def qimage_to_numpy(self, image: QImage) -> Image:
image = image.convertToFormat(QImage.Format.Format_RGB32)
width = image.width()
height = image.height()
ptr = image.constBits()
arr = np.array(ptr).reshape((height, width, 4))[:, :, :3]
return arr
def qimg_to_rgb_arr(qimg: QImage) -> RGBArrayF:
"""Convert a :class:`QtGui.QImage` to an :data:`RGBArrayF`
"""
fmt = QImage.Format_RGB32
if qimg.format() != fmt:
qimg = qimg.convertToFormat(fmt)
width, height = qimg.width(), qimg.height()
num_pixels = width * height
bfr = qimg.constBits()
int_arr = np.frombuffer(bfr, dtype=np.uint8, count=num_pixels * 4)
bgra_arr = int_arr.reshape((height, width, 4)) / 255
# Format_RGB32 stored as 0xffRRGGBB
# so take only the first 3 items but in reverse
rgb_arr = bgra_arr[..., 2::-1]
return rgb_arr
class Canvas(QWidget):
content_changed = Signal()
_background_color = QColor.fromRgb(0, 0, 0)
_foreground_color = QColor.fromRgb(255, 255, 255)
def __init__(self, parent, w, h, pen_width, scale):
super().__init__(parent)
self.w = w
self.h = h
self.scaled_w = scale * w
self.scaled_h = scale * h
self.scale = scale
# Set size
self.setFixedSize(self.scaled_w, self.scaled_h)
# Create image
self.small_image = QImage(self.w, self.h, QImage.Format_RGB32)
self.small_image.fill(self._background_color)
self.large_image = QImage(self.scaled_w, self.scaled_h,
QImage.Format_RGB32)
self.large_image.fill(self._background_color)
# Create pen
self.pen = QPen()
self.pen.setColor(self._foreground_color)
self.pen.setJoinStyle(Qt.RoundJoin)
self.pen.setCapStyle(Qt.RoundCap)
self.pen.setWidthF(scale * pen_width)
# There is currently no path
self.currentPath = None
self.content_changed.connect(self.repaint)
def _get_painter(self, paintee):
painter = QPainter(paintee)
painter.setPen(self.pen)
painter.setRenderHint(QPainter.Antialiasing, True)
return painter
def _derive_small_image(self, large_image=None):
if large_image is None:
large_image = self.large_image
# Downsample image
self.small_image = large_image.scaled(self.w,
self.h,
mode=Qt.SmoothTransformation)
self.content_changed.emit()
def _current_path_updated(self, terminate_path=False):
# Determine whether to draw on the large image directly or whether to make a temporary copy
paintee = self.large_image if terminate_path else self.large_image.copy(
)
# Draw path on the large image of choice
painter = self._get_painter(paintee)
if self.currentPath.elementCount() != 1:
painter.drawPath(self.currentPath)
else:
painter.drawPoint(self.currentPath.elementAt(0))
painter.end()
# Optionally terminate the path
if terminate_path:
self.currentPath = None
# Downsample image
self._derive_small_image(paintee)
def _clear_image(self):
self.large_image.fill(self._background_color)
self._derive_small_image()
def get_content(self):
return np.asarray(self.small_image.constBits()).reshape(
(self.h, self.w, -1))
def set_content(self, image_rgb):
for row in range(image_rgb.shape[0]):
for col in range(image_rgb.shape[1]):
self.small_image.setPixel(col, row, image_rgb[row, col])
self.large_image = self.small_image.scaled(
self.scaled_w, self.scaled_h, mode=Qt.SmoothTransformation)
self._derive_small_image()
self.content_changed.emit()
def mousePressEvent(self, event):
if event.button() == Qt.LeftButton:
# Create new path
self.currentPath = QPainterPath()
self.currentPath.moveTo(event.pos())
self._current_path_updated()
def mouseMoveEvent(self, event):
if (event.buttons() & Qt.LeftButton) and self.currentPath is not None:
# Add point to current path
self.currentPath.lineTo(event.pos())
self._current_path_updated()
def mouseReleaseEvent(self, event):
if (event.button() == Qt.LeftButton) and self.currentPath is not None:
# Add terminal point to current path
self.currentPath.lineTo(event.pos())
self._current_path_updated(terminate_path=True)
elif event.button() == Qt.RightButton:
self._clear_image()
def paintEvent(self, event):
paint_rect = event.rect() # Only paint the surface that needs painting
painter = self._get_painter(self)
# Draw image
painter.scale(self.scale, self.scale)
painter.drawImage(paint_rect, self.small_image, paint_rect)
painter.end()
painter = self._get_painter(self)
#if self.currentPath is not None:
# painter.drawPath(self.currentPath)
@Slot()
def repaint(self):
super().repaint()
