如何在openCV c++中填充圆角矩形

在OpenCV C++中填充圆角矩形，可以使用以下步骤：

导入OpenCV库：

#include <opencv2/opencv.hpp>

创建一个空白图像：

cv::Mat image(height, width, CV_8UC3, cv::Scalar(0, 0, 0));

其中，height和width分别表示图像的高度和宽度，CV_8UC3表示图像类型为8位无符号整数，3个通道（RGB），cv::Scalar(0, 0, 0)表示填充颜色为黑色。

绘制圆角矩形：

cv::Scalar fill_color(255, 255, 255);  // 填充颜色为白色
cv::Point2f center(center_x, center_y);  // 圆角矩形的中心点坐标
cv::Size2f size(width, height);  // 圆角矩形的宽度和高度
int corner_radius = radius;  // 圆角的半径
cv::Rect rect(center - size / 2, center + size / 2);
cv::rectangle(image, rect, fill_color, -1);
cv::Scalar corner_fill_color(0, 0, 0);  // 圆角填充颜色为黑色
cv::RNG rng;
for (int i = 0; i < corner_radius; ++i) {
    cv::Point2f center_top_left(rect.x + corner_radius, rect.y + corner_radius);
    cv::Size2f size_top_left(corner_radius * 2 - i * 2, corner_radius * 2 - i * 2);
    cv::ellipse(image, center_top_left, size_top_left, 180.0, 0.0, 90.0, corner_fill_color, -1);
    cv::Point2f center_top_right(rect.x + rect.width - corner_radius, rect.y + corner_radius);
    cv::Size2f size_top_right(corner_radius * 2 - i * 2, corner_radius * 2 - i * 2);
    cv::ellipse(image, center_top_right, size_top_right, 270.0, 0.0, 90.0, corner_fill_color, -1);
    cv::Point2f center_bottom_left(rect.x + corner_radius, rect.y + rect.height - corner_radius);
    cv::Size2f size_bottom_left(corner_radius * 2 - i * 2, corner_radius * 2 - i * 2);
    cv::ellipse(image, center_bottom_left, size_bottom_left, 90.0, 0.0, 90.0, corner_fill_color, -1);
    cv::Point2f center_bottom_right(rect.x + rect.width - corner_radius, rect.y + rect.height - corner_radius);
    cv::Size2f size_bottom_right(corner_radius * 2 - i * 2, corner_radius * 2 - i * 2);
    cv::ellipse(image, center_bottom_right, size_bottom_right, 0.0, 0.0, 90.0, corner_fill_color, -1);
}

其中，fill_color表示填充颜色，center_x和center_y表示圆角矩形的中心点坐标，width和height表示圆角矩形的宽度和高度，radius表示圆角的半径。

显示图像：

cv::imshow("Filled Round Rect", image);
cv::waitKey(0);

完整的代码示例：

#include <opencv2/opencv.hpp>

int main() {
    int width = 640;
    int height = 480;
    int center_x = width / 2;
    int center_y = height / 2;
    int radius = 50;

    cv::Mat image(height, width, CV_8UC3, cv::Scalar(0, 0, 0));
    cv::Scalar fill_color(255, 255, 255);  // 填充颜色为白色
    cv::Point2f center(center_x, center_y);  // 圆角矩形的中心点坐标
    cv::Size2f size(width, height);  // 圆角矩形的宽度和高度
    int corner_radius = radius;  // 圆角的半径
    cv::Rect rect(center - size / 2, center + size / 2);
    cv::rectangle(image, rect, fill_color, -1);
    cv::Scalar corner_fill_color(0, 0, 0);  // 圆角填充颜色为黑色
    cv::RNG rng;
    for (int i = 0; i < corner_radius; ++i) {
        cv::Point2f center_top_left(rect.x + corner_radius, rect.y + corner_radius);
        cv::Size2f size_top_left(corner_radius * 2 - i * 2, corner_radius * 2 - i * 2);
        cv::ellipse(image, center_top_left, size_top_left, 180.0, 0.0, 90.0, corner_fill_color, -1);
        cv::Point2f center_top_right(rect.x + rect.width - corner_radius, rect.y + corner_radius);
        cv::Size2f size_top_right(corner_radius * 2 - i * 2, corner_radius * 2 - i * 2);
        cv::ellipse(image, center_top_right, size_top_right, 270.0, 0.0, 90.0, corner_fill_color, -1);
        cv::Point2f center_bottom_left(rect.x + corner_radius, rect.y + rect.height - corner_radius);
        cv::Size2f size_bottom_left(corner_radius * 2 - i * 2, corner_radius * 2 - i * 2);
        cv::ellipse(image, center_bottom_left, size_bottom_left, 90.0, 0.0, 90.0, corner_fill_color, -1);
        cv::Point2f center_bottom_right(rect.x + rect.width - corner_radius, rect.y + rect.height - corner_radius);
        cv::Size2f size_bottom_right(corner_radius * 2 - i * 2, corner_radius * 2 - i * 2);
        cv::ellipse(image, center_bottom_right, size_bottom_right, 0.0, 0.0, 90.0, corner_fill_color, -1);
    }

    cv::imshow("Filled Round Rect", image);
    cv::waitKey(0);

    return 0;
}

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