar FINAL_LINE_COLOR (255, 255, 255);
cv::Scalar WORKING_LINE_COLOR(127, 127, 127);
class PolygonDrawer {
public:
std::string window_name_;
bool done_;
cv::Point current_;
std::vector<cv::Point> points_;
boost::shared_ptr<cv::Mat> imgPtr;
PolygonDrawer(const std::string window_name, std::string imgName){
window_name_ = window_name;
done_ = false;
current_ = cv::Point(0, 0); // Current position, so we can draw the line-in-progress
imgPtr.reset(new cv::Mat(cv::imread(imgName)));
}
static void onMouse( int event, int x, int y, int f, void* data ) {
PolygonDrawer *curobj = reinterpret_cast<PolygonDrawer*>(data);
if (curobj->done_) // Nothing more to do
return;
if(event == cv::EVENT_MOUSEMOVE)
// We want to be able to draw the line-in-progress, so update current mouse position
curobj->current_ = cv::Point(x, y);
else if(event == cv::EVENT_LBUTTONDOWN) {
// Left click means adding a point at current position to the list of points
printf("Adding point #%zu with position(%d,%d) \n", curobj->points_.size(), x, y);
curobj->points_.push_back(cv::Point(x, y));
} else if(event == cv::EVENT_RBUTTONDOWN) {
// Right click means we're done
printf("Completing polygon with %zu points \n", curobj->points_.size());
curobj->done_ = true;
}
}
void run() {
// Let's create our working window and set a mouse callback to handle events
cv::namedWindow(window_name_, cv::WINDOW_KEEPRATIO);
cv::imshow(window_name_, *imgPtr);
cv::waitKey(1);
cv::setMouseCallback(window_name_, onMouse, this);
while(!done_) {
cv::Mat img;
imgPtr->copyTo(img);
if (points_.size() > 0){
// Draw all the current polygon segments
const cv::Point *pts = (const cv::Point*) cv::Mat(points_).data;
int npts = cv::Mat(points_).rows;
cv::polylines(img, &pts, &npts, 1, false, FINAL_LINE_COLOR);
// And also show what the current segment would look like
cv::line(img, points_[points_.size()-1], current_, WORKING_LINE_COLOR, 1.0);
// Update the window
}
cv::imshow(window_name_, img);
// And wait 50ms before next iteration (this will pump window messages meanwhile)
if(cv::waitKey(50) == 27)
done_ = true;
}
const cv::Point *pts = (const cv::Point*) cv::Mat(points_).data;
int npts = cv::Mat(points_).rows;
// user finished entering the polygon points
if (points_.size() > 0) {
cv::fillPoly(*imgPtr, &pts, &npts, 1, FINAL_LINE_COLOR);
cv::imshow(window_name_, *imgPtr);
//Waiting for the user to press any key
cv::waitKey();
cv::destroyWindow(window_name_);
}
}
};
int main(int argc, char** argv) {
PolygonDrawer pd("Polygon", argv[1]);
pd.run();
// cv2.imwrite("polygon.png", image)
// print("Polygon = %s" % pd.points)
}
I modified Dan Mašek's code to draw polygons into images - the Python counterpart to user2848052's C++ implementation. 我修改了DanMašek的代码,将多边形绘制成图像 - 与user2848052的C ++实现相对应的Python。 Can be found here: https://github.com/mluerig/iso_track 可以在这里找到: https : //github.com/mluerig/iso_track
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