在用于洋葱皮的 QLabel 中叠加图像
Overlaying Images in a QLabel for Onion Skinning
我正在尝试使用 PyQt 中的 QLabel 产生洋葱皮效果。在下面的简化示例中，使用 QPainter 加载并绘制了三个图像。
from PyQt5.QtWidgets import QApplication, QWidget, QGridLayout, QLabel
from PyQt5.QtCore import Qt, QPoint
from PyQt5.QtGui import QImage, QPixmap, QPainter
import sys
from pathlib import Path
class MainWindow(QWidget):
def __init__(self):
super().__init__()
# -------------------------------------------------------------
# Define the display.
self.display = QLabel()
# -------------------------------------------------------------
# Import the frames
frame_1 = QImage(str(Path(f'fixtures/test_onion_skin/frame_{1}.png')))
frame_2 = QImage(str(Path(f'fixtures/test_onion_skin/frame_{2}.png')))
frame_3 = QImage(str(Path(f'fixtures/test_onion_skin/frame_{3}.png')))
# -------------------------------------------------------------
# Populate the display
frame_1_scaled = frame_1.scaled(self.size(), Qt.KeepAspectRatio)
frame_2_scaled = frame_2.scaled(self.size(), Qt.KeepAspectRatio)
frame_3_scaled = frame_3.scaled(self.size(), Qt.KeepAspectRatio)
base_pixmap = QPixmap(frame_1_scaled.size())
painter = QPainter(base_pixmap)
painter.drawImage(QPoint(), frame_3_scaled)
painter.setOpacity(0.5)
painter.drawImage(QPoint(), frame_2_scaled)
painter.setOpacity(0.3)
painter.drawImage(QPoint(), frame_1_scaled)
painter.end()
self.display.setPixmap(base_pixmap)
# -------------------------------------------------------------
# Set the layout.
layout = QGridLayout()
layout.addWidget(self.display, 0, 0)
self.setLayout(layout)
if __name__ == '__main__':
app = QApplication(sys.argv)
window = MainWindow()
window.show()
app.exec()
理想情况下，最后一张图片将显示为完全不透明，而较早的图片具有越来越高的透明度。相反，我得到一个输出，其中所有三个图像均等地混合在一起。这似乎是一个解决起来很简单的问题，但我的 'Google Fu' 这次并没有产生太大的影响。
编辑
这是图像文件。不幸的是，它们似乎已自动转换为 .jpg。如果有更好的方法来包含它们，请告诉我。
frame_1
frame_2
frame_3
编辑 2
经过一些实验后，我决定妥协并允许一些 'blending' 基本图像。我正在处理来自相机设备的原始图像，因此每张图像的背景总是不透明的。
如果有人感兴趣，这里是代码：
from PyQt5.QtWidgets import QApplication, QWidget, QGridLayout, QLabel, QSizePolicy
from PyQt5.QtCore import Qt, QPoint
from PyQt5.QtGui import QImage, QPixmap, QPainter
import sys
from pathlib import Path
class MainWindow(QWidget):
def __init__(self):
super().__init__()
# -------------------------------------------------------------
# Define values used for image painting.
self.first_opacity = 1 # Set first image to fully opaque so it does not blend into background.
self.falloff_value = 0.15 # The opacity of the second image.
self.falloff_rate = 0.5 # A factor used to decrement subsequent image transparencies.
# -------------------------------------------------------------
# Define the display.
self.display = QLabel()
self.display.setSizePolicy(QSizePolicy.MinimumExpanding, QSizePolicy.MinimumExpanding)
self.display.setMinimumSize(1, 1)
# -------------------------------------------------------------
# Import frames.
self.images = []
for i in range(1, 4, 1):
self.images.append(QImage(str(Path(f'fixtures/test_onion_skin/frame_{i}.png'))))
# -------------------------------------------------------------
# Set the display.
self.update_display()
# -------------------------------------------------------------
# Set the layout.
layout = QGridLayout()
layout.addWidget(self.display, 0, 0)
self.setLayout(layout)
def update_display(self):
# -------------------------------------------------------------
# Define the base pixmap on which to merge images.
base_pixmap = QPixmap(self.display.size())
base_pixmap.fill(Qt.transparent)
# -------------------------------------------------------------
# Preform paint cycle for images.
painter = QPainter(base_pixmap)
for (image, opacity) in zip(reversed(self.images), reversed(self.get_opacities(len(self.images)))):
painter.setOpacity(opacity)
painter.drawImage(QPoint(), image.scaled(base_pixmap.size(), Qt.KeepAspectRatio))
painter.end()
# -------------------------------------------------------------
self.display.setPixmap(base_pixmap)
def get_opacities(self, num_images):
