I am trying to make a cross-platform app to measure FPS. In windows it works but in macos using only QT, I couldn't capture other apps in the area. So I uses CoreGraphics for Mac but I am still getting the same problem.
Here is my code that captures the screen.
#include "framecounter.h"
#include <QtGui/QGuiApplication>
#include <QDir>
FrameCounter::FrameCounter(QWidget* parent) : QWidget(parent)
{
// Connect the captureTimer's timeout signal to the captureScreen slot.
connect(&m_captureTimer, &QTimer::timeout, this, &FrameCounter::captureScreen);
m_elapsedTimer.start(); // Start the elapsed timer.
}
void FrameCounter::captureScreen()
{
#ifdef Q_OS_MAC
// Capture the screen using Core Graphics
CGImageRef cgImage = CGWindowListCreateImage(CGRectMake(m_x, m_y, m_size, m_size), kCGWindowListOptionOnScreenOnly, kCGNullWindowID, kCGWindowImageDefault);
QImage screenCapture = CGImageToQImage(cgImage);
CGImageRelease(cgImage);
// Save the captured image
static int i = 0;
QString fileName = QString("capture_%1.png").arg(i++);
saveImage(screenCapture, fileName);
#else
// Capture the screen using Qt
QScreen* screen = QGuiApplication::primaryScreen();
if (!screen)
return;
QImage screenCapture = screen->grabWindow(0, m_x, m_y, m_size, m_size).toImage();
#endif
if (!m_previousFrame.isNull() && screenCapture != m_previousFrame)
{
++m_frameCount;
}
m_previousFrame = screenCapture;
calculateFps();
}
void FrameCounter::calculateFps()
{
qint64 elapsed = m_elapsedTimer.elapsed();
// Calculate the current FPS and update the list of FPS values every 300 milliseconds.
if (elapsed >= 300)
{
m_currentFps = static_cast<double>(m_frameCount) / (static_cast<double>(elapsed) / 1000.0);
m_listOfFps.append(m_currentFps);
// Reset the frame count and restart the timer.
m_frameCount = 0;
m_elapsedTimer.restart();
emit newfpsvalue();
}
}
void FrameCounter::startMeasurement(int x, int y, int size)
{
// Define the measurement area and start timers
m_x = x;
m_y = y;
m_size = size;
// Start the capture timer to capture frames every 16 milliseconds.
m_captureTimer.start(16);
m_elapsedTimer.restart();
}
void FrameCounter::stopMeasurement()
{
m_captureTimer.stop();
// Reset FPS and clear the list of FPS values.
m_currentFps = 0;
m_listOfFps.clear();
}
#ifdef Q_OS_MAC
CGBitmapInfo FrameCounter::CGBitmapInfoForQImage(const QImage &image)
{
CGBitmapInfo bitmapInfo = kCGImageAlphaNone;
switch (image.format()) {
case QImage::Format_ARGB32:
bitmapInfo = kCGImageAlphaFirst | kCGBitmapByteOrder32Host;
break;
case QImage::Format_RGB32:
bitmapInfo = kCGImageAlphaNoneSkipFirst | kCGBitmapByteOrder32Host;
break;
case QImage::Format_RGBA8888_Premultiplied:
bitmapInfo = kCGImageAlphaPremultipliedLast | kCGBitmapByteOrder32Big;
break;
case QImage::Format_RGBA8888:
bitmapInfo = kCGImageAlphaLast | kCGBitmapByteOrder32Big;
break;
case QImage::Format_RGBX8888:
bitmapInfo = kCGImageAlphaNoneSkipLast | kCGBitmapByteOrder32Big;
break;
case QImage::Format_ARGB32_Premultiplied:
bitmapInfo = kCGImageAlphaPremultipliedFirst | kCGBitmapByteOrder32Host;
break;
default:
break;
}
return bitmapInfo;
}
QImage FrameCounter::CGImageToQImage(CGImageRef cgImage)
{
const size_t width = CGImageGetWidth(cgImage);
const size_t height = CGImageGetHeight(cgImage);
QImage image(static_cast<int>(width), static_cast<int>(height), QImage::Format_ARGB32_Premultiplied);
image.fill(Qt::transparent);
CGColorSpaceRef colorSpace = CGColorSpaceCreateWithName(kCGColorSpaceSRGB);
CGContextRef context = CGBitmapContextCreate(static_cast<void*>(image.bits()), static_cast<size_t>(image.width()), static_cast<size_t>(image.height()), 8,
static_cast<size_t>(image.bytesPerLine()), colorSpace, CGBitmapInfoForQImage(image));
// Scale the context so that painting happens in device-independent pixels
const qreal devicePixelRatio = image.devicePixelRatio();
CGContextScaleCTM(context, devicePixelRatio, devicePixelRatio);
CGRect rect = CGRectMake(0, 0, width, height);
CGContextDrawImage(context, rect, cgImage);
CFRelease(colorSpace);
CGContextRelease(context);
return image;
}
#endif
void FrameCounter::saveImage(const QImage& image, const QString& fileName)
{
QDir dir;
if (!dir.exists("captures"))
{
dir.mkpath("captures");
}
image.save("captures/" + fileName);
}
How can I change my code to make it capture all the apps of the screen then convert it to QImage?
I deleted my app and reinstalled it, then gave permission to record and worked this time. I will continue and see if I get the same problem again.