处理动画图像文件

目录

• 目标
• 源代码
• 解释
• 初始化动画结构
• 加载帧
• 显示帧
• 保存动画
• 总结

原始作者	Suleyman Turkmen (在 ChatGPT 的帮助下)
兼容性	OpenCV >= 4.11

目标

在本教程中，您将学习如何

• 使用 cv::imreadanimation 从动画图像文件加载帧。
• 理解 cv::Animation 结构的结构和参数。
• 显示动画中的单个帧。
• 使用 cv::imwriteanimation 将 cv::Animation 写入文件。

源代码

C++

• 可下载代码: 点击 此处
• 代码概览

  #include <opencv2/highgui.hpp>
  #include <opencv2/imgcodecs.hpp>
  #include <opencv2/imgproc.hpp>
  #include <iostream>
   
  using namespace cv;
   
  int main( int argc, const char** argv )
  {
  std::string filename = argc > 1 ? argv[1] : "animated_image.webp";
   
      if (argc == 1)
      {
          Animation animation_to_save;
          Mat image(128, 256, CV_8UC4, Scalar(150, 150, 150, 255));
          int duration = 200;
   
          for (int i = 0; i < 10; ++i) {
  animation_to_save.frames.push_back(image.clone());
  putText(animation_to_save.frames[i], format("Frame %d", i), Point(30, 80), FONT_HERSHEY_SIMPLEX, 1.5, Scalar(255, 100, 0, 255), 2);
  animation_to_save.durations.push_back(duration);
          }
  imwriteanimation("animated_image.webp", animation_to_save, { IMWRITE_WEBP_QUALITY, 100 });
      }
   
      Animation animation;
   
      bool success = imreadanimation(filename, animation);
      if (!success) {
  std::cerr << "Failed to load animation frames\n";
          return -1;
      }
   
      while (true)
      for (size_t i = 0; i < animation.frames.size(); ++i) {
          imshow("Animation", animation.frames[i]);
          int key_code = waitKey(animation.durations[i]); // Delay between frames
          if (key_code == 27)
  exit(0);
      }
   
      return 0;
  }

Python

• 可下载代码: 点击 此处
• 代码概览

  import cv2 as cv
  import numpy as np
   
  def main(filename)
      
      if filename == "animated_image.webp"
          # 创建要保存的 Animation 实例
  animation_to_save = cv.Animation()
   
          # 生成具有特定颜色的基本图像
  image = np.full((128, 256, 4), (150, 150, 150, 255), dtype=np.uint8)
  duration = 200
  frames = []
  durations = []
   
          # 在 Animation 对象中填充帧和持续时间
          for i in range(10)
  frame = image.copy()
              cv.putText(frame, f"Frame {i}", (30, 80), cv.FONT_HERSHEY_SIMPLEX, 1.5, (255, 100, 0, 255), 2)
  frames.append(frame)
  durations.append(duration)
   
  animation_to_save.frames = frames
  animation_to_save.durations = durations
   
          # 将动画写入文件
          cv.imwriteanimation(filename, animation_to_save, [cv.IMWRITE_WEBP_QUALITY, 100])
          
   
      
  animation = cv.Animation()
      
   
      
  success, animation = cv.imreadanimation(filename)
      if not success
  print("Failed to load animation frames")
          return
      
   
      
      while True
          for i, frame in enumerate(animation.frames)
              cv.imshow("Animation", frame)
  key_code = cv.waitKey(animation.durations[i])
              if key_code == 27: # 如果按下“Esc”键则退出
                  return
      
   
  if __name__ == "__main__"
      import sys
      main(sys.argv[1] if len(sys.argv) > 1 else "animated_image.webp")

解释

初始化动画结构

初始化一个 cv::Animation 结构来保存来自动画图像文件的帧。

C++

    Animation animation;

Python

animation = cv.Animation()

加载帧

使用 cv::imreadanimation 从指定文件加载帧。 在这里，我们从动画 WebP 图像加载所有帧。

C++

    bool success = imreadanimation(filename, animation);
    if (!success) {
std::cerr << "Failed to load animation frames\n";
        return -1;
    }

Python

success, animation = cv.imreadanimation(filename)
    if not success
print("Failed to load animation frames")
        return

显示帧

animation.frames 向量中的每个帧都可以显示为独立的图像。 此循环遍历每一帧，在具有短暂延迟的窗口中显示它以模拟动画。

C++

    while (true)
    for (size_t i = 0; i < animation.frames.size(); ++i) {
        imshow("Animation", animation.frames[i]);
        int key_code = waitKey(animation.durations[i]); // Delay between frames
        if (key_code == 27)
exit(0);
    }

Python

    while True
        for i, frame in enumerate(animation.frames)
            cv.imshow("Animation", frame)
key_code = cv.waitKey(animation.durations[i])
            if key_code == 27: # 如果按下“Esc”键则退出
                return

保存动画

C++

    if (argc == 1)
    {
        Animation animation_to_save;
        Mat image(128, 256, CV_8UC4, Scalar(150, 150, 150, 255));
        int duration = 200;
 
        for (int i = 0; i < 10; ++i) {
animation_to_save.frames.push_back(image.clone());
            putText(animation_to_save.frames[i], format("Frame %d", i), Point(30, 80), FONT_HERSHEY_SIMPLEX, 1.5, Scalar(255, 100, 0, 255), 2);
animation_to_save.durations.push_back(duration);
        }
        imwriteanimation("animated_image.webp", animation_to_save, { IMWRITE_WEBP_QUALITY, 100 });
    }

Python

    if filename == "animated_image.webp"
        # 创建要保存的 Animation 实例
animation_to_save = cv.Animation()
 
        # 生成具有特定颜色的基本图像
image = np.full((128, 256, 4), (150, 150, 150, 255), dtype=np.uint8)
duration = 200
frames = []
durations = []
 
        # 在 Animation 对象中填充帧和持续时间
        for i in range(10)
frame = image.copy()
            cv.putText(frame, f"Frame {i}", (30, 80), cv.FONT_HERSHEY_SIMPLEX, 1.5, (255, 100, 0, 255), 2)
frames.append(frame)
durations.append(duration)
 
animation_to_save.frames = frames
animation_to_save.durations = durations
 
        # 将动画写入文件
        cv.imwriteanimation(filename, animation_to_save, [cv.IMWRITE_WEBP_QUALITY, 100])

总结

cv::imreadanimation 和 cv::imwriteanimation 函数使处理动画图像文件变得容易，方法是将帧加载到 cv::Animation 结构中，从而允许逐帧处理。 使用这些函数，您可以从动画图像文件（如 GIF、AVIF、APNG 和 WebP）加载、处理和保存帧。