video/widget: externalize opencv code

1 files changed, 78 insertions, 0 deletions

diff --git a/cv/video-widget.cpp b/cv/video-widget.cpp
new file mode 100644
index 00000000..7cc6ca2d
--- /dev/null
+++ b/cv/video-widget.cpp
@@ -0,0 +1,78 @@
+#include "video-widget.hpp"
+
+#include <opencv2/imgproc.hpp>
+
+void cv_video_widget::update_image(const cv::Mat& frame)
+{
+    QMutexLocker l(&mtx);
+
+    if (freshp)
+        return;
+
+    if (W < 1 || H < 1 || frame.rows < 1 || frame.cols < 1)
+        return;
+
+    cv::Mat const* __restrict frame_scaled = nullptr;
+
+    if (frame3.cols != W || frame3.rows != H)
+    {
+        frame3 = cv::Mat(H, W, frame.type());
+        frame2 = cv::Mat(H, W, CV_8UC4);
+
+        if (!frame2.isContinuous() || !frame3.isContinuous())
+            std::abort();
+    }
+
+    if (frame.cols != W || frame.rows != H)
+    {
+        cv::resize(frame, frame3, { W, H }, 0, 0, cv::INTER_NEAREST);
+        frame_scaled = &frame3;
+    }
+    else if (!frame.isContinuous())
+    {
+        frame.copyTo(frame3);
+        frame_scaled = &frame3;
+    }
+    else
+        frame_scaled = &frame;
+
+    freshp = true;
+
+    int color_cvt = 0;
+    constexpr int nchannels = 4;
+
+    switch (frame_scaled->channels())
+    {
+    case 1:
+        color_cvt = cv::COLOR_GRAY2BGRA;
+        break;
+    case 3:
+        color_cvt = cv::COLOR_BGR2BGRA;
+        break;
+    case nchannels:
+        break;
+    default:
+        unreachable();
+        break;
+    }
+
+    cv::Mat const* frame_color;
+
+    if (color_cvt != cv::COLOR_COLORCVT_MAX)
+    {
+        cv::cvtColor(*frame_scaled, frame2, color_cvt);
+        frame_color = &frame2;
+    }
+    else
+        frame_color = frame_scaled;
+
+    int stride = frame_color->step.p[0], rows = frame_color->rows;
+    int nbytes = rows * stride;
+    vec.resize(nbytes); vec.shrink_to_fit();
+    std::memcpy(vec.data(), frame_color->data, nbytes);
+
+    texture = QImage((const unsigned char*) vec.data(), W, H, stride, QImage::Format_ARGB32);
+    texture.setDevicePixelRatio(devicePixelRatioF());
+}
+
+cv_video_widget::cv_video_widget(QWidget* parent) : video_widget(parent) {}