working demo of widget using just an np buffer

Author: jmacey

QtWidget/WebGPUWidget.py

@@ -1,11 +1,11 @@
 from abc import ABCMeta, abstractmethod
+from typing import List, Tuple
+
 import numpy as np
 from qtpy.QtCore import QRect, Qt
 from qtpy.QtGui import QColor, QFont, QImage, QPainter
 from qtpy.QtWidgets import QWidget
 
-from typing import List, Optional, Tuple
-
 
 class QWidgetABCMeta(type(QWidget), ABCMeta):
     """
@@ -37,6 +37,7 @@ def __init__(self) -> None:
         super().__init__()
         self.initialized = False
         self.text_buffer: List[Tuple[int, int, str, int, str, QColor]] = []
+        self.buffer = None
 
     @abstractmethod
     def initializeWebGPU(self) -> None:
@@ -83,7 +84,7 @@ def paintEvent(self, event) -> None:
         self.paintWebGPU()
         painter = QPainter(self)
 
-        if hasattr(self, "buffer"):
+        if self.buffer is not None:
             self._present_image(painter, self.buffer)
         for x, y, text, size, font, colour in self.text_buffer:
             painter.setPen(colour)

QtWidget/main.py

@@ -1,9 +1,10 @@
 #!/usr/bin/env python3
-from abc import ABCMeta, abstractmethod
-from qtpy.QtWidgets import QWidget, QApplication
 import sys
-from WebGPUWidget import WebGPUWidget
+
+import numpy as np
 from qtpy.QtCore import Qt
+from qtpy.QtWidgets import QApplication
+from WebGPUWidget import WebGPUWidget
 
 
 class WebGPUScene(WebGPUWidget):
@@ -21,16 +22,19 @@ def initializeWebGPU(self) -> None:
         This method sets up the WebGPU context for the scene.
         """
         print("initializeWebGPU")
+        self.startTimer(100)
 
     def paintWebGPU(self) -> None:
         """
         Paint the WebGPU content.
 
         This method renders the WebGPU content for the scene.
         """
-        print("paintWebGPU")
         self.render_text(10, 20, "PaintGPU Test", size=20, colour=Qt.yellow)
 
+        # going to randomly generate an np buff to fill the screen
+        self.buffer = np.random.randint(0, 255, (1024, 720, 4), dtype=np.uint8)
+
     def resizeWebGPU(self, width: int, height: int) -> None:
         """
         Resize the WebGPU context.
@@ -43,6 +47,9 @@ def resizeWebGPU(self, width: int, height: int) -> None:
         """
         print(f"resizeWebGPU {width} {height}")
 
+    def timerEvent(self, event):
+        self.update()
+
 
 app = QApplication(sys.argv)
 win = WebGPUScene()