# -------------------------------------------------------------
# Define a list to store image opacity values.
opacities = [self.first_opacity]
value = self.falloff_value
# -------------------------------------------------------------
# Calculate additional opacity values if more than one image is desired.
if num_images > 1:
num_decrements = num_images - 1
for i in range(1, num_decrements + 1, 1):
opacities.insert(0, value)
value *= self.falloff_rate
# -------------------------------------------------------------
return opacities
def resizeEvent(self, event):
self.update_display()
event.accept()
if __name__ == '__main__':
app = QApplication(sys.argv)
window = MainWindow()
window.show()
app.exec()
由于OP没有提供图片那么问题可能是由于：
- 设置不透明度的顺序。
- 图片背景色不透明
对于我的演示，我将使用此 gif 并且由于背景不是透明的（这将是理想的），因此我将在绘制每个图像时应用遮罩。
import os
from pathlib import Path
import sys
from PyQt5.QtCore import Qt, QPoint
from PyQt5.QtGui import QColor, QImageReader, QPainter, QPixmap, QRegion
from PyQt5.QtWidgets import QApplication, QLabel, QVBoxLayout, QWidget
CURRENT_DIRECTORY = Path(__file__).resolve().parent
class MainWindow(QWidget):
def __init__(self):
super().__init__()
self.display = QLabel(alignment=Qt.AlignCenter)
lay = QVBoxLayout(self)
lay.addWidget(self.display)
background_color = QColor("white")
filename = os.fspath(CURRENT_DIRECTORY / "Animhorse.gif")
image_reader = QImageReader(filename)
pixmap = QPixmap(image_reader.size())
pixmap.fill(background_color)
images = []
while image_reader.canRead():
images.append(image_reader.read())
painter = QPainter(pixmap)
for image, opacity in zip(images[3:6], (0.3, 0.7, 1.0)):
painter.setOpacity(opacity)
p = QPixmap.fromImage(image)
mask = p.createMaskFromColor(background_color, Qt.MaskInColor)
painter.setClipRegion(QRegion(mask))
painter.drawImage(QPoint(), image)
painter.end()
self.display.setPixmap(pixmap)
if __name__ == "__main__":
app = QApplication(sys.argv)
window = MainWindow()
window.show()
app.exec()
我正在尝试使用 PyQt 中的 QLabel 产生洋葱皮效果。在下面的简化示例中，使用 QPainter 加载并绘制了三个图像。
from PyQt5.QtWidgets import QApplication, QWidget, QGridLayout, QLabel
from PyQt5.QtCore import Qt, QPoint
from PyQt5.QtGui import QImage, QPixmap, QPainter
import sys
from pathlib import Path
class MainWindow(QWidget):
def __init__(self):
super().__init__()
# -------------------------------------------------------------
# Define the display.
self.display = QLabel()
# -------------------------------------------------------------
# Import the frames
frame_1 = QImage(str(Path(f'fixtures/test_onion_skin/frame_{1}.png')))
frame_2 = QImage(str(Path(f'fixtures/test_onion_skin/frame_{2}.png')))
frame_3 = QImage(str(Path(f'fixtures/test_onion_skin/frame_{3}.png')))
# -------------------------------------------------------------
# Populate the display
frame_1_scaled = frame_1.scaled(self.size(), Qt.KeepAspectRatio)
frame_2_scaled = frame_2.scaled(self.size(), Qt.KeepAspectRatio)
frame_3_scaled = frame_3.scaled(self.size(), Qt.KeepAspectRatio)
base_pixmap = QPixmap(frame_1_scaled.size())
painter = QPainter(base_pixmap)
painter.drawImage(QPoint(), frame_3_scaled)
painter.setOpacity(0.5)
painter.drawImage(QPoint(), frame_2_scaled)
painter.setOpacity(0.3)
painter.drawImage(QPoint(), frame_1_scaled)
painter.end()
self.display.setPixmap(base_pixmap)
