您可以创建自己的窗口来显示图像。将 MyWindow.m MyWindow.h 文件添加到项目中。
我的窗口.h
#ifndef MY_WINDOW_H
#define MY_WINDOW_H
#ifdef __cplusplus
extern "C" {
#endif
void* createNSWindow(int x, int y, int w, int h);
void renderNSWindow(void* inwindow, void* data, int w, int h, int c);
void processNSEvent();
#ifdef __cplusplus
}
#endif
#endif
用法，在 main.cpp 中，不要忘记 waitKey
#include "MyWindow.h"
// need create a cv window and do nothing
cv::namedWindow("xxx", 1);
// create window
void* w = createNSWindow(0, 0, 0, 0);
// frame image
cv::Mat frameImage;
// render loop
renderNSWindow(w, frameImage.data, frameImage.cols, frameImage.rows, frameImage.channels());
// need waitKey to display window
processNSEvent();
在 MyWindow.m 中执行删除 import "MyWindow.h"
#import <Cocoa/Cocoa.h>
@interface MyWindow : NSWindow
@property(nonatomic, strong) NSImageView *imgv;
@end
@implementation MyWindow
@end
static NSImage* _createNSImage(void* data, int w, int h, int c);
void* createNSWindow(int x, int y, int w, int h) {
NSRect screenFrame = [[NSScreen mainScreen] frame];
NSRect frame = NSMakeRect(x, y, w, h);
if (w == 0 || h == 0) {
frame = screenFrame;
}
MyWindow* window = [[MyWindow alloc] initWithContentRect:frame
styleMask:NSWindowStyleMaskBorderless
backing:NSBackingStoreBuffered
defer:NO] ;
//_initApp(window);
[window makeKeyAndOrderFront:NSApp];
window.titleVisibility = TRUE;
window.styleMask = NSWindowStyleMaskResizable | NSWindowStyleMaskTitled |NSWindowStyleMaskFullSizeContentView;
window.imgv = [[NSImageView alloc] initWithFrame:NSMakeRect(0, 0, frame.size.width, frame.size.height)];
[window.contentView addSubview:window.imgv];
return (void*)CFBridgingRetain(window);
}
static NSImage* _createNSImage(void* data, int w, int h, int c) {
size_t bufferLength = w * h * c;
CGDataProviderRef provider = CGDataProviderCreateWithData(NULL, data, bufferLength, NULL);
size_t bitsPerComponent = 8;
size_t bitsPerPixel = c * bitsPerComponent;
size_t bytesPerRow = c * w;
CGColorSpaceRef colorSpaceRef = CGColorSpaceCreateDeviceRGB();
CGBitmapInfo bitmapInfo = kCGBitmapByteOrder32Little | kCGImageAlphaPremultipliedLast;
if (c < 4) {
bitmapInfo = kCGBitmapByteOrderDefault | kCGImageAlphaNone;
unsigned char* buf = data;
for(int i = 0; i < w*h; i++) {
unsigned char temp = buf[i*c];
buf[i*c] = buf[i*c+c-1];
buf[i*c+c-1] = temp;
}
}
CGColorRenderingIntent renderingIntent = kCGRenderingIntentDefault;
CGImageRef iref = CGImageCreate(w,
h,
bitsPerComponent,
bitsPerPixel,
bytesPerRow,
colorSpaceRef,
bitmapInfo,
provider, // data provider
NULL, // decode
YES, // should interpolate
renderingIntent);
NSImage* image = [[NSImage alloc] initWithCGImage:iref size:NSMakeSize(w, h)];
return image;
}
void renderNSWindow(void* inwindow, void* data, int w, int h, int c) {
MyWindow* window = (__bridge MyWindow*)inwindow;
window.imgv.image = _createNSImage(data, w, h, c);
}
void processNSEvent() {
for (;;)
{
NSEvent* event = [NSApp nextEventMatchingMask:NSEventMaskAny
untilDate:[NSDate distantPast]
inMode:NSDefaultRunLoopMode
dequeue:YES];
if (event == nil)
break;
[NSApp sendEvent:event];
}
}
其他的，waitKey 现在需要大约 20 毫秒，你可以在后台线程中执行 OpenCV，并在主线程中显示窗口。也使用 processNSEvent 而不是 waitKey 只需要大约 10 毫秒。
完整源代码：
#include <iostream>
#include "opencv2/core/core.hpp"
#include "opencv2/highgui/highgui.hpp"
#include <dispatch/dispatch.h>
#include "MyWindow.h"
using namespace std;
using namespace cv;
int opencvfunc(int argc, const char *argv[]);
bool newFrame = false;
cv::Mat back_frame;
int main(int argc, const char * argv[]) {
cv::namedWindow("render", 1);
void* w = createNSWindow(0, 0, 0, 0);
dispatch_queue_t opencvq = dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_LOW, 0);
dispatch_async(opencvq, ^{
opencvfunc(argc, argv);
});
while(true) {
usleep(3*1000);
if(newFrame) {
std::chrono::system_clock::time_point starttime = std::chrono::system_clock::now();
renderNSWindow(w, back_frame.data, back_frame.cols, back_frame.rows, back_frame.channels());
newFrame = false;
//auto key = cv::waitKey(1);
//if (key == 'q') {
// break;
//}
processNSEvent();
std::chrono::system_clock::time_point endtime = std::chrono::system_clock::now();
std::cout << "imshow:" << std::chrono::duration_cast<std::chrono::duration<double>>(endtime-starttime).count()*1000 << std::endl;
}
}
return 0;
}
int opencvfunc(int argc, const char *argv[]) {
cv::VideoCapture cap;
cap.open(0);
if (!cap.isOpened()) {
std::cout << "Couldn't open camera 0." << endl;
return EXIT_FAILURE;
}
Mat frame, unmodified_frame;
for (;;) {
cap >> frame; // get a new frame from camera
if (frame.empty()) { // stop if we're at the end of the video
break;
}
//unmodified_frame = frame.clone();
// ...
back_frame = frame.clone();
newFrame = true;
}
return EXIT_SUCCESS;
}