Feature request: Support QImage and QQuickImageProvider #233

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1. barche commented on Feb 13, 2026

   

   barche

   on Feb 13, 2026

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   This could indeed be a good idea, do you have an example in QML on how this would be used?
2. rakeshksr commented on Feb 14, 2026

   

   rakeshksr

   on Feb 14, 2026

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   Currently, my use case involves displaying image that are generated dynamically based on user input.

   With assistance from Gemini, I have created an example demonstrating real-time edge detection using OpenCV integrated with QML in Python.

   edge_detect.py

   import sys
   
   import cv2
   import numpy as np
   from PySide6.QtCore import QObject, QSize, Qt, QTimer, Signal, Slot
   from PySide6.QtGui import QGuiApplication, QImage
   from PySide6.QtQml import QQmlApplicationEngine
   from PySide6.QtQuick import QQuickImageProvider
   
   
   class ImageProvider(QQuickImageProvider):
       def __init__(self):
           super().__init__(QQuickImageProvider.Image)
           self.image = QImage()
   
       def requestImage(self, id, size, requestedSize):
           if self.image.isNull():
               return QImage(640, 480, QImage.Format_RGB32)
           return self.image
   
   
   class VideoProcessor(QObject):
       imageChanged = Signal()
   
       def __init__(self, provider):
           super().__init__()
           self.provider = provider
           self.cap = cv2.VideoCapture(0)
   
           self.timer = QTimer()
           self.timer.timeout.connect(self.update_frame)
           self.timer.start(30)
   
       @Slot()
       def update_frame(self):
           ret, frame = self.cap.read()
           if not ret:
               return
   
           # Example: Simple Canny Edge Detection
           gray = cv2.cvtColor(frame, cv2.COLOR_BGR2GRAY)
           edges = cv2.Canny(gray, 100, 200)
   
           detection_overlay = cv2.cvtColor(edges, cv2.COLOR_GRAY2BGR)
   
           output = cv2.addWeighted(frame, 0.7, detection_overlay, 0.3, 0)
   
           rgb_frame = cv2.cvtColor(output, cv2.COLOR_BGR2RGB)
           h, w, ch = rgb_frame.shape
   
           # Create QImage and store in provider
           qt_img = QImage(rgb_frame.data, w, h, ch * w, QImage.Format_RGB888)
           self.provider.image = qt_img.copy()  # Copy to avoid memory issues
           self.imageChanged.emit()
   
   
   if __name__ == "__main__":
       app = QGuiApplication(sys.argv)
       engine = QQmlApplicationEngine()
   
       stream_provider = ImageProvider()
       engine.addImageProvider("live_stream", stream_provider)
   
       processor = VideoProcessor(stream_provider)
   
       engine.rootContext().setContextProperty("videoProcessor", processor)
   
       engine.load("edge_detect.qml")
       if not engine.rootObjects():
           sys.exit(-1)
   
       sys.exit(app.exec())

   edge_detect.qml

   import QtQuick
   import QtQuick.Window
   import QtQuick.Controls
   
   Window {
       width: 800
       height: 600
       visible: true
       title: "OpenCV + QML Live Detection"
       color: "#222"
   
       property int frameCounter: 0
   
       Column {
           anchors.centerIn: parent
           spacing: 10
   
           Text {
               text: "Live Edge Detection"
               color: "white"
               font.pixelSize: 24
               anchors.horizontalCenter: parent.horizontalCenter
           }
   
           Image {
               id: liveView
               width: 640
               height: 480
               fillMode: Image.PreserveAspectFit
   
               // The "id=" part forces a reload by changing the URL
               source: "image://live_stream/camera?id=" + frameCounter
               cache: false
           }
       }
   
       Connections {
           target: videoProcessor
           function onImageChanged() {
               frameCounter++
           }
       }
   }
   
3. barche commented on Jun 21, 2026

   

   barche

   on Jun 21, 2026

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   This has been in QML.jl for a while, but now there is also an extensive example on how to use it: https://github.com/barche/QmlJuliaExamples/blob/master/basic/imageprovider.jl
4. barche

   closed this as completedon Jun 21, 2026