# -------------------------------------------------------------
# Set the layout.
layout = QGridLayout()
layout.addWidget(self.display, 0, 0)
self.setLayout(layout)
if __name__ == '__main__':
app = QApplication(sys.argv)
window = MainWindow()
window.show()
app.exec()
理想情况下，最后一张图片将显示为完全不透明，而较早的图片具有越来越高的透明度。相反，我得到一个输出，其中所有三个图像均等地混合在一起。这似乎是一个解决起来很简单的问题，但我的 'Google Fu' 这次并没有产生太大的影响。
编辑
这是图像文件。不幸的是，它们似乎已自动转换为 .jpg。如果有更好的方法来包含它们，请告诉我。
frame_1
frame_2
frame_3
编辑 2
经过一些实验后，我决定妥协并允许一些 'blending' 基本图像。我正在处理来自相机设备的原始图像，因此每张图像的背景总是不透明的。
如果有人感兴趣，这里是代码：
from PyQt5.QtWidgets import QApplication, QWidget, QGridLayout, QLabel, QSizePolicy
from PyQt5.QtCore import Qt, QPoint
from PyQt5.QtGui import QImage, QPixmap, QPainter
import sys
from pathlib import Path
class MainWindow(QWidget):
def __init__(self):
super().__init__()
# -------------------------------------------------------------
# Define values used for image painting.
self.first_opacity = 1 # Set first image to fully opaque so it does not blend into background.
self.falloff_value = 0.15 # The opacity of the second image.
self.falloff_rate = 0.5 # A factor used to decrement subsequent image transparencies.
# -------------------------------------------------------------
# Define the display.
self.display = QLabel()
self.display.setSizePolicy(QSizePolicy.MinimumExpanding, QSizePolicy.MinimumExpanding)
self.display.setMinimumSize(1, 1)
# -------------------------------------------------------------
# Import frames.
self.images = []
for i in range(1, 4, 1):
self.images.append(QImage(str(Path(f'fixtures/test_onion_skin/frame_{i}.png'))))
# -------------------------------------------------------------
# Set the display.
self.update_display()
# -------------------------------------------------------------
# Set the layout.
layout = QGridLayout()
layout.addWidget(self.display, 0, 0)
self.setLayout(layout)
def update_display(self):
# -------------------------------------------------------------
# Define the base pixmap on which to merge images.
base_pixmap = QPixmap(self.display.size())
base_pixmap.fill(Qt.transparent)
# -------------------------------------------------------------
# Preform paint cycle for images.
painter = QPainter(base_pixmap)
for (image, opacity) in zip(reversed(self.images), reversed(self.get_opacities(len(self.images)))):
painter.setOpacity(opacity)
painter.drawImage(QPoint(), image.scaled(base_pixmap.size(), Qt.KeepAspectRatio))
painter.end()
# -------------------------------------------------------------
self.display.setPixmap(base_pixmap)
def get_opacities(self, num_images):
# -------------------------------------------------------------
# Define a list to store image opacity values.
opacities = [self.first_opacity]
value = self.falloff_value
# -------------------------------------------------------------
# Calculate additional opacity values if more than one image is desired.
if num_images > 1:
num_decrements = num_images - 1
for i in range(1, num_decrements + 1, 1):
opacities.insert(0, value)
value *= self.falloff_rate
# -------------------------------------------------------------
return opacities
def resizeEvent(self, event):
self.update_display()
event.accept()
if __name__ == '__main__':
app = QApplication(sys.argv)
window = MainWindow()
window.show()
app.exec()
由于OP没有提供图片那么问题可能是由于：
- 设置不透明度的顺序。
- 图片背景色不透明
对于我的演示，我将使用此 gif 并且由于背景不是透明的（这将是理想的），因此我将在绘制每个图像时应用遮罩。
import os
from pathlib import Path
import sys
from PyQt5.QtCore import Qt, QPoint
from PyQt5.QtGui import QColor, QImageReader, QPainter, QPixmap, QRegion
from PyQt5.QtWidgets import QApplication, QLabel, QVBoxLayout, QWidget
CURRENT_DIRECTORY = Path(__file__).resolve().parent
class MainWindow(QWidget):
def __init__(self):
super().__init__()
self.display = QLabel(alignment=Qt.AlignCenter)
lay = QVBoxLayout(self)
lay.addWidget(self.display)
background_color = QColor("white")
filename = os.fspath(CURRENT_DIRECTORY / "Animhorse.gif")
image_reader = QImageReader(filename)
pixmap = QPixmap(image_reader.size())
pixmap.fill(background_color)
images = []
while image_reader.canRead():
images.append(image_reader.read())
painter = QPainter(pixmap)
for image, opacity in zip(images[3:6], (0.3, 0.7, 1.0)):
painter.setOpacity(opacity)
p = QPixmap.fromImage(image)
mask = p.createMaskFromColor(background_color, Qt.MaskInColor)
painter.setClipRegion(QRegion(mask))
painter.drawImage(QPoint(), image)
painter.end()
self.display.setPixmap(pixmap)
if __name__ == "__main__":
app = QApplication(sys.argv)
window = MainWindow()
window.show()
app.exec()